We read with interest the meta-analysis conducted by our colleague Dr Waleed Brinjikji (1). In the text (section "Limitations", he stated: "Data from the Interest of Direct Aspiration First Pass Technique (ADAPT) for Thrombectomy Revascularization of Large Vessel Occlusion in Acute Ischemic Stroke (ASTER) trial suggest that there were no statistically significant differences in revascularization rates when performing the ADAPT technique compared with using a stent retriever. However, it is unclear at this time whether BGCs were used in this trial."
Nevertheless in our publication of the ASTER trial results (2), we clearly stated in the Results section that a balloon-guide catheter was used to allow proximal flow arrest during stent retriever removal in 92% of patients treated with the stent retriever technique.
1. Brinjikji W, Starke RM, Murad MH, et al. Impact of balloon guide catheter on technical and clinical outcomes: a systematic review and meta-analysis. J Neurointerv Surg 2018;10:335–339.
2. Lapergue B, Blanc R, Gory B, et al. JAMA. 2017;318:443-452.
We read with interest the editorial by Darsaut and colleagues entitled, “PHASES and the natural history of unruptured aneurysms: science or pseudoscience?”[1]. Beginning with references to Aristotle and Pliny the Elder (always impressive), the authors launch a critique of studies of the natural history of unruptured aneurysms. With attention to ISUIA and the PHASES system, the contributors from Quebec call attention to limitations in both prospective and retrospective studies of the risk of rupture and associated risk factors for rupture of intracranial aneurysms. In their view, these imperfect studies are so deeply flawed that they are essentially useless as tools to inform decision-making with patients with unruptured intracranial aneurysms. Ending with the umpteenth call for a randomized trial, the authors create the impression that, for all patients with all kinds, sizes and locations of intracranial aneurysms, clinicians are powerless to use data from the available studies, condensed in the PHASES Score, to guide decision-making.
The PHASES score, developed from a pooled analysis of six prospective cohort studies of patients with unruptured intracranial aneurysms, was designed to use existing natural history data (limited though that may be), to provide some estimate of future rupture risk and to aid in identifying risk factors for rupture that may push clinician and patient past the treatment threshold. Several lines of evidence support the use of PHASES...
We read with interest the editorial by Darsaut and colleagues entitled, “PHASES and the natural history of unruptured aneurysms: science or pseudoscience?”[1]. Beginning with references to Aristotle and Pliny the Elder (always impressive), the authors launch a critique of studies of the natural history of unruptured aneurysms. With attention to ISUIA and the PHASES system, the contributors from Quebec call attention to limitations in both prospective and retrospective studies of the risk of rupture and associated risk factors for rupture of intracranial aneurysms. In their view, these imperfect studies are so deeply flawed that they are essentially useless as tools to inform decision-making with patients with unruptured intracranial aneurysms. Ending with the umpteenth call for a randomized trial, the authors create the impression that, for all patients with all kinds, sizes and locations of intracranial aneurysms, clinicians are powerless to use data from the available studies, condensed in the PHASES Score, to guide decision-making.
The PHASES score, developed from a pooled analysis of six prospective cohort studies of patients with unruptured intracranial aneurysms, was designed to use existing natural history data (limited though that may be), to provide some estimate of future rupture risk and to aid in identifying risk factors for rupture that may push clinician and patient past the treatment threshold. Several lines of evidence support the use of PHASES in the day-to-day management of patients with unruptured intracranial aneurysms.
First, conservative management of selected unruptured intracranial aneurysms, along with attention to risk factors for growth and rupture, such as hypertension and cigarette smoking, is both widespread and valid[2]. Interesting recent retrospective studies have shed light on both the risk of aneurysm enlargement during serial surveillance imaging (overall annual risk of 2-5%) and whether risk of rupture is elevated in patients with enlargement during surveillance (it is, to the tune of an annual risk of rupture of 18.5%) [3-6]. Thus, although treatment of unruptured aneurysms is extensive worldwide, conservative management is widespread also, and methods to inform decision-making in this setting are much needed.
Second, the authors of the editorial take issue with the limitations and imprecision of both ISUIA and PHASES, stating that “PHASES…has never predicted a single event…” and that three large Japanese cohorts “have refuted the ISUIA predictions.” Although Greving and colleagues did indeed use the unfortunate phrase “prediction of risk” in the title of their paper about PHASES, the actual purpose of PHASES (and ISUIA) was to estimate risk, given patient-specific factors, rather than predict risk[7]. The term predict implies a degree of precision that is not realistic in this setting. Rather, estimations of risk, however flawed and imprecise they are, serve to nudge patients and their clinicians toward one direction or another. In the absence of Level I evidence, black and white decision tools are simply not possible. On the other hand, when an accumulation of factors that are associated with growth and rupture are present in an individual patient, this individual may be inclined to seek treatment, even though a precise “prediction” of rupture risk is not possible.
Lastly, the authors conclude their editorial with a spirited call for a randomized trial. However, it is nearly impossible to imagine that a multicenter randomized trial comparing medical management to treatment of unruptured aneurysms could be accomplished in the current environment. Indeed in a previously published assessment of the failed TEAM Trial, the authors outline three compelling reasons for the futility of any attempt at conducting a randomized trial of unruptured aneurysms: 1) Lack of funding support and bureaucratic barriers from scientific agencies (NINDS, CIHR) 2) Physician unwillingness to enter patients in such a trial due to lack of equipoise, and 3) Patient disinterest in trial participation where a desired intervention would be denied[8]. Unless major changes have occurred in bureaucratic and funding processes, physician opinion, and patient desires in the last few years, we agree with the authors prior work on the futility of hoping for such a trial. Furthermore, any serious attempt at a randomized trial would be at risk of suffering the same fate as the ARUBA trial. Strenuous opposition to ARUBA arose long before trial completion. Objection to ARUBA centered on the argument that a randomized trial of treatment of a life-long condition such as brain AVMs, with only 5-year follow-up, could not fairly compare to interventions with very different risk functions over time. A similar study conducted on unruptured intracranial aneurysms would be hampered by identical limitations.
In the absence of a hypothetical “ideal” study, which the hard nature of reality is unlikely to deliver, clinicians and patients must make decisions, and make them today. PHASES while distinctly not an ideal study, provides guidance based on evidence, when an ideal study is unlikely to be accomplished in the foreseeable future.
References
1 Darsaut T, Fahed R, Raymond J. PHASES and the natural history of unruptured aneurysms: science or pseudoscience? J Neurointerventional Surg 2016;:neurintsurg–2016.
2 Thompson BG, Brown RD, Amin-Hanjani S, et al. Guidelines for the management of patients with unruptured intracranial aneurysms: a guideline for healthcare professionals from the American Heart Association/American Stroke Association. Stroke 2015;46:2368–2400.
3 Sonobe M, Yamazaki T, Yonekura M, et al. Small Unruptured Intracranial Aneurysm Verification Study: SUAVe Study, Japan. Stroke 2010;41:1969–77. doi:10.1161/STROKEAHA.110.585059
4 Inoue T, Shimizu H, Fujimura M, et al. Annual rupture risk of growing unruptured cerebral aneurysms detected by magnetic resonance angiography. J Neurosurg 2012;117:20–25.
5 Backes D, Vergouwen MD, Groenestege ATT, et al. PHASES score for prediction of intracranial aneurysm growth. Stroke 2015;46:1221–1226.
6 Serrone JC, Tackla RD, Gozal YM, et al. Aneurysm growth and de novo aneurysms during aneurysm surveillance. J Neurosurg 2016;125:1374–82. doi:10.3171/2015.12.JNS151552
7 Greving JP, Wermer MJ, Brown RD, et al. Development of the PHASES score for prediction of risk of rupture of intracranial aneurysms: a pooled analysis of six prospective cohort studies. Lancet Neurol 2014;13:59–66.
8 Raymond J, Darsaut TE, Molyneux AJ. A trial on unruptured intracranial aneurysms (the TEAM trial): results, lessons from a failure and the necessity for clinical care trials. Trials 2011;12:64.
We appreciate the interest shown by Drs. Yao and You (1) in our paper (2) and find it our pleasure to address their concerns.
The first point raised by Drs. Yao and You is that our search strategy missed two articles, namely those of Mortimer et al (2015) (3) and Morgan et al (1996) (4). We would like to reassure Drs. Yao and You that we did screen these articles, and decided against including them in our meta-analysis based on our inclusion criteria. The article by Mortimer et al (2015) (3) describes a patient population where balloon angioplasty, verapamil, and papaverine infusions were used separately or in various combinations. They did not break down their results by the specific intra-arterial vasodilator (IAD) used, and therefore we decided not to include this information. The paper by Morgan et al (1996) (4) describes a patient population which overlapped with that described by the same group in another paper, Morgan et al (2000) (5). We had personally communicated with the authors in 2016 regarding the multiple papers from this group, such as Little et al (1994) (6) and Morgan et al (2000)
(5) that described papaverine infusions for vasospasm. We found out that there were overlaps in these study populations, and that the cohort in the 2000 paper(5) was the most complete. Therefore, only this paper was included in our meta-analysis, while the earlier ones were excluded.
The second suggestion by Drs. Yao and You was to perform a regression ana...
We appreciate the interest shown by Drs. Yao and You (1) in our paper (2) and find it our pleasure to address their concerns.
The first point raised by Drs. Yao and You is that our search strategy missed two articles, namely those of Mortimer et al (2015) (3) and Morgan et al (1996) (4). We would like to reassure Drs. Yao and You that we did screen these articles, and decided against including them in our meta-analysis based on our inclusion criteria. The article by Mortimer et al (2015) (3) describes a patient population where balloon angioplasty, verapamil, and papaverine infusions were used separately or in various combinations. They did not break down their results by the specific intra-arterial vasodilator (IAD) used, and therefore we decided not to include this information. The paper by Morgan et al (1996) (4) describes a patient population which overlapped with that described by the same group in another paper, Morgan et al (2000) (5). We had personally communicated with the authors in 2016 regarding the multiple papers from this group, such as Little et al (1994) (6) and Morgan et al (2000)
(5) that described papaverine infusions for vasospasm. We found out that there were overlaps in these study populations, and that the cohort in the 2000 paper(5) was the most complete. Therefore, only this paper was included in our meta-analysis, while the earlier ones were excluded.
The second suggestion by Drs. Yao and You was to perform a regression analysis to “solve” the heterogeneity. For a methodically sound meta-analysis, heterogeneity is always presumed to exist, as statistical analysis is but one means of measuring it. When statistically significant heterogeneity is found, it should be quantified and accounted for with subgroup and sensitivity analysis, and subsequently potential contributors to it also discussed subjectively. Meta-regression is another step to account for it. Given the relatively small sample sizes and the observational nature of the included studies, we felt a meta-regression would not do justice to the available data, and would be overreaching.
Finally, they note that several of our studies used balloon angioplasty in addition to IADs, which might have significantly influenced our findings of IAD efficacy and safety. This is a valid concern, which we had anticipated and stated in the limitations section of our manuscript that, “IAD and balloon angioplasty were used in combination in many patients, which may confound our results when the aim was to isolate the effects of IADs”(2). During our data abstraction, we noted that most studies did not separately report data for IADs and balloon angioplasty, and often used these in conjunction. In the interest of retaining sufficient sample sizes for our analysis, we were left with no recourse but to accept even those studies that included balloon angioplasty along with IADs.
We would once again like to thank Drs. Yao and You for their interest in our paper, and their insightful questions.
Authors
References
1. Yao ZY, C. Intra-arterial vasodilators for vasospasm following aneurysmal subarachnoid hemorrhage. Journal of Neurointerventional Surgery. 2017.
2. Venkatraman A, Khawaja AM, Gupta S, Hardas S, Deveikis JP, Harrigan MR, et al. Intra-arterial vasodilators for vasospasm following aneurysmal subarachnoid hemorrhage: a meta-analysis. J Neurointerv Surg. 2017.
3. Mortimer AM, Steinfort B, Faulder K, Bradford C, Finfer S, Assaad N, et al. The detrimental clinical impact of severe angiographic vasospasm may be diminished by maximal medical therapy and intensive endovascular treatment. J Neurointerv Surg. 2015;7(12):881-7.
4. Morgan M, Halcrow S, Sorby W, Grinnell V. Outcome of aneurysmal subarachnoid haemorrhage following the introduction of papaverine angioplasty. J Clin Neurosci. 1996;3(2):139-42.
5. Morgan MK, Jonker B, Finfer S, Harrington T, Dorsch NW. Aggressive management of aneurysmal subarachnoid haemorrhage based on a papaverine angioplasty protocol. J Clin Neurosci. 2000;7(4):305-8.
6. Little N, Morgan MK, Grinnell V, Sorby W. Intra-arterial papaverine in the management of cerebral vasospasm following subarachnoid haemorrhage. J Clin Neurosci. 1994;1(1):42-6.
With great interest, we read the article of Venkatraman et al.[1] published in the Journal of NeuroInterventional Surgery recently. They presented a comprehensive picture depicting the effect of intra-arterial vasodilators (IADs) on the vasospasm following aneurysmal subarachnoid hemorrhage. But we were concerned with several questions weakening the reliability and generalization of the meta-analysis.
Firstly , though the detailed including criteria and searching strategy were provided in their meta-analysis, at least two eligible studies2,3 were missed which conformed to their including criteria and unfulfilled the excluding criteria. Two cohort studies of Morgan [2] and Mortimer [3] reported the effects of IADs on vasospasm with documentation of interested events, which should be included in Venkatraman’s analysis. Whether addition of these two studies could change the overall effect of IADs was unclear, but including any eligible study was in accordance with PRISMA principle.
Secondly, owing to the large number of included studies, the heterogeneity was substantial. Venkatraman et al.[1] conducted subgroup and sensitivity analyses, in which the heterogeneity remained significant (most values of I2 greater than 50%). It was rationale to turn to regression analyses in order to find and solve the heterogeneity.
Besides, this article included studies combining IADs with balloon angioplasty, which might overestimate effectiveness of IADs. IADs w...
With great interest, we read the article of Venkatraman et al.[1] published in the Journal of NeuroInterventional Surgery recently. They presented a comprehensive picture depicting the effect of intra-arterial vasodilators (IADs) on the vasospasm following aneurysmal subarachnoid hemorrhage. But we were concerned with several questions weakening the reliability and generalization of the meta-analysis.
Firstly , though the detailed including criteria and searching strategy were provided in their meta-analysis, at least two eligible studies2,3 were missed which conformed to their including criteria and unfulfilled the excluding criteria. Two cohort studies of Morgan [2] and Mortimer [3] reported the effects of IADs on vasospasm with documentation of interested events, which should be included in Venkatraman’s analysis. Whether addition of these two studies could change the overall effect of IADs was unclear, but including any eligible study was in accordance with PRISMA principle.
Secondly, owing to the large number of included studies, the heterogeneity was substantial. Venkatraman et al.[1] conducted subgroup and sensitivity analyses, in which the heterogeneity remained significant (most values of I2 greater than 50%). It was rationale to turn to regression analyses in order to find and solve the heterogeneity.
Besides, this article included studies combining IADs with balloon angioplasty, which might overestimate effectiveness of IADs. IADs worked in coordination with balloon angioplasty, for balloon angioplasty dilated proximal vessel assisting IADs to expand distal vessels. We could not exclude the possibility partial effect on the outcomes was attributable to balloon angioplasty. Similarly, it was reasonable to ascribe many complications to the balloon angioplasty, like vessel perforation.
In all, we would like to congratulate Venkatraman for the great work of meta-analyzing the impact of IADs on the treatment of vasospasm following subarachnoid hemorrhage.
References
1. Venkatraman A, Khawaja AM, Gupta S, et al. Intra-arterial vasodilators for vasospasm following aneurysmal subarachnoid hemorrhage: a meta-analysis. J Neurointerv Surg. 2017.
2. Morgan M, Halcrow S, Sorby W, Grinnell V. Outcome of aneurysmal subarachnoid haemorrhage following the introduction of papaverine angioplasty. J Clin Neurosci. 1996;3(2):139-142.
3. Mortimer AM, Steinfort B, Faulder K, et al. The detrimental clinical impact of severe angiographic vasospasm may be diminished by maximal medical therapy and intensive endovascular treatment. Journal of Neurointerventional Surgery. 2015;7(12):881-887.
We read with great interest the article of Haussen et al. 1 outlining the problem of identifying patients with minor stroke symptoms (low NIHSS) despite proximal vessel occlusion who should undergo thrombectomy. Intension-to-treat analysis showed significantly higher reduction of stroke severity in the primary thrombectomy group compared to the medical group. But more interestingly, per-protocol analysis revealed a high propo...
We read with great interest the article of Haussen et al. 1 outlining the problem of identifying patients with minor stroke symptoms (low NIHSS) despite proximal vessel occlusion who should undergo thrombectomy. Intension-to-treat analysis showed significantly higher reduction of stroke severity in the primary thrombectomy group compared to the medical group. But more interestingly, per-protocol analysis revealed a high proportion of rescue thrombectomies due to neurological deterioration with a clearly time-dependent effect on outcome after the procedure in the medical group. In our opinion, the problem is multidimensional. In proximal vessel occlusion, intravenous thrombolysis combined with thrombectomy is superior to thrombolysis alone. Current guidelines strongly recommend thrombectomy in these patients and not to stop after intravenous thrombolysis 2. Therefore, it is critical to identify ischemic stroke due to proximal vessel occlusion. High stroke severity measured by the NIHSS has been used as a clinical surrogate to detect major vessel occlusion. Fischer et al. reported an NIHSS threshold of 12 to have a positive predictive value of 91% for central occlusion 3. But this approach can be misleading as the NIHSS represents the amount of ischemic tissue, which is influenced by residual blood supply beyond the occlusion, especially by collateral circulation. Good collaterals can lead to a low NIHSS score in stroke with proximal vessel occlusion. Maas et al. showed that higher NIHSS cutoffs to predict major vessel occlusion missed more proximal occlusions, concluding that there was no NIHSS threshold to identify the majority of clinically important occlusive lesions. An NIHSS threshold of 10, for example had only 48% sensitivity 4. Minor stroke severity resulting in a low NIHSS is not uncommon in proximal vessel occlusion. One group identified 23% of patients with NIHSS <8 in a retrospective database search 5. In another population, approx. 90% of patients presenting with an NIHSS <=10 were found to have major vessel occlusion 4. In our opinion, current data indicate that all stroke patients admitted within the therapeutic time window should undergo vascular imaging. Another question is how to treat these patients. Until a few years ago intravenous thrombolysis was given only to patients with a "significant" neurological deficit, commonly defined as an NIHSS of 4 or higher. Today we know that low NIHSS stroke, even without proximal vessel occlusion, has unfavourable long-term outcome and that intravenous thrombolysis seems to be beneficial in this setting 6 with low risk of intracrcanial bleeding 7. In clinical practice, we today concentrate on individual deficits and try to individualize the treatment decision. In patients with central occlusion and NIHSS 2-7, the natural course is also rather unfavourable. Even in this low NIHSS stratum higher stroke severity was significantly associated with discharge into a facility and gait problems 5. The current study adds important knowledge for decision making in this situation as 41% of the medical group deteriorated a few hours after admission, which was likely caused by failure of the collateral system. Those who were "lucky" to suffer fast breakdown of collateral supply had better functional outcome after rescue thrombectomy than those with later failure. For future treatment algorithms, it will be essential to know more about the dynamics of collateral circulation and to develop a strategy to predict their failure. Currently, it is very difficult to make individual treatment decisions in this subset of patients as the thrombectomy procedure itself has a risk of recurrent stroke, vasospasm and subarchnoid hemorrhage 8.
References
1. Haussen DC, Bouslama M, Grossberg JA, et al. Too good to
intervene? Thrombectomy for large vessel occlusion strokes with minimal
symptoms: an intention-to-treat analysis. J Neurointerv Surg Published
Online First: 2 Sep 2016. doi: 10.1136/neurintsurg-2016-012633.
2. Powers WJ, Derdeyn CP, Biller J, et al. 2015 AHA/ASA Focused Update of
the 2013 Guidelines for the Early Management of Patients With Acute
Ischemic Stroke Regarding Endovascular Treatment: A Guideline for
Healthcare Professionals From the American Heart Association/American
Stroke Association. Stroke 2015;46:3020-3035.
3. Fischer U, Arnold M, Nedeltchev K, et al. NIHSS score and
arteriographic findings in acute ischemic stroke. Stroke 2005;36:2121-
2125.
4. Maas MB, Furie KL, Lev MH, et al. National Institutes of Health Stroke
Scale score is poorly predictive of proximal occlusion in acute cerebral
ischemia. Stroke 2009;40:2988-2993.
5. Mokin M, Masud MW, Dumont TM, et al. Outcomes in patients with acute
ischemic stroke from proximal intracranial vessel occlusion and NIHSS
score below 8. J Neurointerv Surg 2014;6:413-417.
6. Greisenegger S, Seyfang L, Kiechl S, et al. Thrombolysis in Patients
With Mild Stroke. Stroke 2014;45:765-769.
7. Strbian D, Piironen K, Meretoja A, et al. Intravenous Thrombolysis for
Acute Ischemic Stroke Patients Presenting with Mild Symptoms. Int J Stroke
2013;8:293-299.
8. Emprechtinger R, Piso B, Ringleb PA. Thrombectomy for ischemic stroke:
meta-analyses of recurrent strokes, vasospasms, and subarachnoid
hemorrhages. Journal of Neurology Published Online First: 20 Jun 2016.
doi: 10.1007/s00415-016-8205-1
We read with interest the article entitled: “Delayed enhancing lesions after coil embolization of aneurysms: clinical experience and benchtop analyses” by Oh et al [1]. This interesting case series deals with a recently described complication of intracranial endovascular procedures [2–8]: delayed enhancing lesions (DELs), also known as NICE (non-ischemic cerebral enhancing) lesions [8]. This rare complication consists in delayed appearance of cortical leptomeningeal enhancement associated with vasogenic subcortical edema [8]. The authors describe 3 more cases, in addition to the 19 previously reported [8]. We congratulate the authors for their efforts to understand the mechanism of this rare complication by performing benchtop tests.
Numerous hypotheses have been proposed to explain this complication.
First, an allergic reaction to nickel has been suggested [4,7]. In a series we recently published in Neuroradiology [8], we did not find any allergic reaction to the devices used for the embolization of the patients who presented NICE lesions. The fact that, in the series of Oh et al [1], none of the three patients had an allergic background, seems to confirm the absence of any relationship between these lesions and allergy.
The second hypothesis is a reaction to foreign bodies (catheter coating) released during the embolization. We do believe that, according to our experience [8] and to the data of the literature [2,3,5,6], these lesions are more likely to...
We read with interest the article entitled: “Delayed enhancing lesions after coil embolization of aneurysms: clinical experience and benchtop analyses” by Oh et al [1]. This interesting case series deals with a recently described complication of intracranial endovascular procedures [2–8]: delayed enhancing lesions (DELs), also known as NICE (non-ischemic cerebral enhancing) lesions [8]. This rare complication consists in delayed appearance of cortical leptomeningeal enhancement associated with vasogenic subcortical edema [8]. The authors describe 3 more cases, in addition to the 19 previously reported [8]. We congratulate the authors for their efforts to understand the mechanism of this rare complication by performing benchtop tests.
Numerous hypotheses have been proposed to explain this complication.
First, an allergic reaction to nickel has been suggested [4,7]. In a series we recently published in Neuroradiology [8], we did not find any allergic reaction to the devices used for the embolization of the patients who presented NICE lesions. The fact that, in the series of Oh et al [1], none of the three patients had an allergic background, seems to confirm the absence of any relationship between these lesions and allergy.
The second hypothesis is a reaction to foreign bodies (catheter coating) released during the embolization. We do believe that, according to our experience [8] and to the data of the literature [2,3,5,6], these lesions are more likely to be related to fragments migration of the inner wall’s coating of the guiding catheter and/or of the outer wall of the microcatheters, rather than from the inner wall of the microcatheters. Indeed, as in our experience [8], in all the patients of the series published by Oh et al [1], the lesions were located in the territory of the endovascular treatment (i.e.: in the territory of the parent artery in which the guiding catheter was positioned). If the coating fragments have come from the inner lumen of the microcatheters, as claimed by the authors, the emboli would have only occur distally to the microcatheter’s tip (i.e. in the aneurysm’s sac). This hypothesis does not explain the distribution of the lesions observed on MRI. Additionally, as underlined by the authors, the patient treated with the microcatheter that showed coating fragments at the location of the friction on bench tests did not have DEL.
Shapiro et al [5] reported three cases of delayed NICE lesions after endovascular aneurysm treatment with pathological examination of the lesions. Foreign bodies were found and identified as being identical in stain appearance to polyvinylpolypyrrolidone (PVP) catheter coating.
What seems very surprising for us, is the recent increasing of these complications reported in the literature. Indeed, brain aneurysms treated by embolizations have been followed by MRI for many years but this complication has only been recently described. Three hypotheses may be advanced. First, the neurointerventional community only recently became aware of this complication first published in the cardiology and pathology literature [3]. Second, the emergence of this complication may be related to increased use of triaxial catheter access in endovascular aneurysm treatments, that may favor mechanical stress on the inner lumen coating of the guiding catheters. Finally, the emergence of this complication may be related to a recent modification of coating technology, which has yet to be identified.
References:
1 Oh SW, Shin NY, Lee H-J, et al. Delayed enhancing lesions after coil embolization of aneurysms: clinical experience and benchtop analyses. J Neurointerventional Surg Published Online First: 6 January 2017. doi:10.1136/neurintsurg-2016-012833
2 Cruz JP, Marotta T, O’Kelly C, et al. Enhancing brain lesions after endovascular treatment of aneurysms. AJNR Am J Neuroradiol 2014;35:1954–8. doi:10.3174/ajnr.A3976
3 Fealey ME, Edwards WD, Giannini C, et al. Complications of endovascular polymers associated with vascular introducer sheaths and metallic coils in 3 patients, with literature review. Am J Surg Pathol 2008;32:1310–6. doi:10.1097/PAS.0b013e318165582a
4 Lobotesis K, Mahady K, Ganesalingam J, et al. Coiling-associated delayed cerebral hypersensitivity: Is nickel the link? Neurology 2015;84:97–9. doi:10.1212/WNL.0000000000001106
5 Shapiro M, Ollenschleger MD, Baccin C, et al. Foreign Body Emboli following Cerebrovascular Interventions: Clinical, Radiographic, and Histopathologic Features. AJNR Am J Neuroradiol Published Online First: 20 August 2015. doi:10.3174/ajnr.A4415
6 Skolarus LE, Gemmete JJ, Braley T, et al. Abnormal white matter changes after cerebral aneurysm treatment with polyglycolic-polylactic acid coils. World Neurosurg 2010;74:640–4. doi:10.1016/j.wneu.2010.03.026
7 Ulus S, Yakupoğlu A, Kararslan E, et al. Reversible intracranial parenchymal changes in MRI after MCA aneurysm treatment with stent-assisted coiling technique; possible nickel allergy. Neuroradiology 2012;54:897–9. doi:10.1007/s00234-012-1048-2
8 Shotar E, Law-Ye B, Baronnet-Chauvet F, et al. Non-ischemic cerebral enhancing lesions secondary to endovascular aneurysm therapy: nickel allergy or foreign body reaction? Case series and review of the literature. Neuroradiology Published Online First: 23 May 2016. doi:10.1007/s00234-016-1699-5
We have read with great interest the article describing the CAPTIVE technique for endovascular acute ischemic treatment by McTaggart et al.1. Firstly, we would like to commend the great clarity they used to describe the combination of distal aspiration and stent retriever to perform mechanical thrombectomy. Notably, they illustrated the rationale for aspiration prior to stent deployment as well as the removal of both distal aspiration catheter and stent as a single unit to decrease possible clot fragmentation.
We adopt a very similar approach for most of our cases, although we would like to emphasize a slight variant that appears clinically interesting.
In combination with stent retrievers, the balloon guide catheter (BGC) has been shown to improve the effectiveness of mechanical thrombectomy2, 3. In our experience, we typically use the CAPTIVE technique in association with a BGC which presents several potential advantages.
Firstly, in cases of tortuous anatomy it provides excellent support for navigating the distal aspiration catheter. In addition, the balloon can be temporarily inflated at this stage to provide an anchoring effect in order to avoid potential push back of the guiding catheter4.
Secondly, McTaggart et al. reported 5% embolization to new territory with the CAPTIVE technique; an equivalent rate to previous reports on distal aspiration with no stent retriever5. In an in vitro study, Chueh et al.6 demonstrated a significant decrease o...
We have read with great interest the article describing the CAPTIVE technique for endovascular acute ischemic treatment by McTaggart et al.1. Firstly, we would like to commend the great clarity they used to describe the combination of distal aspiration and stent retriever to perform mechanical thrombectomy. Notably, they illustrated the rationale for aspiration prior to stent deployment as well as the removal of both distal aspiration catheter and stent as a single unit to decrease possible clot fragmentation.
We adopt a very similar approach for most of our cases, although we would like to emphasize a slight variant that appears clinically interesting.
In combination with stent retrievers, the balloon guide catheter (BGC) has been shown to improve the effectiveness of mechanical thrombectomy2, 3. In our experience, we typically use the CAPTIVE technique in association with a BGC which presents several potential advantages.
Firstly, in cases of tortuous anatomy it provides excellent support for navigating the distal aspiration catheter. In addition, the balloon can be temporarily inflated at this stage to provide an anchoring effect in order to avoid potential push back of the guiding catheter4.
Secondly, McTaggart et al. reported 5% embolization to new territory with the CAPTIVE technique; an equivalent rate to previous reports on distal aspiration with no stent retriever5. In an in vitro study, Chueh et al.6 demonstrated a significant decrease of distal emboli when a BGC is combined with a stent retriever. They also showed an increased risk of distal embolization when using the direct aspiration technique (ADAPT). Since the CAPTIVE technique has evolved from the ADAPT technique, so similarly, once the clot is engaged inside the aspiration catheter the flow reversal stops. By promoting flow arrest, the addition of a BGC could potentially decrease the rate of embolization in new territory, particularly in cases of either long clots incompletely covered by the stent or soft elastic clots, as suggested in vitro6.
Finally, the large lumen of the BGC is likely to avoid any shearing of the embolus during withdrawal of the distal aspiration catheter inside the guiding catheter. A similar potential hazard was importantly illustrated by McTaggart et al. in cases of inadvertent advance of the distal aspiration catheter over the clot-stent complex during removal of the stent.
The use of a BGC in addition to the CAPTIVE technique could however pose certain limitations. Firstly, navigating a 9F catheter is clearly more challenging than a 6F catheter, particularly in cases of tortuous anatomy; although often an exchange manoeuver over a stiff wire allows an appropriate positioning of the BGC in the targeted vessel. The aspiration from the BGC is here limited due to the triaxial approach, hower the additional effect of blockage of the flow could also support the aspiration force of the distal catheter.
Also, in cases of M1 occlusion inflating the balloon may limit collateral flow to the ischemic area. Considering this, and as described by McTaggart et al., our strategy is to turn on distal aspiration prior to deployment of the stent retriever but only prior to removal of the stent the BGC is inflated and proximal aspiration is turned on.
To conclude we would like to thank McTaggart et al. for sharing their experience. In accordance with other recently published studies7 their work emphasize the need to reach high rates of TICI3 recanalization to maximize the likelihood of good clinical outcomes for our patients.
1. McTaggart RA, Tung EL, Yaghi S, et al. Continuous aspiration prior to intracranial vascular embolectomy (CAPTIVE): a technique which improves outcomes. Journal of NeuroInterventional Surgery; 2016:neurintsurg-2016-012838-012836
2. Velasco A, Buerke B, Stracke CP, et al. Comparison of a Balloon Guide Catheter and a Non–Balloon Guide Catheter for Mechanical Thrombectomy. Radiology; 2016:169-176
3. Nguyen TN, Malisch T, Castonguay AC, et al. Balloon Guide Catheter Improves Revascularization and Clinical Outcomes With the Solitaire Device: Analysis of the North American Solitaire Acute Stroke Registry. Stroke; 2013:141-145
4. Matsumoto H, Nishiyama H, Tetsuo Y, et al. Initial clinical experience using the two-stage aspiration technique (TSAT) with proximal flow arrest by a balloon guiding catheter for acute ischemic stroke of the anterior circulation. Journal of NeuroInterventional Surgery: British Medical Journal Publishing Group; 2016:neurintsurg-2016-012787-012786
5. Kowoll A, Weber A, Mpotsaris A, et al. Direct aspiration first pass technique for the treatment of acute ischemic stroke: initial experience at a European stroke center. Journal of NeuroInterventional Surgery; 2016:230-234
6. Chueh J-Y, Puri AS, Wakhloo AK, et al. Risk of distal embolization with stent retriever thrombectomy and ADAPT. Journal of NeuroInterventional Surgery; 2016:197-202
7. Dargazanli C, Consoli A, Barral M, et al. Impact of Modified TICI 3 versus Modified TICI 2b Reperfusion Score to Predict Good Outcome following Endovascular Therapy. American Journal of Neuroradiology: American Society of Neuroradiology; 2017:90-96
We read with great interest the article by McTaggart et al. on the new embolectomy technique called Continuous Aspiration Prior To Intracranial Vascular Embolectomy (CAPTIVE).(1) The paper adds information on the supporting evidence that a combined approach of stentretriever and aspiration-catheter utilization may be the optimal path in achieving higher rates of complete reperfusion in patients with large vessel occlusions.(2, 3) While the idea of starting aspiration with the intermediate catheter prior to and during the stentretriever placement is intriguing, attention has to be paid on the effect of prolonged aspiration on collateral flow, as reported in a recent JNIS publication.(4) Additionally, the ‘continuous’ part of the title may be misleading, as the authors state that they advance the aspiration-catheter towards the face of the clot until the drip rate has stopped. As seen in Fig 1E of the CAPTIVE publication, the tip of the aspiration-catheter becomes clogged with clot as ‘a portion is held captive within the distal aspiration catheter.’ This probably results in vacuum within the aspiration-catheter and non-existent aspiration in the vicinity of the aspiration-catheter tip during immobilization of the stentretriever/clot/aspiration-catheter unit. At last, the authors describe thoroughly a ‘De-CAPTIVE shear’ on Fig 2 but neglect to acknowledge that the same danger of clot-shearing applies to the moments of stentretriever/clot/aspiration-cath...
We read with great interest the article by McTaggart et al. on the new embolectomy technique called Continuous Aspiration Prior To Intracranial Vascular Embolectomy (CAPTIVE).(1) The paper adds information on the supporting evidence that a combined approach of stentretriever and aspiration-catheter utilization may be the optimal path in achieving higher rates of complete reperfusion in patients with large vessel occlusions.(2, 3) While the idea of starting aspiration with the intermediate catheter prior to and during the stentretriever placement is intriguing, attention has to be paid on the effect of prolonged aspiration on collateral flow, as reported in a recent JNIS publication.(4) Additionally, the ‘continuous’ part of the title may be misleading, as the authors state that they advance the aspiration-catheter towards the face of the clot until the drip rate has stopped. As seen in Fig 1E of the CAPTIVE publication, the tip of the aspiration-catheter becomes clogged with clot as ‘a portion is held captive within the distal aspiration catheter.’ This probably results in vacuum within the aspiration-catheter and non-existent aspiration in the vicinity of the aspiration-catheter tip during immobilization of the stentretriever/clot/aspiration-catheter unit. At last, the authors describe thoroughly a ‘De-CAPTIVE shear’ on Fig 2 but neglect to acknowledge that the same danger of clot-shearing applies to the moments of stentretriever/clot/aspiration-catheter unit retraction within the tip of the guide catheter/sheath. This exact case is depicted in our example ( http://onestopinstroke.eu/wp-content/uploads/Fig1-1.jpg ) during embolectomy of a mid-basilar occlusion (A). B shows recanalization of the occlusion after one maneuver but without proximal aspiration on the guide catheter there is clot-shearing at the catheter tip seen on the early images of the series (C), with dislocation of the clot towards the basilar artery during the angiogram (D and E). Control-angiogram shows re-occlusion of the basilar artery (F) which could be recanalized with another maneuver (G), but resulted in an incomplete reperfusion of the downstream territory. This danger can be reduced by applying aspiration on the guide catheter during retraction of the unit, while preserving vacuum within the aspiration catheter either with pump-aspiration or with the use of a vacuum-lock syringe. In our experience, the addition of proximal aspiration to a primarily combined approach (stentretriever plus aspiration-catheter) results in high rates of mTICI3 reperfusion.(3)
1. McTaggart RA, Tung EL, Yaghi S, Cutting SM, Hemendinger M, Gale HI, et al. Continuous aspiration prior to intracranial vascular embolectomy (CAPTIVE): a technique which improves outcomes. Journal of neurointerventional surgery. 2016. Epub 2016/12/18.
2. Massari F, Henninger N, Lozano JD, Patel A, Kuhn AL, Howk M, et al. ARTS (Aspiration-Retriever Technique for Stroke): Initial clinical experience. Interventional neuroradiology : journal of peritherapeutic neuroradiology, surgical procedures and related neurosciences. 2016;22(3):325-32. Epub 2016/02/26.
3. Maus V, Behme D, Kabbasch C, Borggrefe J, Tsogkas I, Nikoubashman O, et al. Maximizing First-Pass Complete Reperfusion with SAVE. Clinical neuroradiology. 2017. Epub 2017/02/15.
4. Lally F, Soorani M, Woo T, Nayak S, Jadun C, Yang Y, et al. In vitro experiments of cerebral blood flow during aspiration thrombectomy: potential effects on cerebral perfusion pressure and collateral flow. Journal of neurointerventional surgery. 2016;8(9):969-72. Epub 2015/09/01.
We would like to thank Dr. Shotar and colleagues for their interest in our article. As highlighted by Dr. Shotar, delayed enhancing lesions (DEL) after coil embolization of aneurysm are suspected as a result of foreign body reaction 1-5. We agree with their opinion that the catheter coating of the inner wall of guiding catheter and/or the outer wall of microcatheter may be the source of foreign body. However, according to our experiences and analysis, it is our opinion that the coating material of the inner wall of microcatheter may also be the source.
Dr Shotar suggests that the distribution of the MR lesions in the territory of the parent artery (i.e.: ICA) in our series suggests the guiding catheter as the culprit. However, in all our cases 6, the aneurysms were located at the distal ICA (Ophthalmic artery, IC-anterior choroidal artery, superior hypophyseal artery). Thus, we believe that the distribution of the DELs on MR is not in conflict with our claim that the inner wall of the microcatheter is the source. Foreign body fragments from the microcatheter probably migrated into the aneurysmal sac during multiple coil introduction attempts under unusual friction and were swept downstream. Our benchtop analyses also support this finding.
Regarding Dr Shotar’s suggestion that "the patient treated with the microcatheter that showed coating fragments at the location of the friction on bench tests did not have DELs", this microcatheter was withdrawn imme...
We would like to thank Dr. Shotar and colleagues for their interest in our article. As highlighted by Dr. Shotar, delayed enhancing lesions (DEL) after coil embolization of aneurysm are suspected as a result of foreign body reaction 1-5. We agree with their opinion that the catheter coating of the inner wall of guiding catheter and/or the outer wall of microcatheter may be the source of foreign body. However, according to our experiences and analysis, it is our opinion that the coating material of the inner wall of microcatheter may also be the source.
Dr Shotar suggests that the distribution of the MR lesions in the territory of the parent artery (i.e.: ICA) in our series suggests the guiding catheter as the culprit. However, in all our cases 6, the aneurysms were located at the distal ICA (Ophthalmic artery, IC-anterior choroidal artery, superior hypophyseal artery). Thus, we believe that the distribution of the DELs on MR is not in conflict with our claim that the inner wall of the microcatheter is the source. Foreign body fragments from the microcatheter probably migrated into the aneurysmal sac during multiple coil introduction attempts under unusual friction and were swept downstream. Our benchtop analyses also support this finding.
Regarding Dr Shotar’s suggestion that "the patient treated with the microcatheter that showed coating fragments at the location of the friction on bench tests did not have DELs", this microcatheter was withdrawn immediately after detection of unusual friction without additional coil introduction attempts. We believe that ‘immediate withdrawl’ was essential in preventing distal migration of foreign body materials.
We agree with Dr Shotar’s analyses on the recent increase in the literature on such complications. Further investigation is necessary for identification of its causes. In the meanwhile, based on our series and the experiences of others, we believe that both the inner and outer walls of the micro and/or guiding catheters may be the source 1 6. Our main interest was to identify the cause and elucidate the signs during the procedure –unusual friction development- at which such phenomenon occurs so that clinical complications may be prevented.
1. Shotar E, Law-Ye B, Baronnet-Chauvet F, et al. Non-ischemic cerebral enhancing lesions secondary to endovascular aneurysm therapy: nickel allergy or foreign body reaction? Case series and review of the literature. Neuroradiology 2016 doi: 10.1007/s00234-016-1699-5 [published Online First: 2016/05/25]
2. Shapiro M, Ollenschleger MD, Baccin C, et al. Foreign Body Emboli following Cerebrovascular Interventions: Clinical, Radiographic, and Histopathologic Features. AJNR American journal of neuroradiology 2015;36(11):2121-6. doi: 10.3174/ajnr.A4415 [published Online First: 2015/08/22]
3. Cruz J, Marotta T, O'Kelly C, et al. Enhancing Brain Lesions after Endovascular Treatment of Aneurysms. American Journal of Neuroradiology 2014
4. Skolarus LE, Gemmete JJ, Braley T, et al. Abnormal white matter changes after cerebral aneurysm treatment with polyglycolic-polylactic acid coils. World neurosurgery 2010;74(6):640-4. doi: 10.1016/j.wneu.2010.03.026 [published Online First: 2011/04/16]
5. Fealey ME, Edwards WD, Giannini C, et al. Complications of endovascular polymers associated with vascular introducer sheaths and metallic coils in 3 patients, with literature review. The American journal of surgical pathology 2008;32(9):1310-16.
6. Oh SW, Shin NY, Lee HJ, et al. Delayed enhancing lesions after coil embolization of aneurysms: clinical experience and benchtop analyses. Journal of neurointerventional surgery 2017 doi: 10.1136/neurintsurg-2016-012833 [published Online First: 2017/01/08]
We read with interest the recent paper looking at venous sinus pressure gradients prior to stenting (1), and commend the authors for their work on this interesting topic. We also share an interest in the subject, and recently published our experience looking at venous stenting in a similar patient population (2). The authors of the current paper documented significant differences in trans-stenotic venous pressure-gradients measured under general anaesthesia (GA), and suggested that pressure measurements should be performed with patients awake to counteract this. Another paper published in this issue of JNIS also documented the disparities between pressure measurements performed under GA versus those performed under conscious sedation (CS) (3). The pressure differences in our paper were significantly more marked in those patients who underwent measurements under local anaesthesia alone versus under CS. We can therefore hypothesise that even the use of CS can result in changes in the measured venous pressures in these patients, and indeed in the current paper the authors noted that the use of midazolam in their awake patients had a statistically significant effect on the pressures obtained. Since the decision to treat often hinges on this all-important measurement, we thus propose that venous sinus pressure measurements should be always performed using local anaesthesia alone, in an effort to minimise this variability.
1: Fargen KM, Spiotta AM, Hyer M, et al, Comparis...
We read with interest the recent paper looking at venous sinus pressure gradients prior to stenting (1), and commend the authors for their work on this interesting topic. We also share an interest in the subject, and recently published our experience looking at venous stenting in a similar patient population (2). The authors of the current paper documented significant differences in trans-stenotic venous pressure-gradients measured under general anaesthesia (GA), and suggested that pressure measurements should be performed with patients awake to counteract this. Another paper published in this issue of JNIS also documented the disparities between pressure measurements performed under GA versus those performed under conscious sedation (CS) (3). The pressure differences in our paper were significantly more marked in those patients who underwent measurements under local anaesthesia alone versus under CS. We can therefore hypothesise that even the use of CS can result in changes in the measured venous pressures in these patients, and indeed in the current paper the authors noted that the use of midazolam in their awake patients had a statistically significant effect on the pressures obtained. Since the decision to treat often hinges on this all-important measurement, we thus propose that venous sinus pressure measurements should be always performed using local anaesthesia alone, in an effort to minimise this variability.
1: Fargen KM, Spiotta AM, Hyer M, et al, Comparison of venous sinus manometry gradients obtained while awake and under general anesthesia before venous sinus stenting. Journal of NeuroInterventional Surgery 2017;9:990-993
2: Lenck S, Vallée F, Labeyrie MA et al, Stenting of the lateral sinus in idiopathic intracranial hypertension according to the type of stenosis. Neurosurgery. 2017 Jan 13;80(3):393-400
3: Raper DMS, Buell TJ, Chen C, et al, Intracranial venous pressures under conscious sedation and general anesthesia Journal of NeuroInterventional Surgery 2017;9:986-989
We read with interest the meta-analysis conducted by our colleague Dr Waleed Brinjikji (1). In the text (section "Limitations", he stated: "Data from the Interest of Direct Aspiration First Pass Technique (ADAPT) for Thrombectomy Revascularization of Large Vessel Occlusion in Acute Ischemic Stroke (ASTER) trial suggest that there were no statistically significant differences in revascularization rates when performing the ADAPT technique compared with using a stent retriever. However, it is unclear at this time whether BGCs were used in this trial."
Nevertheless in our publication of the ASTER trial results (2), we clearly stated in the Results section that a balloon-guide catheter was used to allow proximal flow arrest during stent retriever removal in 92% of patients treated with the stent retriever technique.
1. Brinjikji W, Starke RM, Murad MH, et al. Impact of balloon guide catheter on technical and clinical outcomes: a systematic review and meta-analysis. J Neurointerv Surg 2018;10:335–339.
2. Lapergue B, Blanc R, Gory B, et al. JAMA. 2017;318:443-452.
We read with interest the editorial by Darsaut and colleagues entitled, “PHASES and the natural history of unruptured aneurysms: science or pseudoscience?”[1]. Beginning with references to Aristotle and Pliny the Elder (always impressive), the authors launch a critique of studies of the natural history of unruptured aneurysms. With attention to ISUIA and the PHASES system, the contributors from Quebec call attention to limitations in both prospective and retrospective studies of the risk of rupture and associated risk factors for rupture of intracranial aneurysms. In their view, these imperfect studies are so deeply flawed that they are essentially useless as tools to inform decision-making with patients with unruptured intracranial aneurysms. Ending with the umpteenth call for a randomized trial, the authors create the impression that, for all patients with all kinds, sizes and locations of intracranial aneurysms, clinicians are powerless to use data from the available studies, condensed in the PHASES Score, to guide decision-making.
The PHASES score, developed from a pooled analysis of six prospective cohort studies of patients with unruptured intracranial aneurysms, was designed to use existing natural history data (limited though that may be), to provide some estimate of future rupture risk and to aid in identifying risk factors for rupture that may push clinician and patient past the treatment threshold. Several lines of evidence support the use of PHASES...
Show MoreWe appreciate the interest shown by Drs. Yao and You (1) in our paper (2) and find it our pleasure to address their concerns.
The first point raised by Drs. Yao and You is that our search strategy missed two articles, namely those of Mortimer et al (2015) (3) and Morgan et al (1996) (4). We would like to reassure Drs. Yao and You that we did screen these articles, and decided against including them in our meta-analysis based on our inclusion criteria. The article by Mortimer et al (2015) (3) describes a patient population where balloon angioplasty, verapamil, and papaverine infusions were used separately or in various combinations. They did not break down their results by the specific intra-arterial vasodilator (IAD) used, and therefore we decided not to include this information. The paper by Morgan et al (1996) (4) describes a patient population which overlapped with that described by the same group in another paper, Morgan et al (2000) (5). We had personally communicated with the authors in 2016 regarding the multiple papers from this group, such as Little et al (1994) (6) and Morgan et al (2000)
(5) that described papaverine infusions for vasospasm. We found out that there were overlaps in these study populations, and that the cohort in the 2000 paper(5) was the most complete. Therefore, only this paper was included in our meta-analysis, while the earlier ones were excluded.
The second suggestion by Drs. Yao and You was to perform a regression ana...
Show MoreWith great interest, we read the article of Venkatraman et al.[1] published in the Journal of NeuroInterventional Surgery recently. They presented a comprehensive picture depicting the effect of intra-arterial vasodilators (IADs) on the vasospasm following aneurysmal subarachnoid hemorrhage. But we were concerned with several questions weakening the reliability and generalization of the meta-analysis.
Show MoreFirstly , though the detailed including criteria and searching strategy were provided in their meta-analysis, at least two eligible studies2,3 were missed which conformed to their including criteria and unfulfilled the excluding criteria. Two cohort studies of Morgan [2] and Mortimer [3] reported the effects of IADs on vasospasm with documentation of interested events, which should be included in Venkatraman’s analysis. Whether addition of these two studies could change the overall effect of IADs was unclear, but including any eligible study was in accordance with PRISMA principle.
Secondly, owing to the large number of included studies, the heterogeneity was substantial. Venkatraman et al.[1] conducted subgroup and sensitivity analyses, in which the heterogeneity remained significant (most values of I2 greater than 50%). It was rationale to turn to regression analyses in order to find and solve the heterogeneity.
Besides, this article included studies combining IADs with balloon angioplasty, which might overestimate effectiveness of IADs. IADs w...
We read with great interest the article of Haussen et al. 1 outlining the problem of identifying patients with minor stroke symptoms (low NIHSS) despite proximal vessel occlusion who should undergo thrombectomy. Intension-to-treat analysis showed significantly higher reduction of stroke severity in the primary thrombectomy group compared to the medical group. But more interestingly, per-protocol analysis revealed a high propo...
We read with interest the article entitled: “Delayed enhancing lesions after coil embolization of aneurysms: clinical experience and benchtop analyses” by Oh et al [1]. This interesting case series deals with a recently described complication of intracranial endovascular procedures [2–8]: delayed enhancing lesions (DELs), also known as NICE (non-ischemic cerebral enhancing) lesions [8]. This rare complication consists in delayed appearance of cortical leptomeningeal enhancement associated with vasogenic subcortical edema [8]. The authors describe 3 more cases, in addition to the 19 previously reported [8]. We congratulate the authors for their efforts to understand the mechanism of this rare complication by performing benchtop tests.
Show MoreNumerous hypotheses have been proposed to explain this complication.
First, an allergic reaction to nickel has been suggested [4,7]. In a series we recently published in Neuroradiology [8], we did not find any allergic reaction to the devices used for the embolization of the patients who presented NICE lesions. The fact that, in the series of Oh et al [1], none of the three patients had an allergic background, seems to confirm the absence of any relationship between these lesions and allergy.
The second hypothesis is a reaction to foreign bodies (catheter coating) released during the embolization. We do believe that, according to our experience [8] and to the data of the literature [2,3,5,6], these lesions are more likely to...
We have read with great interest the article describing the CAPTIVE technique for endovascular acute ischemic treatment by McTaggart et al.1. Firstly, we would like to commend the great clarity they used to describe the combination of distal aspiration and stent retriever to perform mechanical thrombectomy. Notably, they illustrated the rationale for aspiration prior to stent deployment as well as the removal of both distal aspiration catheter and stent as a single unit to decrease possible clot fragmentation.
We adopt a very similar approach for most of our cases, although we would like to emphasize a slight variant that appears clinically interesting.
In combination with stent retrievers, the balloon guide catheter (BGC) has been shown to improve the effectiveness of mechanical thrombectomy2, 3. In our experience, we typically use the CAPTIVE technique in association with a BGC which presents several potential advantages.
Show MoreFirstly, in cases of tortuous anatomy it provides excellent support for navigating the distal aspiration catheter. In addition, the balloon can be temporarily inflated at this stage to provide an anchoring effect in order to avoid potential push back of the guiding catheter4.
Secondly, McTaggart et al. reported 5% embolization to new territory with the CAPTIVE technique; an equivalent rate to previous reports on distal aspiration with no stent retriever5. In an in vitro study, Chueh et al.6 demonstrated a significant decrease o...
To the Editor:
We read with great interest the article by McTaggart et al. on the new embolectomy technique called Continuous Aspiration Prior To Intracranial Vascular Embolectomy (CAPTIVE).(1) The paper adds information on the supporting evidence that a combined approach of stentretriever and aspiration-catheter utilization may be the optimal path in achieving higher rates of complete reperfusion in patients with large vessel occlusions.(2, 3) While the idea of starting aspiration with the intermediate catheter prior to and during the stentretriever placement is intriguing, attention has to be paid on the effect of prolonged aspiration on collateral flow, as reported in a recent JNIS publication.(4) Additionally, the ‘continuous’ part of the title may be misleading, as the authors state that they advance the aspiration-catheter towards the face of the clot until the drip rate has stopped. As seen in Fig 1E of the CAPTIVE publication, the tip of the aspiration-catheter becomes clogged with clot as ‘a portion is held captive within the distal aspiration catheter.’ This probably results in vacuum within the aspiration-catheter and non-existent aspiration in the vicinity of the aspiration-catheter tip during immobilization of the stentretriever/clot/aspiration-catheter unit. At last, the authors describe thoroughly a ‘De-CAPTIVE shear’ on Fig 2 but neglect to acknowledge that the same danger of clot-shearing applies to the moments of stentretriever/clot/aspiration-cath...
Show MoreWe would like to thank Dr. Shotar and colleagues for their interest in our article. As highlighted by Dr. Shotar, delayed enhancing lesions (DEL) after coil embolization of aneurysm are suspected as a result of foreign body reaction 1-5. We agree with their opinion that the catheter coating of the inner wall of guiding catheter and/or the outer wall of microcatheter may be the source of foreign body. However, according to our experiences and analysis, it is our opinion that the coating material of the inner wall of microcatheter may also be the source.
Show MoreDr Shotar suggests that the distribution of the MR lesions in the territory of the parent artery (i.e.: ICA) in our series suggests the guiding catheter as the culprit. However, in all our cases 6, the aneurysms were located at the distal ICA (Ophthalmic artery, IC-anterior choroidal artery, superior hypophyseal artery). Thus, we believe that the distribution of the DELs on MR is not in conflict with our claim that the inner wall of the microcatheter is the source. Foreign body fragments from the microcatheter probably migrated into the aneurysmal sac during multiple coil introduction attempts under unusual friction and were swept downstream. Our benchtop analyses also support this finding.
Regarding Dr Shotar’s suggestion that "the patient treated with the microcatheter that showed coating fragments at the location of the friction on bench tests did not have DELs", this microcatheter was withdrawn imme...
We read with interest the recent paper looking at venous sinus pressure gradients prior to stenting (1), and commend the authors for their work on this interesting topic. We also share an interest in the subject, and recently published our experience looking at venous stenting in a similar patient population (2). The authors of the current paper documented significant differences in trans-stenotic venous pressure-gradients measured under general anaesthesia (GA), and suggested that pressure measurements should be performed with patients awake to counteract this. Another paper published in this issue of JNIS also documented the disparities between pressure measurements performed under GA versus those performed under conscious sedation (CS) (3). The pressure differences in our paper were significantly more marked in those patients who underwent measurements under local anaesthesia alone versus under CS. We can therefore hypothesise that even the use of CS can result in changes in the measured venous pressures in these patients, and indeed in the current paper the authors noted that the use of midazolam in their awake patients had a statistically significant effect on the pressures obtained. Since the decision to treat often hinges on this all-important measurement, we thus propose that venous sinus pressure measurements should be always performed using local anaesthesia alone, in an effort to minimise this variability.
1: Fargen KM, Spiotta AM, Hyer M, et al, Comparis...
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