30 e-Letters

published between 2014 and 2017

  • Prediction of hyperperfusion phenomenon after carotid artery stenting and carotid angioplasty using quantitative DSA with cerebral circulation time imaging; methodological issues

    I was interested to read the paper by Yamauchi K and colleagues published in J Neurointerv Surg 2017 Sep. Hyperperfusion syndrome after carotid interventions has a low incidence but it can lead to morbidity and mortality. The aim of the authors was to evaluate the usefulness of quantitative DSA for predicting hyperperfusion phenomenon (HPP) after carotid artery stenting and angioplasty. Thirty-three consecutive patients with carotid stenosis treated with carotid artery stenting or angioplasty between February 2014 and August 2016 were included. The cerebral circulation time (CCT) was defined as the difference in the relative time to maximum intensity between arterial and venous regions of interest set on the angiograms. HPP was diagnosed straight after the procedure with qualitative 123I-IMP single-photon emission CT (SPECT). Cut-off points for detecting HPP for preprocedural CCT and periprocedural change of CCT were assessed by receiver operating characteristic analysis using 123I-IMP SPECT as reference standard. Differences between patients with and without HPP were analyzed by Student's t test for continuous variables and Fisher`s exact test for categorical variables. A p value of <0.05 was considered statistically significant. Receiver operating characteristic curve analysis of preprocedural CCT and ΔCCT was performed for the prediction of HPP, with 123I-IMP SPECT as standard of reference. They reported that the optimal cut-off points of preprocedural CCT and c...

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  • Venous Sinus Pressure Measurement Technique

    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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  • The Authors' response to "Intra-arterial vasodilators for vasospasm following aneurysmal subarachnoid hemorrhage"

    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...

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  • Intra-arterial vasodilators for vasospasm following aneurysmal subarachnoid hemorrhage

    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...

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  • Re:Comment on “Delayed enhancing lesions after coil embolization of aneurysms: clinical experience and benchtop analyses”

    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...

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  • ‘Continuous’ vs. continuous

    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...

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  • No thromboembolic complications after Pipeline Embolization Device with Shield Technology treatment: the possible role of aneurysm size

    To the editor,

    With great interest we read the recent paper by Martinez-Galdámez et al. regarding the periprocedural outcomes and early safety after placement of a Pipeline Embolization Device with Shield Technology (PEDshield) (1). Evaluation of new endovascular devices, such as PEDshield, is of the utmost importance to give future users a chance to objectively review possible benefits for their clinical practice.

    In the study of Martinez-Galdámez et al. 76% of the target aneurysms were small (< 10 mm). It is known that small aneurysms are associated with a lower probability of thromboembolisms and ischemic stroke after flow diverter treatment than large and giant aneurysms (2,3). The size of the treated aneurysms, and not the PEDshield, might therefore explain the lack of thromboembolic complications reported in the study of Martinez-Galdámez et al. Selection bias might thus have led to the conclusion that the early safety of the PEDshield device is warranted.

    Furthermore, it is hard to understand why only 21 out of 50 patients (42%) underwent platelet reactivity testing, especially since the primary outcome measure focused on identifying thromboembolic complications in the territory supplied by the treated artery. To make matters worse: when platelet reactivity tests revealed the presence of hyporesponders, anti-platelet therapy was left unchanged in most cases. If thromboembolic complications do occur in the 6-month and 1-year follow-up of this...

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  • Interest of a balloon guide catheter in association with the CAPTIVE technique

    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...

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  • Aspiration with distal filter protection: an effective management for carotid floating thrombus

    To the editor,

    Giragani S et al. (published online 25 January 2017) described a remarkable case of recurrent transient ischemic attacks (TIA) due to carotid free floating thrombus. They successfully used stentriever with distal filter protection in retrieving the thrombus.

    Here we share a similar case of TIA with right common carotid artery (CCA) floating thrombus that was effectively managed with distal filter protection and aspiration. A 48-year-male with recurrent ischemic symptoms detected to have right CCA long segment floating thrombus (approximately 4.5 cm) extending upto right proximal external carotid artery.* Under general anaesthesia through right femoral route long sheath guiding catheter (Neuron Max 6F088; Penumbra, Inc. Alameda, USA) was placed in right proximal CCA. After parking the filter device (Spider FX 6mm; eV3, Plymouth, Minnesota, USA) at distal cervical segment, thrombus was aspirated using penumbra system (5MAX ACE, 132 cm; Penumbra, Inc. Alameda, USA).* Final check angiography showed 80 % reduction in clot burden .*

    Placing the filter protection device in the distal cervical segment does not protect thrombus migration to ECA, although it primarily prevent intracranial shower. In our index case thrombus fragment migrated to ECA, although it did not cause any neurological deficit. These cases highlight a novel technique to treat free floating thrombus.

    *Representative image available.

  • Transcranial antegrade approach for the treatment of dural sinus thrombosis

    With interest, I read this article and the authors' claim that their technique has not been previously described. A cursory search using PubMed would have shown that we described this approach almost 30 years ago:

    Treatment of dural sinus thrombosis with local urokinase infusion. Case report. Scott JA, Pascuzzi RM, Hall PV, Becker GJ. J Neurosurg. 1988 Feb;68(2):284-7.