Introduction Various large-bore catheters can be employed for manual aspiration thrombectomy (MAT); clinical differences are rarely explored.
Methods Prospectively collected demographic, angiographic, and clinical data for patients with acute internal carotid artery, middle cerebral artery M1, or basilar occlusions undergoing MAT over 23 months at a comprehensive stroke center were reviewed. We excluded patients in stentriever-based randomized trials/registries. The four most commonly utilized aspiration catheters were analyzed, and multivariate logistic regression analyses were performed to determine the effect of primary aspiration catheter choice on first-pass success, final reperfusion, and modified Rankin Scale (mRS) score at 90 days.
Results Of 464 large vessel thrombectomies, 180 were performed via MAT on the first pass with one of four catheters. First-pass success was achieved in 42% of cases overall; this rate did not differ significantly between catheters: 50% for Sofia, 45% for CAT6, 40% for 0.072 inch Navien, and 36% for ACE68, p=0.67. Final Thrombolysis in Cerebral Infarction 2b or 3 reperfusion was achieved in 94% of cases overall: 97% of cases with CAT6, 95% with Sofia, 92% with Navien, and 92% with ACE68, p=0.70. Mean number of passes for index thrombus (2.0 overall), median procedure time (32 min overall), 90-day good outcome (mRS 0–2, mean 36%), and 90-day mortality (mean 27%) did not differ significantly between patients treated with different initial catheters.
Conclusion Among large-bore aspiration catheters, catheter selection is not an independent predictor of first-pass success, final reperfusion, or clinical outcome.
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Manual aspiration thrombectomy (MAT) is a well-accepted approach for the treatment of acute large vessel occlusion (LVO).1 2 MAT has been demonstrated to be similar in safety and efficacy to stentriever thrombectomy for anterior circulation LVOs.3 4 A number of aspiration catheters are endorsed for MAT and have been shown to be safe and efficacious in single-center case series5–8; however, no direct comparison analyses between aspiration catheters exists.
There is a paucity of literature addressing the impact of aspiration catheter selection on rates of single-pass success using MAT, and an investigation into whether the aspiration catheter used for manual aspiration thrombectomy affects outcome bears further study. The objective of this study was to compare large-bore aspiration catheters across three distinct domains: first-pass success rate, final reperfusion status, and clinical outcome.
A retrospective analysis of prospectively collected data was performed for all patients undergoing MAT for acute LVO over 23 months (December 2015 to November 2017) at a tertiary care academic comprehensive stroke center. Patients were excluded if they underwent first-pass stentriever-assisted thrombectomy or if they underwent thrombectomy for distal intracranial (M2, M3, A1/A2, or PCA) or extracranial occlusions (n=249). Cases were also excluded if an aspiration catheter was used in fewer than 20 cases (n=22). Demographic, clinical, radiographic, and angiographic data were collected, including specific catheters used and perfusion results of each pass during a given thrombectomy. This study was approved by the local Institutional Review Board.
The MAT procedure was performed at one of two comprehensive stroke centers affiliated with a large academic institution by one of four neurointerventionalists. Through a transfemoral approach, the cervical vasculature was catheterized using standard techniques with a long 6F sheath (AXS Infinity, Stryker Neurovascular, Fremont, California, USA; or Neuronmax, Penumbra, Alameda, California, USA). After an LVO was confirmed via base catheter fluoroscopy, a triaxial system comprised of the large-bore catheter chosen by the neurointerventionalist, a microcatheter, and microwire were advanced through the thrombus.
Four catheters used for aspiration were analyzed in this study: ACE68 Reperfusion Catheter (Penumbra), Sofia Plus (MicroVention, Aliso Viejo, California, USA), AXS Catalyst 6 Distal Access Catheter (CAT6; Stryker Neurovascular), and the 6F 0.072 inch Navien Intracranial Support Catheter (Medtronic, Irvine, California, USA). The large-bore catheter was advanced to the face of the thrombus and the microcatheter and wire were removed. Manual aspiration was applied via syringe and the aspiration catheter was withdrawn under continuous aspiration. The 6F sheath was then aspirated to remove any additional thrombus. A Thrombolysis in Cerebral Infarction (TICI) score was then assigned according to the original TICI classification,9 with TICI 2b representing reperfusion of two-thirds or more of the vascular territory affected.
Catheter performance was assessed by first-pass success, a measure defined as the proportion of cases in which TICI 2b or higher reperfusion was achieved on the first pass in the absence of a downstream occlusion treated with subsequent thrombectomy/passes (ie, no M2 or M3 downstream occlusion after the first pass). Final reperfusion was assessed at the end of each case regardless of the number of passes. Clinical outcome was assessed as the mRS measured at 90 days post-stroke during routine clinical follow-up visits performed at our Stroke Institute by practitioners trained and certified in mRS scoring.
Statistical analysis was performed using IBM SPSS Statistics 23 (Armonk, New York, USA). Univariate analyses were performed using analysis of variance for continuous variables and Pearson χ2 tests for categorical variables. Multivariate logistic regression analysis was subsequently performed to identify independent predictors of first-pass success, final successful reperfusion, and good clinical outcome at 90 days (mRS 0–2).
Of 464 patients undergoing thrombectomy during the study period, 180 consecutive patients underwent MAT for LVO with one of four aspiration catheters used in at least 20 cases (table 1). The average age was 70.7 years and 54.4% were female. The majority of patients had comorbidities including hypertension (76.7%), hyperlipidemia (52.8%), atrial fibrillation (40.6%), active tobacco use (25.0%), and diabetes mellitus (23.3%). A significant number of patients had a history of prior transient ischemic attack or stroke (17.2%). Of the 180 patients, 113 (62.8%) were diagnosed with M1 middle cerebral artery (MCA) occlusions, 56 (31.1%) had internal carotid artery (ICA) terminus occlusions, and there were 11 (6.1%) basilar occlusions. The overall mean National Institute of Health Stroke Scale (NIHSS) score was 17.4, mean Alberta Stroke Program Early CT Score was 8.8±1.2, and 67 patients (37.2%) received intravenous tissue plasminogen activator (tPA).
Initial aspiration catheter choice at the discretion of the treating neurointerventionalist included the CAT6 (n=69, 38.3%), ACE68 (n=66, 36.7%), 6F 0.072 inch Navien (n=25, 13.9%), and the Sofia Plus (n=20, 11.1%). There was no significant difference in patient demographics between the groups, including rates of intravenous tPA, ASPECTS, and NIHSS. The CAT6 was the aspiration catheter selected in 73% of basilar thrombectomies at the discretion of the neurointerventionalist; this was the only significant difference between patient groups.
Seventy-five of the 180 patients (41.7%) had first-pass succes, defined as TICI 2b or higher reperfusion after the first pass without the need for subsequent thrombectomy (table 2). Rates of first-pass success were 50% for Sofia Plus, 45% for CAT6, 40% for the 0.072 inch Navien, and 36% for ACE68. On multivariate logistic regression analyses controlling for age, NIHSS, ASPECTS, tPA, and occlusion location, no individual catheter was an independent predictor of first-pass success or total number of passes for index thrombus.
Of all 180 thrombectomies, 170 (94%) resulted in a final reperfusion of TICI 2b or higher (table 2). This rate did not differ significantly between catheters on univariate or multivariate analysis: 97% for CAT6, 95% for Sofia Plus, 92% for ACE68, and 92% for 0.072 inch Navien. The mean number of passes for the index thrombus was 2.0 and did not differ significantly between catheters: 2.0 for Sofia Plus, 2.1 for CAT6, 2.0 for 0.072 inch Navien, and 2.0 for ACE68. Median puncture to final reperfusion time was 31.7 min and did not differ significantly between catheters: 22 min for Sofia Plus, 29 min for ACE68, 32 min for CAT6, and 46 min for 0.072 inch Navien.
Of the 180 patients, 65 (36%) had 90-day outpatient follow-up with documented mRS scores of 0–2 (table 2). This rate did not differ between the aspiration catheter initially employed: 47% for CAT6, 37% for ACE68, 29% for 0.072 inch Navien, and 22% for Sofia Plus. Forty-nine patients (27.2%) had died at 90 days, a rate that was not dependent on aspiration catheter used: 23% for CAT6, 25% for 0.072 inch Navien, 33% for Sofia Plus, and 36% for ACE68. On multivariate logistic regression analyses, both age (p=0.004) and final reperfusion of TICI 2b or better (p=0.062) were independent predictors of mRS 0–2 at 90 days, but not whether tPA was given (p=0.154). Primary aspiration catheter choice is not an independent predictor of mRS ≤2 at 90 days (p=0.179) or of 90-day mortality (p=0.421).
There is an expanding library of catheters available for MAT. A number of single-arm studies of individual catheters have been published7–9; however, a more clinically practical analysis comparing catheters of similar internal diameters does not currently exist.
Prior reports have demonstrated that achieving reperfusion after a single pass results in a shorter time to revascularization, lower rates of distal emboli, and better 90-day clinical outcomes for patients undergoing stentriever-assisted mechanical thrombectomy.10 One prior retrospective analysis of 76 patients identified younger age as the only predictor of aspiration success, but did not directly compare aspiration catheters.11 In this analysis we compare large-bore catheters with similar internal diameters directly with each other and report rates of first-pass reperfusion success, final reperfusion, and clinical outcome. We also introduce the concept of first-pass success, defined as the rate of achieving TICI 2b or greater reperfusion after a single pass of MAT without the need for subsequent embolectomy.
Several prior reports have demonstrated improved results with larger-bore aspiration catheters when compared with previous generation smaller-bore catheters of the same catheter line.5 6 Delgado Almandoz et al reviewed their experience with the ACE68, ACE64, and ACE60 catheters in a consecutive series of 152 thrombectomies with the ADAPT technique and reported higher rates of successful first-pass reperfusion, shorter reperfusion times, and lower need for stentriever rescue with the larger-bore ACE68 catheter.6 Alawieh et al similarly reported higher rates of recanalization and shorter procedural time in patients treated with larger ACE catheters compared with their earlier generation, smaller catheters.5 It is possible that the shorter reperfusion times demonstrated in both of these prior series with larger-bore catheters is due to improved operator technique and may reflect an underlying learning curve, as the larger catheters in these series were not available at the start of patient enrollment. However, recent versions of advanced aspiration catheters not only have larger internal diameters, purportedly providing additional aspiration force, but also contain design tweaks to optimize performance. For example, the ACE68 reperfusion catheter, when compared with the earlier generation ACE60 and ACE64 catheters, contains additional transition zones designed to improve force transmission and enhanced tracking and a larger internal diameter. The Sofia Plus, when compared with the Sofia, has a longer distal tip length designed for easier navigation in tortuous vessels in addition to a larger internal diameter.
In this analysis of 180 consecutive patients with LVOs of the ICA terminus, M1, or basilar artery using one of four large-bore aspiration catheters, the overall first-pass success rate was 41.7%. The only significant difference between catheter groups in this report is that the CAT6 was used preferentially in fewer ICA terminus occlusions. First-pass succes for individual catheters ranged from 36.4% to 50%, which did not differ to a level of statistical significance. This is similar to previously published reports using both stentrievers10 and the MAT technique.6 Regardless of the result of the first pass, the overall rate of successful final reperfusion in this cohort is 94.4%. The rate of good clinical outcome defined as mRS 0–2 in this cohort is 36.1%, similar to large randomized clinical trials.12–16 When these outcome measures were compared between aspiration catheters with multivariate logistic regression analyses controlling for demographics including age, NIHSS, tPA, and occlusion location, the aspiration catheter chosen was not an independent predictor of first-pass success, final reperfusion, or clinical outcome.
The clinical goal in the management of a patient with an LVO is urgent uncomplicated thrombectomy as quickly as possible. Overall, our findings suggest that, among aspiration catheters of similar internal diameter, the aspiration catheter alone is not an independent predictor of first-pass efficacy, final reperfusion, or clinical outcome in patients undergoing MAT for LVO. Future reports of the newest generation catheters of even larger internal diameter warrant further study.
Our study is limited by its modest size and retrospective design, subjecting it to the biases inherent to the treating physicians, which we have attempted to mitigate bias as much as possible by collecting data prospectively and by standardizing thrombectomy technique. The determination of reperfusion grade is made by the neurointerventionalist at the time of the thrombectomy and lacks external confirmation. The results presented here are dependent on a vessel diameter sufficient to accommodate a large-bore aspiration catheter; anatomic variations may require a smaller-bore catheter.
In this retrospective cohort series of patients undergoing first-pass MAT for LVOs at a large academic stroke center, aspiration catheter alone is not an independent predictor of first-pass efficacy, final reperfusion, or clinical outcome.
Contributors Conception/design: BAG, APJ, TGJ. Drafting the article: DAT, BAG. Acquisition of data/analysis: DAT, SMD, SC. Reviewed and revised prior to submission: All authors. Study supervision: BAG, APJ, TGJ.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests BTJ: Consultant: Medtronic. MWB: Investor: Penumbra. BAG: Consultant: Microvention. TGJ: Consultant: Stryker Neurovascular (PI DAWN-unpaid); Ownership Interest: Anaconda; Advisory Board/Investor: FreeOx Biotech, Advisory Board/Investor: Route92; Advisory Board/Investor: Blockade Medical, Consultant; Honoraria: Cerenovus.
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Provenance and peer review Not commissioned; externally peer reviewed.