Thrombectomy for Primary Distal Posterior Cerebral Artery Occlusion Stroke: The TOPMOST Study

Abstract

Importance: Clinical evidence of the potential treatment benefit of mechanical thrombectomy for posterior circulation distal, medium vessel occlusion (DMVO) is sparse.

Objective: To investigate the frequency as well as the clinical and safety outcomes of mechanical thrombectomy for isolated posterior circulation DMVO stroke and to compare them with the outcomes of standard medical treatment with or without intravenous thrombolysis (IVT) in daily clinical practice.

Design, setting, and participants: This multicenter case-control study analyzed patients who were treated for primary distal occlusion of the posterior cerebral artery (PCA) of the P2 or P3 segment. These patients received mechanical thrombectomy or standard medical treatment (with or without IVT) at 1 of 23 comprehensive stroke centers in Europe, the United States, and Asia between January 1, 2010, and June 30, 2020. All patients who met the inclusion criteria were matched using 1:1 propensity score matching.

Interventions: Mechanical thrombectomy or standard medical treatment with or without IVT.

Main outcomes and measures: Clinical end point was the improvement of National Institutes of Health Stroke Scale (NIHSS) scores at discharge from baseline. Safety end point was the occurrence of symptomatic intracranial hemorrhage and hemorrhagic complications were classified based on the Second European-Australasian Acute Stroke Study (ECASSII). Functional outcome was evaluated with the modified Rankin Scale (mRS) score at 90-day follow-up.

Results: Of 243 patients from all participating centers who met the inclusion criteria, 184 patients were matched. Among these patients, the median (interquartile range [IQR]) age was 74 (62-81) years and 95 (51.6%) were female individuals. Posterior circulation DMVOs were located in the P2 segment of the PCA in 149 patients (81.0%) and in the P3 segment in 35 patients (19.0%). At discharge, the mean NIHSS score decrease was -2.4 points (95% CI, -3.2 to -1.6) in the standard medical treatment cohort and -3.9 points (95% CI, -5.4 to -2.5) in the mechanical thrombectomy cohort, with a mean difference of -1.5 points (95% CI, 3.2 to -0.8; P = .06). Significant treatment effects of mechanical thrombectomy were observed in the subgroup of patients who had higher NIHSS scores on admission of 10 points or higher (mean difference, -5.6; 95% CI, -10.9 to -0.2; P = .04) and in the subgroup of patients without IVT (mean difference, -3.0; 95% CI, -5.0 to -0.9; P = .005). Symptomatic intracranial hemorrhage occurred in 4 of 92 patients (4.3%) in each treatment cohort.

Conclusions and relevance: This study suggested that, although rarely performed at comprehensive stroke centers, mechanical thrombectomy for posterior circulation DMVO is a safe, and technically feasible treatment option for occlusions of the P2 or P3 segment of the PCA compared with standard medical treatment with or without IVT.

Conflict of interest statement

Conflict of Interest Disclosures: Dr Dorn reported receiving personal fees from Cerus Consulting, Phenox, and Balt Germany outside the submitted work. Dr Kabbasch reported receiving personal fees from Microvention Proctor and Acandis Consultant outside the submitted work. Dr Möhlenbruch reported receiving grants from Balt, Medtronic, Microvention, and Stryker outside the submitted work. Dr Anil reported receiving personal fees from Medtronic Neurovascular, Stryker Neurovascular, and Penumbra Inc paid to the National University Health System, Singapore, and nonfinancial support from Abbott Lab outside the submitted work. Dr Schüller-Arteaga reported receiving personal fees from Medtronic and Stryker outside the submitted work. Dr Navia reported receiving personal fees from Balt Consultant, Stryker Consultant, and Penumbra Consultant outside the submitted work. Dr Raz reported receiving personal fees from Phenox and Medtronic, and stock from Siemens, outside the submitted work and nonfinancial support from Rapid Medical Travel during the conduct of the study. Dr Shapiro reported serving as a consultant to Medtronic outside the submitted work. Dr Fischer reported receiving grants from Medtronic, Swiss National Science Foundation, and Swiss Heart Foundation outside the submitted work and serving as a consultant to Medtronic, Stryker, and CSL Behring, with funds paid to the institution. Dr Gralla reported receiving grants from Medtronic Global during the conduct of the study and grants from Swiss National Science Foundation outside the submitted work. Dr Andersson reported receiving personal fees from Anaconda and Cerenovus-Neuravi, nonfinancial support from Rapid Medical, and personal fees from Stryker outside the submitted work. Dr Chapot reported being a lecturer for Microvention, Balt, Siemens, and Rapid Medical. Dr Fiehler reported receiving personal fees from Acandis, Cerenovus, Microvention, Medtronic, Phenox, and Penumbra outside the submitted work; receiving grants from Stryker and Route 92; being CEO of eppdata; and owning shares in Tegus. Dr Kaesmacher reported receiving grants from Clinical Trial Unit Bern, Schweizerische Akademie der Medizinischen Wissenschaften/Bangerter Foundation, and Swiss Stroke Society during the conduct of the study. No other disclosures were reported.

Figures

Figure 1.. Endovascular Complications and Angiographic Outcomes Stratified by Vessel Segment

The P2 vessel segment begins from the posterior cerebral artery branch point of the posterior communicating artery, curving around the midbrain within the ambient cistern, to the beginning of the quadrigeminal cistern. The P3 vessel segment begins from the entrance point of the quadrigeminal cistern, through its lateral aspect, to the anterior limit of the calcarine fissure. DE indicates downstream emboli; ENT, emboli to new territory; ID, iatrogenic dissection; IP, iatrogenic perforation; and TICI, Thrombolysis in Cerebral Infarction.

Figure 2.. Early Clinical Outcome at Discharge

Improvement of National Institutes of Health Stroke Scale (NIHSS) scores and differences were compared by treatment group and stratified by subgroups. IVT indicates intravenous thrombolysis.

Figure 3.. Modified Rankin Scale (mRS) Scores at 90 Days

Functional outcome rates (mRS) at 90 days were stratified and compared by treatment status after propensity score matching.