Endovascular Thrombectomy as a Means to Improve Survival in Acute Ischemic Stroke: A Meta-analysis

Abstract

Importance: Although endovascular thrombectomy (EVT) in acute ischemic stroke is recommended by guidelines to improve functional recovery, thus far there are insufficient data on its association with mortality.

Objective: To identify guideline-relevant trials of EVT vs medical therapy reporting 90-day mortality and perform a meta-analysis.

Data sources: All randomized clinical trials cited for recommendations on EVT vs medical therapy in the latest 2018 American Stroke Association/American Heart Association guidelines.

Study selection: Ten American Stroke Association/American Heart Association guideline-relevant randomized clinical trials of EVT vs medical therapy were selected for inclusion. Two EVT trials were excluded owing to infrequent use of EVT.

Data extraction and synthesis: Data were abstracted by 2 independent investigators and double-checked by 4 others. Singular study data were integrated using the Cochran-Mantel-Haenszel method and a random-effects model to compute summary statistics of risk ratios (RR) with 95% CIs.

Main outcomes and measures: Risk of 90-day mortality and 90-day intracranial hemorrhage was analyzed; sensitivity analyses were performed in early-window EVT trials (which included patients from the onset of symptoms onward) vs late-window EVT trials (which included patients from 6 hours after onset of symptoms onward).

Results: In 10 trials with 2313 patients, EVT significantly reduced the risk for 90-day mortality by 3.7% compared with medical therapy (15.0% vs 18.7%; RR, 0.81; 95% CI, 0.68-0.98; P = .03). Trends were similar in early-window (RR, 0.83; 95% CI, 0.67-1.01; P = .06) and late-window trials only (RR, 0.76; 95% CI, 0.41-1.40; P = .38). There was no difference in the risk for intracranial hemorrhage in EVT vs medical therapy (4.2% vs 4.0%; RR, 1.11; 95% CI, 0.71-1.72; P = .65). Limitations of the studies include trial protocol heterogeneity and bias originating from prematurely terminated trials.

Conclusions and relevance: This meta-analysis of all evidence on EVT cited in the 2018 American Stroke Association/American Heart Association guidelines shows significant benefits for survival during the first 90 days after acute ischemic stroke compared with medical therapy alone.

Figure 1.. All-Cause Mortality in Randomized Clinical Trials of Endovascular Thrombectomy (EVT) vs Medical Therapy (MT) at 90 Days

Individual and summary risk ratios (RRs) with 95% CIs for all-cause mortality in randomized clinical trials of EVT vs MT at 90 days of follow-up. The size of the data markers indicates the study weight within the pooled meta-analysis. Detailed study weights are given in the respective column and correspond to the size of the data markers. Study weights were calculated according to the random-effects Cochran-Mantel-Haenszel model used. DAWN indicates DWI or CTP Assessment With Clinical Mismatch in the Triage of Wake-Up and Late Presenting Strokes Undergoing Neurointervention With Trevo; DEFUSE 3, Endovascular Therapy Following Imaging Evaluation for Ischemic Stroke; ESCAPE, Endovascular Treatment for Small Core and Anterior Circulation Proximal Occlusion With Emphasis on Minimizing CT to Recanalization Times; EXTEND-IA, Extending the Time for Thrombolysis in Emergency Neurological Deficits—Intra-Arterial; MR CLEAN, Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands; MR RESCUE, Mechanical Retrieval and Recanalization of Stroke Clots Using Embolectomy; REVASCAT, Randomized Trial of Revascularization With Solitaire FR Device vs Best Medical Therapy in the Treatment of Acute Stroke Due to Anterior Circulation Large Vessel Occlusion Presenting Within Eight Hours of Symptom Onset; SWIFT PRIME, Solitaire With the Intention for Thrombectomy as Primary Endovascular Treatment; THERAPY, The Randomized, Concurrent Controlled Trial to Assess the Penumbra System’s Safety and Effectiveness in the Treatment of Acute Stroke; and THRACE, Mechanical Thrombectomy After Intravenous Alteplase vs Alteplase Alone After Stroke.

Figure 2.. Symptomatic Intracranial Hemorrhage in Randomized Clinical Trials of Early-Window Endovascular Thrombectomy (EVT) vs Medical Therapy (MT) at 90 Days

Individual and summary risk ratios (RRs) with 95% CIs for symptomatic intracranial hemorrhage in randomized clinical trials of early-window EVT vs MT. The size of the data markers indicates the study weight within the pooled meta-analysis. Detailed study weights are given in the respective column and correspond to the size of the data markers. Study weights were calculated according to the random-effects Cochran-Mantel-Haenszel model used. ESCAPE, Endovascular Treatment for Small Core and Anterior Circulation Proximal Occlusion With Emphasis on Minimizing CT to Recanalization Times; EXTEND-IA, Extending the Time for Thrombolysis in Emergency Neurological Deficits—Intra-Arterial; MR CLEAN, Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands; MR RESCUE, Mechanical Retrieval and Recanalization of Stroke Clots Using Embolectomy; REVASCAT, Randomized Trial of Revascularization With Solitaire FR Device vs Best Medical Therapy in the Treatment of Acute Stroke Due to Anterior Circulation Large Vessel Occlusion Presenting Within Eight Hours of Symptom Onset; SWIFT PRIME, Solitaire With the Intention for Thrombectomy as Primary Endovascular Treatment; THERAPY, The Randomized, Concurrent Controlled Trial to Assess the Penumbra System’s Safety and Effectiveness in the Treatment of Acute Stroke; and THRACE, Mechanical Thrombectomy After Intravenous Alteplase vs Alteplase Alone After Stroke.