Contact aspiration versus stent-retriever thrombectomy for distal middle cerebral artery occlusions in acute ischemic stroke: meta-analysis

PURPOSE: The evidence for endovascular therapy and choice of technique in distal middle cerebral artery (MCA) M2 segment occlusions in acute ischemic stroke remains controversial. We aimed to conduct a systematic review and meta-analysis primarily comparing reperfusion rates of stent-retrieval versus contact aspiration for M2 occlusions. MATERIALS AND METHODS: Study selection included cohorts of patients with distal MCA occlusions in acute ischemic strokes treated with an endovascular approach including stent-retrieval or contact aspiration. Twelve studies were selected for meta-analysis for a total of 835 cases. Meta-analysis by proportions was conducted on parameters including baseline and procedural characteristics, thrombolysis in cerebral infarction (TICI) 2b-3 outcomes, and 90-day modified Rankin scale (mRS) outcomes. RESULTS: Hypertension and hyperlipidemia were more prevalent in stent-retriever patients. Pooled baseline National Institute of Health Stroke Scale scores and Alberta Stroke Program Early Computed Tomography Score imaging scores were similar. Pooled time onset of symptoms to door arrival was higher for the stent-retrieval group (154 vs. 97.4 minutes, P=0.01), as was time to groin puncture (259.9 vs. 156.2 minutes, P=0.02), but there was no difference in procedure time. The TICI 2b-3 recanalization rate was similar (80.5% vs. 86.8%, P=0.168). The frequency of mRS 0-2 at 90-day was also similar (74.5% vs. 59.9%, P=0.120), and an excellent mRS 0-1 was lower for stent-retrievers (39.9% vs. 65.6%, P=0.003). A significant negative correlation was found between onset to groin puncture time and the proportion of patients with a good mRS (r=-0.71, P=0.048). CONCLUSION: Both endovascular techniques achieved recanalization rates greater than 80% and 90-day outcomes of minimal disability with similar complication rates. The literature is skewed by aspiration cases being performed sooner after onset of stroke compared to stent-retriever cases.