Mechanical thrombectomy beyond the circle of Willis: efficacy and safety of different techniques for M2 occlusions

Abstract

BackgroundM2 segment occlusions represent approximately one-third of non-lacunar ischemic stroke and can lead to permanent neurological deficits. Various techniques are available for mechanical thrombectomy beyond the circle of Willis, but data evaluating their effectiveness and safety are lacking.MethodsA retrospective review of patients with ischemic stroke undergoing mechanical thrombectomy for M2 occlusions from 13 centers in North American and Europe was performed. Tandem or multiple-territory occlusions were excluded. The primary outcome was 90-day modified Rankin Scale and reperfusion rates across stent-retriever, direct aspiration and combined techniques.ResultsThere were 465 patients (mean age 71.48±14.03 years, 53.1% female) with M2 occlusions who underwent mechanical thrombectomy. Stent-retriever alone was used in 133 (28.6%), direct aspiration alone in 93 (20.0%) and the combined technique in 239 (51.4%) patients. Successful reperfusion was achieved with the combined technique in 198 (82.2%; OR 2.6 (1.1–6.9)), with stent-retriever alone in 112 (84.2%; OR 9.2 (1.9–44.6)) and with direct aspiration alone in 62 (66.7%; referencecategory). Intraprocedural subarachnoid hemorrhages (iSAH) were 36 (7.7%) and were more likely to occur in patients treated with the stent-retrievers (OR 5.0 (1.1–24.3)) and combined technique (OR 4.6 (1.1–20.9)). Good clinical outcome was achieved in 260 (61.8%) patients, while 59 (14.0%) patients died. Older age, higher baseline NIHSS (National Institutes of Health Stroke Scale), parenchymal hemorrhage and iSAH were associated with poor outcome while successful recanalization and higher baseline ASPECTS (Alberta Stroke Program Early CT Score) were associated with good outcome. No differences were found among the three techniques in terms of clinical outcome.ConclusionStent-retrievers and a combined approach for M2 occlusions seem more effective than direct aspiration, but with higher rates of iSAH. This leads to no detectable difference in clinical outcome at 3 months.

First-line thrombectomy strategy for distal and medium vessel occlusions: a systematic review

“…Six two-armed studies compared the performance of SR and ASP techniques 16–21. Four three-armed studies compared the performance of SR+ASP to ASP and SR 22–25. Three two-armed studies compared the safety and efficacy of SR+ASP with SR or ASP alone 26–28…”

“…All studies provided data for thrombus location. Data regarding IVT utilization in DMVOs were available in 10 studies 16 17 19 20 22 24–28. Even though Bernsen et al provided overall IVT utilization data, they did not provide separate baseline characteristics for DMVOs 18.…”

“…Even though Bernsen et al provided overall IVT utilization data, they did not provide separate baseline characteristics for DMVOs 18. Functional independence data were available in nine studies,16–19 21 24–26 28 and eight articles presented complete recanalization16 18 20–22 24 26 27 data. Also, nine studies provided sICH data,16–22 27 28 and seven articles presented SAH data 16 19 21 24 26–28.…”

“…Functional independence data were available in nine studies,16–19 21 24–26 28 and eight articles presented complete recanalization16 18 20–22 24 26 27 data. Also, nine studies provided sICH data,16–22 27 28 and seven articles presented SAH data 16 19 21 24 26–28. Alawieh et al provided raw overall functional independence, successful recanalization, and sICH data for their cohort 25.…”

“…Renieri et al conducted a retrospective multicenter study to compare the safety and efficacy of first-line MT strategies in M2 occlusions. There were 465 patients in their study (93 ASP, 133 SR, and 239 SR+ASP cases) 24. SR and SR+ASP techniques provided significantly higher rates of successful recanalization (mTICI ≥2b) compared with ASP alone (OR 9.2, 95% CI 1.9 to 44.6; OR 2.6, 95% CI 1.1 to 6.9, respectively).…”