Background To assess whether thrombus surface morphology has an impact on first pass reperfusion in contact aspiration (CA) and stent retriever (SR) thrombectomy.

Methods From January 2016 to December 2018, consecutive stroke patients with an occlusion of the middle cerebral artery and thrombectomy (CA or SR) were examined in this retrospective study. We assessed patients’ characteristics, procedural data and clinical outcome. Thrombus surface on pretreatment digital subtraction angiography (DSA) was categorized into regular versus irregular phenotype by blinded three-reader-consensus. Primary outcome was successful reperfusion (modified treatment in cerebral ischemia (mTICI) 2b-3) after first pass. Data analysis was stratified according to thrombectomy technique and thrombus phenotype.

Results Among 203 patients (76 years (IQR 65.5–81.9), 47.3% male, National Institutes of Health Stroke Scale Score 16 (IQR 12–20)), 155 patients were treated primarily with CA and 48 with SR. 40% (n=62/155) CA and 41.7% (n=20/48) SR-treated patients had a regular thrombus phenotype. In the CA group, successful reperfusion after first pass was more frequently obtained in patients with regular compared with irregular phenotype (69.4% (n=43/62) vs 34.4% (n=32/93); P<0.0001). In contrast, in the SR group, reperfusion after first pass was achieved in 35% (n=7/20; P=0.01) of patients with regular phenotypes. In the CA group, median number of passes (1 (1–2) vs 2 (1–4); P<0.00001) and time from reaching the thrombus to reperfusion (19±27 vs 38±36 min; P=0.0001) were lower among patients with a regular phenotype.

Conclusion Direct CA is associated with higher rates of successful first pass reperfusion in patients with a regular thrombus phenotype in pretreatment DSA.