Vessel diameter and catheter-to-vessel ratio affect the success rate of clot aspiration

Background A direct aspiration first pass technique (ADAPT) is an efficient, safe, cost-effective, and fast thrombectomy technique. Objective To evaluate anatomical and clot characteristics associated with success of the aspiration component as part of ADAPT. Methods 106 cases of acute carotid-T, basilar, and middle cerebral artery occlusion undergoing endovascular treatment with ADAPT were retrospectively assessed for successful catheter-clot contact and successful primary aspiration, defined as a Thrombolysis in Cerebral Infarction score >= 2b after primary aspiration with 5F or 6F aspiration catheters. Patient age, National Institutes of Health Stroke Scale (NIHSS) score, time from symptom onset to groin puncture, time from groin puncture to revascularization, aortic arch type, access vessel tortuosity, vessel diameter at the proximal end of the thrombus, catheter-to-vessel ratio (CVR), clot density, length, and perviousness were determined. Results Successful clot contact with the aspiration catheter was achieved in 76 cases (72%); these patients were younger (67.7 +/- 15.2 vs 73.7 +/- 11.4 years; p=0.05) and had less tortuous access vessels (1 vs 2 reverse curves; p=0.004) than those in whom clot contact failed. Successful primary aspiration occurred in 36 of these cases (47%) and was associated with significantly smaller vessel diameter at the proximal thrombus end (2.5 +/- 0.7 mm vs 3.1 +/- 1.3 mm; p=0.01) and higher CVR (CVR outer diameter: 0.85 +/- 0.2 vs 0.68 +/- 0.2; p=0.01 and CVR inner diameter: 0.72 +/- 0.2 vs 0.58 +/- 0.2; p<0.001). No significant differences were seen in aortic arch type, radiographic clot features, and NIHSS score. Conclusion With ADAPT, patient age and vessel tortuosity affect the ability to deliver the aspiration catheter and achieve clot contact, whereas vessel diameter and CVR at the aspiration site seem to affect the effectiveness of clot aspiration. Strategies aimed at improving catheter deliverability and increasing CVR may increase the efficacy of ADAPT.