Arterial Recanalization During Interhospital Transfer for Thrombectomy

Abstract

Background: Patients with acute ischemic stroke harboring a large vessel occlusion admitted to nonendovascular-capable centers often require interhospital transfer for thrombectomy. We evaluated the incidence and predictors of arterial recanalization during transfer, as well as the relationship between interhospital recanalization and clinical outcomes.

Methods: We analyzed data from 2 cohorts of patients with an anterior circulation large vessel occlusion transferred for consideration of thrombectomy to a comprehensive center, with arterial imaging at the referring hospital and on comprehensive stroke center arrival. Interhospital recanalization was determined by comparison of the baseline and posttransfer arterial imaging and was defined as revised arterial occlusive lesion (rAOL) score 2b to 3. Pretransfer variables independently associated with interhospital recanalization were studied using multivariable logistic regression analysis.

Results: Of the 520 included patients (Montpellier, France, n=237; Stanford, United States, n=283), 111 (21%) experienced interhospital recanalization (partial [rAOL=2b] in 77% and complete [rAOL=3] in 23%). Pretransfer variables independently associated with recanalization were intravenous thrombolysis (adjusted odds ratio, 6.8 [95% CI, 4.0-11.6]), more distal occlusions (intracranial carotid occlusion as reference: adjusted odds ratio, 2.0 [95% CI, 0.9-4.5] for proximal first segment of the middle cerebral artery, 5.1 [95% CI, 2.3-11.5] for distal first segment of the middle cerebral artery, and 5.0 [95% CI, 2.1-11.8] for second segment of the middle cerebral artery), and smaller clot burden (clot burden score 0-4 as reference: adjusted odds ratio, 3.4 [95% CI, 1.5-7.6] for 5-7 and 5.6 [95% CI, 2.4-12.7] for 8-9). Recanalization on arrival at the comprehensive center was associated with less interhospital infarct growth (rAOL, 0-2a: 11.6 mL; rAOL, 2b: 2.2 mL; rAOL, 3: 0.6 mL; P_trend<0.001) and greater interhospital National Institutes of Health Stroke Scale score improvement (0 versus -5 versus -6; P_trend<0.001). Interhospital recanalization was associated with reduced 3-month disability (adjusted common odds ratio, 2.51 [95% CI, 1.68-3.77]) with greater benefit from complete than partial recanalization.

Conclusions: Recanalization is frequently observed during interhospital transfer for thrombectomy and is strongly associated with favorable outcomes, even when partial. Broadening thrombolysis indications in primary centers, and developing therapies that increase recanalization during transfer, will likely improve clinical outcomes.

Keywords: endovascular procedures; incidence; infarction; ischemic stroke; thrombolytic therapy.

Figure 1 –

Arterial Recanalization During Inter-hospital Transfer According To Intravenous Thrombolysis Use, Occlusion Site And Clot Burden Score

Figure 2 –. Relationship Between Inter-hospital Arterial Recanalization And 3-month Functional Outcome

Panel A: inter-hospital arterial recanalization was associated with better 3-month functional outcomes (adjusted common OR=2.51; 95%CI 1.68–3.77; P<0.001). Panel B: There was an increase in the odds of improved outcome with increasing recanalization grade (no recanalization as the reference, adjusted common OR=2.24 [95%CI 1.44–3.49] for rAOL 2b and adjusted common OR=3.70 [95%CI 1.73–7.92] for rAOL 3, P<0.001. The 3-month mRS was missing in 42/520 (8%) patients (7/111 [6%] with recanalization and 35/409 [9%] without). mRS indicates modified Rankin Scale score. The models were adjusted for center, age, pre-transfer occlusion site and NIHSS score, and time from last-seen-well to comprehensive stroke center arterial imaging.