Abstract 186: IV tPA Recanalization Rates by Site of Occlusion and Time After tPA Bolus- Main Results Of The Interrsect Multinational Multicenter Prospective Cohort Study

Abstract

Introduction: Decisions to transport patients from primary to comprehensive stroke centre would be influenced by info on likelihood/timing of spontaneous or IV tPA recanalization (recan). We examined recan rates by time for a wide range of occlusion sites in the INTERRSeCT multicenter prospective cohort study. Methods: Acute stroke patients consented/enrolled at 12 centers/5 countries if intracranial occlusion present on baseline CTA; eGFR≥60 ml/min. CTA was repeated 2-6 hrs later for recan unless patient taken for EVT (first run of angio used instead). Primary outcome was successful recan (rAOL scale score 2b/3) interpreted by central core lab. Results: 619 patients enrolled, 81.6% received IV tPA. 59.9% recan by follow-up CTA and 40.1% by first run angio. Median baseline NIHSS 14 (IQR 11); mean age 70.1 yrs (SD 13); median onset to baseline CTA 115 mins (IQR 108). Recan assessment imaging median 162 mins (IQR 198) from IV tPA bolus or baseline CTA (if no IV tPA). Successful recan (rAOL 2b-3) rates comparing baseline to repeat imaging shown in Figure 1a (IV tPA red; no IV tPA blue). IV tPA had much higher recan than non-IV tPA group (30.5% vs 11%, p<0.0001). Successful recan rates by occlusion site and by time from IV tPA bolus shown in Figure 1b. Site of occlusion, tPA administration, time from tPA to recan assessment and baseline residual flow were the only independent predictors of recan (all p<0.0001). Distal M1 MCA had highest recan [RR 4.12; 95% CI 1.91-8.86 vs. ICA]. Conclusions: Early recan rates were low across all occlusion sites. Beyond 6 hrs post tPA, recan rates approached EVT levels except for ICA. Imaging factors such as residual flow may further refine transport/triage decisions.

Mechanical Thrombectomy After Intravenous Thrombolysis vs Mechanical Thrombectomy Alone in Acute Stroke

“…In our meta-analysis reviewing all 26 studies implementing vascular imaging before starting IVT —which therefore excluded the previously mentioned trials but included EXTEND-IA— complete ER within 3 hours of undergoing IVT was indeed very low (4%) in intracranial carotid occlusion, but substantial in M1 and M2 occlusions (21% and 38%, respectively) . These figures were recently confirmed in a large prospective study, even when recanalization was evaluated 60 minutes after IVT …”

“…Early recanalization rates depend on the amount of time that has elapsed since IVT . Thus, ER rates are expected to be lower in the case of direct admissions to comprehensive stroke centers (the “mothership” paradigm) but substantial with the “drip and ship” paradigm, in which IVT-to-angiography times are often less than 60 minutes vs up to 3 hours, respectively.…”

Should Primary Stroke Centers Perform Advanced Imaging?

“…If the duration of transfer (the door-in-door-out plus the transfer time) is long, ischemia may progress to irreversible infarction making reperfusion ineffective or possibly harmful. Alternately, successful reperfusion with intravenous thrombolysis is asymptotically (to an imperfect ceiling of recanalization rates <100%) 33,34 time-dependent resulting in removal of the target occlusion for EVT or an uncommon complication such as intracranial hemorrhage may occur all making the patient no longer a candidate for EVT at arrival at the CSC.…”