Mechanical Thrombectomy After Intravenous Thrombolysis Vs Mechanical Thrombectomy Alone In Acute Stroke.
Published 2017 · Medicine
Mechanical Thrombectomy After Intravenous Thrombolysis vs Mechanical Thrombectomy Alone in Acute Stroke To the Editor In their recent article, Coutinho et al1 address whether patients who have had an acute stroke with proximal occlusion should undergo intravenous thrombolysis (IVT) before a mechanical thrombectomy (MT). In this analysis of pooled data from the SWIFT and STAR trials, MT after IVT did not appear to provide clinical benefits over MT alone. The authors concluded that randomized clinical trials should confirm their observation.1 The main reason for withholding IVT would be that the occurrence of early recanalization (ER) after IVT is too low to justify the additional hemorrhagic risk, cost, and time lost. However, the SWIFT and STAR trials were not designed to compare these 2 paradigms, as in both trials persistent proximal occlusion on the first angiographic run was an inclusion criterion.2,3 To address this shortcoming, Coutinho et al1 argue that ER following IVT is rare in proximal occlusions. Based on the ESCAPE, SWIFT PRIME, REVASCAT, and MR CLEAN trial data, they quote post-IVT recanalization rates of 3% to 7% on the first angiographic run. However, this is an underestimation, because in these trials, patient selection was based on vascular imaging that was mostly conducted after the start of IVT. Thus, an unknown fraction of patients with post-IVT ER before selection imaging were excluded a priori. 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—4 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).4 These figures were recently confirmed in a large prospective study, even when recanalization was evaluated 60 minutes after IVT.5 Early recanalization rates depend on the amount of time that has elapsed since IVT.5 Thus, ER rates are expected to be lower in the case of direct admissions to comprehensive stroke “drip and ship” paradigm, in which IVT-to-angiography times are often less than 60 minutes vs up to 3 hours, respectively. Consequently, the results of Coutinho et al1 may approximate the former, but they cannot be translated to the latter paradigm, which is the most frequent day-to-day situation currently and will likely remain so in most countries. We concur with Coutinho et al1 that randomized clinical trials comparing MT after IVT with MT alone are needed. However, given the substantial ER rates among unselected populations, such trials should only include patients with a very low probability of developing IVT-related ER.