Editors' note: Comparative safety and efficacy of combined IVT and MT with direct MT in large vessel occlusion

In their multicenter observational study titled “Comparative safety and efficacy of combined IVT and MT with direct MT in large vessel occlusion,” Goyal et al. found that IV thrombolysis (IVT) before mechanical thrombectomy (MT) was associated with higher odds of functional independence at 3 months. Ganesh et al. propose that this may be related to a lower risk of infarction in unrelated vascular territories among patients pretreated with IVT. Further, Ganesh et al. note that an important minority of patients selected for thrombectomy may not achieve successful recanalization; therefore IVT may be the only chance to facilitate reperfusion. LeCouffe et al.—who represent the Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands (MR CLEAN)–NO IV Investigators and are prospectively evaluating the benefit of IVT before MT—address the importance of blood pressure and coagulopathy as confounders. These unmeasured variables might have influenced the propensity matching in this investigation. In response to these comments, Goyal et al. acknowledge the limitations of observational studies where unmeasured, but important, clinical variables may not be captured during data acquisition. Ultimately, the superiority of combination IVT + MT over MT alone may not be confirmed until the results of ongoing prospective clinical trials are published.