Direct thrombectomy versus bridging thrombolysis with mechanical thrombectomy in middle cerebral artery stroke: a real-world analysis through National Inpatient Sample data
Authors: Kandregula Sandeep , Savardekar Amey R. , Sharma Pankaj , McLarty Jerry , Kosty Jennifer , Trosclair Krystle , Cuellar Hugo , Guthikonda Bharat 
Published: July 2021

OBJECTIVE
A paradigm shift in the management of acute ischemic stroke (AIS) due to large-vessel occlusion (LVO) occurred after 2015 when 7 randomized controlled trials demonstrated better outcomes using second-generation thrombectomy devices combined with best medical management than did stand-alone intravenous thrombolysis (IVT) with tissue plasminogen activator (tPA). All recently published landmark trials were designed to study the outcome of mechanical thrombectomy (MT); therefore, the majority of the patients enrolled in these trials received intravenous tPA. Currently, initiating IVT before MT is a matter of debate. Recent trials (DIRECT-MT, DEVT) exploring this clinical question showed noninferiority of MT alone compared with the combined treatment. With this uncertainty, the authors aimed to explore real-world data through the latest National Inpatient Sample (NIS) to compare the safety and outcomes of MT alone with bridging IVT and MT in AIS due to LVO in the middle cerebral artery (MCA).

METHODS
NIS data from 2017 to 2018 were analyzed to compare the outcomes and safety profiles of patients who underwent MT+IVT with those who underwent MT alone.

RESULTS
A total of 2895 patients were included in the final analysis (MT, n = 1669; MT+IVT, n = 1226). The mean National Institutes of Health Stroke Scale score was 16.2 (SD 6.1) in the MT group and 16.6 (SD 5.97) in the MT+IVT group (p = 0.04). With respect to comorbidities, the two groups did not differ in rates of hypertension (p = 0.730), atrial fibrillation/flutter (p = 0.828), and smoking status (p = 0.914). The rate of diabetes mellitus was significantly higher in the MT group (28%) than in the MT+IVT group (22.1%) (p < 0.001). The frequency of intracerebral hemorrhage (ICH) in the MT group was 17.7% (n = 296) and 21.5% (n = 263) in the MT+IVT group (p = 0.012). Intraventricular hemorrhage (p = 0.875), subarachnoid hemorrhage (p = 0.99), and vasospasm (p = 0.976) did not differ significantly between the groups. The primary outcome considered was disability status between the groups; 23.8% of patients in the MT+IVT group had minimal disability versus 18.2% in the MT group (p = 0.001). The risk of progressing to severe disability from minimal disability decreased with the addition of IVT to MT (OR 0.762, 95% CI 0.637–0.912). The adjusted odds ratio for ICH in the MT+IVT group was 1.28 (95% CI 1.043–1.571, p = 0.018) and 2.676 (95% CI 1.259–5.686, p = 0.01) for access-site hemorrhages.

CONCLUSIONS
In the analysis of the NIS database, the MT+IVT group had significantly higher rates of minimal disability at the time of hospital discharge versus the MT-alone group, despite a higher rate of ICH. The question of whether to treat patients with MT+IVT rather than MT alone is currently being addressed in ongoing prospective clinical trials (SWIFT-DIRECT [NCT03494920], MR CLEAN–NO IV [ISRCTN80619088], and DIRECT-SAFE [NCT03494920]). The results of these studies will contribute to greater understanding and progressive improvement in outcomes for AIS patients.