Abstract DP379: Potential Missed Opportunities to Administer Intravenous Thrombolysis to Patients with Acute Ischemic Stroke

Introduction: Prior studies reported that up to 40% of patients arriving to the hospital within 4.5 hours of acute ischemic stroke (AIS) do not receive intravenous thrombolysis (IVT) despite no exclusions. The top reasons for withholding IVT were mild or resolving symptoms, yet 10-20% of these patients were disabled at 3 months. In recent years, there have been improvements in stroke-care pathways, including mobile stroke units (MSUs) which represent an idealized stroke-care system. These interventions may have affected the rate, predictors, and outcomes of AIS patients not treated with IVT. Methods: This was a secondary analysis of the prospective, multicenter BEST-MSU trial comparing MSU care vs standard emergency department (ED) management in IVT-eligible suspected AIS patients. The analytical cohort comprised enrolled patients in either the MSU or ED group with no contraindications to IVT and confirmed AIS. The outcome was a potential missed opportunity to administer IVT, defined as patients not treated with IVT despite lacking contraindications. Logistic regression models evaluated whether demographics, prestroke modified Rankin Scale (mRS), study site, comorbidities, MSU care, NIHSS, blood pressure, INR, glucose, prior antithrombotic use, and thrombectomy were associated with the outcome. Results: From 2014-2020, of 1,515 enrolled patients, 927 met criteria for this analysis. Median age was 67 (IQR, 57-79) years; 477 (52%) were men. Fifty-one participants (5.5%) had a potential missed IVT opportunity, including 4 of 555 (0.7%) in the MSU group vs 47 of 372 (12.6%) in the ED group (OR, 0.05; 95% CI, 0.02-0.12). In multivariable analysis omitting study group, factors independently associated with a potential missed IVT opportunity included baseline lower NIHSS (OR, 0.95; 95% CI, 0.90-0.99) and longer LKW-to-door time (OR, 1.01; 95% CI, 1.00-1.01). The leading reasons posited by treating practitioners for withholding IVT were resolving symptoms (n=22, 43%), time window concerns (n=9, 18%), and minor deficits (n=5, 10%). Among participants with a potential missed IVT opportunity, 19 (37%) had a 3-month mRS score of 3-6 and 27 (53%) had a worse mRS than before their stroke. Conclusion: In modern times, at large centers, potential missed IVT opportunities occurred in one-in-eight patients in the ED, and rarely on the MSU. Although often due to early neurological improvement or minor deficits, more than one-third of patients were disabled at 3-months.