Abstract WP029: Extending Intravenous Tenecteplase Beyond 4.5-hour in a Community-based Cohort Study

Background: Clinical trial data suggest that treating patients presenting as wake-up stroke or in the 4.5 to 9-hour window from last seen normal (LSN) who meet advanced neuroimaging criteria with intravenous thrombolytic may lead to better functional outcome. We conducted a pilot to assess the logistics of screening and treating these patients with tenecteplase (TNKase) in a large integrated community healthcare system. Methods: Kaiser Permanente Northern California consists of 19 certified primary stroke centers and 2 comprehensive stroke centers serving 4.6+ million members. The region has a standardized Telestroke program that includes video evaluation by a teleneurologist. From 6/1/2023 to 3/31/2025, teleneurologists screened all non-cancelled stroke alerts who met clinical criteria (presenting as wake-up stroke or in the 4.5 to 9-hour window and had baseline mRS 0-2 and NIHSS ≥ 6) with advanced neuroimaging. Those who met advanced neuroimaging criteria (mismatch ratio >1.2, mismatch volume >10mL, and ischemic core volume <70mL) and did not have endovascular therapy (EVT) were treated with intravenous TNKase. Assessments included demographics, neuroimaging, treatment time, and outcomes. Results: During the 21-month study period, 13,634 stroke alerts were seen in the extended window, of which 726 met clinical criteria and had further workup. The final study cohort included 449 patients who had no bleed on head CT and did not need EVT. Of these, 24 (5.3%) were treated with TNKase Figure. Among those treated, 14 (58.3%) were wake-up strokes. TNKase-treated patients were more likely to be walk-in stroke (25% vs. 11.6%; p=0.05), had a longer time from LSN to ED arrival (8.7 hours vs. 6.0 hours; p<0.001) and lower initial NIHSS Table 1. Inpatient (0% vs. 8%; p=0.15) and 90-day mortality (4.2% vs. 16.2%; p=0.11) were suggestively less for those treated with TNKase Table 2. One (4.3%) treated patient had a symptomatic intracranial hemorrhage (sICH). For 90-day mRS score among those treated, there were 8 missing and 25% (95% CI: 7.3-52.4) with mRS 0-2. Conclusions: In a 21-month period, relatively few patients presenting as wake-up stroke or in the 4.5 to 9-hour window met all clinical and advanced neuroimaging criteria to receive TNKase in a large integrated healthcare system. Rates of sICH and 90-day mortality were low. Additional studies are needed to understand the cost-effectiveness of screening and treating this population in the extended window.