Abstract 2722: Anti-hypertensive Treatment Prolongs tPA Door-to-treatment Time: Secondary Analysis Of The Increasing Stroke Treatment Through Interventional Behavior Change Tactics (INSTINCT) Trial.

Abstract

Background/Purpose: Increased time to tPA treatment is associated with worse outcomes. Thus, identifying modifiable treatment delays may improve stroke outcomes. We hypothesized that pre-thrombolytic anti-hypertensive treatment (AHT) may prolong door to treatment time (DTT). Methods: Secondary data analysis of consecutive tPA-treated patients at 24 randomly selected Michigan community hospitals in the INSTINCT trial. DTT among stroke patients who received pre-thrombolytic AHT were compared to those that did not receive pre-thrombolytic AHT. We then calculated a propensity score for the probability of receiving pre-thrombolytic AHT using a logistic regression model with covariates including demographics, stroke risk factors, antiplatelet or beta blocker as home medication, stroke severity (NIHSS), onset to door time, admission glucose, pretreatment systolic and diastolic blood pressure, EMS usage and location at time of stroke. A paired t-test was then performed to compare the DTT between the propensity matched groups. A separate generalized estimating equations (GEE) approach was also used to estimate the differences between patients receiving pre-thrombolytic AHT and those that did not while accounting for within hospital clustering. Results: A total of 557 patients were included in INSTINCT, however onset, arrival or treatment times were not able to be determined in 23, leaving 534 patients for this analysis. The unmatched cohort consisted of 95 stroke patients who received pre-thrombolytic AHT and 439 stroke patients who did not receive AHT from 2007-2010 ( table ). In the unmatched cohort, patients who received pre-thrombolytic AHT had a longer DTT (mean increase 9 minutes; 95% confidence interval (CI) 2-16 minutes) than patients who did not receive pre-thrombolytic AHT. After propensity matching (table), patients who received pre-thrombolytic AHT had a longer DTT (mean increase 10.4 minutes, 95% CI 1.9 - 18.8) than patients who did not receive pre-thrombolytic AHT. This effect persisted and its magnitude was not altered by accounting for clustering within hospitals. Conclusion: Pre-thrombolytic AHT is associated with modest delays in DTT. This represents a feasible target for physician educational interventions and quality improvement initiatives. Further research evaluating optimum hypertension management pre-thrombolytic treatment is warranted.