Abstract WP47: Combined Treatment of Rt-PA With Mechanical Thrombectomy is Associated With Better Outcome Than Mechanical Thrombectomy Alone and Possibly Underutilized - A National Inpatient Sample Study

Abstract

Background and Purpose: 2015 AHA/ASA guidelines recommend mechanical thrombectomy (MT) with rt-PA for eligible patients within 6 hours of acute ischemic stroke (AIS). We evaluated the real world impact of the guidelines by analyzing trends and outcomes of stroke patients discharged from 2012 to 2016 in National Inpatient Sample database. Methods: Patients discharged with primary diagnosis of AIS were identified with ICD-9 codes for 2012 to third quarter of 2015 and ICD-10 codes for 2016 and last quarter of 2015. Patients who received only rt-PA, only MT, rt-PA+MT or no treatment were analyzed for discharge outcomes including length of stay (LOS), inpatient mortality and discharge status to home. Survey procedures were used for analysis. Multivariable regression analysis with pairwise comparison of treatment groups with no treatment group was performed to evaluate outcomes controlling for risk factors and all patient refined DRG severity of illness and risk of mortality scores. Results: A total of 2,290,520 adult AIS patients were in the study with mean age 70.4 years (SE 0.03) and 51.1% (SE 0.08) women. There was a significant increase in treatment with rt-PA (5.86% in 2012 to 7.67% in 2016, OR=1.07, 95% CI 1.05-1.08); and MT (0.55% in 2012 to 1.75% in 2016, OR=1.38, 95%CI 1.31-1.45); but not combination rt-PA+MT (0.54% in 2012 to 0.57% in 2016, OR=1.04, 95% CI 0.99 - 1.08). LOS was significantly reduced for rt-PA (mean 6.07 days in 2012 to 4.91 days in 2016, p<0.0001, 1.7 percent reduction/year), and rt-PA+MT (mean 9.19 days in 2012 to 7.10 days in 2016, p=0.0067, 2.9 percent reduction/year) but not for MT alone (9.61 days in 2012 to 8.51 days in 2016, p=0.50). The odds of patients discharged home was significantly higher by 8%, 9% and 15% among patients who received rt-PA (p<0.0001), MT (p=0.0095) and rt-PA+MT group (p=0.0004), respectively, compared to those who did not receive treatment. There was no significant change in inpatient mortality between the groups. Conclusion: The utilization of MT increased but that of rt-PA+MT remained unchanged from 2012 to 2016. Patients with AIS have better LOS and discharge disposition to home when treated with rt-PA+MT than MT alone. Combined treatment of rt-PA with MT may be underutilized in clinical practice.