Abstract Number ‐ 145: Impact of Landmark Trials on Intracranial Stenting Utilization for Intracranial Atherosclerotic Disease in the US
Authors: Otite Fadar O , Patel Smit , Hoffman Haydn , Hassan Ameer , Zaidat Osama O , Ortega‐Gutierrez Santiago , Yavagal Dileep , Khandelwal Priyank 
Published: April 2023

Introduction
The Stenting versus Aggressive Medical Therapy for Intracranial Arterial Stenosis (SAMMPRIS) trial published in 2010 showed aggressive medical therapy is superior to percutaneous transluminal angioplasty and stenting (PTAS) for intracranial atherosclerotic disease (ICAD). Following the pivotal positive mechanical thrombectomy (MT) trials in 2015, MT utilization in the United States (US) has increased. Rescue ICAD stenting may be needed in MT patients with underlying ICAD but it remains uncertain whether PTAS use for ICAD has changed over this time. The aim of this study is to describe national trends in the utilization of PTAS for ICAD in the US before and after SAMMPRIS and following the pivotal MT trials.

Methods
We used a constellation of International Classification of Diseases ninth and tenth revision diagnostic/procedural codes to identify all elective and non‐elective adult (> = 18 years) ICAD admissions with or without infarction containing concomitant codes for PTAS in the 2007–2019 National Inpatient Sample. Admissions containing codes for subarachnoid hemorrhage, unruptured intracranial aneurysms or benign intracranial hypertension were excluded. We combined weighted counts of PTAS admissions with annual US adult census data to obtain prevalence of PTAS. We used joinpoint regression to evaluate trends in PTAS use over time.

Results
Across the study period, there were 16,477 weighted admissions for ICAD undergoing PTAS in the US. 52.4% of these admissions were in patients 60–79years and 43.2% were in women. 74.3% of these admissions were non‐elective and this proportion increased over time (P = 0.019). 26.5% of all admissions had concurrent codes for MT but this proportion increased by almost ten‐fold over time from 4.3% in 2007 to 40.0% in 2019. On join point regression, PTAS utilization increased but insignificantly from 3.0/million population in 2007 to 5.7/million population in 2010 (Annualized percentage change, APC 11.2%, 95%CI ‐11.8 to 40.3, p = 0.290), declined also insignificantly from 2010–2013 (APC ‐13.2, 95%CI ‐48.4 to 45.8, p = 0.514) and increased significantly from 3.55/million in 2013 to 3.80/million in 2014 and exponentially across the rest of the period to 8.4 cases/million in 2019 (APC 15.4, 95%CI 9.2 to 22.0, p = 0.001). Upon stratification by admission type, most of the increase across the period 2013/2014 to 2019 occurred in non‐elective admissions (Figure 1). Utilization in elective admissions varied from 0.92 to 1.96 cases per million population but this did not change significantly across the study period.

Conclusions
PTAS utilization for ICAD declined in the US after SAMMPRIS but has increased following publication of pivotal MT trials mainly in non‐elective admissions. PTAS utilization increased significantly following publication of pivotal MT trials likely in ICAD patients who required rescue stenting.. Additional prospective studies are needed to determine the long‐term outcomes of concurrent PTAS and MT as this is not a group of patients that was studied in SAMMPRIS.