Abstract TMP81: Nationally Representative Estimates of Readmission Rates After Extracranial-Intracranial Bypass Surgery for Moyamoya Disease

Abstract

Background: International trials have suggested benefit of extracranial- intracranial bypass (ECICB) for Moyamoya disease (MMD). However, nationally representative US data on demographics and adverse outcomes after ECICB in MMD are lacking. We aimed to estimate nationally representative 30, 60 and 90-day readmission rates for ischemic stroke (IS), subarachnoid hemorrhage (SAH) and intracerebral hemorrhage (ICH) after an index admission for MMD with ECICB. Methods: The Nationwide Readmissions Database contains data on >14 million discharges for all payers and the uninsured in 2013. Index admissions for ECICB for MMD, and readmissions for IS, SAH, and ICH, were identified using validated International Classification of Diseases, 9th Revision, Clinical Modification codes. We summarized demographics, comorbidities, and the Charlson Comorbidity Index (CCI) during the index admission, and calculated 30-, 60-, and 90-day readmission rates per 100,000 index admissions. Preventable causes of admission were determined by Prevention Quality Indicators. Results: Among 201 index admissions for ECICB for MMD, mean age (SD) was 41.7 (12.6) years; 75% were female; 24% had diabetes; 53% had hypertension; 40% had hypercholesterolemia; and mean CCI (SD) was 3.2 (1.5). For concurrent or previous cerebrovascular events, 3% had ICH; 16% had IS; and 1% had SAH. ECICB was performed at large hospitals in 83%, urban hospitals in 85%, and teaching hospitals in 97%. 80% were discharged home. 1% died during index hospitalization. 34% had a readmission during follow-up, 3% of which were preventable. Leading reasons for readmission up to 90 days included MMD (62%), postoperative infection (10%), sickle cell crisis (4%), ischemic stroke (4%), epilepsy (2%), subdural hemorrhage (2%) and headache (2%). Readmission rates (per 100,000 index admissions) were 559 at 30 days, 1829 at 60 days, and 2027 at 90 days for IS. There were no readmissions for SAH or ICH. Conclusions: This analysis of nationally representative US data suggests that although readmission after ECICB for MMD is not uncommon, cerebral hemorrhagic events during the 90-day postoperative period are rare. Readmission for ischemic stroke, in comparison, is more prevalent, and only 3% of readmissions were preventable.