Abstract TP36: Medical Specialty and Training of Physicians Performing Mechanical Thrombectomy for Acute Ischemic Stroke in the U.S

Abstract

Introduction: We sought to determine the medical specialty and training of U.S. physicians who perform mechanical thrombectomy for stroke. Methods: We analyzed claims between 2009-2015 from a 5% nationally representative sample of Medicare beneficiaries ≥65 years of age. Validated ICD-9-CM diagnosis codes were used to identify hospitalizations for acute ischemic stroke. Mechanical thrombectomy was defined as a physician claim with CPT code 37184 and an accompanying diagnosis of cerebrovascular disease. Medical specialty was identified using the claim’s Medicare provider specialty code. We reviewed public online profiles to ascertain providers’ residency and fellowship training. Statistical analysis involved chi-square tests and kappa statistics. Results: During 77,774 stroke hospitalizations, we identified 555 thrombectomies, of which 341 (61.4%; 95% CI, 57.2-65.5%) were performed by radiologists, 110 (19.8%; 95% CI, 16.6-23.4%) by neurologists, 91 (16.4%; 95% CI, 13.4-19.7%) by neurosurgeons, and 13 (2.3%; 95% CI, 1.3-4.0%) by others such as cardiologists and vascular surgeons. Of the 555 procedures, 367 (66.1%; 95% CI, 62.0-70.1%) were performed by a physician who had completed a dedicated neurointerventional fellowship. There was excellent agreement (91.4%; kappa, 0.86) between Medicare specialty designations and the online profiles of the 350 physicians who performed these 555 procedures. The rate of mechanical thrombectomy rose from 0.62% (95% CI, 0.56-0.68%) before publication of the MR CLEAN trial to 1.45% (95% CI, 1.21-1.72%) after, but there was no significant change after its publication in the distribution of providers’ specialties or the proportion of procedures performed by those with neurointerventional fellowship training (Figure). Conclusions: Most mechanical thrombectomies for stroke in the U.S. are performed by radiologists, neurologists, and neurosurgeons with dedicated neurointerventional fellowship training.