Abstract P618: Cardiac Amyloidosis and Risk of Ischemic Stroke
Background and Purpose: Cardiac amyloidosis is increasingly recognized as an important cause of heart failure. Given the paucity of data on cerebrovascular complications of cardiac amyloidosis, we evaluated whether cardiac amyloidosis is associated with ischemic stroke. Methods: We performed a retrospective cohort study of Medicare beneficiaries using a 5% sample of inpatient and outpatient claims from January 1, 2008 through October 1, 2015. We identified patients with cardiac amyloidosis using International Classification of Diseases, 9th Revision, Clinical Modification ( ICD-9-CM ) code 277.3x in combination with a diagnosis code for heart failure or cardiomyopathy. The primary outcome was ischemic stroke, identified by a previously validated ICD-9-CM code algorithm. We used survival statistics to determine incidence rates. Cox proportional hazard analysis, adjusted for demographics, vascular risk factors, and the Elixhauser comorbidity index, was used to study the risk of ischemic stroke. Results: Among 1.8 million beneficiaries with mean follow-up of 4.6 years (standard deviation ±2.2), 454 (0.03%) had a diagnosis of cardiac amyloidosis. Patients with cardiac amyloidosis were older (78.1±7.4 versus 73.4±7.7 years) and had a greater comorbidity burden than those without the diagnosis. A total of 63,627 (3.6%) developed an ischemic stroke in the entire cohort. The incidence of ischemic stroke was 47 per 1,000 patients per year in those with cardiac amyloidosis compared to 7.8 per 1,000 patients per year in those without cardiac amyloidosis. In the adjusted Cox regression analysis, cardiac amyloidosis was associated with an increased risk of ischemic stroke (HR, 2.4; 95% confidence interval, 1.6-3.6). Conclusions: In a large heterogenous cohort of elderly patients, cardiac amyloidosis was associated with a 2.5-fold heightened risk of ischemic stroke.