Stroke Risk and Mortality With Ventricular Assist Devices
What are the incidence, risk factors, and outcomes for ischemic and hemorrhagic strokes after ventricular assist device (VAD) placement?
The study authors used administrative claims data from acute care hospitals in California, Florida, and New York (which comprise ~25% of the US population) from 2005 to 2013, to identify patients who underwent durable continuous flow LVAD placement. They also identified ischemic (using an algorithm that was 86% sensitive and 95% specific) and hemorrhagic strokes (using an algorithm that was 82% sensitive and 93% specific for intracranial hemorrhage and 98% sensitive and 92% specific for subarachnoid hemorrhage) in this cohort. They used survival statistics to determine the incidence rates and Cox proportional hazard analyses to examine the associations. They excluded patients with a documented stroke before the index visit for VAD placement.
The study authors identified 1,813 VAD patients. The mean age of the patients was 56.1 (±13.1) years, and they were predominantly men (79.8%). In this cohort, they identified 201 ischemic strokes and 116 hemorrhagic strokes during 3.4 (±2.0) years of follow-up after implantation of a VAD. The incidence of stroke was 8.7% per year (95% confidence interval [CI], 7.7–9.7). The annual incidence of ischemic stroke (5.5%; 95% CI, 4.8–6.4) was nearly double that of hemorrhagic stroke (3.1%; 95% CI, 2.6–3.8). By 3 years after VAD placement, this resulted in a cumulative overall stroke rate of 22.2% (95% CI, 19.9–24.7), a cumulative ischemic stroke rate of 14.9% (95% CI, 13.0–17.2%), and a cumulative hemorrhagic stroke rate of 8.6% (95% CI, 7.1–10.4%). Patients who experienced a stroke after VAD implantation were younger and more likely to be women (hazard ratio, 1.6; 95% CI, 1.2–2.1), particularly those with hemorrhagic stroke (hazard ratio, 2.2; 95% CI, 1.4–3.4). Stroke was strongly associated with subsequent in-hospital mortality (hazard ratio, 6.1; 95% CI, 4.6–7.9).
The authors concluded that incidence of stroke in VAD patients was 8.7% per year, and incident stroke was strongly associated with subsequent in-hospital mortality. Ischemic stroke occurred at nearly twice the rate of hemorrhagic stroke and women seemed to face a higher risk for hemorrhagic stroke than men.
As the authors point out, approximately 1 in every 10 patients experienced a stroke each year after VAD implantation when compared to gastrointestinal hemorrhage of approximately 10% per year and pump thrombosis of 9% at 12 months. The burden of strokes after left VAD (LVAD) is of concern particularly due to the potential devastating effects of a stroke. Managing anticoagulation in VAD patients is a challenge given that pump thrombosis is also a complication of VAD. Although the incidence of hemorrhagic stroke is lower in women in the general population, the higher incidence after a VAD reported in this study is intriguing. This manuscript should prompt investigation into the mechanisms of stroke of both men and women VAD recipients with the aim of identifying modifying risk factors for stroke.
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