Stroke and death risk in ventricular assist device patients varies by ISHLT infection category: An INTERMACS analysis

Abstract

Background: Ventricular assist device (VAD) patients often experience infections, which increase the risk of stroke and mortality. Using the definitions of the International Society for Heart and Lung Transplantation (ISHLT), we have characterized differences in clinical outcomes for categories of infection: VAD-specific (e.g., pump component related); VAD-related (e.g., bloodstream infection, BSI); and non-VAD infections (e.g., pneumonia).

Methods: Querying of the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) identified 16,597 continuous-flow VAD recipients. Categories of infection were tested in multivariate models to determine the risk of stroke and death.

Results: After implant, 7,046 patients (42%) developed an infection at a median of 69 (interquartile range 12 to 272) days. A majority were non-VAD infections (49%), followed by VAD-related (26%) and VAD-specific infections (25%). BSIs were the most common form of VAD-related infection (92%), and the majority (59%) had no associated infection, that is, idiopathic bacteremia. Internal pump component infections were rare (0.003 event per patient-year [EPPY]). Infected VAD patients had a higher prevalence of stroke compared to patients without an infection (18% vs 11%, p < 0.001). The lowest stroke rate occurred after a VAD-specific infection (0.11 EPPY) compared with VAD-related (0.17 EPPY) and non-VAD infections (0.15 EPPY, p < 0.001). Hemorrhagic strokes were more common than ischemic strokes in all infection groups and highest after a VAD-related infection (0.13 EPPY). One-year survival after an infection was 87% in VAD-specific infections, as compared with VAD-related (71%) and non-VAD infections (72%, p < 0.001).

Conclusions: The ISHLT categorization of VAD infections unveils notable differences in associated risk of stroke and mortality. A re-assessment of transplant prioritization for eligible infected VAD patients may be useful to increase transplant-related survival benefit.

Keywords: cardiac transplantation; heart failure; infection; stroke; ventricular assist device.