The evolving risk of sudden cardiac death after heart transplant. An analysis of the ISHLT Thoracic Transplant Registry

Sudden cardiac death (SCD) is responsible for ~10% of post-heart transplant deaths. We conducted a retrospective analysis of the ISHLT registry evaluating the risk of post-transplant SCD. Adult heart transplant recipients (2004-2014) surviving the first year were included. We used multivariable multistate competing risk survival analysis to evaluate the impact of history of treated rejection and cardiac allograft vasculopathy (CAV) on SCD risk. We used a probabilistic analytical model and Monte Carlo simulation to estimate the impact of CAV severity and graft dysfunction on SCD. We included 25 242 recipients. During a median follow-up of 4.7 (2.3-7.0) years, 582 patients died suddenly. Treated rejection (HR 1.76, 95% CI 1.36-2.31) and CAV (HR 3.32, 95% CI 2.73-4.03) were important risk factors for SCD. The estimated SCD risk in patients with severe CAV without and with graft dysfunction was 3.2% (95% CI 2.0-4.6) and 5.4% (95% CI 3.8-7.0), respectively, at 2 years from the CAV diagnosis, and 4.9% (95% CI 3.4-6.5) and 8.0% (95% CI 6.1-10.0), respectively, in those who also had treated rejection. These results provide evidence that recipients with severe CAV and graft dysfunction or treated rejection are at clinically significant increased SCD risk. The benefit of ICD post-transplant remains uncertain.