The Importance of Cold and Warm Cardiac Ischemia for Survival After Heart Transplantation

Abstract

Ischemia time is a risk factor for mortality after heart transplantation that can be influenced by organizational factors such as transport arrangements and organ allocation. We used the United Kingdom Cardiothoracic Transplant Audit database to analyze the outcome of 1491 first isolated orthotopic adult heart transplants performed between April 1995 and March 2004. Ischemia time and its components (transport time and surgical implant time) were related to 30-day mortality using a multivariable logistic regression model. The median total ischemia time increased from 171 min (interquartile range: 149-198) to 213 min (interquartile range: 181-256) during the study period (P<0.0001). This was due to an increase in transport times that was partly explained by increased organ exchange between centers and also because of an increase in surgical implant times. Thirty-day survival decreased over the study period (91%-84%) with some evidence of a linear trend towards decreasing survival over time (P=0.089). After correcting for other known risk factors, the odds ratio of death within 30 days associated with each 15 min increment in transport time was 1.06 (95% confidence interval: 1.01-1.12) and with each 15 min increment in surgical implant time was 1.11 (95% confidence interval: 1.04-1.18). Both transport and implant times were directly related to 30-day mortality after heart transplantation. Ischemia time should be considered in organ allocation and controlled during the heart transplant procedure.