Validation of the International Society for Heart and Lung Transplantation primary graft dysfunction instrument in heart transplantation

Background: In 2014, the International Society for Heart and Lung Transplantation (ISHLT) developed a classification instrument for left ventricular (LV) and isolated right ventricular (RV) primary graft dysfunction post‒heart transplant. The instrument classifies LV-PGD as mild, moderate, or severe. In this study, we evaluated the predictive validity of this instrument.

Methods: We conducted a cohort study of 412 consecutive patients transplanted between 2004 and 2015 at the Toronto General Hospital and Ottawa Heart Institute (Canada). We classified LV-PGD as mild, moderate, or severe, using the ISHLT instrument. To assess predictive validity, we evaluated the association between LV-PGD severity and 1-year post-transplant mortality using a Cox regression model adjusted for recipient age.

Results: The cohort was predominantly male (71%), mean age 50 ± 13 years, mean donor age 38 ± 14 years, with 25% female donors. Mean ischemic time was 3.7 ± 1.1 hours. LV-PGD was mild in 3.6% of patients, moderate in 9.5%, and severe in 3.9%. All levels of LV-PGD were associated with increased 1-year mortality, with a gradient in the association between mild, moderate, and severe. We only observed a statistically significant association for moderate and severe forms of LV-PGD (mild: hazard ratio [HR] 2.4, 95% confidence interval [CI] 0.6 to 10.2; moderate: HR 7.0, 95% CI 3.4 to 14.6; severe: HR 15.9, 95% CI 7.2 to 35.0).

Conclusions: The ISHLT LV-PGD classification convincingly identifies a substantial increase in the risk of death at 1 year, and an increased gradient of risk, in those with moderate or severe LV-PGD.