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The International Consortium on Primary Graft Dysfunction: Redefining Clinical Risk Factors in the Contemporary Era
Y Moayedi1, L K Truby2, F Foroutan1
1Ted Rogers Centre for Heart Research, University of Toronto, Toronto, Ontario, Canada.
Insights
Primary graft dysfunction (PGD) after heart transplantation is increasing. Preoperative dialysis, LVAD support, and longer ischemic times are key risk factors for severe PGD, impacting survival.
Area of Science:
- Cardiology
- Transplantation Medicine
- Immunology
Background:
- Primary graft dysfunction (PGD) is a major cause of early morbidity and mortality following heart transplantation (HT).
- The International Consortium on PGD aims to identify contemporary clinical risk factors for PGD.
- This study assesses PGD incidence, evaluates the RADIAL score, and redefines risk factors in current HT practices.
Purpose of the Study:
- To assess the incidence of severe PGD in an international heart transplant cohort.
- To evaluate the performance of the RADIAL score in predicting severe PGD.
- To identify and redefine contemporary clinical risk factors for severe PGD.
Main Methods:
- Retrospective, observational study of 2746 adult HT recipients from 2010-2020 across 10 international centers.
- Comparison of patients with severe PGD versus those without severe PGD.
- Multivariable mixed-effects logistic regression to identify risk factors, accounting for center variability.
Main Results:
- Severe PGD occurred in 7.8% of patients, with an increasing incidence over the study period.
- The RADIAL score demonstrated poor performance (AUC 0.53) in this contemporary cohort.
- Acute preoperative dialysis, durable LVAD support, and total ischemic time were associated with increased severe PGD risk.
Conclusions:
- The incidence of PGD is rising in the modern heart transplant era.
- Contemporary risk factors for severe PGD have been identified, highlighting significant mortality risk.
- These findings can inform management strategies to identify and mitigate PGD risk in high-risk patients.
Background:
Primary graft dysfunction (PGD) is the leading cause of morbidity and mortality early after heart transplantation (HT). The International Consortium on PGD is a multicenter collaboration dedicated to identifying the clinical risk factors for PGD in the contemporary era of HT. The objectives of the current report were (1) to assess the incidence of severe PGD in an international cohort; (2) to evaluate the performance of the most strongly validated PGD risk tool, the RADIAL score, in a contemporary cohort; and (3) to redefine clinical risk factors for severe PGD in the current era of HT.
Methods:
This is a retrospective, observational study of consecutive adult HT recipients between 2010 and 2020 in 10 centers in the United States, Canada and Europe. Patients with severe PGD were compared to those without severe PGD (comprising those with no, mild and moderate PGD). The RADIAL score was calculated for each transplant recipient. The discriminatory power of the RADIAL score was evaluated using receiver operating characteristic (ROC) analysis, and its calibration was assessed by plotting the percentage of PGD predicted vs that which was observed. To identify clinical risk factors associated with severe PGD, we performed multivariable mixed-effects logistic regression modeling to account for among-center variability.
Results:
A total of 2746 patients have been enrolled in the registry to date, including 2015 (73.4%) from North America, and 731 (26.6%) from Europe; 215 participants (7.8%) met the criteria for severe PGD. There was an increase in the incidence of severe PGD over the study period (P value for trend by difference sign test = 0.004). The Kaplan-Meier estimate for 1-year survival was 75.7% (95% CI 69.4-80.9%) in patients with severe PGD as compared to 94.4% (95% CI 93.5-95.2%) in those without severe PGD (log-rank P value < 0.001). The RADIAL score performed poorly in our contemporary cohort and was not associated with severe PGD; it had an AUC of 0.53 (95% CI 0.48-0.58). In the multivariable regression model, acute preoperative dialysis (OR 2.41, 95% CI 1.31-4.43), durable left ventricular assist device support (OR 1.77, 95% CI 1.13-2.77), and total ischemic time (OR 1.20 for each additional hour, 95% CI 1.02-1.41) were associated with an increased risk of severe PGD.
Conclusions:
Our consortium has identified an increasing incidence of PGD in the modern transplant era. We identified contemporary risk factors for this early post-transplant complication, which confers a high mortality risk. These results may enable the identification of patients at high risk for developing severe PGD in order to inform peri-transplant donor and recipient management practices.
