The International Consortium on Primary Graft Dysfunction: Redefining Clinical Risk Factors in the Contemporary Era of Heart Transplantation

BACKGROUND

Primary Graft Dysfunction (PGD) is the leading cause of morbidity and mortality early after heart transplant (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 to 1) assess the incidence of severe PGD in an international cohort, 2) evaluate the performance of the most validated PGD risk tool, the RADIAL score, in a contemporary cohort, and 3) 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 versus 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 2,746 patients have been enrolled in the registry to date, including 2,015 (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 with 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 LVAD 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.

Severe and Moderate Primary Graft Dysfunction in Adult Heart Recipients

INTRODUCTION

The aims of this study were to determine the incidence of severe and moderate primary graft dysfunction (PGD) in our center, to identify, retrospectively, donors' and recipients' risk factors for PGD development, and to evaluate the impact of PGD within 30 days after heart transplantation.

METHODS

Donors' and recipients' medical records of 64 consecutive adult cardiac transplantations performed between January 2016 and June 2017 were reviewed. The International Society for Heart and Lung Transplantation (ISHLT) criteria were used to diagnose moderate and severe PGD. Associations of risk factors for combined moderate/severe PGD were assessed with appropriate statistical analyses.

RESULTS

Sixty-four patients underwent heart transplantation in this period. Twelve recipients (18.7%) developed severe or moderate PGD. Development of PGD was associated with previous donor cardiopulmonary resuscitation and a history of prior heart surgery in the recipient (P=0.01 and P=0.02, respectively). The 30-day in hospital mortality was similar in both PGD and non-PGD patients.

CONCLUSION

The use of the ISHLT criteria for PGD is important to identify potential risk factor. The development of PGD did not affect short-term survival in our study. More studies should be done to better understand the pathophysiology of PGD.

Heavy alcohol use in lung donors increases the risk for primary graft dysfunction

BACKGROUND

Heavy alcohol use is known to increase the risk of acute lung injury and the acute respiratory distress syndrome. This is in part due to increased production of reactive oxygen species. We hypothesized that recipients of lungs from heavy drinkers would be more susceptible to lung injury following transplantation.

METHODS

In this retrospective cohort study, donor histories and transplant outcomes were reviewed in 192 consecutive lung transplant recipients. Donors were classified as No Alcohol Use, Moderate Alcohol Use, or Heavy Alcohol Use based on documented donor histories.

RESULTS

Freedom from mechanical ventilation took longer in the lung transplant recipients whose donors had Heavy Alcohol Use, compared with those whose donors had No Alcohol Use or Moderate Alcohol Use (p = 0.01). At admission to the intensive care unit, the Heavy Alcohol Use group had median PaO2 /FiO2 ratio 219 (interquartile range [IQR]: 162 to 382), compared with 305 (IQR: 232 to 400) in the Moderate Alcohol Use group and 314 (IQR: 249 to 418) in the No Alcohol Use group (p = 0.005). The odds of developing severe primary graft dysfunction (PGD) in the Heavy Alcohol Use group versus the No Alcohol Use group were 8.7 times greater (95% confidence interval 1.427 to 53.404, p = 0.019) after controlling for factors known to be associated with PGD.

CONCLUSIONS

Recipients of donors with a heavy alcohol use history had an over 8 times greater risk of developing severe PGD following lung transplant. The increase in PGD resulted in poorer gas exchange in the recipients of donor lungs from heavy alcohol users, and these recipients subsequently required mechanical ventilation for a longer time following transplant. Further investigation into lung donors with heavy alcohol use histories is necessary to determine those at highest risk for PGD following transplant.