Acute Kidney Injury After Heart Transplant: The Importance of Pulmonary Hypertension

Objective: To determine whether relative pulmonary hypertension (PH), defined as the ratio of mean arterial pressure to mean pulmonary artery pressure, is associated with severe acute kidney injury (AKI) after heart transplant (HT).

Design: An institutional review board-approved retrospective observational study.

Setting: Tertiary care university hospital.

Participants: A total of 184 consecutive adult patients who underwent HT between January 2009 and December 2017 were included, and were followed up through December 2019. Using the Kidney Disease: Improving Global Outcomes classification, recipients were categorized into two groups: patients who developed stage 3 AKI (severe AKI) and those with minor or without AKI (nonsevere AKI) within seven days after transplant.

Interventions: None.

Measurements and main results: Of the included patients, 83.2% developed AKI, in whom 40.8%, 19.6%, and 22.8% were stage 1, 2, and 3, respectively. With use of the multivariate logistic regression analysis, independent risk factors for stage 3 AKI post-HT included preoperative relative PH (odds ratio [OR]: 1.62, 95% confidence interval [95% CI]: 1.05-2.49, p = 0.028), central venous-to-pulmonary capillary wedge pressure ratio ≥0.86 (OR: 3.59, 95% CI: 1.13-11.43, p = 0.030), and postoperative right ventricular dysfunction (OR: 3.63, 95% CI: 1.50-8.75, p = 0.004). Conversely, preoperative estimated glomerular filtration rate (OR: 0.99, 95% CI: 0.97-1.00, p = 0.143) was not related to the development of stage 3 AKI post-HT.

Conclusions: Preoperative relative PH, central venous-to-pulmonary capillary wedge pressure ratio, and postoperative right ventricular failure by echocardiographic assessment were associated with severe AKI post-HT.