Outcomes After Lung or Combined Heart Lung Transplantation for PAH and CTEPH According to Baseline Kidney Function

Abstract

<h3>Purpose</h3> Decreased renal function is often considered as a contraindication for lung (LTX) or combined heart-lung (HLTX) transplantation due to poorer prognosis and risk of further decline due to nephrotoxic medication. Severe pulmonary hypertension (PH) may decrease renal function because of low cardiac output and renal congestion, which may be reversible with transplantation. We aimed to assess whether pre-transplant kidney function is a predictor for mortality or need for renal replacement therapy (RRT) and evaluated the evolution of renal function after LTX or HLTX in PH patients. <h3>Methods</h3> We conducted a retrospective study in 68 consecutive patients diagnosed with PAH, chronic thromboembolic pulmonary hypertension (CTEPH) or PAH due to congenital heart disease who had undergone LTX or HLTX in our center between 1996 and 2019. 3 year survival according to pre-transplant kidney function was evaluated using the Kaplan-Meier method and by log-rank test. The evolution of eGFR according to pre-transplant kidney function was evaluated using mixed model effect test. Predictors of the need for RRT in the first 90 days and mortality after 1 year were identified by univariate analysis. <h3>Results</h3> 35 of 68 patients had an abnormal pre-transplant creatinine (cut off >1.15mg/dL for males, >0.95mg/dL for females). eGFR range was 38-121 ml/min/1.73m². 3 year survival was similar in both groups (67% versus 69%). In all patients, there was a trend to an improvement of kidney function at one month (eGFR +11.5 ml/min, P=0.055). At 6 months there was no longer a significant difference between the eGFR of both groups. A pre-transplant right atrial pressure of >15 mmHg was predictive for the need of RRT in the first 90 days, a baseline abnormal creatinine was not. The need for RRT in the first 90 days was predictive for mortality in the first year. <h3>Conclusion</h3> In patients with PAH, CTEPH or PAH related to congenital heart disease, a mild abnormal kidney function does not correlate with a higher risk of RRT or mortality after LTX or HLTX. eGFR may improve at one month suggesting an impairment due to hemodynamic status pre-transplant. At 6 months, there was no difference in eGFR according to the baseline kidney function. This suggests that pre-transplant kidney dysfunction is mostly determined by a hemodynamic factor and that it should only be considered as a relative contraindication for transplantation.