Renal outcomes according to baseline kidney function after lung or combined heart-lung transplantation for pulmonary hypertension

Abstract

<b>Introduction:</b> Poor pretransplant renal function is associated with a worse outcome after lung (LTX) and combined heart-lung (HLTX) transplantation. In pulmonary hypertension (PH) poor renal function may be secondary to low cardiac output and renal congestion, which improve drastically after transplantation. <b>Aims:</b> We hypothesized that PH patients with the worst renal function might see improvement of eGFR after (H)LTX. <b>Methods:</b> We conducted a retrospective study in 68 consecutive patients diagnosed with pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension, who underwent (H)LTX between 1996 and 2019. Data on eGFR were collected before (H)LTX and at follow-up. The change of eGFR was expressed as a slope (absolute eGFR change per year) and compared using a mixed model effect test. Survival data were collected until end 2021 and compared using Kaplan Meier. <b>Results:</b> 15 patients had a pretransplant eGFR of less than 60ml/min/1,73m2 (median 51.7, IQR 5.6) and 53 patients had an eGFR of more than 60ml/min/1.73m2 (median 77.4, IQR 22.3). After 1 year the group with low eGFR displayed a 10.3mL/min/1.73m2/year increase, whereas the group with high eGFR showed a 16.3mL/min/1.73m2/year decrease (p=0.002). After 2 years, these results were a 5.5mL/min/1.73m²/year increase and a 14.0mL/min/1.73m²/year decrease (p=0.037), respectively.&nbsp;There was no difference in survival between both groups (p=0.64). <b>Conclusion:</b> PH patients with moderate renal impairment before (H)LTX have an improvement of their renal function after transplantation compared to patients with an eGFR &gt; 60 ml/min/1.73m², who may experience a decline in renal function.