Association of pretransplant pulmonary hypertension with posttransplant renal Doppler ultrasonography findings and biopsy-proven rejection

Pulmonary hypertension (PH) is a complex systemic disease. There are insufficient studies in the literature regarding its effect on renal hemodynamics following transplantation. This retrospective cohort study included 244 kidney transplant (KT) recipients. Patients were classified according to the severity of preoperative pulmonary hypertension based on echocardiographic systolic pulmonary artery pressure. Renal Doppler ultrasound (USG) parameters (resistive index [RI] and peak systolic velocity [PSV]) were measured at standard time points (day 3, week 1, month 1, month 3, and month 6) that have long been routinely used. Generalized estimating equations were used in longitudinal analyses to account for repeated measurements within each patient. Additionally, the relationship between PH severity and biopsy-confirmed rejection was examined. Pretransplant PH severity was significantly associated with posttransplant renal Doppler USG findings, particularly RI measurements. Patients with moderate and severe PH had consistently higher RI values during follow-up compared with the other groups. Although RI values generally decreased over time after KT, they remained relatively higher in patients with increasing PH severity. No significant association was observed between PH severity and clinically indicated biopsy-proven rejection. PSV findings showed greater variability and less consistent associations during follow-up. Increased pretransplant PH severity was associated with higher posttransplant RI values, independent of clinically indicated biopsy-proven rejection. These findings suggest that elevated RI values in patients with PH may reflect systemic and graft-related hemodynamic changes rather than rejection alone. Therefore, Doppler USG findings should be interpreted carefully in KT recipients with preexisting PH. Not applicable.