Incidence and Progression of Chronic Kidney Disease after Vascularized Composite Allotransplantation.

BACKGROUND

Vascularized composite allotransplantation (VCA) offers functional, social and aesthetic benefits for patients with complex tissue defects. However, long-term immunosuppressive therapy places recipients at risk of developing metabolic complications, including chronic kidney disease (CKD). Despite well-documented kidney dysfunction in non-renal solid organ transplantation (NRSOT), data on VCA recipients remain limited, and estimated glomerular filtration rate (eGFR) equations lack validation. This study aimed to assess the long-term kidney function in VCA recipients using measured glomerular filtration rate (mGFR), and to evaluate the performance of eGFR equations.

METHODS

A retrospective, single-center study was conducted on seven upper extremity transplants and three face transplants. Demographic data, immunosuppression, renal parameters-including mGFR and eGFR using Chronic Kidney Disease - Epidemiology Collaboration (CKD-EPI) and Modification of Diet in Renal Disease (MDRD) equations-and potential renal risk factors were collected.

RESULTS

The median pre-transplant mGFR was 102.4 mL/min/1.73m², with no patient presenting preexisting CKD. Over the median follow-up period of 132 (111 - 171) months, 60% of VCA recipients developed CKD (mGFR <60 mL/min/1.73 m²) after a median delay of 8.5 years. At 10 years post-transplantation, the median mGFR had decreased by 27%, following a biphasic pattern characterized by an initial decline of 34.4 mL/min/1.73m² within the first year, followed by a slower decline. eGFR equations demonstrated poor performance and significantly overestimated kidney function, with a P30 <70% and a mean bias exceeding +10 mL/min/1.73m².

CONCLUSIONS

This study highlights a high incidence of CKD in VCA recipients, comparable to NRSOT populations, with significant early and long-term declines in kidney function. Standard eGFR equations overestimate kidney function, underscoring the necessity of mGFR assessments for accurate monitoring.