Temporary contraindication of obese recipients in kidney transplantation: A new morphometric tool for decision support

Surgical complications and graft survival in kidney transplant recipients according to CT-scans evaluation

INTRODUCTION

Obesity is a risk factor for significant surgical complications following kidney transplantation. We examined morphometric parameters other than the body mass index (BMI) that could predict surgical complications and determine their impact on graft survival.

MATERIALS

Kidney transplantations performed at our center between 2012 and 2019 were retrospectively evaluated. Data for visceral adipose tissue (VAT), subcutaneous adipose tissue, psoas surface, abdominal perimeter (AP), and vessel-to-skin distance (VSK) were collected from pre-transplant computed tomography (CT) scans. The primary outcome was the occurrence of surgical complications within 1 year of transplantation; the secondary outcome was graft survival.

RESULTS

We included 321 (88%) of 364 kidney transplant recipients, of which 154 (46.5%) patients experienced some form of surgical complication in the 1st year of follow-up. Univariate analysis revealed that higher VAT (P=0.004), VSK (P=0.007), and AP (P=0.01) values were potential risk factors for early postoperative morbidity. However, none of these factors were significant in the multivariate analysis. Concerning the secondary outcome, while the univariate analysis identified higher VAT (P=0.001) value as a risk factor, in the multivariate analysis only delayed graft function demonstrated a significant impact on graft survival (P=0.002).

CONCLUSIONS

Although morphological parameters showed greater accuracy in predicting surgical complications in univariate analysis, these results were not significant in multivariate analysis. Moreover, these factors were not significantly associated with graft survival. Therefore, routine application of analyses based on these parameters, regardless of BMI, may not be useful.

LEVEL OF EVIDENCE: 5

Pre-transplant morphometry by computed tomography scan and post-transplant dialysis risk in overweight or obese kidney transplant recipients

PURPOSE

Adipose distribution and sarcopenia could better assess kidney transplantation outcomes than body mass index (BMI) and have been poorly evaluated among obese and overweight recipients. We aimed to evaluate morphometric radiologic markers to predict post-operative dialysis within this population.

METHODS

We conducted a retrospective study including patients with a BMI > 25 kg/m² undergoing kidney transplantation during 5 years. Subcutaneous adipose tissue surface (SAT), visceral adipose tissue surface (VAT), and psoas surface were measured on CT scans sections. A model predictive of post-transplantation dialysis was elaborated through a multivariable logistic regression and was compared to a model including only BMI.

RESULTS

Overall, 248 patients were included whom mean (SD) BMI and age were, respectively, 29.7 kg/m2 (3.6) and 56 years (12.7). Of them, 83 (33.5%) needed dialysis: 14 (5.7%) for primary kidney failure and 69 (27.8%) for delayed kidney function. On multivariable analysis, SAT, VAT and deceased donor were significantly associated with post-operative dialysis (respectively, OR [95%CI]:1.6 [1.1-2.6], 1.6[1.1-2.6], and 7.5 [1.6-56]). The area under the curve of this predictive model was 0.70 versus 0.64 for a BMI-based model.

CONCLUSION

High VAT and SAT were associated with post-transplantation dialysis. A predictive model based on these morphometrics could provide a better appreciation of graft recovery after transplantation among obese and overweight recipients. External validation is needed.

Surgical complications risk in obese and overweight recipients for kidney transplantation: a predictive morphometric model based on sarcopenia and vessel-to-skin distance

PURPOSE

Sarcopenia or adipose tissue distribution within obese and overweight renal transplanted have been poorly evaluated. Our objective was to evaluate morphometric markers to predict surgical complications in kidney transplantation.

METHODS

We retrospectively included patients with a BMI > 25 kg/m² undergoing kidney transplantation from 2012 to 2017. Following measurements were performed on CT-scan sections: Sub-cutaneous Adipose Tissue surface (SAT), Visceral Adipose Tissue surface (VAT), Vessel-to-Skin distance (VSK), Abdominal Perimeter (AP), and Psoas surface. A multivariable logistic regression model with BMI was compared to a model containing morphometric variables to determine the best predictive model for surgical complications.

RESULTS

248 patients were included, 15 (6%) experienced transplant nephrectomy, 18 (7.3%) urinary leakage, and 29 (11.7%) subcapsular renal hematoma. Multivariable logistic regression evidenced that sarcopenia and VSK were risk factors of surgical complication within a year post-transplantation (respectively, OR = 0.9, 95%CI (0.8-0.9), p = 0.04 and OR = 1.2, 95%CI (1.1-1.3), p = 0.002). Area under the curve for a predictive model including VSK, age and psoas surface was 0.69, whereas BMI model was 0.65.

CONCLUSION

Combined morphometric parameters of obesity were associated with surgical complications in kidney transplantation. Morphometric threshold may provide a more accurate and objective criteria than BMI to evaluate kidney transplantation outcomes. External validation is needed.