Myosteatosis as a New Risk Factor of Surgical Complications in Kidney Transplant Recipients: A Retrospective Study

Abstract

Background: Computed tomography (CT) scan-defined myosteatosis is a common feature in ESKD patients receiving kidney transplantation (KT) and is associated with mortality after KT. We aimed to explore the impact of myosteatosis and other CT scan based morphometric data on the occurrence of early surgical complications after KT.

Methods: We retrospectively measured on an unenhanced cross-sectional CT scan taken at the middle of the third lumbar vertebra performed within the previous year or at the time of KT: surface muscle index (total lumbar cross-sectional muscle area [CSMA] divided by height squared), subcutaneaous adipose tissue index, visceral adipose tissue index and muscle density (MD: mean CT attenuation of CSMA). Vessel to skin distance was the distance between iliac vein and skin. Myosteatosis was defined as MD below age- and sex-specific normal values. Logistic regression models were constructed to identify predictive factor of 90 days postoperative surgical complications with Clavien-Dindo score greater than or equal to 2, CD ≥ 2).

Results: Among the N = 200 patients, 61.5% were male with a mean age of 54.8 (± 13.8) years and a mean BMI of 25.1 (± 4.4) kg/m². Sixty patients (30%) developed at least one postoperative complication (CD ≥ 2) in the first 3 months after KT. In two different multivariate analyses, MD (aOR: 0.95 for one Hounsfield unit increase, 95% CI: 0.91-0.99, p = 0.028) and myosteatosis status (aOR: 4.64, 95% CI: 2.18-9.90, p < 0.0001) were the only independent risk factors for postsurgical complication.

Conclusions: Myosteatosis is independently associated with the occurrence of CD ≥ 2 postoperative complication within 90 days of surgery.

FIGURE 1

(A) Cross‐sectional computed tomography images in a kidney transplant recipient after muscle and fat segmentation at the level of the third lumbar vertebra. Skeletal muscle area (red) was identified by using computed tomography attenuation values of −29 to +150 Hounsfield units (HU). Subcutaneous fat area (yellow) was depicted by using attenuation values of −190 to −30 HU. For visceral fat area (orange), −150 to −50 HU attenuation values were used. (B) Vessel‐to‐skin (VSK) distance measurement on abdominal CT scan. VSK was defined by the distance between the anterior edge of the iliac vein and the skin, passing through the semilunar line.