Evaluation of the prognostic value of computed tomography‐derived body composition in patients undergoing endovascular aneurysm repair

Abstract

Background Endovascular aneurysm repair (EVAR) is the most common mode of repair of abdominal aortic aneurysms (AAA) in the UK. EVAR ranges from standard infrarenal repair to complex fenestrated and branched EVAR (F/B‐EVAR). Sarcopenia is defined by lower muscle mass and function, which is associated with inferior perioperative outcomes. Computed tomography‐derived body composition analysis offers prognostic value in patients with cancer. Several authors have evaluated the role of body composition analysis in predicting outcomes in patients undergoing EVAR; however, the evidence base is limited by heterogeneous methodology. Methods Six hundred seventy‐four consecutive patients (58 (8.6%) female, mean (SD) age 74.4 (6.8) years) undergoing EVAR and F/B‐EVAR at three large tertiary centres were retrospectively recruited. Subcutaneous and visceral fat indices (SFI and VFI), psoas and skeletal muscle indices, and skeletal muscle density were measured at the L3 vertebral level from pre‐operative computed tomographies. The maximally selected rank statistic technique was used to define optimal thresholds to predict mortality. Results There were 191 deaths during the median follow‐up period of 60.0 months. Mean (95% CI) survival in the low SMI versus high SMI subgroups was 62.6 (58.5–66.7) versus 82.0 (78.7–85.3) months (P < 0.001). Mean (95% CI) survival in the low SFI versus high SFI subgroups was 56.4 (48.2–64.7) versus 77.1 (74.2–80.1) months (P < 0.001). One‐year mortality in the low SMI versus high SMI subgroups was 10% versus 3% (P < 0.001). Low SMI was associated with increased odds of one‐year mortality (OR 3.19, 95% CI 1.60–6.34, P < 0.001). Five‐year mortality in the low SMI versus high SMI subgroups was 55% versus 28% (P < 0.001). Low SMI was associated with increased odds of five‐year mortality (OR 1.54, 95% CI 1.11–2.14, P < 0.01). On multivariate analysis of all patients, low SFI (HR 1.90, 95% CI 1.30–2.76, P < 0.001) and low SMI (HR 1.88, 95% CI 1.34–2.63, P < 0.001) were associated with poorer survival. On multivariate analysis of asymptomatic AAA patients, low SFI (HR 1.54, 95% CI 1.01–2.35, P < 0.05) and low SMI (HR 1.71, 95% CI 1.20–2.42, P < 0.01) were associated with poorer survival. Conclusions Low SMI and SFI are associated with poorer long‐term survival following EVAR and F/B‐EVAR. The relationship between body composition and prognosis requires further evaluation, and external validation of the thresholds proposed in patients with AAA is required.

Cardiopulmonary exercise testing, computed tomography-derived body composition, systemic inflammation and survival after elective abdominal aortic aneurysm repair

“…Thresholds to define 'High'/'Low' value of each CT-BC variable have been reported previously and are derived from a larger multicentre cohort of patients with AAA undergoing EVAR. 10 In addition, thresholds from the present cohort were derived using RStudio v. 1.4.1717 and ROC analyses. These were compared to the previously reported thresholds and were similar; therefore, the existing thresholds were preferred because of their derivation from a larger sample (Supplemental Table 1, http://links.lww.com/EJA/A960).…”

“…CT-BC shows promise in this field, and whilst the evaluation of its role as a prognostic factor is beyond the scope of this study, other studies suggest it may play a role in this patient group. 10 Importantly, predicting peri-operative mortality is a key component of any prospective risk stratification tool. In our study, the low (0.6%) 30-day mortality precludes meaningful analysis of peri-operative mortality, highlighting the need for further investigation.…”

“…Historically, it has been more extensively studied in patients with cancer, but recently an association between a poorer prognosis and preoperative CT-BC analysis has been described in patients with AAA. 9,10 The mechanism by which sarcopenia leads to poorer outcomes is poorly understood and is probably a complex interaction between reduced physiological reserve, increasing comorbidity and a chronic inflammatory state. 11 The relationship between objective measures of physiological fitness derived from CPEX and sarcopenia has been previously investigated in patients undergoing hepatobiliary resection.…”

CT-derived body composition: Differential association with disease, age and inflammation in a retrospective cohort study

“…Sarcopenia is defined as a progressive loss of skeletal muscle volume and progressive reduction in skeletal muscle function [ 8 ], and can be assessed radiologically through CT body composition analysis (CT-BC), which allows for quantification of sarcopenia using the skeletal muscle index (SMI) and the skeletal muscle density (SMD), typically at the L3 vertebral level. Low skeletal muscle mass, as measured by SMI, has been found to be prevalent in both cancer and non-cancer patient groups, and appears to confer a worse prognosis in both of these cohorts [ 9 , 10 ]. Low SMD appears to be associated with increased lipid content within myocytes [ 11 ], and may therefore represent poor quality muscle through accumulation of fat droplets in otherwise healthy muscle tissue.…”

“…Low SMD appears to be associated with increased lipid content within myocytes [ 11 ], and may therefore represent poor quality muscle through accumulation of fat droplets in otherwise healthy muscle tissue. Low SMD is also associated with inferior prognosis in cancer and non-cancer populations [ 9 , 12 ].…”