A. A. Mazurek1, J. F. Friedman1, A. Hammoud1, C. Inglis1, J. Haugen1, A. Hallway1, J. Lawton1, J. Ruan1, B. Derstine1, J. S. Lee1, S. C. Wang1, M. J. Englesbe1, N. H. Osborne1 1University Of Michigan,Morphomic Analysis Group, Department Of Surgery,Ann Arbor, MI, USA
Introduction:
Risk stratification for patients undergoing open or endovascular abdominal aortic aneurysm (AAA) repair has focused primarily on utilizing patient comorbidities as predictors of operative outcomes. However, there is often minimal variation in the burden of comorbid disease among patients with AAAs. Analytic morphomics is a novel method of risk-stratification that uses cross-sectional images to quantitatively measure domains of patient health. The utility of morphometric measurements as predictors of surgical outcome has been validated in several patient populations. Previously, AAA mortality after open repair has been associated with total psoas area. This study sought to further understand the role of both core muscle size and adiposity on the risk of mortality following open and endovascular AAA repair.
Methods:
A total of 795 patients underwent open or endovascular AAA repair between 2000 and 2012. 722 patients (91%) had preoperative abdominal CT scans available for analysis. After excluding patients with incomplete medical records, manual chart review was used to identify patient demographics and comorbidities. Validated methods of analytic morphomics, previously described, were used to measure cross-sectional areas and densities of psoas muscle, dorsal (paraspinous) muscle groups and subcutaneous and visceral fat at the vertebral levels T12 through L5. Univariate and multivariate analyses were used to determine which morphometric variables were significant predictors of mortality, controlling for traditional patient factors.
Results:
A total of 610 patients were identified; 322 patients underwent open repairs and 288 underwent endovascular repairs between the years 2000 and 2012. Following open repair, overall mortality ranged from 7% at 90 days to 21.1% at 3 years. Following endovascular repair, overall mortality ranged from 4% at 90 days to 21.3% at 3 years. Morphometric variables associated with mortality between 90 and 1095 days included measures of subcutaneous fat, visceral fat and both dorsal muscle group and psoas muscle density and area. After controlling for patient comorbidities and type of repair, a composite score of morphometric variables continued to be highly associated with mortality between 90 days and 1095 days; important variables included subcutaneous fat density at L2 (OR 1.09, p<0.001) and visceral fat density at L3 (OR 1.08, p<0.001).
Conclusion:
Morphometric measurements of adiposity and muscle mass correlate strongly with intermediate and late-term mortality after both open and endovascular AAA repair. Traditional methods of risk stratification in patients undergoing AAA repair may be augmented using analytic morphomics. These objective measures of frailty may aid in patient decision-making and provide insight into domains of health that clinicians and patients can work to optimize preoperatively in order to maximize positive outcomes for the patient.