Frailty, Core Muscle Size, and Mortality in Patients Undergoing Open Abdominal Aortic Aneurysm Repair
Is core muscle size an objective measure of frailty and predictor of survival after abdominal aortic aneurysm (AAA) repair?
A total of 479 open AAA repairs were performed at a single institution over an 8-year period from 2000-2008. Cross-sectional areas of the psoas muscle at the L4 vertebral level were measured in 262 computed tomographic images available for review. The effect of psoas area on postoperative mortality was determined.
Mean follow-up for the study was 2.3 years; 55 of the 262 patients died during the follow-up period (mortality rate was 1.9%, 5%, and 8.8% at 30 days, 90 days, and 1 year). Mean AAA diameter at the time of repair was 6 ± 1.5 cm. Mean total psoas area (TPA; the sum of right and left psoas area at L4) was 2166.8 ± 727.3 mm2. Cox regression revealed a significant association between TPA and postoperative mortality (p = 0.003). The effect of psoas area on mortality was noted to decrease significantly over time from operation (p = 0.008). The hazard ratio was noted to be 4.5, 3.01, and 1.42 immediately after surgery, at 90 days, and at 180 days, respectively. Of all the covariates evaluated in this study (including such variables as American Society of Anesthesiologists classification), TPA was noted to be the strongest predictor of mortality after AAA repair.
Core muscle size, as measured by total psoas area, appears to be an objective measure of frailty, and correlated strongly with mortality after elective AAA repair. Such analysis may aid in risk stratification for, or timing of, elective aortic surgery.
This study attempts to quantify and make objective what many experienced surgeons call the ‘eyeball’ test—a gut feeling of the patient’s fitness for surgery based on a subjective, experience-based assessment of the patient’s overall appearance and his or her subsequent ability to tolerate a large operation. The ability to accurately calculate frailty, based on an imaging study that is universally obtained prior to AAA repair, is appealing and would be useful in risk stratification for elective AAA surgery. Clearly, this study is an excellent start, but needs to be validated in a prospective study with larger numbers.
Clinical Topics: Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Vascular Medicine, Interventions and Imaging, Interventions and Vascular Medicine, Computed Tomography, Nuclear Imaging
Keywords: Surgical Procedures, Elective, Follow-Up Studies, Tomography, X-Ray Computed, Aortic Aneurysm, Abdominal, Vascular Surgical Procedures, United States, Postoperative Period
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