D. Strosberg1, T. Yoo1, K. Lecurgo1, M. J. Haurani1 1Ohio State University,Division Of Vascular Surgery / Department Of Surgery,Columbus, OH, USA
Introduction:
Sarcopenia, the measurement of muscle decline, has been shown to be an independent predictor of performance status and mortality in the cancer and trauma literature. Others have applied frailty scores and other measures to predict outcomes after surgical procedures, but these require information that is not always readily available in the electronic health records. Total psoas muscle area (TPA) normalized for body surface area (TPA/m^2) can quickly be assessed with most modern image viewing software available to surgeons. There are also no accepted guidelines for what constitutes sarcopenia in a subset of patients with critical limb ischemia. The objectives of this study were to evaluate the feasibility of easily calculating TPA/m^2, and then studying whether lower TPA/m^2 predicted mortality in patients undergoing above knee amputation (AKA) for critical limb ischemia.
Methods:
We evaluated patients who underwent AKA between July 2013 and July 2016 at a single institution. Patients with abdominal/pelvis computed tomography (CT) scans within 3 months of their amputation were included. Total psoas muscle area (TPA) was manually measured at L3, and then normalized for body surface area (TPA/m2) calculated using height and weigh from the anesthesiology records at the time of surgery. We defined sarcopenia as patients whose TPA/m^2 were in the lowest quartile of our cohort. Univariate analysis was used to look for difference in mortality between patients undergoing AKA for critical limb ischemia.
Results:
97 patients underwent AKA, of whom 48 had a CT scan that met inclusion criteria. Total mortality was 44% (21 patients), with a median survival of 90 days (range 1-648 days). 35 patients (70%) were cleared for prosthetic use, however only 5 patients (10%) were noted to be using a prosthesis on follow up, and 13 patients were ambulatory with or without a prosthetic at their last clinic visit (26%). 4 patients (8%) required revision of their residual limb. Mean TPA/m^2 was 1156.3mm2/m2 (range 372.7 – 2572.5mm2/m2). When comparing the demographics of the amputees in the lowest quartile based on TPA/m^2, there was no differences noted in their age (63 vs 59y.o. P=0.1), or discharge status (21% vs 33% discharged home P=0.5). The mortality rate of patients in the lowest TPA/m^2 quartile (372.7 – 781.1mm2/m2) was significantly higher at 62% (8 patients), compared to 35% (13 patients) (P=0.04).
Conclusion:
CT imaging was available making TPA/m^2 measurement possible in this subset of patients undergoing AKA. Patients with low TPA/m^2 have a significantly higher mortality rate following AKA for critical limb ischemia, despite no differences in age or discharge status. Psoas muscle mass may be used as a predictive indicator for mortality risk, and patients should be counseled accordingly prior to AKA.