The Correlation between the Psoas Muscle/Vertebral Body Ratio and the Severity of Peripheral Artery Disease

Abstract

The measurement of psoas muscle area is a new and potentially useful tool for assessing the frailty of patients in the context of various disease states ranging from cancer to abdominal aortic aneurysms (AAAs). Considering the similarity of risk factors for frailty and atherosclerosis, we sought to investigate whether patients with peripheral artery disease (PAD) have smaller psoas muscle areas in general. Furthermore, we investigated whether PAD symptom severity correlates with psoas muscle size. A chart review was conducted on 146 patients with PAD. Of these patients, 85 (58%) had a computed tomography scan within the last 5 years and were included in the study. Fifty-five patients with AAA and no occlusive disease were included as controls. Cross-sectional areas of the psoas muscles and L4 vertebral body were collected at the mid-L4 level for all patients. Total psoas muscle area was calculated and divided by L4 area to correct for body habitus. Ankle-brachial indices and Rutherford classification were collected as measures of PAD severity. Logistic and multiple regressions were run to assess the difference in psoas muscle/vertebral body ratio between patients with PAD and AAA and within PAD patients, respectively. PAD patients have a lower psoas muscle/vertebral body ratio controlled for sex and age than patients with AAA (P<0.05). However, among patients with PAD, psoas muscle/vertebral body ratio does not correlate with severity of symptoms. Using psoas muscle area as a measure of frailty, patients with PAD may be frail as a group. However, the severity of each patient's symptoms does not appear to correlate with the patient's degree of frailty. Prospective studies with larger populations are needed to clarify whether the psoas muscle area has any prognostic value in PAD.