Magnetic Resonance Imaging - Derived Psoas Muscle Area and Survival in Patients Treated Invasively for Peripheral Arterial Disease.

Background and aims: Psoas muscle parameters estimated from computed tomography images, as surrogates for sarcopenia, have been found to be associated with post-interventional outcomes after a wide range of cardiovascular procedures. The pre-interventional assessment in patients undergoing invasive treatment for peripheral arterial disease is increasingly often carried out with magnetic resonance imaging (MRI), and we therefore sought to investigate the predictive potential of MRI-derived psoas muscle area in this cohort.

Methods: A total of 899 patients with available sufficient quality pre-interventional MRI conducted within 6 months prior to treatment undergoing open, endovascular, or hybrid revascularization procedures for claudication and/or limb-threatening ischemia at Tampere University hospital between 2010 and 2020 were retrospectively studied in this single-center cohort study. The follow-up lasted until 17 June 2021. Psoas muscle areas were measured from the magnetic resonance images at the L4 level, and the reliability of muscle parameter measurements was tested with intraclass correlation coefficient analysis. The average psoas muscle area values (mean of left and right psoas surface areas) were z-scored and analyzed separately for men and women.

Results: The median follow-up time was 5.9 years (interquartile range (IQR) = 2.7-7.8), and the overall mortality count was 259 (28.8%) (29.5% n = 168/569 for men and 27.6% n = 91/330 for women). The intraclass correlation coefficient analysis showed excellent interrater reliability for psoas muscle measurements. The muscle surface areas were larger in men (mean = 7.58 cm²) compared to women (mean = 5.27 cm²) (p < 0.001). Higher psoas muscle area was associated with better survival in women (p = 0.003, hazard ratio (HR) = 0.71, 95% confidence interval (CI) = 0.6-0.9 per 1 SD), whereas in men, an independent association of the muscle parameter with mortality was not found.

Conclusions: MRI-derived psoas muscle area may be a prognostic factor for clinical use.