Low Psoas Muscle Area is Associated with Increased Mortality and Spinal Cord Injury After Complex Endovascular Aortic Aneurysm Repair.

Background: Low psoas muscle area (PMA) is associated with worse post-operative outcomes. Our objective was to evaluate the association of PMA and postoperative outcomes in patients undergoing fenestrated/branched endovascular aneurysm repair (F/BEVAR).

Methods: Patient characteristics, anatomical and clinical information, and post-operative outcomes were collected from patients undergoing F/BEVAR between 2005-February 2019 who were deemed too high-risk for open repair. PMA was measured using a validated web-based software (coreslicer.com). Post-operative outcomes were compared between patients with low PMA (lowest quartiles) and high PMA (highest quartiles).

Results: We included 129 patients with a mean age of 74.6 ± 8.1, 81.4% male, and a mean follow-up of 29.4 ± 32.2 months. Patients in the low PMA group were more likely to be female (33.8% vs. 3.1%, P < 0.0001), less likely to have hypertension (72.3% vs. 87.5%, P = 0.03), dyslipidemia (63.1% vs. 78.1%, P = 0.06), and a trend towards a greater history of endovascular aneurysm repair (4.6% vs. 0%, P = 0.08). There were no significant differences in aneurysm or device characteristics between groups. In a multivariate model including age, sex, aneurysm type, and presence of prophylactic spinal drain, the low PMA group had a significantly increased risk of spinal cord injury (odds ratio 12.7, 95% CI 1.1-143.6). There were no significant differences in other 30-day outcomes. When compared to the highest quartile, the lowest PMA quartile patients had a hazard ratio of 4.6 (95% CI 1.2-17.6) for mortality during follow-up in a model with age, sex, and aneurysm type. For each 1 cm increase in PMA, the HR was 0.90 (95% CI 0.82-0.99) for mortality during follow-up.

Conclusions: In high-risk patients undergoing F/BEVAR low PMA is associated with spinal cord injury and mortality during follow-up. We found no association between PMA and 30-day mortality. PMA measurement is a simple method to assess for sarcopenia and frailty and may be useful for risk stratification pre-operatively.