The masseter muscle thickness is a predictive marker for postoperative pneumonia after endovascular aneurysm repair

Oral frailty is characterized by a decrease in the oral and swallowing function and is a risk factor for pneumonia. In the current study, we analyzed the association between the masseter muscle thickness (MMT) and postoperative pneumonia and mortality after endovascular aneurysm repair (EVAR) for abdominal aortic aneurysm.

Overall, 247 patients were retrospectively evaluated. The primary end point was postoperative pneumonia. The MMT was measured as the maximum thickness of the masseter muscle 2 cm caudal to the zygomatic arch using computed tomography images obtained within 3 months before EVAR. Pneumonia was defined as the presence of progressive infiltrates, consolidation, or cavitation on imaging and a fever or leukocytosis.

Twenty (8.1%) cases of postoperative pneumonia occurred within 1 year after EVAR. We found that patients with a low MMT (≤ 30th percentile: males, 10.4 mm; females: 8.8 mm) had a significantly higher risk of developing postoperative pneumonia within 1 year after elective EVAR than those with a high value. A comparison of the utility of the MMT and psoas muscle index (PMI) for predicting the 1-, 3-, and 5-year all-cause mortality revealed that the MMT had superior predictive performance.

The MMT before elective EVAR predicted postoperative pneumonia and life expectancy, and its predictive performance was superior to that of the PMI.