Low skeletal muscle density combined with muscle dysfunction predicts adverse events after adult cardiovascular surgery

Background and aims: Although muscle dysfunctions are widely known as a poor prognostic factor in patients with cardiovascular disease, no study has examined whether the addition of low skeletal muscle density (SMD) assessed by computed tomography (CT) to muscle dysfunctions is useful. This study examined whether SMDs can strengthen the predictive ability of muscle dysfunctions for adverse events in patients who underwent cardiovascular surgery. Methods and results: We retrospectively reviewed 853 patients aged >40 years who had preoperative CT for risk management purposes and who measured muscle dysfunctions (weakness: low grip strength and slowness: slow gait speed). Low SMD based on transverse abdominal CT images was defined as a mean Hounsfield unit of the psoas muscle <45. All definitions of muscle dysfunction (weakness only, slowness only, weakness or slowness, weakness and slowness), the addition of SMDs was shown to significantly improve the continuous net reclassification improvement and integrated discrimination improvement for adverse events in all analyses (p < 0.05). Low SMDs combined with each definition of muscle dysfunction had the highest risk of all-cause death (hazard ratio: lowest 3.666 to highest 6.002), and patients with neither low SMDs nor muscle dysfunction had the lowest risk of all-cause and cardiovascular-related events. Conclusion: The addition of SMDs consistently increased the predictive ability of muscle dysfunctions for adverse events. Our results suggest that when CT is performed for any clinical investigation, the addition of the organic assessment of skeletal muscle can strengthen the diagnostic accuracy of muscle wasting. (c) 2021 The Italian Diabetes Society, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.

Automated summary

This study found that low skeletal muscle density (SMD) added to the predictive ability of muscle dysfunctions for adverse events in patients undergoing cardiovascular surgery, increasing the risk for patients with both low SMD and muscle dysfunction while decreasing the risk for those with neither low SMD nor muscle dysfunction.