Effects of preoperative beta-hydroxy-beta-methylbutyrate, arginine, and glutamine supplementation on cardiac surgery: A randomized controlled trial.

Background & Aims: In older patients undergoing cardiac surgery, physical function is a critical determinant of postoperative outcomes. Beta-hydroxy-beta-methylbutyrate (HMB) supplementation has been shown to promote muscle protein anabolism and inhibit catabolism, thereby preventing muscle weakness. However, its efficacy in older patients undergoing cardiac surgery remains unknown. This study aimed to examine the effects of preoperative HMB supplementation on postoperative physical function and complications in this population.

Methods: In this single-center, open-label, randomized controlled trial, patients aged ≥65 years scheduled for cardiac surgery were randomized to receive HMB supplementation or no nutritional intervention. The HMB group received HMB 1200 mg, l-glutamine 7000 mg, and l-arginine 7000 mg, once or twice daily, for at least 2 weeks before surgery. Evaluations were performed at baseline and before and after surgery. The primary outcome was the 6-min walking distance (6MWD) before and after surgery. Secondary outcomes included the incidence of complications, muscle mass and strength, physical performance, and length of hospital stay.

Results: Forty-four patients with a mean age of 72.5 years (women, 38 %) were randomized to the HMB (n = 22) or control (n = 22) group. Compared with the control group, the HMB group demonstrated a statistically significant improvement in the 6MWD both at the pre-surgery (448.0 ± 73.5 m vs. 375.5 ± 58.8 m; P = 0.01) and post-surgery time points (428.9 ± 76.4 m vs. 304.5 ± 52.3 m; P = 0.001). Muscle strength and physical performance also showed significant improvements in the HMB group. However, no significant difference in muscle mass was observed between the groups at any time point. The HMB group had a shorter hospital length of stay compared with that of the control group (16.1 ± 3.8 days vs. 20.4 ± 7.6 days, P = 0.03), and no adverse events were observed with the intervention.

Conclusions: Preoperative HMB supplementation in older adults undergoing cardiac surgery resulted in significant improvements in postoperative exercise capacity and physical function, along with a reduction in the length of hospital stay, without affecting muscle mass.

Registration Number Of Clinical Trial: UMIN000030490 (UMINhttps://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000034773).