Preoperative Malnutrition Calculated Using the Geriatric Nutritional Risk Index in Off-Pump Coronary Artery Bypass Grafting

Background: The Geriatric Nutritional Risk Index (GNRI), which assesses nutritional status using the ideal body weight ratio and albumin level, is a useful predictor of long-term cardiovascular disease prognosis. This study aimed to investigate the impact of preoperative GNRI on off-pump coronary artery bypass (OPCAB) surgical outcomes. Methods: We analyzed 632 elective OPCAB procedures performed between July 2008 and July 2018. GNRI was calculated as 14.89 x albumin level (g/dL) + 41.7 x (current body weight [kg]/ideal body weight [kg]). Patients were divided into two groups: the low GNRI (<= 98, L group, n = 155) and high GNRI (>98, H group, n = 477) groups. We compared perioperative variables and mid-term outcomes, particularly survival rates and freedom from major adverse cardiac or cerebrovascular events (MACCE). Results: Patients in the L group were older (72.4 +/- 8.6 vs. 67.9 +/- 10.1 years, p < 0.001) and had lower GNRI scores (90.9 +/- 5.8 vs. 106.0 +/- 4.8, p < 0.001) than patients in the H group. Perioperative results, including operation time and number of anastomoses, were similar between the groups, with no significant differences in 30-day mortality, perioperative intra-aortic balloon pump use, bleeding, stroke, or mediastinitis rates were observed. However, patients in the L group had a longer postoperative hospital stay than those in the H group (15.4 +/- 13.5 vs. 12.6 +/- 5.8 days, p = 0.01). Analyses of long-term outcomes revealed a significant difference in 5-year survival rates (70.9% for the L group vs. 83.3% for the H group, p = 0.002) but no significant difference in 5-year MACCE rates (84.1% for the L group vs. 80.3% for the H group, p = 0.19). Conclusions: Despite the longer hospital stay for patients in the L group, other perioperative outcomes were similar between the groups, suggesting that a low GNRI should not preclude patients from undergoing OPCAB surgery.