Does a Poor Preoperative Nutritional Status Impact outcomes of Heart Valve Surgery?

Background: Malnutrition has been variously associated with poor postoperative outcomes. Of note, 10-25 % of cardiac surgery patients are reported to be malnourished. Objectives: To assess the impact of nutritional status (evaluated with the Geriatric Nutritional Risk Index-GNRI) on outcomes of older patients undergoing heart valve surgery. Design: Retrospective, single-center. Setting: Cardiac Surgery Unit, Fondazione Policlinico Universitario "A. Gemelli" IRCCS, Rome, Italy. Participants: 448 patients older than 75 years who had undergone isolated, elective heart valve surgery. Patients were divided into low (GNRI >= 92; 346 patients) and moderate-to-high (GNRI<92; 102 patients) risk groups of nutrition-related complications. Measurements: Demographic, clinical, and biological variables were retrieved from the institutional Heart Valve Database. GNRI was calculated as follows: [1.489 x serum albumin (g/dL)] + [41.7 x actual body weight (kg)/ideal body weight (kg)]. Operative and postoperative outcomes were compared between GNRI groups. Survival at 3 years follow-up was analyzed using the Kaplan-Meier method and log-rank test. Cox regression was used to identify variables associated with survival. Results: Mortality at 30 days did not differ between groups (0.98% vs 0.58% for GNRI < 92 and GNRI >= 92, respectively; p=0.54). Those with a GNRI < 92 required more frequently dialysis (2.9% vs 0.3%, p=0.04), inotropes (33.3% vs 22.8%, p=0.04), red blood cells transfusions (63.7% vs 19.9%, p<0.01), and longer mechanical ventilation support (12 +/- 2 vs 6 +/- 1.5 hours, p=0.03). Intensive care unit (4.7 +/- 0.9 vs 1.6 +/- 0.8 days, p=0.05) and total postoperative hospital (11.1 +/- 1.9 vs 5.2 +/- 1.5 days, p=0.05) stays were significantly longer in the GNRI < 92 group. Conclusion: A poor nutritional status may increase morbidity and prolong hospitalization after cardiac surgery. GNRI might improve risk assessment and should be integrated into traditional surgical risk models to offer tailored care to older patients.