Study of predictors of low cardiac output syndrome after cardiac valve surgery

Abstract

Objective: Low cardiac output syndrome (LCOS) is defined as a decrease in cardiac index (CI) <2.0L/min/m2 and systolic blood pressure <90mmHg, accompanied by signs of a tissue hypoperfusion (cool peripheries, clammy skin, altered mental status, reduced urine output, elevated serum lactate levels) and the need for medication or mechanical circulatory support to improve hemodynamics [4,7]. LCOS is one of the serious complications after open cardiac surgery with a rate of 2-14% depending on the patient and the risk of death increases 12-25 times [3]. Besides modern equipment, early detection and timely treatment reduce mortality as well as increase myocardial recovery. LCOS prognostic factors play an important role. The aim of this study is to identify the prognostic signs of LCOS after valvular surgery.
 Subjects and methods: A cross-sectional descriptive study on patients undergoing valvular heart surgery at the Cardiovascular Anesthesiology Department - Cardiovascular Center - Hue Central Hospital from February 2022 to July 2022. LCOS is the dependent variable and the independent variable was divided into three groups before surgery, during surgery and after surgery. The data were processed by software R4.2.2. Using univariate logistic regression to identify independent prognostic factors. 
 Results: A study on 60 patients after heart valve surgery showed that: LCOS after heart valve surgery has a rate of 28.3% with an average time of 5.88 hours after surgery. Through univariate logistic regression analysis, the results found independent prognostic factors including: EF <=40% at preoperative time points (OR=12.9, 95%CI 1.73 – 26.5), EF 0h (OR) =2.3, 95%CI 2.4-8.9), EF 4h (OR=2.9, 95%CI 1.9-6.7), EF 24h (OR=1.9, 95%CI 1.5-9.5), lactate at 0h postoperative time (OR=1.81, 95%CI 1.25-2.8), 4h (OR=1.41, 95%CI 1.13-1.85), 8h (OR=1.38, 95%CI 1.14-1.73), 12h (OR=1.35, 95%CI 1.11-1.72), creatinine at 24 h after surgery (OR=1.02, 95%CI 1.01-1.04), time to extracorporeal circulation (OR=1.02, 95%CI 1.02-1.04), time to clamp aorta (OR=1.2, 95%CI 1.1-1.2).[1]
 Conclusion: Low cardiac output syndrome is one of the serious complications after heart valve surgery, early detection and timely treatment reduce the risk of death for patients. The study showed that many factors before, during and after surgery are independent prognostic factors for LCOS after surgery.