Determinants and Prediction Equations of Six-Minute Walk Test Distance Immediately After Cardiac Surgery

The effect of a selenium-based anti-inflammatory strategy on postoperative functional recovery in high-risk cardiac surgery patients - A nested sub-study of the sustain CSX trial

AIM

The cardiac surgery-related ischemia-reperfusion-related oxidative stress triggers the release of cytotoxic reactive oxygen and nitrogen species, contributing to organ failure and ultimately influencing patients' short- and long-term outcomes. Selenium is an essential co-factor for various antioxidant enzymes, thereby contributing to the patients' endogenous antioxidant and anti-inflammatory defense mechanisms. Given these selenium's pleiotropic functions, we investigated the effect of a high-dose selenium-based anti-inflammatory perioperative strategy on functional recovery after cardiac surgery.

MATERIALS AND METHODS

This prospective study constituted a nested sub-study of the SUSTAIN CSX trial, a double-blinded, randomized, placebo-controlled multicenter trial to investigate the impact of high-dose selenium supplementation on high-risk cardiac surgery patients' postoperative recovery. Functional recovery was assessed by 6-min walk distance, Short Form-36 (SF-36) and Barthel Index questionnaires.

KEY FINDINGS

174 patients were included in this sub-study. The mean age (SD) was 67.3 (8.9) years, and 78.7 % of the patients were male. The mean (SD) predicted 30-day mortality by the European System for Cardiac Operative Risk Evaluation II score was 12.6 % (9.4 %). There was no difference at hospital discharge and after three months in the 6-min walk distance between the selenium and placebo groups (131 m [IQR: not performed - 269] vs. 160 m [IQR: not performed - 252], p = 0.80 and 400 m [IQR: 299-461] vs. 375 m [IQR: 65-441], p = 0.48). The SF-36 and Barthel Index assessments also revealed no clinically meaningful differences between the selenium and placebo groups.

SIGNIFICANCE

A perioperative anti-inflammatory strategy with high-dose selenium supplementation did not improve functional recovery in high-risk cardiac surgery patients.

Enhancing early functional independence following cardiac surgery: a quality improvement programme

Early mobility and activity programmes following cardiac surgery are vital for improved patient outcomes, as they accelerate the recovery of functional capacity and walking distance. We observed that only 5.3% of our patients achieved a Functional Independence Measurement (FIM) score of 80% or more by the third postoperative day (POD). Additionally, the average 6-minute walk distance achieved by the fourth POD was only 188 m. Therefore, a quality improvement (QI) project was implemented with the aim of attaining a FIM score of 80% by the third POD for more than 80% of patient underwent/undergoing cardiac surgery without complications.A model-for-improvement framework was used to drive continuous improvement. This project was implemented in February 2021. Baseline data were prospectively collected between November 2020 and January 2021 (preintervention). Outcomes were analysed using standard control chart rules to detect changes over time. Unpaired Student t-tests assessed significant differences in mean levels between two groups, (preintervention vs postintervention).χ2 tests were conducted between the two groups according to gender and patient satisfaction scores.The percentage of patients who achieved a FIM score of 80% or more by the third POD gradually increased to 91.4% 5 months following programme implementation and was sustained thereafter. The mean patient FIM score significantly improved to 81.20±3.77 (p<0.001) by the third POD. Similarly, the mean 6-minute walk distance increased to 267.90±36.10 m (p<0.001) by the fourth POD. The percentage of patients who displayed the level of confidence needed to carry out activities of daily living (ADL) and exercises independently at home increased to 89.4% (p<0.001) by the fifth POD. No adverse events associated with the mobility and activity programme were reported.This QI project demonstrated a substantial improvement in patient functional independence, walking distance and the level of confidence needed to independently carry out ADL and exercises following cardiac surgery.

Factors Affecting Recovery of 6-Minute Walk Distance After Coronary Artery Bypass Grafting

Background: This single-center retrospective analysis investigated the number of days required for postoperative 6-minute walk distance (6MWD) to recover to preoperative values after coronary artery bypass grafting (CABG) and the factors influencing this recovery. Methods and Results: The 6MWD was measured in 101 patients (median age 69 years; 18 women) before and every day after CABG. Univariate and multivariate analyses were performed to identify factors affecting 6MWD recovery to preoperative values after CABG. The median number of days required for recovery of 6MWD after CABG was 9 (interquartile range 7-11 days). Patients were divided into 2 groups based on the median number of days required for recovery of 6MWD; there were 60 patients in the early recovery group (<9 days) and 41 in the "non-early" recovery group (38 who recovered after the median 9 days, and 3 who did not recover during hospitalization). Using univariate logistic regression analysis, diabetes (P=0.01), stroke (P=0.26), left ventricular ejection fraction (P=0.27), and grip strength (P=0.13) were selected for multivariate analysis. Multivariate logistic regression analysis revealed that diabetes (odds ratio 2.955; 95% confidence interval 1.208-7.229; P=0.02) was the only independent predictor of 6MWD recovery. Conclusions: Diabetes was the single factor influencing the recovery of postoperative 6MWD in patients undergoing CABG.

Factors Determining the Functional State of Cardiac Surgery Patients with Complicated Postoperative Period

The purpose of this work was to study the factors determining the functional state of cardiac surgery patients with a complicated postoperative period upon discharge from the hospital. This observational study included 60 patients who underwent cardiac surgery with a complicated postoperative course and with a prolonged intensive care unit stay of more than 72 h. We assessed handgrip and lower-extremity muscle strength and the six-minute walk test (6MWT) distance 3 days after the surgery and at discharge from the hospital. Some patients (53%) additionally underwent a course of neuromuscular electrostimulation (NMES). Two groups of patients were formed: first (6MWT distance at discharge of more than 300 m) and second groups (6MWT distance of 300 m or less). The patients of the second group had less lower-extremity muscle strength and handgrip strength on the third postoperative day, a longer aortic clamping time and a longer stay in the intensive care unit. Independent predictors of decreased exercise tolerance at discharge were body mass index, foot extensor strength and baseline 6MWT distance in the general group, duration of cardiopulmonary bypass in the NMES group and in the general group, and age in the NMES group. Thus, the muscle status on the third postoperative day was one of the independent factors associated with the 6MWT distance at discharge in the general group, but not in patients who received NMES. It is advisable to use these results in patients with complications after cardiac surgery with the use of NMES rehabilitation.