Risk stratification in cardiac surgery

Preoperative bioelectrical impedance, measured phase angle, and hand-grip strength as predictors of postoperative outcomes in patients undergoing cardiac surgery: a systematic review

BACKGROUND

Postoperative problems are a major danger for patients after heart surgery. Predicting postoperative outcomes for cardiac surgery is limited by current preoperative evaluations. Handgrip strength (HGS) testing and bioelectrical impedance analysis (BIA) may provide extra ways to identify individuals at risk of surgical problems, enhancing risk assessment and results.

OBJECTIVE

The purpose of this systematic review is to assess the utility of measured phase angle (PA), HGS, and bioelectrical impedance as perioperative risk markers in adult patients undergoing elective heart surgery.

METHOD

The PRISMA principles were followed in this review. We searched all available electronic databases, including the Science Direct search engine and PubMed, MEDLINE, EMBASE, Cochrane Library, Web of Science, PsycINFO, CINAHL, Google Scholar, Scopus, and the Science Direct search engine, from their creation to the present, as well as the medRxiv pre-print site. We considered studies with adult subjects undergoing elective heart surgery who were monitored for problems after surgery and had perioperative BIA and HGS testing.

RESULTS

As a result, out of the 1544 pieces of research that were discovered, eight studies were deemed suitable for inclusion in the review and supplied data from 2781 people. The findings demonstrated a substantial correlation between poor preoperative PA and a higher risk of serious postoperative morbidity, as well as prolonged hospital stays. Furthermore, poor HGS and low PA were linked to greater death rates. Additionally, there was a strong correlation found between low PA and HGS and longer stays in the ICU, as well as an increased chance of dying from all causes in a year. In conclusion these results imply that preoperative HGS and PA may be significant indicators of postoperative results and may assist in identifying patients who are more vulnerable to problems and death.

Long-term mortality after isolated coronary artery bypass grafting and risk factors for mortality

BACKGROUND

Patients requiring coronary artery bypass grafting (CABG) have multiple co-morbidities which need to be considered in totality when determining surgical risks. The objective of this study is to evaluate short-term and long-term mortality rates of CABG surgery, as well as to identify the most significant risk factors for mortality after isolated CABG.

METHODS

All patients with complete dataset who underwent isolated CABG between January 2008 and December 2017 were included. Univariate and multivariate Cox regression was performed to determine the risk factors for all-cause mortality. Classification and regression tree analysis was performed to identify the relative importance of these risk factors.

RESULTS

3,573 patients were included in the study. Overall mortality rate was 25.7%. In-hospital mortality rate was 1.62% overall. 30-day, 1-year, 5-year, 10-year and 14.5-year mortality rates were 1.46%, 2.94%, 9.89%, 22.79% and 36.30% respectively. Factors associated with death after adjustment for other risk factors were older age, lower body mass index (BMI), hypertension, diabetes mellitus, chronic obstructive pulmonary disease, pre-operative renal failure on dialysis, higher last pre-operative creatinine level, lower estimated glomerular filtration rate (eGFR), heart failure, lower left ventricular ejection fraction and New York Heart Association class II, III and IV. Additionally, female gender and logistic EuroSCORE were associated with death on univariate Cox analysis, but not associated with death after adjustment with multivariate Cox analysis. Using CART analysis, the strongest predictor of mortality was pre-operative eGFR < 46.9, followed by logistic EuroSCORE ≥ 2.4.

CONCLUSION

Poorer renal function, quantified by a lower eGFR, is the best predictor of post-CABG mortality. Amongst other risk factors, logistic EuroSCORE, age, diabetes and BMI had a relatively greater impact on mortality. Patients with chronic kidney disease stage 3B and above are at highest risk for mortality. We hope these findings heighten awareness to optimise current medical therapy in preserving renal function upon diagnosis of any atherosclerotic disease and risk factors contributing to coronary artery disease.

Comparison of European System for Cardiac Operative Risk Evaluation (EuroSCORE) and the Society of Thoracic Surgeons(STS) score for risk prediction in Indian patients undergoing coronary artery bypass grafting

BACKGROUND

For risk stratifying patients undergoing coronary artery bypass graft (CABG), the Society of Thoracic Surgeons (STS) risk score and the European System for Cardiac Operative Risk Evaluation (EuroSCORE) are currently used. However, the superiority of one over the other in the context of Indian patients has not been assessed. The aim of this study was to compare these 2 scoring systems in Indian patients undergoing CABG.

METHODOLOGY

This was a retrospective analysis of prospectively collected data between January 2015 and September 2020 of all patients undergoing CABG. Observed mortality in the cohort was compared with the predicted mortality using the STS and the EuroSCORE II. Sensitivity and specificity were calculated for both the scores. Receiver operating characteristic (ROC) curves were constructed for both the STS and the EuroSCORE II and area under the ROC curve (AUC) was calculated.

RESULTS

A total of 4895 patients were included in the study. The overall observed mortality in the entire cohort was 74 (1.5%). The EuroSCORE II-predicted mortality was 1.9 ± 2.5 whereas the STS score-predicted mortality was 1.2 ± 1.8. The observed to predicted mortality ratio for EuroSCORE was 0.79 and 1.25 for the STS score. The discriminative ability for operative mortality of the STS score was 0.72 (0.71 to 0.74) and 0.713 for the EuroSCORE, suggesting satisfactory discriminatory power. There was no difference between the STS score and the EuroSCORE in terms of discriminatory power (p = 0.58) and a difference in the AUC being 0.01. The discriminatory power of the EuroSCORE and the STS score was best in the high-risk category.

CONCLUSIONS

Both the EuroSCORE and the STS scores had satisfactory and similar discriminatory power. However, in the Indian population, while the EuroSCORE II overestimated mortality, the STS score underestimated it to a similar degree of error.

Scoring Systems for Risk Stratification in Patients Undergoing Cardiac Surgery

Cardiac surgery is associated with significant mortality rates. Careful selection of surgical candidates is, therefore, vital to optimize morbidity and mortality outcomes. Risk scores can be used to inform this decision-making process. The European System for Cardiac Operative Risk Evaluation Score and the Society of Thoracic Surgeons score are among the most commonly used risk scores. There are many other scoring systems in existence; however, no perfect scoring system exists, therefore, additional research is needed as clinicians strive toward a more idealized risk stratification model. The purpose of this review is to discuss the advantages and limitations of some of the most commonly used risk stratification systems and use this to determine what an ideal scoring system might look like. This includes not only the generalizability of available scores but also their ease of use and predictive power.