The importance of independent risk-factors for long-term mortality prediction after cardiac surgery

Risk Prediction Models for Long-Term Survival after Cardiac Surgery: A Systematic Review

BACKGROUND

The reporting of alternative postoperative measures of quality after cardiac surgery is becoming increasingly important as in-hospital mortality rates continue to decline. This study aims to systematically review and assess risk models designed to predict long-term outcomes after cardiac surgery.

METHODS

The MEDLINE and Embase databases were searched for articles published between 1990 and 2020. Studies developing or validating risk prediction models for long-term outcomes after cardiac surgery were included. Data were extracted using checklists for critical appraisal and systematic review of prediction modeling studies.

RESULTS

Eleven studies were identified for inclusion in the review, of which nine studies described the development of long-term risk prediction models after cardiac surgery and two were external validation studies. A total of 70 predictors were included across the nine models. The most frequently used predictors were age (n = 9), peripheral vascular disease (n = 8), renal disease (n = 8), and pulmonary disease (n = 8). Despite all models demonstrating acceptable performance on internal validation, only two models underwent external validation, both of which performed poorly.

CONCLUSION

Nine risk prediction models predicting long-term mortality after cardiac surgery have been identified in this review. Statistical issues with model development, limited inclusion of outcomes beyond 5 years of follow-up, and a lack of external validation studies means that none of the models identified can be recommended for use in contemporary cardiac surgery. Further work is needed either to successfully externally validate existing models or to develop new models. Newly developed models should aim to use standardized long-term specific reproducible outcome measures.

The ability of the logistic EuroSCORE to predict long-term outcomes after coronary artery bypass graft surgery

OBJECTIVES

The European System for Cardiac Operative Risk Evaluation (EuroSCORE) predicts in-hospital mortality for patients undergoing cardiac surgery. Many variables associated with increased surgical mortality persist postoperatively. The aim of this study was to investigate the predictive value of the logistic EuroSCORE to long-term survival after coronary artery bypass surgery.

METHODS

Data were collected retrospectively for all patients undergoing coronary artery bypass graft (CABG) at a single center between January 1, 2009 and December 31, 2009. Data submitted to NICOR were used for EuroSCORE and in-hospital outcomes; longer-term, all-cause mortality from NHS digital Personal Demographic Service. Low (<3), intermediate (3-6), and high-risk (>6) logistic EuroSCORE groups were identified and analyzed using the appropriate statistical methodology, with p values less than .05 being taken as significant.

RESULTS

Six hundred and sixty-three patients underwent isolated CABG procedures during the study. The 1-, 3-, 5-, and 10-year survival rates were 97.6%, 94.3%, 89.3%, and 73.5%, respectively. Comparing survival outcomes between low-, intermediate-, and high-risk groups showed that the logistic EuroSCORE was able to predict long-term outcomes (p < .05). In addition, poor left ventricular ejection fraction, serum creatinine above 200 ml, chronic pulmonary disease, extracardiac arteriopathy, and pulmonary hypertension were identified as independent predictors of long-term mortality.

CONCLUSIONS

Our study demonstrates the logistic EuroSCORE predicted long-term outcomes following CABG surgery. This finding can inform patients of the long-term risks of CABG surgery and guide MDT decision-making.

Performance of the original EuroSCORE

The European system for cardiac operative risk evaluation (EuroSCORE) is a commonly used risk score for operative mortality following cardiac surgery. We aimed to conduct a systematic review of the performance of the additive and logistic EuroSCORE. A literature search resulted in 67 articles. Studies applying the EuroSCORE on patients undergoing cardiac surgery and which reported early mortality were included. Weighted meta-regression showed that the EuroSCORE overestimated mortality. However, this performance depended on the risk profile of patients: in high-risk patients, the additive model actually underestimated mortality. Discriminative performance was good. Given the poor predictive performance, the EuroSCORE may not be suitable as a tool for patient selection nor for benchmarking.

EuroSCORE predicts short- and mid-term mortality in combined aortic valve replacement and coronary artery bypass patients

BACKGROUND AND AIM OF THE STUDY

European system for cardiac operative risk evaluation (EuroSCORE) has been studied for its effectiveness in predicting operative mortality, and more recently, long-term mortality in a wide variety of cardiac surgical procedures. Combined coronary artery bypass and aortic valve replacement (AVR-CABG) carries increased perioperative risk, and tends to have higher-risk patients. Performance of the EuroSCORE system in patients undergoing concomitant AVR-CABG has not been well established. Thus, we aimed to analyze the accuracy of both additive and logistic EuroSCOREs in predicting operative and mid-term mortality.

METHODS

We retrospectively reviewed and calculated EuroSCOREs for all patients who underwent AVR-CABG between January 2000 and December 2004. Patients who had previous cardiac surgery and those undergoing any concomitant procedures were excluded. Areas under the receiver operator curves (ROC) were determined to assess EuroSCORE's accuracy in predicting operative mortality. Kaplan-Meier analysis and Cox regression were used to determine mid-term survival, freedom from repeat revascularization, and predictors of these outcomes.

RESULTS

There were 233 patients who met study criteria. Mean follow-up period was 2.2 +/- 1.7 years with one patient lost to follow-up. Mean additive and logistic EuroSCOREs were 8.77 and 16.1, respectively, with an observed mortality of 9.44%. The area under the ROC curves for additive EuroSCORE was 0.76 and for logistic EuroSCORE was 0.75. Regression analysis revealed additive EuroSCORE, but not logistic EuroSCORE, to be predictive of mid-term mortality.

CONCLUSIONS

Both additive and logistic EuroSCOREs were accurate in predicting operative morality. Only additive EuroSCORE was predictive of mid-term mortality in AVR-CABG patients. EuroSCORE remains a good and well-validated risk stratification model applicable to patients who undergo concomitant AVR-CABG.

Thoracoscore predicts midterm mortality in patients undergoing thoracic surgery

OBJECTIVE

Thoracoscore is the first multivariate model for the prediction of in-hospital mortality after general thoracic surgery. We aimed to evaluate the performance of Thoracoscore in predicting in-hospital and midterm all-cause mortality.

METHODS

We retrospectively evaluated 1675 patients who underwent thoracic surgery (lung resections [n = 626], mediastinum [n = 535], pleura and pericardium [n = 268], esophagus [n = 88], chest wall [n = 90], trachea [n = 45], and other procedures [n = 23]) from October 2002 to March 2006 at a single institution. Midterm survival data (mean follow-up 25 +/- 16 months) were obtained from the National Death Index. Kaplan-Meier survival plots of the quartiles of Thoracoscore were constructed and compared with the log-rank test with adjustment for trend.

RESULTS

Starting from the lower-risk to the higher-risk quartile, the in-hospital mortality rates were 0% (0/418), 1% (4/415), 2.5% (11/435), and 9.6% (54/407). Thoracoscore was a strong independent predictor for in-hospital mortality (odds ratio 1.20, 95% confidence intervals 1.15-.25; P < .001). The 2-year survivals of the Thoracoscore quartiles were 98.7% +/- 0.6%, 87.0% +/- 1.8%, 73.8% +/- 2.3%, and 54.8% +/- 2.7%, respectively (P < .0001). Thoracoscore was a strong independent predictor for midterm mortality (hazard ratio 1.12, 95% confidence intervals 1.11-1.14; P < .001).

CONCLUSION

Thoracoscore is a good and useful clinical tool for preoperative prediction of in-hospital and midterm mortality among patients undergoing general thoracic surgery.