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.

Predictors of Long-Term Outcomes after Surgical Myocardial Revascularization

High mortality from cardiovascular diseases (CVD) requires improved approaches to the treatment of this socially significant pathology. Wide implementation of surgical myocardial revascularization makes it possible to improve significantly both life quality and expectancy in patients with coronary heart disease. The aim of this work was to analyze the literature on the impact of preoperative, operative and postoperative factors on the long-term prognosis after coronary artery bypass grafting (CABG). The review refers to both recent and earlier informative works. The target groups for this article are therapists, cardiologists, rehabilitologists, who work with patients in the short and long term after CABG. Data of Russian and foreign literature show that the long-term prognosis after CABG is largely determined by preoperative factors, in particular – age, set of cardiovascular risk factors (RF) and comorbidity, specifically – severity of coronary and systemic atherosclerosis, incident cardiovascular complications, structural and functional state of the heart. In the aggregate these factors reflect the cumulative effect and further potential of actual cardiovascular RFs, affect longterm risk of adverse events, and determine the therapeutic targets of secondary prevention. Priority of arterial conduits and completeness of revascularization are the main operative factors that determine the course of the long-term period after CABG. Among the postoperative factors, the efficiency of secondary CVD prevention is of paramount importance, in particular – achievement of target RF levels, compensation of cardiac and extracardiac pathology, adherence to the long-term medical therapy, known to improve outcomes based on specific comorbidity. Efficiency of secondary CVD prevention largely depends on patient's health attitudes, the key influence on which beyond attending physician can be provided by participation in rehabilitation programs, teaching patients the meaning and essentials of lifestyle modification and cardiovascular RFs’ control.

Development and Validation of Global Leadership Initiative on Malnutrition for Prognostic Prediction in Patients Who Underwent Cardiac Surgery

The Global Leadership Initiative on Malnutrition (GLIM) has achieved a consensus for the diagnosis of malnutrition in recent years. This study aims to determine the prognostic effect of the GLIM after cardiac surgery. A total of 603 patients in the training cohort and 258 patients in the validation cohort were enrolled in this study. Perioperative characteristics and follow-up data were collected. A nomogram based on independent prognostic predictors was developed for survival prediction. In total, 114 (18.9%) and 48 (18.6%) patients were defined as being malnourished according to the GLIM criteria in the two cohorts, respectively. Multivariate regression analysis showed that GLIM-defined malnutrition was an independent risk factor of total complication (OR 1.661, 95% CI: 1.063–2.594) and overall survival (HR 2.339, 95% CI: 1.504–3.637). The c-index was 0.72 (95% CI: 0.66–0.79) and AUC were 0.800, 0.798, and 0.780 for 1-, 2-, and 3-year survival prediction, respectively. The calibration curves of the nomogram fit well. In conclusion, GLIM criteria can efficiently identify malnutrition and has a prognostic effect on clinical outcomes after cardiac surgery. GLIM-based nomogram has favorable performance in survival prediction.

A novel nomogram for predicting 3-year mortality in critically ill patients after coronary artery bypass grafting

Background

The long-term outcomes for patients after coronary artery bypass grafting (CABG) have been received more and more concern. The existing prediction models are mostly focused on in-hospital operative mortality after CABG, but there is still little research on long-term mortality prediction model for patients after CABG.

Objective

To develop and validate a novel nomogram for predicting 3-year mortality in critically ill patients after CABG.

Methods

Data for developing novel predictive model were extracted from Medical Information Mart for Intensive cart III (MIMIC-III), of which 2929 critically ill patients who underwent CABG at the first admission were enrolled.

Results

A novel prognostic nomogram for 3-year mortality was constructed with the seven independent prognostic factors, including age, congestive heart failure, white blood cell, creatinine, SpO₂, anion gap, and continuous renal replacement treatment derived from the multivariable logistic regression. The nomogram indicated accurate discrimination in primary (AUC: 0.81) and validation cohort (AUC: 0.802), which were better than traditional severity scores. And good consistency between the predictive and observed outcome was showed by the calibration curve for 3-year mortality. The decision curve analysis also showed higher clinical net benefit than traditional severity scores.

Conclusion

The novel nomogram had well performance to predict 3-year mortality in critically ill patients after CABG. The prediction model provided valuable information for treatment strategy and postdischarge management, which may be helpful in improving the long-term prognosis in critically ill patients after CABG.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12893-021-01408-8.

Applying a framework to assess the impact of cardiovascular outcomes improvement research

Background

Health and medical research funding agencies are increasingly interested in measuring the impact of funded research. We present a research impact case study for the first four years of an Australian National Health and Medical Research Council funded Centre of Research Excellence in Cardiovascular Outcomes Improvement (2016–2020). The primary aim of this paper was to explore the application of a research impact matrix to assess the impact of cardiovascular outcomes improvement research.

Methods

We applied a research impact matrix developed from a systematic review of existing methodological frameworks used to measure research impact. This impact matrix was used as a bespoke tool to identify and understand various research impacts over different time frames. Data sources included a review of existing internal documentation from the research centre and publicly available information sources, informal iterative discussions with 10 centre investigators, and confirmation of information from centre grant and scholarship recipients.

Results

By July 2019, the impact on the short-term research domain category included over 41 direct publications, which were cited over 87 times (median journal impact factor of 2.84). There were over 61 conference presentations, seven PhD candidacies, five new academic collaborations, and six new database linkages conducted. The impact on the mid-term research domain category involved contributions towards the development of a national cardiac registry, cardiovascular guidelines, application for a Medicare Benefits Schedule reimbursement item number, introduction of patient-reported outcome measures into several databases, and the establishment of nine new industry collaborations. Evidence of long-term impacts were described as the development and use of contemporary management for aortic stenosis, a cardiovascular risk prediction model and prevention targets in several data registries, and the establishment of cost-effectiveness for stenting compared to surgery.

Conclusions

We considered the research impact matrix a feasible tool to identify evidence of academic and policy impact in the short- to midterm; however, we experienced challenges in capturing long-term impacts. Cost containment and broader economic impacts represented another difficult area of impact to measure.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12961-021-00710-4.

Disability-free survival after major cardiac surgery: a population-based retrospective cohort study

BACKGROUND

Cardiovascular research has traditionally been dedicated to "tombstone" outcomes, with little attention dedicated to the patient's perspective. We evaluated disability-free survival as a patient-defined outcome after cardiac surgery.

METHODS

We conducted a retrospective cohort study of patients aged 40 years and older who underwent coronary artery bypass grafting (CABG) or single or multiple valve (aortic, mitral, tricuspid) surgery in Ontario between Oct. 1, 2008, and Dec. 31, 2016. The primary outcome was disability (a composite of stroke, 3 or more nonelective hospital admissions and admission to a long-term care facility) within 1 year after surgery. We assessed the procedure-specific risk of disability using cumulative incidence functions, and the relative effect of covariates on the subdistribution hazard using Fine and Gray models.

RESULTS

The study included 72 824 patients. The 1-year incidence of disability and death was 2431 (4.6%) and 1839 (3.5%) for CABG, 677 (6.5%) and 539 (5.2%) for single valve, 118 (9.0%) and 140 (10.7%) for multiple valve, 718 (9.0%) and 730 (9.2%) for CABG and single valve, and 87 (13.1%) and 94 (14.1%) for CABG and multiple valve surgery, respectively. With CABG as the reference group, the adjusted hazard ratios for disability were 1.34 (95% confidence interval [CI] 1.21-1.48) after single valve, 1.43 (95% CI 1.18-1.75) after multiple valve, 1.38 (95% CI 1.26-1.51) after CABG and single valve, and 1.78 (95% CI 1.43-2.23) after CABG and multiple valve surgery. Combined CABG and multiple valve surgery, heart failure, creatinine 180 μmol/L or greater, alcohol use disorder, dementia and depression were independent risk factors for disability.

INTERPRETATION

The cumulative incidence of disability was lowest after CABG and highest after combined CABG and multiple valve surgery. Our findings point to a need for models that predict personalized disability risk to enable better patient-centred care.

Effect of Information-Motivation-Behavioral Model Based on Protection Motivation Theory on the Psychological Resilience and Quality of Life of Patients with Type 2 DM

Diabetes mellitus (DM) is one of the remarkable disease challenges in the twenty-first century and poses threat to patients' physical health. Given the difficulty of treatment and the high possibility of relapse, patients often have mental illness. A total of 117 patients with type 2 DM were randomly divided into two groups for a 2-month intervention. The intervention group underwent an Information-Motivation-Behavioral skills (IMB) intervention program based on protection motivation theory, and traditional intervention was applied to the control group. No significant difference is found between the intervention and control groups before the intervention (P > 0.05). However, after the intervention, the blood glucose level and depression score of the intervention group are lower than those of the control group (P < 0.05), and the psychological resilience and quality of life are significantly higher than those of the control group (P < 0.05). The blood glucose level and depression score of the intervention group decrease after the intervention (P < 0.05), and the psychological resilience and quality of life are significantly increase (P < 0.05). No significant difference is found in the blood glucose level, depression, psychological resilience, and quality of life of the control group before and after the intervention (P > 0.05). The combination of IMB intervention and protection motivation theory is important to improving the psychological resilience of patients with type 2 DM, raising their quality of life and reducing their blood glucose level.

Prevalence of Depression in Coronary Artery Bypass Surgery: A Systematic Review and Meta-Analysis

Coronary artery bypass graft surgery (CABG) might adversely affect the health status of the patients, producing cognitive deterioration, with depression being the most common symptom. The aim of this study is to analyse the prevalence of depression in patients before and after coronary artery bypass surgery. A systematic review and meta-analysis was carried out, involving a study of the past 10 years of the following databases: CINAHL, LILACS, MEDLINE, PsycINFO, SciELO, Scopus, and Web of Science. The total sample comprised n = 16,501 patients. The total number of items was n = 65, with n = 29 included in the meta-analysis. Based on the different measurement tools used, the prevalence of depression pre-CABG ranges from 19-37%, and post-CABG from 15-33%. There is a considerable presence of depression in this type of patient, but this varies according to the measurement tool used and the quality of the study. Systematically detecting depression prior to cardiac surgery could identify patients at potential risk.

A simple-to-use nomogram to predict long term survival of patients undergoing coronary artery bypass grafting (CABG) using bilateral internal thoracic artery grafting technique

BACKGROUND

Several risk scores have been created to predict long term mortality after coronary artery bypass grafting (CABG). Several studies demonstrated a reduction in long-term mortality following bilateral internal thoracic arteries (BITA) compared to single internal thoracic artery. However, these prediction models usually referred to long term survival as survival of up to 5 years. Moreover, none of these models were built specifically for operation incorporating BITA grafting.

METHODS

A historical cohort study of all patients who underwent isolated BITA grafting between 1996 and 2011 at Tel-Aviv Sourasky medical center, a tertiary referral university affiliated medical center with a 24-bed cardio-thoracic surgery department. Study population (N = 2,935) was randomly divided into 2 groups: learning group which was used to build the prediction model and validation group. Cox regression was used to predict death using pre-procedural risk factors (demographic data, patient comorbidities, cardiac characteristics and patient's status). The accuracy (discrimination and calibration) of the prediction model was evaluated.

METHODS AND FINDINGS

The learning (1,468 patients) and validation (1,467 patients) groups had similar preoperative characteristics and similar survival. Older age, diabetes mellitus, chronic obstructive lung disease, congestive heart failure, chronic renal failure, old MI, ejection fraction ≤30%, pre-operative use of intra-aortic balloon, and peripheral vascular disease, were significant predictors of mortality and were used to build the prediction model. The area under the ROC curves for 5, 10, and 15-year survival ranged between 0.742 and 0.762 for the learning group and between 0.766 and 0.770 for the validation group. The prediction model showed good calibration performance in both groups. A nomogram was built in order to introduce a simple-to-use tool for prediction of 5, 10, and 15-year survival.

CONCLUSIONS

A simple-to-use validated model can be used for a prediction of 5, 10, and 15-year mortality after CABG using the BITA grafting technique.

Sex Differences in Long-Term Survival After Major Cardiac Surgery: A Population-Based Cohort Study

Background

Little attention has been paid to the importance of sex in the long‐term prognosis of patients undergoing cardiac surgery.

Methods and Results

We conducted a retrospective cohort study of Ontario residents, aged ≥40 years, who underwent coronary artery bypass grafting (CABG) and/or aortic, mitral, or tricuspid valve surgery between October 1, 2008, and December 31, 2016. The primary outcome was all‐cause mortality. The mortality rate in each surgical group was calculated using the Kaplan‐Meier method. The risk of death was assessed using multivariable Cox proportional hazard models. Sex‐specific mortality risk factors were identified using multiplicative interaction terms. A total of 72 824 patients were included in the study (25% women). The median follow‐up period was 5 (interquartile range, 3–7) years. The long‐term age‐standardized mortality rate was lowest in patients who underwent isolated CABG and highest among those who underwent combined CABG/multiple valve surgery. Women had significantly higher age‐standardized mortality rate than men after CABG and combined CABG/mitral valve surgery. Men had lower rates of long‐term mortality than women after isolated mitral valve repair, whereas women had lower rates of long‐term mortality than men after isolated mitral valve replacement. We observed a statistically significant association between female sex and long‐term mortality after adjustment for key risk factors.

Conclusions

Female sex was associated with long‐term mortality after cardiac surgery. Perioperative optimization and long‐term follow‐up should be tailored to younger women with a history of myocardial infarction and percutaneous coronary intervention and older men with a history of chronic obstructive pulmonary disease and depression.

Impact of reduced left ventricular function on repairing acute type A aortic dissection: Outcome and risk factors analysis from a single institutional experience

Preoperative left ventricular dysfunction is a risk factor for postoperative mortality and morbidity in cardiovascular surgeries with cardiopulmonary bypass, including thoracic aortic surgery. Using a retrospective study design, this study aimed to clarify the short- and mid-term outcomes of patients who underwent acute type A aortic dissection (ATAAD) repair with reduced left ventricular function.Between July 2007 and February 2018, a total of 510 adult patients underwent surgical repair of ATAAD in a single institution. The patients were classified as having left ventricular ejection fraction (LVEF) <50% (low EF group, n = 86, 16.9%) and LVEF ≥50% (normal group, n = 424, 83.1%) according to transesophageal echocardiographic assessment at the operating room. Preoperative demographics, surgical information, and postoperative complication were compared between the two groups. Three-year survival was analyzed using the Kaplan-Meier actuarial method. Serial echocardiographic evaluations were performed at 1, 2, and 3 years postoperation.Demographics, comorbidities, and surgical procedures were generally homogenous between the 2 groups, except for a lower rate of aortic arch replacement in the low EF group. The averaged LVEFs were 44.3 ± 2.5% and 65.8 ± 6.6% among the low EF and normal groups, respectively. The patients with low EF had higher in-hospital mortality (23.3% versus 13.9%, P = .025) compared with the normal group. Multivariate analysis revealed that intraoperative myocardial failure requiring extracorporeal membrane oxygenation support was an in-hospital mortality predictor (odds ratio, 16.99; 95% confidence interval, 1.23-234.32; P = .034), as was preoperative serum creatinine >1.5 mg/dL. For patients who survived to discharge, the 3-year cumulative survival rates were 77.8% and 82.1% in the low EF and normal groups, respectively (P = .522). The serial echocardiograms revealed no postoperative deterioration of LVEF during the 3-year follow-up.Even with a more conservative aortic repair procedure, the patients with preoperative left ventricular dysfunction are at higher surgical risk for in-hospital mortality. However, once such patients are able to survive to discharge, the midterm outcome can still be promising.