The Society of Thoracic Surgeons 2008 cardiac surgery risk models: part 2--isolated valve surgery.
ABSTRACT Adjustment for case-mix is essential when using observational data to compare surgical techniques or providers. That is most often accomplished through the use of risk models that account for preoperative patient factors that may impact outcomes. The Society of Thoracic Surgeons (STS) uses such risk models to create risk-adjusted performance reports for participants in the STS National Adult Cardiac Surgery Database (NCD). Although risk models were initially developed for coronary artery bypass surgery, similar models have now been developed for use with heart valve surgery, particularly as the proportion of such procedures has increased. The last published STS model for isolated valve surgery was based on data from 1994 to 1997 and did not include patients undergoing mitral valve repair. STS has developed new valve surgery models using contemporary data that include both valve repair as well as replacement. Expanding upon existing valve models, the new STS models include several nonfatal complications in addition to mortality.
Using STS data from 2002 to 2006, isolated valve surgery risk models were developed for operative mortality, permanent stroke, renal failure, prolonged ventilation (> 24 hours), deep sternal wound infection, reoperation for any reason, a major morbidity or mortality composite endpoint, prolonged postoperative length of stay, and short postoperative length of stay. The study population consisted of adult patients who underwent one of three types of valve surgery: isolated aortic valve replacement (n = 67,292), isolated mitral valve replacement (n = 21,229), or isolated mitral valve repair (n = 21,238). The population was divided into a 60% development sample and a 40% validation sample. After an initial empirical investigation, the three surgery groups were combined into a single logistic regression model with numerous interactions to allow the covariate effects to differ across these groups. Variables were selected based on a combination of automated stepwise selection and expert panel review.
Unadjusted operative mortality (in-hospital regardless of timing, and 30-day regardless of venue) for all isolated valve procedures was 3.4%, and unadjusted in-hospital morbidity rates ranged from 0.3% for deep sternal wound infection to 11.8% for prolonged ventilation. The number of predictors in each model ranged from 10 covariates in the sternal infection model to 24 covariates in the composite mortality plus morbidity model. Discrimination as measured by the c-index ranged from 0.639 for reoperation to 0.799 for mortality. When patients in the validation sample were grouped into 10 categories based on deciles of predicted risk, the average absolute difference between observed versus predicted events within these groups ranged from 0.06% for deep sternal wound infection to 1.06% for prolonged postoperative stay.
The new STS risk models for valve surgery include mitral valve repair as well as multiple endpoints other than mortality. Model coefficients are provided and an online risk calculator is publicly available from The Society of Thoracic Surgeons website.
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ABSTRACT: Frailty is a state of late life decline and vulnerability, typified by physical weakness and decreased physiologic reserve. The epidemiology and pathophysiology of frailty share features with those of cardiovascular disease. Gait speed can be used as a measure of frailty and is a powerful predictor of mortality. Advancing age is a potent risk factor for cardiovascular disease and has been associated with an increased risk of adverse outcomes. Older adults comprise approximately half of cardiac surgery patients, and account for nearly 80% of the major complications and deaths following surgery. The ability of traditional risk models to predict mortality and major morbidity in older patients being considered for cardiac surgery may improve if frailty, as measured by gait speed, is included in their assessment. It is possible that in the future frailty assessment may assist in choosing among therapies (e.g., surgical vs. percutaneous aortic valve replacement for patients with aortic stenosis).Journal of Geriatric Cardiology 01/2015; 12(1):44-56. DOI:10.11909/j.issn.1671-5411.2015.01.006 · 1.06 Impact Factor
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ABSTRACT: Frailty is a geriatric syndrome characterised by reductions in muscle mass, strength, endurance and activity level. The frailty syndrome, prevalent in 25-50% of patients undergoing cardiac surgery, is associated with increased rates of mortality and major morbidity as well as function decline postoperatively. This trial will compare a preoperative, interdisciplinary exercise and health promotion intervention to current standard of care (StanC) for elective coronary artery bypass and valvular surgery patients for the purpose of determining if the intervention improves 3-month and 12-month clinical outcomes among a population of frail patients waiting for elective cardiac surgery. This is a multicentre, randomised, open end point, controlled trial using assessor blinding and intent-to-treat analysis. Two-hundred and forty-four elective cardiac surgical patients will be recruited and randomised to receive either StanC or StanC plus an 8-week exercise and education intervention at a certified medical fitness facility. Patients will attend two weekly sessions and aerobic exercise will be prescribed at 40-60% of heart rate reserve. Data collection will occur at baseline, 1-2 weeks preoperatively, and at 3 and 12 months postoperatively. The primary outcome of the trial will be the proportion of patients requiring a hospital length of stay greater than 7 days. The healthcare team is faced with an increasingly complex older adult patient population. As such, this trial aims to provide novel evidence supporting a health intervention to ensure that frail, older adult patients thrive after undergoing cardiac surgery. Trial results will be published in peer-reviewed journals, and presented at national and international scientific meetings. The University of Manitoba Health Research Ethics Board has approved the study protocol V.1.3, dated 11 August 2014 (H2014:208). The trial has been registered on ClinicalTrials.gov, a registry and results database of privately and publicly funded clinical studies (NCT02219815). Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.BMJ Open 01/2015; 5(3):e007250. DOI:10.1136/bmjopen-2014-007250 · 2.06 Impact Factor
Journal of the American College of Cardiology 06/2014; 63(22):2438-2488. DOI:10.1016/j.jacc.2014.02.537 · 15.34 Impact Factor