Risk stratification for cardiac valve replacement. National Cardiac Surgery Database. Database Committee of The Society of Thoracic Surgeons.

BACKGROUND: The Society of Thoracic Surgeons National Database Committee is committed to risk stratification and assessment as integral elements in the practice of cardiac operations. The National Cardiac Surgery Database was created to analyze data from subscribing institutions across the country. We analyzed the database for valve replacement procedures with and without coronary artery bypass grafting to determine trends in risk stratification. METHODS: The database contains complete records of 86,580 patients who had valve replacement procedures at the participating institutions between 1986 and 1995, inclusive. The 1995 harvest of data was conducted in late 1996 and available for evaluation in 1997. These records were used to conduct an in-depth analysis of risk factors associated with valve replacement and to provide prediction of operative death by using regression analysis. Regression models were made for six subgroups. RESULTS: Adverse patient risk factors, including diabetes, hypertension and reoperation, but not ventricular function, increased over time. There were trends with regard to increasing age of the various population subsets. The types of prostheses used remained similar over time, with more mechanical prostheses than bioprostheses used for both aortic and mitral valve replacement. There was a trend toward increased use of bioprostheses in aortic replacements and decreased use in mitral replacements between 1991 and 1995 than between 1986 and 1990. The mortality rate was determined by patient subset for primary operation and reoperation and by urgency status. The modeling showed that the predicted and observed mortality correlated for all age groups and within patient subsets. CONCLUSIONS: Risk modeling is a valuable tool for predicting the probability of operative death in any individual patient. This large, multiinstitutional database is capable of determining modern operative risk and should provide standards for acceptable care. The study illustrates the importance of risk stratification for early death both for the patient and the surgeon.

Impact of gender on coronary bypass operative mortality.

BACKGROUND: In spite of many reports investigating the influence of gender on coronary artery operations, it is still uncertain whether gender is an independent risk factor for operative mortality. A major problem of previous reports has centered around the fact that men and women constitute quite different populations, thereby making direct comparisons difficult. METHODS: The Society of Thoracic Surgeons National Cardiac Surgery Database was used to retrospectively examine 344,913 patients undergoing coronary artery bypass graft operations from 1994 through the most recent data harvest. The operative mortality of male and female patients was compared for a variety of single risk factors and combinations of risk factors. A logistic risk model was used to account for all important patient parameters so that individuals could be stratified into comparable categories allowing for direct comparisons of risk-matched male and female patients. RESULTS: The univariate analysis showed that the 97,153 women carried a significantly higher mortality for each of the risk factors examined. The multivariate analysis and the risk model stratification showed that women had significantly higher mortality as compared to equally matched men in the low- and medium-risk part of the spectrum, but in high-risk patients, there was no difference between male and female mortality. CONCLUSIONS: Gender is an independent predictor of operative mortality except for patients in very high-risk categories.

Evaluation of 7,000+ patients with two different routes of cardioplegia.

BACKGROUND: This study examined the efficacy and safety of retrograde cardioplegia in comparison with an antegrade/retrograde approach. METHODS: Between January 1, 1991, and December 31, 1995, 7,032 coronary artery bypass procedures, alone or in combination with valve replacement/repair, were performed using either retrograde cardioplegia (R) or an antegrade/retrograde (AR) approach. There were 4,224 patients in the R group and 2,808 in the AR group. These included elective, urgent, emergent/salvage, first operative, and redo cases. RESULTS: All preoperative, intraoperative, and postoperative variables listed in The Society of Thoracic Surgeons National Cardiac Surgery Database were used to compare the two groups using univariate analysis. The pump time was longer in the AR group, with fewer grafts per patient. The R group had higher predicted risk (3.2% versus 3.0%; p = 0.04), more postoperative atrial fibrillation (34% versus 31%; p = 0.006), and longer postoperative length of stay (8.8 versus 8.0 days; p < 0.001). Using The Society of Thoracic Surgeons National Cardiac Surgery Database predicted risk group model, a subgroup of 221 coronary artery bypass grafting patients in the retrograde (s-R) and 132 coronary artery bypass grafting patients in the antegrade/retrograde (s-AR) group fell into a greater incidence of predicted mortality group (> or = 10%). The s-R subgroup had more patients in New York Heart Association functional class IV. Univariate analysis revealed higher postoperative atrial fibrillation (51% versus 41%; p = 0.05) and longer postoperative length of stay (12.8 versus 10.8 days; p = 0.03) in the s-R subgroup versus the s-AR subgroup. CONCLUSIONS: The results appear to favor neither approach. Preoperatively, both retrograde groups (R and s-R) had higher preoperative predicted risk, but operative mortality or complications were not significantly increased when compared with the AR and s-AR groups. Retrograde cardioplegia alone was shown to be effective in the R and s-R groups, but atrial fibrillation developed in more patients, which could have contributed to longer length of stay in these groups. Antegrade/retrograde cardioplegia offers good immediate outcome but the delivery method can be cumbersome and confusing during the adjustments of flow clamps for antegrade/retrograde delivery and may contribute to prolonged pump times. From this retrospective, nonrandomized review, it appears that retrograde cardioplegia alone provides as good myocardial protection and safety as an antegrade/retrograde approach in either the low-risk or high-risk patient.