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Objectives: The study was done to determine whether race is an independent predictor of operative mortality after coronary artery bypass graft (CABG) surgery., Background: Blacks are less frequently referred for cardiac catheterization and CABG than are whites. Few reports have investigated the relative fate of patients who undergo CABG as a function of race., Methods: The Society of Thoracic Surgeons National Database was used to retrospectively review 25,850 black and 555,939 white patients who underwent CABG-alone from 1994 through 1997. A multivariate logistic regression model was developed to determine whether race affected risk-adjusted operative mortality., Results: Operative mortality was 3.83% for blacks versus 3.14% for whites (unadjusted black/white odds ratio [OR] 1.23 [1.15-1.31]). Blacks were younger, more likely female, hypertensive, diabetic and in heart failure. Nonetheless, the influence of these and other preoperative risk factors on procedural mortality was quite similar in black and white patients. After controlling for all risk factors, race remained a significant independent predictor of mortality in the multivariate logistic model (adjusted black/white OR 1.29 [1.21, 1.38]). Proportionately, these differences were greatest among lower-risk patients. The race-by-gender interaction was significant (p<0.05). The unadjusted mortality for black men, 3.30% and white men, 2.64% differed significantly (p<0.05), whereas for women there was no difference (black, 4.49%; white 4.41%)., Conclusions: Black race is an independent predictor of operative mortality after CABG except for very high-risk patients. The difference in mortality is greatest for male patients and, though statistically significant, is small in absolute terms. Therefore, patients should be referred for CABG based on clinical characteristics irrespective of race.

Background: The Society of Thoracic Surgeons Adult Cardiac National Database has recently completed the update for the 1996 risk model to be used to estimate the risk of operative death for isolated coronary artery bypass graft (CABG) procedures., Methods: We placed emphasis on clinical relevance, data quality, data completeness, and univariate analyses. A logistic regression approach was used to develop the 1996 CABG-only risk model., Results: Odds ratios for the factors with highest risk are multiple reoperations (OR = 4.3), emergent salvage status (OR = 3.7), and first reoperation (OR = 2.7). Standard performance measures indicated the model had high predictive power and an acceptable level of calibration after adjustment for a large sample size effect., Conclusion: The most current STS risk model of CABG operative mortality is a reliable and statistically valid tool. The 1996 CABG-only model has been approved for use by The Society of Thoracic Surgeons.

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.

Background: The Society of Thoracic Surgeons (STS) Adult Cardiac National Database has recently completed the development of the 1995 risk model to be used to estimate the risk of operative death for isolated coronary artery bypass graft (CABG) procedures. This article describes the detailed methodology used, as well as a new Expert Advisory Panel review mechanism that was initiated by The Society., Methods: Placing emphasis on clinical relevance, data quality, data completeness, and univariate analyses, a logistic regression analysis was used to develop the 1995 CABG-only risk model. The STS National Office invited an Expert Advisory Panel (composed of nationally recognized, independent biostatisticians) to review the modeling process used., Results: The 1995 CABG-only model details are reported. Standard performance measures indicated the model had high predictive power and an acceptable level of calibration. The Expert Advisory Panel reviewed the 1995 CABG model and concluded that the current modeling techniques were adequate. Suggestions for future model development and reporting were proposed by the Panel., Conclusions: The most current STS risk model of CABG operative mortality is a reliable and statistically valid tool. Its development and performance have been critically examined and approved by an independent panel of experts.

Background: The Society of Thoracic Surgeons National Cardiac Surgery Database has recently completed gathering patient data from 1990 through 1994. Using information from more than 300,000 patients undergoing isolated coronary artery bypass grafting in this period, new risk models of operative mortality were developed., Methods: Logistic regression analysis was used to develop a risk model for each calendar year. A standard "training set/test set" approach was used for each model., Results: Five validation techniques were used to evaluate the reliability of the risk models. All models were found to predict operative mortality with good accuracy in this population., Conclusions: The new risk models for isolated coronary artery bypass operations serve as reliable predictors of operative mortality for the most recent harvest of patient data from The Society of Thoracic Surgeons National Cardiac Surgery Database.

A computerized statistical model based on the theorem of Bayes was developed to predict mortality after coronary artery bypass grafting. From January, 1984, to April, 1987, at our hospital, 700 patients underwent isolated coronary artery bypass grafting. The presence or absence of 20 risk factors was determined for each patient. The first 300 patients formed the initial database of the Bayesian predictive model, and the remaining 400 patients were prospectively evaluated in four groups of 100 each. Each group was prospectively evaluated and then incorporated into the database to update the model. There was good agreement between predicted and observed results. Bayesian theory is particularly suited to this task because it (1) accommodates multiple risk factors, (2) is tailored to one's specific practice, (3) determines individual, rather than group, prognosis, and (4) can be updated with time to compensate for a changing patient population. These flexible attributes are especially valuable in light of recent changes in the coronary artery bypass graft patient profile.

The Society of Thoracic Surgeons' National Cardiac Database was used to determine the changes in preoperative characteristics and the predicted and observed risk of operative mortality of patients undergoing coronary artery bypass grafting during the decade of 1984 to 1993. During this period, the data show an increase of 2.5 years in age and decreases of 3% both in incidence of male patients and in incidence of first operation. There was little change in the percentages of urgent/emergent procedures or mean left ventricular ejection fraction. There was a significant 17.5% decrease in the proportion of lowest risk patients (0% to 2.5% predicted mortality) from 61.1% to 43.6%. Although no change in the next higher risk group (> 2.5% to 5.0% predicted mortality) occurred, the higher risk groups showed increases of 6.2%, 9.1%, 1.4%, and 1.1% for the > 5% to 10%, > 10% to 20%, > 20% to 30%, and > 30% to 50% risk groups, respectively. Over the past 2 years, there have been no significant changes in the distribution of the risk groups. These data will provide a base for comparison of future endeavors to lower complication rates and cost of coronary artery bypass graft operations.

Forty-three patients undergoing median sternotomy were evaluated for postoperative pain and pulmonary function. Group 1 (n = 26) had harvest of the internal mammary artery (IMA) and group 2 (n = 17) did not. Postoperative pain and pulmonary function were evaluated on the fifth postoperative day. Both groups showed a decrease in forced expiratory volume in 1 second (group 1, 44%; group 2, 39%), but there was no significant difference in the loss between the two groups (p = 0.32). Using a numeric rating scale, there was significant increase in postoperative pain in group 1 (group 1, 6.35; group 2, 3.82; p = 0.0002). There is a suggestion that internal mammary artery harvesting itself worsens postoperative pulmonary function tests, and this may be related to a significant increase in postoperative pain.

Previous reports of elderly patients undergoing coronary artery bypass grafting have not addressed the current era of aggressive percutaneous angioplasty and frequent urgent or emergent operation. To investigate this important subgroup of patients, we analyzed our recent coronary artery bypass grafting experience with patients 70 years of age or older. From January 1984 to January 1989, 121 consecutive patients in this age range underwent surgical revascularization at our institution. Overall in-hospital operative mortality (OM) was 7.4% (9/121), with 77.8% (7/9) of deaths due to cardiac causes. Serious postoperative morbidity occurred in 71.1% (86/121). Surgical priority was significantly correlated with operative mortality: for elective cases, the OM was 2.9% (2/68), but it was 8.6% (3/35) for urgent cases (p less than 0.05) and 22.2% (4/18) for emergency cases (p less than 0.05). Univariate analysis isolated the need for inotropic support, intraaortic balloon pump, reoperation, cardiopulmonary resuscitation, and emergency status as significant risk factors for OM (p less than 0.05). Multivariate stepwise logistic regression analysis identified the need for inotropic support, intravenous nitroglycerin, reoperative coronary artery bypass grafting, and hypertension as independently significant risk factors. A logistic risk equation developed from this population accurately modeled OM at the extremes of operative risk. Three (3.1%) of the 97 patients predicted to have less than 5% OM died, whereas all patients predicted by the model to have greater than 90% OM died. These results indicate that in spite of relatively high morbidity and mortality rates, elderly patients have a very acceptable operative risk in the current era of high-risk coronary artery bypass grafting. This is particularly true if elective revascularization is possible.

A statistical model has been developed to allow for prediction of individual patient prognosis following urgent/emergent coronary artery bypass grafting (CABG). None of the models previously described for use in coronary artery surgery has been tested with a prospective patient series that confirms the true predictive capacity of the model. Ideally, the predictive ability of such models should be validated with prospective trials. To examine the feasibility of statistical modeling in this clinical context, a computerized model based on the theorem of Bayes was developed to predict operative mortality for urgent coronary artery surgery. The presence or absence of 20 risk factors was determined for each of 405 consecutive patients undergoing urgent coronary artery surgery from January 1984 to January 1989. The first 100 patients were used to develop a database for the model, which was then used to prospectively evaluate the remaining 305 patients. There was good agreement between predicted and observed results. Models of this kind are particularly advantageous because of the ability to (1) accommodate multiple risk factors, (2) become tailored to a specific practice, and (3) determine individual rather than group prognosis. Validation with a prospective trial confirms the practical utility of this approach. This model has reliably predicted the risk associated with urgent coronary artery surgery and may provide important clinical information for the management of patients being evaluated for urgent revascularization.

Previous reports of emergency coronary artery bypass grafting often included cases that were not true surgical emergencies, thereby creating inappropriately favorable results. To accurately investigate this important subgroup of patients, we analyzed our recent experience with truly emergent coronary artery bypass grafting. From January 1984 to January 1989, 117 patients underwent true emergency bypass grafting for acute refractory coronary artery ischemia. Clinical deterioration was associated with failure of percutaneous angioplasty in 37 patients and instability during diagnostic catheterization in 13 patients. Refractory ischemia developed in the remaining patients while on the ward or in the intensive care unit. All operations were performed within four hours of surgical consultation, most within one hour. Overall in-hospital operative mortality was 14.5% (17/117), and 76.5% of deaths (13/17) were due to cardiac-related causes. Major morbidity occurred in 35.9% (42/117). Univariate analysis isolated ejection fraction, extent of coronary artery disease, previous myocardial infarction, hypertension, need for inotropic support, use of an intraaortic balloon pump, and cardiopulmonary resuscitation as risk factors for operative mortality. Stepwise multivariate analysis confirmed that previous myocardial infarction, hypertension, cardiopulmonary resuscitation, and reoperation were independently significant risk factors. Age, sex, diabetes, left main disease, and peripheral vascular disease had no significant impact on the prognosis. The 4% operative mortality (2/50) for patients taken directly to the operating room from the catheterization suite was significantly lower than the 22.4% mortality (15/67) associated with emergencies arising on the ward or intensive care unit (p less than 0.01). A logistic risk equation developed from this population accurately modeled operative mortality.(ABSTRACT TRUNCATED AT 250 WORDS)

A patient with coronary artery disease and idiopathic thrombocytopenia purpura underwent coronary artery bypass grafting without splenectomy. Our experience indicates that use of cardiopulmonary bypass in patients with idiopathic thrombocytopenic purpura does not invariably mandate splenectomy.

Quality assurance in coronary artery bypass grafting (CABG) surgery requires a comparison of operative mortality against an accepted standard of care. Raw mortality statistics are unacceptable in this context, and risk factor analysis is essential. However, this principle has not been adequately demonstrated in previous reports. Our goal in this study was to develop a risk model of accepted CABG mortality and illustrate its proper use in coronary artery surgery. The model was derived from a Bayesian analysis of 6,630 patients undergoing CABG in the Coronary Artery Surgery Study (CASS) registry. Age, sex, ventricular function, previous myocardial infarction, extent of coronary artery disease, unstable angina, and surgical priority were used by the model to sort patients into risk categories. From January 1984 through December 1987, 840 patients underwent isolated CABG at our hospital. With raw mortality data, the 3.9% (33/840) mortality of our patients was significantly different from the 2.3% (153/6,630) CASS mortality (p less than 0.001). When our patients were entered into the CASS model for risk stratification, however, our CABG mortality conformed to the CASS experience. These results illustrate the fallacy of using raw mortality statistics for interinstitutional comparisons. This type of risk model is a fundamental element of CABG quality assurance.

A computerized statistical model based on the theorem of Bayes was developed to predict mortality after coronary artery bypass grafting. From January, 1984, to April, 1987, at our hospital, 700 patients underwent isolated coronary artery bypass grafting. The presence or absence of 20 risk factors was determined for each patient. The first 300 patients formed the initial database of the Bayesian predictive model, and the remaining 400 patients were prospectively evaluated in four groups of 100 each. Each group was prospectively evaluated and then incorporated into the database to update the model. There was good agreement between predicted and observed results. Bayesian theory is particularly suited to this task because it (1) accommodates multiple risk factors, (2) is tailored to one's specific practice, (3) determines individual, rather than group, prognosis, and (4) can be updated with time to compensate for a changing patient population. These flexible attributes are especially valuable in light of recent changes in the coronary artery bypass graft patient profile.