The effect of race on coronary bypass operative mortality.

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.

Prediction of operative mortality after valve replacement surgery.

OBJECTIVES: We sought to develop national benchmarks for valve replacement surgery by developing statistical risk models of operative mortality. BACKGROUND: National risk models for coronary artery bypass graft surgery (CABG) have gained widespread acceptance, but there are no similar models for valve replacement surgery. METHODS: The Society of Thoracic Surgeons National Cardiac Surgery Database was used to identify risk factors associated with valve surgery from 1994 through 1997. The population was drawn from 49,073 patients undergoing isolated aortic valve replacement (AVR) or mitral valve replacement (MVR) and from 43,463 patients undergoing CABG combined with AVR or MVR. Two multivariable risk models were developed: one for isolated AVR or MVR and one for CABG plus AVR or CABG plus MVR. RESULTS: Operative mortality rates for AVR, MVR, combined CABG/AVR and combined CABG/ MVR were 4.00%, 6.04%, 6.80% and 13.29%, respectively. The strongest independent risk factors were emergency/salvage procedures, recent infarction, reoperations and renal failure. The c-indexes were 0.77 and 0.74 for the isolated valve replacement and combined CABG/valve replacement models, respectively. These models retained their predictive accuracy when applied to a prospective patient population undergoing operation from 1998 to 1999. The Hosmer-Lemeshow goodness-of-fit statistic was 10.6 (p = 0.225) for the isolated valve replacement model and 12.2 (p = 0.141) for the CABG/valve replacement model. CONCLUSIONS: Statistical models have been developed to accurately predict operative mortality after valve replacement surgery. These models can be used to enhance quality by providing a national benchmark for valve replacement surgery.

Primary mediastinal masses. A comparison of adult and pediatric populations.

Since 1944 62 pediatric patients with primary cysts and tumors of the mediastinum have been operated on at our institution. We compared this group with 195 adult patients with similar diagnoses who were operated on during this period. Comparisons were made with regard to histologic type, location, presenting symptoms, physical findings, and surgical complications. We found significant increases in the prevalence of lymphoma in adults (41/195 versus 4/62, p < 0.05) and of neurogenic tumors in children (21/62 versus 24/195, p < 0.05). There were no significant differences in the prevalence of thymic tumors (51/195 versus 22/62), germ cell tumors (24/195 versus 4/62), and cysts (32/195 versus 15/62). There was no difference in the prevalence of symptomatic patients (99/195 versus 36/62). The prevalence of malignancy has increased in both groups since 1970 (2/28 versus 16/34 in children, p < 0.01; and 14/56 versus 69/139 in adults, p < 0.05). This is attributed to a rise in the prevalence of malignant neurogenic tumors in children and to an increase in the prevalence of lymphomas in adults. Tumor size, location, and the presence of symptoms were predictive of malignancy in the adult population but not in the pediatric population. No difference existed in mortality and morbidity between the two groups. All three pediatric deaths were directly related to loss of airway control as a result of mass effect from the tumor. Definite differences exist between the adult and pediatric populations with regard to mediastinal tumors. These differences need to be considered carefully when evaluating and planning treatment for a child with a mediastinal mass.

Risk assessment in urgent/emergent coronary artery surgery.

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.

Surgical implications of intraoperative postinfarction ventricular rupture.

This case report documents that ventricular myocardial rupture after acute infarction may seal with clot, only to rupture again with potentially lethal consequences. At exploration, the clot over a fresh rupture was intact. As closure was started, the clot disrupted, causing severe hemorrhage. Rupture was successfully repaired and the patient survived.

Bayesian statistical theory in the preoperative diagnosis of pulmonary lesions.

We used a computerized Bayesian algorithm to assist in the preoperative diagnosis of pulmonary lesions. One hundred consecutive patients who were undergoing exploratory thoracotomy for newly discovered pulmonary lesions were prospectively evaluated. The Bayesian model used a total of 44 preoperative clinical and roentgenographic factors to categorize the lesions as benign or malignant. The Bayesian algorithm correctly categorized 96 of the 100 lesions, thereby providing an accuracy of 96 percent. The sensitivity of the model was 98 percent and the specificity was 87 percent. All but two of the 85 malignant lesions were correctly categorized and 13 of the 15 benign lesions were correctly analyzed by the model. These results indicate that computer-assisted diagnosis using the Theorem of Bayes may provide valuable preoperative information for the management of selected patients.

Surgical management of posteroseptal accessory atrioventricular pathways.

From October 1988 through January 1991, 22 consecutive patients with Wolff-Parkinson-White syndrome underwent surgical ablation of symptomatic accessory posteroseptal atrioventricular pathways at our institution. As our experience with posteroseptal tracts accumulated, we found that surgical technique was logically dictated by the presence of free wall tracts and the exact location of the posteroseptal tract. Accordingly, we developed an operative approach that involves the selective use of endocardial, epicardial, and cryoablation techniques depending on the anatomic location of accessory tracts. This selective approach allows one to exploit the advantages of each technique while minimizing associated disadvantages. There were 14 men and 8 women with an average age of 25 years (range, 19 to 39 years). All patients had symptomatic tachyarrhythmias caused by accessory atrioventricular pathway(s). Most required several antiarrhythmic medications and 17 (77%) had poor arrhythmia control despite maximal medical therapy. Twelve patients had two accessory pathways and 3 also had dual atrioventricular nodal pathways. There were no early or late deaths. In 2 patients, a delta wave associated with a free wall tract reappeared 3 to 5 days after the initial operation, necessitating a second operation which successfully eliminated the accessory tract. All posteroseptal tracts were successfully eliminated during the initial operation. All patients were relieved of symptoms and are now free of medical therapy. Each patient has undergone a postoperative electrophysiologic study which confirms the absence of posteroseptal accessory conduction. The selective approach has been totally successful in our hands and should prove useful to those interested in optimizing the efficiency of surgical procedures for Wolff-Parkinson-White syndrome.

Practical considerations in the management of large multiinstitutional databases.

Large multiinstitutional databases are excellent sources of information that provide clinically useful insight into the practice of cardiac surgery. Fully informed subscribers should be aware of the practical concerns associated with the management and interpretation of database results. During development of The Society of Thoracic Surgeons National Database, three such areas have become particularly important: the database population, the database quality, and the significance of results. Appreciation of the real and philosophical problems associated with these issues will allow for greater appreciation of the intricacies of the database and will enhance the users' ability to interpret information gained from the database.

Profile of preoperative characteristics of patients having CABG over the past decade.

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.

Impact of internal mammary artery conduits on operative mortality in coronary revascularization.

The long-term advantages of internal mammary artery (IMA) conduits in coronary artery bypass graft (CABG) procedures are widely recognized, but the immediate short-term impact of IMA grafts is not well defined. The purpose of this study was to investigate the influence of IMA conduits on CABG operative mortality (OM). A retrospective study of two groups of patients undergoing isolated CABG was performed. Patients having at least one IMA graft (group 1) were compared with those with only venous conduits (group 2). The patient population was taken from The Society of Thoracic Surgeons National Cardiac Surgery Database, which contains a broad multi-institutional experience. A total of 38,578 registered patients undergoing isolated CABG from 1987 through 1991 were studied. Of these, 18,614 patients had at least one IMA conduit (group 1), whereas 19,964 had CABG using entirely venous conduits (group 2). The OM for group 1 was 2.0% (365/18,614), whereas the mortality was 4.5% (903/19,964) for group 2 (p < 0.005). Patient subgroups were examined to determine if the improved OM associated with IMA grafting was present in these patient subsets. The population was broken down according to age, sex, ejection fraction, extent of coronary disease, and operative priority. For each subset, univariate analysis showed that group 1 OM was significantly less (p < 0.005) than the OM for group 2. Numerous combinations of these patient parameters were also analyzed. Group 1 patients had a significant (p < 0.05) improvement in OM in each combination except for patients more than 70 years of age requiring reoperations.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary artery bypass grafting: the Society of Thoracic Surgeons National Database experience.

The need for accurate risk assessment has become an indispensable element in the practice of cardiac surgery. The Society of Thoracic Surgeons National Cardiac Surgery Database allows subscribing institutions to perform sophisticated patient risk assessment using traditional statistical tools and a newly developed risk model of operative mortality. The database experience with isolated coronary artery bypass grafting has been studied most closely at this point and serves as the basis for this report. The approach to operative risk assessment is presented along with an analysis of important risk factors in the practice of coronary artery surgery from 1980 through 1990. The database contains records of 80,881 patients undergoing coronary artery bypass grafting in numerous institutions from 1980 through 1990. These records were used to conduct a detailed analysis of risk factors associated with coronary operations in this time interval and to present statistical methods used to formulate a risk equation that allows one to predict the probability of operative death. In the course of this decade, there were clearly defined trends showing a statistically significant increase in adverse patient risk factors. The risk model has proven to be a reliable tool for predicting the probability of operative death in an individual patient and may be valuable in both patient counseling and medical decision making. Large multi-institutional databases of this type are key ingredients of modern operative risk assessment. A database containing a broad national experience of this type can represent an aggregate experience that may well approximate a universally accepted standard of care.

Post-atherectomy coronary artery aneurysm.

A 52-year-old man underwent an uneventful directional atherectomy of the left anterior descending coronary artery. Four months after the procedure unstable angina developed and on angiogram an aneurysm of the left anterior descending coronary artery was noted. The patient underwent bypass of the left anterior descending coronary artery. An attempt to exclude the aneurysm resulted in hemodynamic compromise and was discontinued. Follow-up angiogram 2 months after operation showed the aneurysm to be smaller. The patient is doing well 6 months after operation.

Primary cysts and tumors of the mediastinum.

A retrospective analysis was performed on 230 patients with primary cysts and tumors of the mediastinum seen at our institution from January 1944 to April 1989. We divided these patients into two groups. Group 1 was seen before 1970 and group 2 was seen from January 1970 to April 1989. There was a significant increase in the prevalence of malignancy in group 2 (47.2% versus 17.1%; p less than 0.0001) due to an increase in the number of lymphomas (22.6% versus 3.5%; p less than 0.001) and malignant neurogenic tumors (6.8% versus 1.1%; p = 0.0528). There was a significant increase in the number of malignant tumors in the anterior (59.5% versus 30.9%; p = 0.0022) and paravertebral (28.5% versus 2.8%; p = 0.0027) compartments in group 2. More patients with these tumors were symptomatic in group 2 (63.6% versus 5%; p = 0.0422). There was an increase of ancillary diagnostic studies performed to evaluate these tumors (76.0% versus 34.5%; p = 0.0422). Logistic regression analysis identified date of presentation (p less than 0.005), symptoms (p less than 0.01), size (p less than 0.005), and the anterior mediastinal compartment (p less than 0.005) as preoperative predictors of malignancy. The surgical approach to these tumors included more median sternotomy (30.1% versus 10.7%; p = 0.0008), anterior mediastinotomy, and cervical mediastinoscopy in group 2 (1.1% versus 17.5%; p = 0.0002). Long-term results support surgical resection in benign lesions and an aggressive multimodality approach to malignant lesions.

1995 coronary artery bypass risk model: The Society of Thoracic Surgeons Adult Cardiac National Database.

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.

Updates to the Data Quality Review Program: the Society of Thoracic Surgeons Adult Cardiac National Database.

To ensure the credibility of this voluntary database, The Society of Thoracic Surgeons' National Database Audit and Validation Sub-Committee has been working during the past year to update and expand the group practice-based indicators used to assess the completeness, accuracy, and generalizability of the Adult Cardiac National Database. With increasing frequency, questions have been raised by third-party payors and regional/state-based groups as to the integrity of the data retained in the Adult Cardiac National Database. To work in conjunction with the Audit and Validation Sub-Committee to explicitly examine these issues, The Society of Thoracic Surgeons initiated a new Expert Advisory Panel review mechanism. This article describes the expanded data completeness and quality criteria that will be implemented in the coming year and summarizes the Expert Advisory Panel's recommendations for improvement.

1988: use of a Bayesian statistical model for risk assessment in coronary artery surgery. Updated in 1995.

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.

Effect of lung contusion on pulmonary hemodynamics.

Our purpose was to examine changes in pulmonary hemodynamics for patients with pulmonary contusion. Pulmonary vascular resistance index (PVRI) and shunt fraction were calculated from standard measurements in 25 traumatized patients. The percent of lung volume injured, measured as air-space filling disease (ASF), was quantitated from computed tomograms using a previously described technique. The amount of reactive pulmonary vasoconstriction per unit of injury (PVRI/ASF) identified 3 groups of patients: 5 were reactors (PVRI/ASF greater than 15), 10 were weak-reactors (PVRI/ASF = 5 to 15), and 10 were nonreactors (PVRI/ASF less than 5). In the reactor group PVRI increased as the size of contusion (ASF) increased (r = 0.99). In weak-reactors PVRI also increased with the size of contusion (r = 0.93), but the slope was less pronounced. In both groups shunt fraction did not rise above 0.31. In the nonreactors, PVRI remained normal while shunt fraction increased with the extent of injury (r = 0.95). These results indicate that pulmonary vasoconstriction often occurs after pulmonary contusion. The vasoconstriction most probably represents a compensatory mechanism to limit perfusion of traumatized parenchyma, thereby minimizing increases in shunt fraction. Some patients (nonreactors) not demonstrating this response have unchecked increases in shunt fraction. This insight into the hemodynamic sequelae of pulmonary contusions may enhance our ability to provide optimal care for patients suffering from this injury.

Anomalous pulmonary venous drainage of the right lung.

An unusual case of anomalous drainage of the right lung is described. The right superior pulmonary vein drained into the superior vena cava, and the middle and lower pulmonary veins drained into the inferior vena cava. Repair was achieved by creating a pericardial baffle that drained the inferior vein and the orifice of the superior vena cava through a surgically created atrial septal defect. The superior vena cava was transected and the distal portion anastomosed to the right atrial appendage.

Three-dimensional image reconstruction for planning of a complex cardiovascular procedure.

A rare left subclavian artery aneurysm associated with a congenital arch anomaly was difficult to visualize using standard radiographic techniques. Three-dimensional computer imaging produced a clear depiction of this unusual anatomy and simplified the preoperative planning.

Pediatric and adult thoracic trauma: age-related impact on presentation and outcome.

UNLABELLED: To assess the impact of age on presentation and outcome, 2,415 cases involving blunt and penetrating thoracic trauma over an 8-year period were reviewed retrospectively from a single level I trauma center. Of the 2,073 patients alive on arrival, 79 were 12 years of age or less (children), 137 were 13 to 17 years of age (adolescent), 1,742 were 18 to 59 years of age (adults), and 115 were 60 years of age or more (elderly). Chi-square analysis was performed relative to presentation (blunt versus penetrating), need for thoracotomy, and hospital mortality. Although blunt thoracic trauma comprised 64/79 of children (81%) and 90/115 of the elderly (78%), penetrating thoracic trauma was more common for adolescents 79/137 (58%) and adults 1013/1742 (58%) (p < 0.05). There was no significant difference in need for thoracotomy among the four age groups after blunt thoracic trauma. For penetrating trauma, however, there was a significantly higher incidence of thoracotomy in children as compared with the other three age groups (p < 0.05). IN CONCLUSION: (1) Blunt injuries comprised a greater proportion of thoracic trauma in children and the elderly. (2) In this series, children with penetrating thoracic trauma underwent thoracotomy more frequently. (3) Hospital mortality appeared to be increased for the elderly. (4) Analyses of pediatric thoracic trauma must separate children from adolescent age groups.