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.

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.

Time series monitors of outcomes. A new dimension for measuring quality of care

OBJECTIVES

Despite the popularity of risk-adjusted outcomes as quality of health care indicators, their instability with time and their inability to provide reliable comparisons of small volume providers have raised questions about the feasibility and credibility of using these measures. In this article the authors describe a new analytic strategy to address these problems by examining risk-adjusted mortality with time, "Time Series Monitors of Outcome" (TSMO), and its application to cardiac surgery performed throughout the Department of Veterans Affairs between April 1987 and September 1992.

METHODS

Expected operative mortality for 24,029 patients undergoing coronary artery bypass surgery at all 43 centers performing this procedure was estimated using a logistic regression model to adjust for patient-specific risk factors. The ratio of observed-to-expected operative mortality was calculated for each hospital for each of the 11 6-month periods. Poisson regression models were used to identify high and low outlier hospitals based on significant deviation from the 5.5 year overall mean and/or the individual hospital's trend of observed-to-expected ratios with time.

RESULTS

This method identified four high and one low outlier hospitals based on significant deviations from the overall mean and three upward and seven downward trending outlier hospitals based on significant deviations in trend with time. A significant downward trend in observed-to-expected ratios of 4% per year also was observed for all coronary artery bypass graft procedures performed throughout the Department of Veterans Affairs during the last 5.5 year period.

CONCLUSIONS

Time Series Monitors of Outcome should help reduce misclassification of outliers due to random variation in outcomes as well as provide more reliable comparative information from which to evaluate provider performance.

Atrial fibrillation after cardiac surgery: a major morbid event?

OBJECTIVE

The purpose of the study was to investigate the incidence, predictors, morbidity, and mortality associated with postoperative atrial fibrillation (AF) and its impact on intensive care unit (ICU) and postoperative hospital stay in patients undergoing cardiac surgery in the Department of Veterans Affairs (VA).

SUMMARY BACKGROUND DATA

Postoperative AF after open cardiac surgery is rather common. The etiology of this arrhythmia and factors responsible for its genesis are unclear, and its impact on postoperative surgical outcomes remains controversial. The purpose of this special substudy was to elucidate the incidence of postoperative AF and the factors associated with its development, as well as the impact of AF on surgical outcome.

METHODS

The study population consisted of 3855 patients who underwent open cardiac surgery between September 1993 and December 1996 at 14 VA Medical Centers. Three hundred twenty-nine additional patients were excluded because of lack of complete data or presence of AF before surgery, and 3794 (98.4%) were male with a mean age of 63.7+/-9.6 years. Operations included coronary artery bypass grafting (CABG) (3126, 81%), CABG + AVR (aortic valve replacement) (228, 5.9%), CABG + MVR (mitral valve replacement) (35, 0.9%), AVR (231, 6%), MVR (41, 1.06%), CABG + others (95, 2.46%), and others (99, 2.5%). The incidence of postoperative AF was 29.6%. Multivariate logistic regression analysis of factors found significant on univariate analysis showed the following predictors of postoperative AF: preoperative patient risk predictors: advancing age (odds ratio [OR] 1.61, 95% confidence interval [CI] 1.48-1.75, p < 0.001), chronic obstructive pulmonary disease (OR 1.37, 95% CI 1.12-1.66, p < 0.001), use of digoxin within 2 weeks before surgery (OR 1.37, 95% CI 1.10-1.70, p < 0.003), low resting pulse rate <80 (OR 1.26, 95% CI 1.06-1.51, p < 0.009), high resting systolic blood pressure >120 (OR 1.19, 95% CI 1.02-1.40, p < 0.026), intraoperative process of care predictors: cardiac venting via right superior pulmonary vein (OR 1.42, 95% CI 1.21-1.67, p < 0.0001), mitral valve repair (OR 2.86, 95% CI 1.72-4.73, p < 0.0001) and replacement (OR 2.33, 95% CI 1.55-3.55, p < 0.0001), no use of topical ice slush (OR 1.29, 95% CI 1.10-1.49, p < 0.0009), and use of inotropic agents for greater than 30 minutes after termination of cardiopulmonary bypass (OR 1.36, 95% CI 1.16-1.59, p < 0.0001). Postoperative median ICU stay (3.6 days AF vs. 2 days no AF, p < 0.001) and hospital stay (10 days AF vs. 7 days no AF, p < 0.001) were higher in AF. Morbid events, hospital mortality, and 6-month mortality were significantly higher in AF (p < 0.001): ICU readmission 13% AF vs. 3.9% no AF, perioperative myocardial infarction 7.41 % AF vs. 3.36% no AF, persistent congestive heart failure 4.57% AF vs. 1.4% no AF, reintubation 10.59% AF vs. 2.47% no AF, stroke 5.26% AF vs. 2.44% no AF, hospital mortality 5.95% AF vs. 2.95% no AF, 6-month mortality 9.36% AF vs. 4.17% no AF.

CONCLUSIONS

Atrial fibrillation after cardiac surgery occurs in approximately one third of patients and is associated with an increase in adverse events in all measurable outcomes of care and increases the use of hospital resources and, therefore, the cost of care. Strategies to reduce the incidence of AF after cardiac surgery should favorably affect surgical outcomes and reduce utilization of resources and thus lower cost of care.

Fast-track cardiac surgery in a Department of Veterans Affairs patient population

BACKGROUND

"Fast-track" (FT) cardiac surgery is popular in the private and university sectors. This study was designed to examine its safety and efficacy in the Department of Veterans Affairs elderly, male patient population, a population with multiple comorbid risk factors, often decreased social functioning, and impaired support systems.

METHODS

Time to extubation, hospital length of stay, perioperative morbidity, and mortality were studied in two consecutive cohorts undergoing cardiac operations requiring cardiopulmonary bypass before (pre-FT: n = 255, January 1992 to September 1993) and after (FT: n = 304, October 1993 to October 1995) institution of an FT protocol at a university-affiliated teaching Department of Veterans Affairs medical center. Preoperative risk factors, including a Department of Veterans Affairs risk-adjusted estimate of operative mortality, and perioperative surgical and anesthetic processes of care were evaluated.

RESULTS

The mean Department of Veterans Affairs risk estimate of perioperative mortality was not different between the pre-FT and FT cohorts (3.5% versus 3.7%, p = 0.13). In the FT cohort, median time to extubation decreased significantly (19.2 versus 10.2 hours; p < 0.001) along with median surgical intensive care unit stay (96 versus 49 hours; p < 0.001) and total postoperative length of stay (222 versus 167 hours; p < 0.001). Median postoperative day of hospital discharge decreased from day 10 to 7 (p < 0.001). One patient (0.3%) required emergent reintubation directly related to early extubation. Reintubation for medical reasons was unchanged between pre-FT and FT groups (6.3% versus 5.0%; p = 0.48). Postoperative morbidity was similar between groups except for nosocomial pneumonia, the rate of which decreased significantly in the FT cohort (14.7% versus 7.3%; p < 0.005). Thirty-day (3.9% versus 4.6%; p = 0.69) and 6-month mortality (6.7% versus 6.9%; p = 0.91) were unchanged.

CONCLUSIONS

An FT cardiac surgery protocol has been instituted in a university-affiliated teaching Department of Veterans Affairs medical center, with decreased length of stay and no significant increase in postoperative morbidity, 30-day mortality, or 6-month mortality. It was associated with a lower rate of nosocomial pneumonia, a finding that must be validated in a prospective study.

The past, present, and future of lung transplantation

BACKGROUND

The history of lung transplantation from the first human transplant performed in 1963 to the present is reviewed with particular focus on the added challenges because of the contaminated bronchus, exposure of the graft to airborne organisms, the poor blood supply to the bronchus, and the problem of reperfusion pulmonary edema.

METHODS

The technical aspects of single and double sequential lung transplantation are reviewed, as are the current indications for single, double sequential, and heart/lung transplantation. Criteria for lung transplant recipients, in addition to their primary disease are noted, as are absolute and relative contraindications. The standard criteria for donor selection are also reviewed.

RESULTS

The results of single, double sequential, and heart-lung transplantation over the past 10 years as reported by the International Society for Heart and Lung Transplantation Database are reviewed. In addition, the statistics of the lung and heart-lung transplantation program at the University of Colorado Health Sciences Center are reviewed, including the current immunosuppressive regimens and early and late monitoring for infection and rejection. This experience includes 3 early deaths in the first 53 patients for an operative mortality of 5.6%, with a 1-year actuarial survival of 90%.

CONCLUSIONS

During the past decade remarkable improvement in the result of single and double sequential lung transplantation have occurred. As 1-year, actuarial survival is now approaching 90% at some institutions. Living related lobar transplantation, new antirejection agents, chimerism, and xenograft transplantation are areas for continuing and future investigation. The shortage in donor organ supply continues to be a very significant factor in limiting human lung transplantation.

Trauma to the heart

Traumatic injury to the heart is no longer a death sentence. Efficient urban transport systems and surgeons who are expert in trauma care combine to achieve meaningful survival rates after both penetrating and blunt violations of the heart. Almost all cases of injury to the heart can be repaired without cardiopulmonary bypass and, therefore, are within the purview of the thoracic surgical trauma specialist.

Variable response to inhaled nitric oxide after cardiac surgery

BACKGROUND

Inhaled nitric oxide (NO) is a promising therapy that may be valuable in the control of pulmonary hypertension in cardiac surgical patients. Patients with valvular heart disease have remodeling of the pulmonary vascular bed that contributes to pulmonary hypertension. The purpose of this study was to compare the efficacy of inhaled NO in cardiac surgical patients with pulmonary hypertension with and without valvular heart disease.

METHODS

The effect of inhaled NO (40 ppm) on pulmonary hemodynamics in patients with pulmonary hypertension (mean pulmonary artery pressure > or = 30 mm Hg) was studied in the operating room after cardiac operation. Fifteen patients with valvular heart disease comprised the study group; 25 patients undergoing aortocoronary bypass grafting were controls.

RESULTS

In patients undergoing aortocoronary bypass grafting, inhaled NO produced a 24% decrease in mean pulmonary artery pressure (33 +/- 1 to 25 +/- 1 mm Hg; p < 0.05), a 36% decrease in pulmonary vascular resistance (375 +/- 30 to 250 +/- 30 dyne.s.cm-5; p < 0.05), and no change in systemic arterial blood pressure. On the other hand, patients with pulmonary hypertension from valvular heart disease did not respond to inhaled NO: mean pulmonary artery pressure was 39 +/- 3 mm Hg and pulmonary vascular resistance was 620 +/- 30 dyne.s.cm-5 before, during, and after NO.

CONCLUSIONS

Among cardiac surgical patients with pulmonary hypertension, the response to inhaled NO is variable. Despite the promise of inhaled NO as a pulmonary vasodilator in cardiac surgical patients, these data suggest that alternative therapies are needed to control pulmonary hypertension in patients with pulmonary hypertension from valvular heart disease.

The Society of Thoracic Surgeons National Cardiac Surgery Database: current risk assessment

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.

Effective control of refractory pulmonary hypertension after cardiac operations

OBJECTIVES

Inhaled nitric oxide is a promising therapy to control pulmonary hypertension. However, pulmonary hypertension caused by valvular heart disease is often refractory to inhaled nitric oxide. The objective of this study was to determine whether the combination of inhaled nitric oxide plus dipyridamole will cause a response in patients with pulmonary hypertension undergoing cardiac operations who had not responded to inhaled nitric oxide alone.

METHODS

Responses in 10 patients (62 +/- 7 years) with pulmonary hypertension caused by aortic or mitral valvular disease (mean pulmonary artery pressure, > or = 30 mm Hg) were studied in the operating room after valve replacement. The effect of inhaled nitric oxide alone (40 ppm) on pulmonary vascular resistance, mean pulmonary artery pressure, cardiac output, and mean arterial pressure was determined. Inhaled nitric oxide administration was then stopped and patients were given dipyridamole (0.2 mg/kg intravenously); the effect of inhaled nitric oxide plus dipyridamole was then examined.

RESULTS

Dipyridamole effected a response in patients who had not responded to nitric oxide. Pulmonary vascular resistance and mean pulmonary artery pressure were significantly reduced and cardiac output was increased without change in mean arterial pressure.

CONCLUSIONS

Patients with refractory pulmonary hypertension in whom inhaled nitric oxide alone fails to cause a response may respond to combined therapy of inhaled nitric oxide plus dipyridamole. This therapy may be particularly valuable in patients with dysfunction of the right side of the heart as a result of pulmonary hypertension because of its effective lowering of right ventricular afterload.

Calculating risk and outcome: the Veterans Affairs database

The methodology used by the Department of Veterans Affairs for data collection and analysis to derive observed/expected mortality ratios in cardiac surgical patients is reviewed. The Department of Veterans Affairs' use of univariate and multivariate analysis to develop risk ratios for individual risk factors is described. Its experience with tracking observed/expected mortality and morbidity associated with cardiac surgery and length of hospital stays is reviewed. Results of the Department of Veterans Affairs study of the relationship between hospital surgical volume and observed/expected ratios are reported. Feasible goals for the improvement of the predictive capability of database models and the limitations affecting model accuracy are discussed.

Data quality review program: the Society of Thoracic Surgeons Adult Cardiac National Database

In summary, the National Database Committee's Audit and Validation Subcommittee is working to maximize the data completeness and quality of the STS National Database. Toward this end, we welcome your suggestions for improvement.

Colon perforation after lung transplantation

BACKGROUND

Colon perforation has been previously described after solid organ transplantation. Since the inception of the lung transplant program at the University of Colorado 60 isolated lung transplantations have been performed. Four of these patients have suffered spontaneous colonic perforation.

METHODS

The case history of each lung transplant patient with a colon perforation and the literature were reviewed.

RESULTS

An increased incidence of colon perforation in lung transplant patients was identified. Diverticulitis was found to be the predominant cause, and an association with steroids was noted. The two deaths in this series were in patients receiving high-dose steroids in whom invasive Aspergillus infections developed.

CONCLUSIONS

Careful screening of the gastrointestinal tract before transplantation is advocated. A steroid-sparing immunosuppressive regimen is recommended. All lung transplant patients with abdominal complaints require an aggressive work-up, and surgeons should have a low threshold for laparotomy. Conservative surgical principles, including resection of the perforated segment of colon and proximal end-colostomy rather than primary anastomosis, are necessary for the optimal outcome.

Adenosine effectively controls pulmonary hypertension after cardiac operations

BACKGROUND

Pulmonary hypertension secondary to increased pulmonary vascular resistance may greatly complicate the perioperative management of patients having cardiac operations. Adenosine may have a therapeutic role as a selective pulmonary vasodilator. The purpose of this study was to examine the pulmonary hemodynamic effects of a central venous infusion of adenosine in cardiac operative patients with pulmonary hypertension.

METHODS

Ten cardiac patients with pulmonary hypertension (age, 62 +/- 6 years) were studied in the operating room under general anesthesia after weaning from cardiopulmonary bypass. Cardiac output, pulmonary vascular resistance, systemic vascular resistance, mean pulmonary arterial pressure, and mean systemic arterial pressure were determined before, during, and after central venous infusion of adenosine (50 micrograms x kg-1 x min -1) for 15 minutes. Statistical analysis was by analysis of variance, and significance was accepted at p < 0.05.

RESULTS

Adenosine produced significant pulmonary vasodilation. Mean pulmonary arterial pressure was lowered from 36 +/- 1 to 28 +/- 2 mm Hg (p < 0.05), and pulmonary vascular resistance was lowered from 560 +/- 30 to 260 +/- 30 dynes x s x cm-5 (p < 0.05) during adenosine administration. At the same time, cardiac output rose from 4.0 +/- 0.6 to 6.2 L/min (p < 0.05). Pulmonary vascular resistance, mean pulmonary arterial pressure, and cardiac output returned to baseline after the adenosine infusion was stopped. There was no change in systemic mean arterial pressure during adenosine infusion.

CONCLUSIONS

Adenosine may be used clinically as a selective pulmonary vasodilating agent to optimize pulmonary hemodynamic indices without adverse systemic hemodynamic effects in patients with pulmonary hypertension having cardiac operations. It may be particularly valuable in patients with right heart dysfunction by selectively lowering right ventricular afterload.

Effective control of pulmonary vascular resistance with inhaled nitric oxide after cardiac operation

Increased pulmonary vascular resistance may greatly complicate the perioperative management of cardiac surgical patients. Inhaled nitric oxide may be a promising new therapy to selectively lower pulmonary vascular resistance. The purpose of this study was to examine the effects of inhaled nitric oxide on pulmonary and systemic hemodynamics in cardiac surgical patients. Twenty patients (age 57 +/- 6 years) were studied in the operating room after weaning from cardiopulmonary bypass. Mean pulmonary artery pressure, pulmonary vascular resistance, systemic vascular resistance, and mean aortic pressure were determined at four points of data collection: before nitric oxide, with 20 ppm nitric oxide, with 40 ppm nitric oxide, and after nitric oxide. Statistical analysis was by analysis of variance; significance was accepted for p < 0.05. Inhaled nitric oxide produced selective pulmonary vasorelaxation. Pulmonary vascular resistance was lowered from 343 +/- 30 before nitric oxide to 233 +/- 25 dynes.sec-1.cm-5 with 20 ppm nitric oxide. Pulmonary vascular resistance was not further lowered by 40 ppm nitric oxide (p < 0.05). Mean pulmonary arterial pressure was 29 +/- 1 mm Hg before nitric oxide and was lowered to 22 +/- 1 mm Hg by 20 ppm nitric oxide and 21 +/- 1 mm Hg by 40 ppm nitric oxide (p < 0.05). Both pulmonary vascular resistance and mean pulmonary arterial pressure returned to baseline after withdrawal of inhaled nitric oxide. Inhaled nitric oxide produced no changes in either systemic vascular resistance or mean aortic pressure. We conclude that nitric oxide may be used as an effective pulmonary vasodilator after cardiac operations. It may be particularly valuable for selectively lowering right ventricular afterload in patients with right ventricular dysfunction.

The bright future of cardiothoracic surgery in the era of changing healthcare delivery

We are currently at a crossroads in our specialty and in the American healthcare delivery system. The manner in which we approach the next 5 to 10 years will deeply affect the future of our specialty. Thoracic surgery has had many accomplishments during my 35-year career that have improved the healthcare for the American public and others. As cardiothoracic surgeons, we have a legacy to be proud of, and the future promises to be every bit as exciting. In spite of these tremendous advances and the potential for future scientific achievements, there has been considerable uncertainty and pessimism because of the changing structure of healthcare in the United States. This has largely been stimulated by increasing health-care expenditures leading to the development of health maintenance organizations in the hopes of curtailing expenses by competition and capitation. In addition to cost containment, managed care is likely to have an impact on the future workforce of cardiothoracic surgeons. Much of our future will be determined by how well we adapt to the changing environment and take charge of our destiny. The demand for performance information for managed care plans will be much greater than it has been in the past. It is, therefore, imperative that we collect data to reflect the quality and value of our work to ensure that significant quality is not being sacrificed for cost containment. We cardiothoracic surgeons must develop our own information management strategies so that we can be in control of our future. If we do this, I am confident that the future of cardiothoracic surgery will be a bright one indeed.

Impact of respiratory acid-base status in patients with pulmonary hypertension

BACKGROUND

The perioperative management of patients undergoing mitral valve replacement (MVR) with pulmonary hypertension from mitral stenosis may be complicated by increased pulmonary vascular resistance. The purpose of this study was to examine the influence of respiratory acid-base status on the pulmonary hemodynamic indices of patients with pulmonary hypertension before and after MVR.

METHODS

Ten patients with pulmonary hypertension from mitral stenosis (mean preoperative systolic pulmonary artery pressure, 73 +/- 8 mm Hg) undergoing MVR were studied in the operating room before and after MVR. Arterial partial pressure of carbon dioxide was manipulated by the addition of 5% carbon dioxide to the breathing circuit. Hemodynamic data were collected as the partial pressure of carbon dioxide rose from 30 mm Hg to 50 mm Hg and decreased back to 30 mm Hg.

RESULTS

There were no differences in mean pulmonary artery pressure or pulmonary vascular resistance before and after MVR. Before MVR, mean pulmonary artery pressure increased from 32 +/- 1 mm Hg to 48 +/- 1 mm Hg as the partial pressure of carbon dioxide rose from 30 mm Hg to 50 mm Hg (p < 0.05), and pulmonary vascular resistance rose from 379 +/- 30 to 735 +/- 40 dynes.second.cm-5 (p < 0.05). These effects on mean pulmonary artery pressure and pulmonary vascular resistance were not different after MVR.

CONCLUSION

Respiratory acid-base status has a profound impact upon pulmonary vascular resistance in patients with pulmonary hypertension from mitral stenosis undergoing MVR. This impact persists in the immediate postoperative period. We conclude that respiratory acidemia should be avoided in these patients, whereas respiratory alkalemia may be used to help minimize pulmonary vascular resistance.

No continuous relationship between Veterans Affairs hospital coronary artery bypass grafting surgical volume and operative mortality

BACKGROUND

The purpose of this study was to determine whether risk-adjusted coronary artery bypass grafting mortality rates are significantly related to coronary artery bypass grafting surgical procedure volume within the Department of Veterans Affairs hospital system.

METHODS

From April 1987 to September 1992, expected mortality rates were calculated for 23,986 coronary artery bypass grafting procedures performed at 44 different Veterans Affairs hospitals.

RESULTS

This study found a statistically significant relationship between annual hospital coronary artery bypass grafting volume and observed mortality rates (p < 0.02). However, no statistically significant relationship between coronary artery bypass grafting volume and risk-adjusted operative mortality was found (p = 0.10). Using analysis of variance on hospital-level data, hospitals with 100 or less cases per year have higher observed to expected mortality ratios than hospitals performing more than 100 cases per year (p = 0.03). Using Poisson regression models, however, a volume threshold could not be found.

CONCLUSIONS

These findings are consistent with the current Veterans Affairs policy requirements to periodically review quality at low-volume hospitals.

Volume requirements for cardiac surgery credentialing: a critical examination. The Ad Hoc Committee on Cardiac Surgery Credentialing of The Society of Thoracic Surgeons

New volume requirements for coronary artery bypass grafting are being imposed on cardiac surgeons by hospitals, managed care groups, and others. The rationale for this is unclear. The available literature as well as additional sources relating volume and outcomes in cardiac surgery were extensively reviewed and reexamined. There are no data to conclusively indicate that outcomes of cardiac operations are related to a specific minimum number of cases performed annually by a cardiac surgeon. Each cardiothoracic surgeon should participate in a national database that permits comparison of his or her outcomes on a risk-adjusted basis with other surgeons. Until conclusive data become available that link volume to outcome, volume should not be used as a criterion for credentialing of cardiac surgeons by hospitals, managed care groups, or others. Instead, each surgeon should be evaluated on his or her individual results.

Cardiac allograft failure: successful use of biventricular assist device

Nonspecific primary allograft dysfunction is an important cause of perioperative death in cardiac transplant recipients. We report a case of severe nonspecific allograft dysfunction that was ultimately reversible after 18 days of biventricular mechanical circulatory support. Allograft recovery was echocardiographically recognized by a positive inotropic response to isoproterenol and milrinone. This case illustrates the potential for recovery of even extreme allograft dysfunction.

Quality initiatives and the power of the database: what they are and how they run

The criteria by which healthcare is judged or measured are quality, accessibility, and cost effectiveness. To evaluate these criteria it is important to have a database. There are many strengths and weakness to large databases. They can be used as an indicator of the level of performance or quality, for clinical decision making, and as a measurement of cost effectiveness. They can also be useful in the evaluation and development of treatment algorithms and critical pathways for patients with entry level disease. In addition, they can measure patient access to healthcare and the appropriateness of care. It is important for these databases to appropriately adjust for preoperative risk factors that may influence outcome. Outcome in most of the databases is measured by mortality, but morbidity, functional status, quality of life, cost of care, length of stay, return to work, and patient satisfaction are also important outcomes. Factors that can influence the quality of the outcome data are the methods by which the data are collected, standardization of definitions, the currentness of the database, adequate numbers of patients and outcomes, and appropriate analytic techniques. It is important to feed back the data to the healthcare providers in a timely enough fashion so that processes and structures of care can be modified to improve treatment and results. The reliability of the databases and the validity must be substantiated for the healthcare provider to have confidence in the database.(ABSTRACT TRUNCATED AT 250 WORDS)

Statistical methods and strategies for working with large data bases

This article describes the statistical methods and strategies to be used in establishing the linkages between processes and structures of care with risk-adjusted outcomes in a large multicenter Veterans Affairs cooperative study in health services of patients undergoing cardiac surgery. The statistical analyses consist of test involving nine specific hypotheses related to the effect of processes and structures of care on risk-adjusted outcomes. From the statistical point of view, the major obstacles of this study are the need for data reduction and imputation of missing data. The former obstacle is addressed through the use of data-reduction techniques, such as principal components and cluster of variables. The latter is addressed through the use of classic and new techniques for imputation of missing data, such as MISSGEN, principal components for qualitative data, and the expectation and maximization algorithm. Data reduction and imputation of missing data are done with clinically derived variable groups called "dimensions" or "subdimensions." The effect of processes and structures of care is assessed by a two-step process. First, outcomes are modeled using only patient risk factors. The selection of risk factors in the modeling process is discussed in detail. Second, these risk-adjusted outcomes are modeled using one of the nine process or structure subhypotheses. The relationship of the processes and structures of care dimensions and/or subdimensions that are linked to risk-adjusted outcomes are identified.

Variations in the processes and structures of cardiac surgery nursing care

Nurses play an invaluable role as key members of the cardiac surgery patient's medical care team. Over the last century, the nursing profession has become more independent and autonomous. Despite the widespread use of nursing quality indicators, the effect of nursing-specific processes and structures of care on patient outcomes is unknown. Thus, the Processes, Structures, and Outcomes of Care in Cardiac Surgery (PSOCS) study was initiated, in part, to determine the potential effect of nursing processes and structures of care on cardiac surgery patients' risk-adjusted outcomes. In this article, the authors summarize the key components of nursing structures of care incorporated in the PSOCS study. Nursing process variables were not sufficiently designed into the study to address hypotheses relating nursing care processes to patient outcomes. An analysis of the pilot test data from September 1992 to September 1993 demonstrated potentially important variations between the six pilot centers regarding nursing care provider profiles (eg, educational preparation, specialty certification, and experience levels) and nursing staff ratios (eg, within the surgical intensive care unit). When linked to risk-adjusted patient outcomes, these variations in nursing structure of care may offer important insights toward improving the quality of care of cardiac surgery patients.