Report cards on cardiac surgeons. Assessing New York State's approach

Coronary artery bypass mortality rates in Ontario. A Canadian approach to quality assurance in cardiac surgery. Steering Committee of the Provincial Adult Cardiac Care Network of Ontario

BACKGROUND

This study was conducted to assess the overall mortality rate and the amount of interhospital variation in risk-adjusted mortality rates after coronary artery bypass graft (CABG) surgery in Ontario, Canada. CABG outcomes data are not publicly disseminated in Ontario.

METHODS AND RESULTS

Clinical risk factors and surgical outcomes were collected on 15,608 patients undergoing isolated CABG surgery between April 1, 1991, and March 31, 1994, at the nine hospitals performing adult cardiac surgery in Ontario. The data were analyzed on the basis of a fiscal year. The overall mortality rate was 3.01%, and the risk-adjusted mortality rate declined from 3.17% in 1991 to 2.93% in 1993. In 1991, one of the nine hospitals had a risk-adjusted mortality rate significantly lower than the provincial average. Otherwise, the hospitals all had risk-adjusted mortality rates within the expected range during the time period of the study. All hospitals performed > 300 CABG procedures in 1992 and 1993, and only 2 of 42 cardiac surgeons performed < 50 CABG procedures in 1993.

CONCLUSIONS

The in-hospital mortality rate after CABG surgery in Ontario is low, and the amount of interhospital variation in risk-adjusted mortality rates is no greater than that expected by chance alone. These outcomes are probably attributable to regionalization of CABG surgery and a very low prevalence of low-volume cardiac surgeons in Ontario.

A model that predicts morbidity and mortality after coronary artery bypass graft surgery

OBJECTIVES

This study was performed to develop a method for identifying patients at increased risk for morbidity or mortality after coronary artery bypass graft surgery.

BACKGROUND

Postoperative morbidity is more common than mortality and is important because of its relation to cost.

METHODS

Univariate and forward stepwise logistic regression analysis was used to retrospectively analyze a group of 1,567 consecutive patients who underwent bypass surgery between July 1991 and December 1992. We developed a model that predicted postoperative morbidity or mortality, or both, which was then prospectively validated in a group of 1,235 consecutive patients operated on between January 1993 and April 1994. A clinical risk score was derived from the model to simplify utilization of the data.

RESULTS

The following factors, listed in decreasing order of significance, were found to be significant independent predictors: cardiogenic shock, emergency operation, catheterization-induced coronary artery closure, severe left ventricular dysfunction, increasing age, cardiomegaly, peripheral vascular disease, chronic renal insufficiency, diabetes mellitus, low body mass index, female gender, reoperation, anemia, cerebrovascular disease, chronic obstructive pulmonary disease, renal dysfunction, low albumin, elevated blood urea nitrogen, congestive heart failure and atrial arrhythmias. Observed morbidity and mortality for the validation group fell within the 95% confidence interval of that predicted by the model. Costs were closely related to the incidence of postoperative morbidity.

CONCLUSIONS

Analysis of preoperative patient variables can predict patients at increased risk for morbidity or mortality, or both, after bypass surgery. Increased morbidity results in higher costs. Different strategies for high and low risk patients should be used in cost reduction efforts.

Judging hospitals by severity-adjusted mortality rates: the influence of the severity-adjustment method

OBJECTIVES

This research examined whether judgments about a hospital's risk-adjusted mortality performance are affected by the severity-adjustment method.

METHODS

Data came from 100 acute care hospitals nationwide and 11880 adults admitted in 1991 for acute myocardial infarction. Ten severity measures were used in separate multivariable logistic models predicting in-hospital death. Observed-to-expected death rates and z scores were calculated with each severity measure for each hospital.

RESULTS

Unadjusted mortality rates for the 100 hospitals ranged from 4.8% to 26.4%. For 32 hospitals, observed mortality rates differed significantly from expected rates for 1 or more, but not for all 10, severity measures. Agreement between pairs of severity measures on whether hospitals were flagged as statistical mortality outliers ranged from fair to good. Severity measures based on medical records frequently disagreed with measures based on discharge abstracts.

CONCLUSIONS

Although the 10 severity measures agreed about relative hospital performance more often than would be expected by chance, assessments of individual hospital mortality rates varied by different severity-adjustment methods.

Coronary bypass graft fate and patient outcome: angiographic follow-up of 5,065 grafts related to survival and reoperation in 1,388 patients during 25 years

OBJECTIVES

We sought to examine, angiographically, the longterm fate of a large number of mainly venous coronary bypass grafts and to correlate graft patency and disease with patient survival and reoperation.

BACKGROUND

Much is known about bypass graft patency and disease, but the precise relation between graft fate and patient outcome has not been substantiated and documented.

METHODS

A total of 1,388 patients underwent a first coronary artery bypass graft procedure at a mean age of 48.9 years, 234 had a second bypass procedure at a mean age of 53.3 years, and 15 had a third bypass procedure at a mean age of 58.2 years during the 25-year period from 1969 to 1994. Most were male military personnel or veterans; 12% were < or = 39 years old. Of 5,284 grafts placed, 91% were venous and 9% arterial. Angiograms were performed on 5,065 (98% of surviving) grafts early, on 3,993 grafts at 1 year and on 1,978 grafts at 5 years after operation; other examinations were also performed up to 22.5 years after operation, and 353 grafts were examined after > or = 15 years. Grafts were graded for patency and disease. The status of all patients was known at the study's end.

RESULTS

The perioperative mortality rate was 1.4% for an isolated first coronary bypass procedure, 6.6% for reoperation. Vein graft patency was 88% early, 81% at 1 year, 75% at 5 years and 50% at > or = 15 years; when suboptimal grafts, graded B, were excluded from calculation, the proportion of excellent grafts, graded A, decreased to 40% after > or = 12.5 years. After the early study, the vein graft occlusion rate was 2.1%/year. Internal mammary artery graft patency was significantly better but decreased with time. Vein graft disease appeared by 1 year and the rate accelerated by > or = 2.5 years, involving 48% of grafts at 5 years and 81% at > or = 15 years; 44% of the latter grafts were narrowed > 50%. Survival of all patients was 93.6% at 5 years. 81.1% at 10 years, 62.1% at 15 years, 46.7% (150 patients) at 20 years and 38.4% (25 patients) at 23 years after operation. Survival decreased as age increased, but curves approximated "normal" life expectancy for older patients. Survival curves at all ages showed a steeper decline after 7 years. The rate of reoperation increased between 5 years and 10 to 14 years, then decreased to stable levels. Coronary atheroembolism from vein grafts was the major cause of morbidity and mortality associated with reoperation. Vein graft patency and disease were temporally and closely related to reoperation and survival.

CONCLUSIONS

Coronary bypass graft disease and occlusion are common after coronary artery bypass grafting and increase with time. They are major determinants of clinical prognosis, specifically measured by reoperation rate and survival. Intraoperative graft atheroembolism was a major reoperation hazard. Reoperation is definitely worthwhile but entails identifiable risks that must be dealt with.

Influence of cardiac-surgery performance reports on referral practices and access to care. A survey of cardiovascular specialists

BACKGROUND

Reports on the comparative performance of physicians are becoming increasingly common. Little is known, however, about the credibility of these reports with target audiences or their influence on the delivery of medical services.

METHODS

Since 1992, Pennsylvania has published the Consumer Guide to Coronary Artery Bypass Graft Surgery, which lists annual risk-adjusted mortality rates for all hospitals and surgeons providing such surgery in the state. In 1995, we surveyed a randomly selected sample of 50 percent of Pennsylvania cardiologists and cardiac surgeons to find out whether they were aware of the guide and, if so, to determine their views on its usefulness, limitations, and influence on providers.

RESULTS

Eighty-two percent of the cardiologists and all the cardiac surgeons were aware of the guide. Only 10 percent of these respondents reported that its mortality rates were "very important" in assessing the performance of a cardiothoracic surgeon. Less than 10 percent reported discussing the guide with more than 10 percent of their patients who were candidates for a coronary-artery bypass graft (CABG). Eighty-seven percent of the cardiologists reported that the guide had a minimal influence or none on their referral recommendations. For both groups, the most important limitations of the guide were the absence of indicators of quality other than mortality (cited by 78 percent), inadequate risk adjustment (79 percent), and the unreliability of data provided by hospitals and surgeons (53 percent). Fifty-nine percent of the cardiologists reported increased difficulty in finding surgeons willing to perform CABG surgery in severely ill patients who required it, and 63 percent of the cardiac surgeons reported that they were less willing to operate on such patients.

CONCLUSIONS

The Consumer Guide to Coronary Artery Bypass Graft Surgery has limited credibility among cardiovascular specialists. It has little influence on referral recommendations and may introduce a barrier to care for severely ill patients. If publicly released performance reports are intended to guide the choice of providers without impeding access to medical care, a collaborative process involving physicians may enhance the credibility and usefulness of the reports.

The annual guide to "America's best hospitals". Evidence of influence among health care leaders

To determine health care leaders' opinions about a prominent guide to hospital quality, we surveyed 82 chief executive officers (CEOs) and 80 chiefs of staff of hospitals listed in the 1994 edition of the guide and 50 directors of employer based coalitions. Most of the CEOs (87%) and chiefs of staff (86%) said the guide was used in advertising. More than three quarters of the CEOs, chiefs of staff, and coalition directors who were familiar with the guide thought it was accurate, and most indicated that key constituencies (e.g., physicians, corporate managers) were aware of the guide. Our results demonstrate the likely influence of one prominent guide to health care quality and highlight the need for formal independent assessment of such guides.

Performance measurement in prostate cancer care: beyond report cards

OBJECTIVES

Review and analyze various approaches to performance measurement in health care, demonstrating the value of provider-initiated performance measurement in which ongoing monitoring of both processes and outcomes of care coupled with the use of clinical guidelines enhances performance improvement efforts. Describe some of the issues and findings associated with the use of such a methodology in prostate cancer care.

METHODS

Literature review and case study.

RESULTS

There are a number of significant limitations in the use of a "report card" methodology to improve quality and efficiency in health care. The complementary approach of combining "instrument panels" and clinical guidelines within an overall continuous quality improvement framework appears to have resulted in improved clinical outcomes and reduced costs in a six-physician urology group located in a heavily managed-care penetrated market.

CONCLUSIONS

Performance measurement tools are integral to efforts to improve outcomes and efficiency in health care. Providers of care might consider adapting the kind of performance improvement methodology described in this article. Practice benefits including improved clinical and economic outcomes are likely to follow.

Outmigration for coronary bypass surgery in an era of public dissemination of clinical outcomes

BACKGROUND

Since 1989, New York State has disseminated comparative information on outcomes of coronary bypass surgery to the public. It has been suggested that this program played a significant role in the 41% decrease in the risk-adjusted mortality rate between 1989 and 1992. We hypothesized that some high-risk patients had migrated out of state for surgery.

METHODS AND RESULTS

We reviewed 9442 isolated coronary bypass operations performed from 1989 through 1993 to assess referral patterns of case-mix and outcome. Expected and risk-adjusted mortality rates were computed using logistic regression models derived from the Cleveland Clinic and New York State databases. A mortality comparison was performed using the 1980 to 1988 time period as a historical control. Patients from New York (n=482) had a higher frequency of prior open heart surgery (44.0%) than patients from Ohio (n=6046) (21.5%, P<.001), other states (n=1923) (37.4%, P=.008), and other countries (n=991) (17.3%, P<.001). They were also more likely to be in NYHA functional class III or IV (47.6% versus Ohio 42.7%, P=.037; other states, 41.2%, P=.011; other countries, 34.1%, P=.001). The expected mortality rate was thus higher than among other referral cohorts. The observed 5.2% mortality rate among these patients was significantly greater than the 2.9%, 3.1%, and 1.4% mortality rates observed for patients from Ohio (P=.004), other states (P=.028), and other countries (P<.001). These differences in outcome were not apparent between 1980 and 1988 among referrals from within the United States.

CONCLUSIONS

Public dissemination of outcome data may have been associated with increased referral of high-risk patients from New York to an out-of-state regional medical center.

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.

Getting there from here: evidentiary quandaries of the US outcomes movement

The US outcomes movement assumes, and sometimes argues, the primacy for medical practice of probabilistic knowledge derived from methodologically rigorous statistical studies. 'Evidence-based medicine,' then, is considered a course of clinical medicine prescribed by such research. Implementation of evidence-based medicine as recently been uneven in the US, manifesting not only the expected 'obstacles to implementation' but several theoretical weakness of the applied science model of medical care. Outcomes researchers claim to provide certainty - certainty of what is probable, as it turns out - in a world of clinical uncertainty. This paper argues that outcomes research actually exacerbates the inferential uncertainty of practising physicians who would use knowledge for practice. Two quandaries are discussed: whether to privilege rigorous or relevant research, and whether to privilege universal or local knowledge. In each case, the logic of 'evidence-based medicine' is insufficient to resolve the quandary and would seem to support conflicting resolutions. Recent developments in US health policy are cited as manifestations of these quandaries. Finally, the reader is asked not to disregard the political implications of the outcomes movement.

Risk stratification in cardiac surgery: is it worthwhile?

Outcome analysis of many surgical procedures has become increasingly important to surgeons, institutions, and the public. Because there may be wide differences in case mix, outcomes must be evaluated in light of the patient's preoperative status. All relevant preoperative conditions must be identified and weighted, so that when risk factor scores are combined in some fashion, they will provide a single preoperative risk estimate for the individual patient, representing the likelihood of dying as a consequence of the operation. Comparing the mean risk adjusted score of a group of patients undergoing the same procedure with the observed mortality rate for the same group yields an index of the quality of care, provided all preoperative risk scores are calculated with reference to the same benchmark. We question the logic and wisdom of surgical outcome analysis because of the infinitely complex nature of biological and pathological processes, as well as the practical problems of reliable data collection. The assumption of true scientific accuracy may be illusory. Even though risk adjusted outcome analysis has merit in studying trends in therapy, it should be regarded with caution when used as a tool for evaluating quality of care. If publicized at all, the results should not be represented as "hard" scientific fact.

Acquisition and use of clinical data for audit and research

Acquisition of adequate patient data for clinical management is hard enough, but higher quality patient data are needed for clinical audit and research. This article discusses some of the problems of using routine clinical data for audit and research, aspects of data quality, sources of audit or research data and their problems, methods for improving data quality, the benefits and problems of computer-based systems and current trends in the capture and processing of clinical data.

BUN as a risk factor for mortality after coronary artery bypass grafting

BACKGROUND

Although information on blood urea nitrogen (BUN) is universally available for patients who undergo coronary artery bypass grafting, BUN has not often been considered as a risk factor for mortality. This study assessed BUN as a risk factor for CABG patients.

METHODS

Four data sets were evaluated that differed with respect to the types of patients and available patient information. In each of these data sets logistic regression analysis was used to examine the relationship between BUN and mortality after adjusting for other risk factors.

RESULTS

Blood urea nitrogen level was strongly associated with mortality in each of the data sets. After adjustment for the available risk factors other than creatinine level, patients with BUN levels greater than 30 mg/dL had a relative odds of mortality ranging between 1.86 and 2.49 (p < 0.0001 in three of the data sets). Even after adjustment for creatinine level as well as the other variables, BUN was statistically significant at the p less than 0.01 level for three of the data sets.

CONCLUSIONS

The results suggest that BUN provides additional information on cardiac function that supplements the information provided by other risk factors.

State involvement in medical technology assessment

State governments are reevaluating their role in the assessment of medical technologies. This paper outlines a range of state technology assessment activities, highlighting programs in Minnesota, Oregon, and Washington, and discusses the issues associated with state government involvement. Clinically oriented activities on the state level can inform efforts to contain costs, educate consumers and providers, and facilitate local consensus on the appropriate uses of new and existing technologies. Although current programs are still in their infancy and their viability remains uncertain, the importance of technology assessment is growing as technology continues to fuel increasing costs. The future of state-level technology assessment may lie in collaborative ventures with other states, the federal government, or private industry.