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E D Peterson

Publications and source records attributed to E D Peterson.

At least 19 recordsLinked to original sources

Effect of clinical factors on length of stay after coronary artery bypass surgery: results of the cooperative cardiovascular project.

BACKGROUND: Rising health care costs have prompted careful review of comparative hospital resource use. Length of stay after bypass surgery has received particular attention. However, many providers assert that these variations are caused by differences in the clinical mix of patients treated. Our goals were to identify the major clinical predictors of postoperative length of stay (PLOS) after coronary artery bypass graft surgery (CABG), document variations in PLOS among 28 hospitals, and assess the degree to which patient characteristics account for hospital variations in PLOS. METHODS: Detailed clinical data on 3605 Medicare patients undergoing CABG in 28 Alabama and Iowa hospitals were analyzed by stepwise linear regression to identify significant clinical predictors of PLOS. Analysis of variance was used to compare hospitals' PLOS while controlling for significant patient risk factors. RESULTS: The mean age was 72.1 years, 34.7% were female, and the in-hospital mortality rate was 5.6%. The median and mean PLOS were 8 and 11.1 days, respectively. Significant predictors of longer PLOS included increasing age, female sex, history of chronic obstructive pulmonary disease, cerebrovascular disease, or mitral valve disease, elevated admission blood urea nitrogen, and preoperative placement of an intraaortic balloon pump. Hospitals varied significantly (P =.0001) in their unadjusted PLOS. These hospital-level variations persisted despite adjustment for both preoperative patient characteristics (P =.0001) and postoperative complications and death (P =.0001). CONCLUSIONS: This study found significant between-hospital variations in PLOS that were not explained by patient factors. This finding suggests the potential for increased efficiency in the care of patients undergoing CABG at many institutions. Further research is needed to determine the practice patterns contributing to variations in length of stay after bypass surgery.

Aged

Acute and long-term cost implications of coronary stenting.

OBJECTIVES: We compared the acute and one year medical costs and outcomes of coronary stenting with those for balloon angioplasty (percutaneous transluminal coronary angioplasty) in contemporary clinical practice. BACKGROUND: While coronary stent implantation reduces the need for repeat revascularization, it has been associated with significantly higher acute costs compared with coronary angioplasty. METHODS: We studied patients treated at Duke University between September 1995 and June 1996 who received either coronary stent (n = 384) or coronary angioplasty (n = 159) and met eligibility criteria. Detailed cost data were collected initially and up to one year following the procedure. Our primary analyses compared six and 12 month cumulative costs for coronary angioplasty- and stent-treated cohorts. We also compared treatment costs after excluding nontarget vessel interventions; after limiting analysis to those without prior revascularization; and after risk-adjusting cumulative cost estimates. RESULTS: Baseline clinical characteristics were generally similar between the two treatment groups. The mean in-hospital cost for stent patients was $3,268 higher than for those receiving coronary angioplasty ($14,802 vs. $11,534, p < 0.001). However, stent patients were less likely to be rehospitalized (22% vs. 34%, p = 0.002) or to undergo repeat revascularization (9% vs. 26%, p = 0.001) than coronary angioplasty patients within six months of the procedure. As such, mean cumulative costs at 6 months ($19,598 vs. $19,820, p = 0.18) and one year ($22,140 vs. $22,571, p = 0.26) were similar for the two treatments. Adjusting for baseline predictors of cost and selectively examining target vessel revascularization, or those without prior coronary intervention yielded similar conclusions. CONCLUSIONS: In contemporary practice, coronary stenting provides equivalent or better one-year patient outcomes without increasing cumulative health care costs.

Aged

A comparison of U.S. and Canadian cardiac catheterization practices in detecting severe coronary artery disease after myocardial infarction: efficiency, yield and long-term implications.

OBJECTIVES: We sought to compare U.S. and Canada's post-myocardial infarction (MI) cardiac catheterization practices in the detection of severe coronary artery disease (CAD). BACKGROUND: Little is known about the efficiency with which the aggressive post-MI catheterization strategy observed in the U.S. detects severe CAD compared with the more conservative strategy observed in Canada. METHODS: From the U.S. and Canadian patients who had participated in the Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Arteries trial (n = 22,280, 11.5% Canadian), we examined the frequency of in-hospital cardiac catheterization, the prevalence of severe CAD observed at catheterization (diagnostic efficiency) and the total number of MI patients with severe CAD identified (diagnostic yield). RESULTS: The rate of catheterization in the U.S. was more than 2.5 times that in Canada (71% vs. 27%, respectively, p < 0.001). With identical prevalences of severe CAD at catheterization (17%) in the two countries, the higher frequency of catheterization in the U.S. resulted in the identification of more than two and a half times as many cases of severe CAD compared with Canada (12 severe CAD cases identified per 100 post-MI patients in the U.S., vs. 4.6 per 100 in Canada). If considered in isolation, we estimated that these differences in severe disease detection might effect a small long-term survival advantage in favor of the U.S. strategy (estimated 5.0 lives saved per 1,000 MI patients). CONCLUSIONS: Canada's more restrictive post-MI cardiac catheterization strategy is no more efficient in identifying severe CAD than the aggressive U.S. strategy, and may fail to identify a substantial number of post-MI patients with high risk coronary anatomy. The long-term impact of these differences in practice patterns requires further evaluation.

Canada

Using an outcomes-based approach to identify candidates for risk stratification after exercise treadmill testing.

OBJECTIVE: To develop a hierarchical approach to cardiac risk stratification after treadmill testing. PATIENTS: Clinical and treadmill test data were used to identify a patient population that may be candidates for further risk stratification with stress tomographic myocardial perfusion imaging. A prospective series of 3, 620 medically treated patients (42% female, mean age 63 years) with a 2.5% mortality was identified (follow-up 2.5 +/- SD 1.5 years). MEASUREMENTS AND MAIN RESULTS: A Cox proportional hazards model was used to estimate a patient's likelihood of cardiac death. Kaplan-Meier survival curves were used to estimate time to cardiac death by nuclear test results. Annual rates of cardiac death were 0. 4% (n = 921), 1% (n = 2,498), and 1% (n = 201) for patients with low, intermediate, and high Duke treadmill scores (DTS). For patients with an intermediate DTS, multivariate estimators of cardiac death included the number of ischemic vascular territories (relative risk per defect 1.4, p =.01), the number of infarcted vascular territories (relative risk per defect 2.4, p =.00001), and the DTS (relative risk per unit 0.97, p =.00001), following adjustment for a patient's pretest risk of coronary disease. For patients with an intermediate DTS, the presence of no, one or two, and three vascular territories with defects was associated with annual rates of cardiac death of 0.5%, 1.4%, and 2.5%, respectively (p <.0001). Kaplan-Meier survival curves exhibited a statistically worsening survival for patients with defects by 1 year after treadmill exercise. CONCLUSIONS: For symptomatic patients with an intermediate treadmill test score, the exercise myocardial perfusion scan may be used to stratify their risk of cardiac death over 3 years of follow-up. Patient management may be efficiently guided by further outcome assessment, with an exercise nuclear scan for patients whose treadmill test score is intermediate.

Aged

Value of exercise treadmill testing in women.

OBJECTIVES: We sought to determine the ability of a treadmill score to provide accurate diagnostic and prognostic risk estimates in women. BACKGROUND: Treadmill testing has been reported to have a lower accuracy for diagnosis of chest pain in women. The diagnostic and prognostic value of the Duke Treadmill Score (DTS) in women is unknown. METHODS: We determined the diagnostic and prognostic value of the DTS in 976 women and 2,249 men who underwent both treadmill testing and cardiac catheterization in a single institution from 1984 to 1994. RESULTS: Women and men differed significantly in DTS (1.6 vs. -0.3, p < 0.0001), disease prevalence (32% vs. 72% significant coronary artery disease [CAD], p < 0.001), and 2-year mortality (1.9% vs. 4.9%, p < 0.0001). The DTS provided information beyond clinical predictors of both coronary disease and survival in women and men. Although overall women had better survival, the DTS performed equally well in stratifying both genders into prognostic categories. The DTS actually performed better in women than in men for excluding disease, with fewer low risk women having any significant coronary disease (> or = 1 vessel with > or =75% stenosis) (20% vs. 47%, p < 0.001), or severe disease (3-vessel disease or > or =75% left main stenosis) (3.5% vs. 11.4%, p < 0.001). CONCLUSIONS: By combining several aspects of treadmill testing, the DTS effectively stratifies women into diagnostic and prognostic risk categories.

Coronary Disease

Use of a prognostic treadmill score in identifying diagnostic coronary disease subgroups.

BACKGROUND: Exercise testing is useful in the assessment of symptomatic patients for diagnosis of significant or extensive coronary disease and to predict their future risk of cardiac events. The Duke treadmill score (DTS) is a composite index that was designed to provide survival estimates based on results from the exercise test, including ST-segment depression, chest pain, and exercise duration. However, its usefulness for providing diagnostic estimates has yet to be determined. METHODS AND RESULTS: A logistic regression model was used to predict significant (>/=75% stenosis) and severe (3-vessel or left main) coronary artery disease, and a Cox regression analysis was used to predict cardiac survival. After adjustment for baseline clinical risk, the DTS was effectively diagnostic for significant (P<0.0001) and severe (P<0.0001) coronary artery disease. For low-risk patients (score >/=+5), 60% had no coronary stenosis >/=75% and 16% had single-vessel >/=75% stenosis. By comparison, 74% of high-risk patients (score <-11) had 3-vessel or left main coronary disease. Five-year mortality was 3%, 10%, and 35% for low-, moderate-, and high-risk DTS groups (P<0.0001). CONCLUSIONS: The composite DTS provides accurate diagnostic and prognostic information for the evaluation of symptomatic patients evaluated for clinically suspected ischemic heart disease.

Adult

Prognostic significance of the initial electrocardiogram in patients with acute myocardial infarction. GUSTO-I Investigators. Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries.

CONTEXT: Early risk stratification of patients with myocardial infarction is critical to determine optimum treatment strategies and enhance outcomes, but knowledge of the prognostic importance of the initial electrocardiogram (ECG) is limited. OBJECTIVE: To assess the independent value of the initial ECG for short-term risk stratification after acute myocardial infarction. DESIGN: Retrospective analysis of the Global Utilization of Streptokinase and t-PA (alteplase) for Occluded Coronary Arteries (GUSTO-I) clinical trial database. SETTING: A total of 1081 hospitals in 15 countries. PATIENTS: From the 41 021 patients enrolled in the overall study, we selected those who presented within 6 hours of chest pain onset with ST-segment elevation and no confounding factors (paced rhythms, ventricular rhythms, or left bundle-branch block) on the ECG performed before thrombolysis was administered (n=34 166). MAIN OUTCOME MEASURE: Ability of initial ECG to predict all-cause mortality at 30 days. RESULTS: Most ECG variables were associated with 30-day mortality in a univariable analysis. In a multivariable analysis combining the initial ECG variables and clinical predictors of mortality, the sum of the absolute ST-segment deviation (both ST elevation and ST depression: odds ratio [OR], 1.53; 95% confidence interval [CI], 1.38-1.69), ECG, heart rate (OR, 1.49; 95% CI, 1.41-1.59), QRS duration (for anterior infarct: OR, 1.55; 95% CI, 1.43-1.68), and ECG evidence of prior infarction (for new inferior infarct: OR, 2.47; 95% CI, 2.02-3.00) were the strongest ECG predictors of mortality. A nomogram based on the multivariable model produced excellent discrimination of 30-day mortality (C-index, 0.830). CONCLUSIONS: In patients presenting with myocardial infarction accompanied by ST-segment elevation, components of the initial ECG help predict 30-day mortality. This information should be valuable in early risk stratification, when the opportunity to reduce mortality is greatest, and may help in assessing outcomes adjusted for patient risk.

Aged

Identification of variables needed to risk adjust outcomes of coronary interventions: evidence-based guidelines for efficient data collection.

OBJECTIVES: Our objectives were to identify and define a minimum set of variables for interventional cardiology that carried the most statistical weight for predicting adverse outcomes. Though "gaming" cannot be completely avoided, variables were to be as objective as possible and reproducible and had to be predictive of outcome in current databases. BACKGROUND: Outcomes of percutaneous coronary interventions depend on patient risk characteristics and disease severity and acuity. Comparing results of interventions has been difficult because definitions of similar variables differ in databases, and variables are not uniformly tracked. Identifying the best predictor variables and standardizing their definitions are a first step in developing a universal stratification instrument. METHODS: A list of empirically derived variables was first tested in eight cardiac databases (158,273 cases). Three end points (in-hospital death, in-hospital coronary artery bypass graft surgery, Q wave myocardial infarction) were chosen for analysis. Univariate and multivariate regression models were used to quantify the predictive value of the variable in each database. The variables were then defined by consensus by a panel of experts. RESULTS: In all databases patient demographics were similar, but disease severity varied greatly. The most powerful predictors of adverse outcome were measures of hemodynamic instability, disease severity, demographics and comorbid conditions in both univariate and multivariate analyses. CONCLUSIONS: Our analysis identified 29 variables that have the strongest statistical association with adverse outcomes after coronary interventions. These variables were also objectively defined. Incorporation of these variables into every cardiac dataset will provide uniform standards for data collected. Comparisons of outcomes among physicians, institutions and databases will therefore be more meaningful.

Adult

The effects of New York's bypass surgery provider profiling on access to care and patient outcomes in the elderly.

OBJECTIVE: The aim of this study was to examine the effects of provider profiling on bypass surgery access and outcomes in elderly patients in New York. BACKGROUND: Since 1989, New York (NY) has compiled provider-specific bypass surgery mortality reports. While some have proposed that "provider profiling" has led to lower surgical mortality rates, critics have suggested that such programs lower in-state procedural access (increasing out-of-state transfers) without improving patient outcomes. METHODS: Using national Medicare data, we examined trends in the percentages of NY residents aged 65 years or older receiving out-of-state bypass surgery between 1987 and 1992 (before and after program initiation). We also examined in-state procedure use among elderly myocardial infarction patients during this period. Finally, we compared trends in surgical outcomes in NY Medicare patients with those for the rest of the nation. RESULTS: Between 1987 and 1992, the percentage of NY residents receiving bypass out-of-state actually declined (from 12.5% to 11.3%, p < 0.01 for trend). An elderly patient's likelihood for bypass following myocardial infarction in NY increased significantly since the program's initiation. Between 1987 and 1992, unadjusted 30-day mortality rates following bypass declined by 33% in NY Medicare patients compared with a 19% decline nationwide (p < 0.001). As a result of this improvement, NY had the lowest risk-adjusted bypass mortality rate of any state in 1992. CONCLUSIONS: We found no evidence that NY's provider profiling limited procedure access in NY's elderly or increased out-of-state transfers. Despite an increasing preoperative risk profile, procedural outcomes in NY improved significantly faster than the national average.

Aged

Potential impact of evidence-based medicine in acute coronary syndromes: insights from GUSTO-IIb. Global Use of Strategies to Open Occluded Arteries in Acute Coronary Syndromes trial.

OBJECTIVES: The purpose of this study to determine whether use of cardiac medications reflects evidence-based recommendations for patients with non-ST elevation acute coronary syndromes. BACKGROUND: Agency for Health Care Policy and Research practice guidelines for unstable angina recommend the use of cardiac medications based on evidence from randomized trials. It is unknown whether practitioners in the U.S., Canada and Europe follow these recommendations in patients with non-ST elevation acute coronary syndromes. METHODS: We studied 7,743 patients with non-ST elevation acute coronary syndromes enrolled in the international Global Use of Strategies to Open Occluded Arteries in Acute Coronary Syndromes trial. The use of aspirin, beta-adrenergic blocking agents, angiotensin-converting enzyme inhibitors and calcium channel blocking agents was determined at discharge for all patients and "ideal" patients (those with indications and no contraindications). Using published estimates of relative mortality reductions with these drugs, we calculated the lives that could have been saved at 1 year if discharge medication use had better matched guideline recommendations. RESULTS: Overall, guideline adherence at discharge in "ideal" patients was 85.6% for aspirin, 59.1% for beta-blockers and 51.7% for angiotensin-converting enzyme inhibitors. Calcium channel blockers were given to 26.7% of patients with a contraindication to these drugs. These rates were similar across locations of enrollment. Women and older patients less often received aspirin when "ideal," and younger patients more often received calcium channel blockers when they were contraindicated. If medication use had been more evidence-based, 1-year mortality might have been reduced by a relative 22%. CONCLUSIONS: There is significant room for improvement in the use of recommended drugs in patients with non-ST elevation acute coronary syndromes. Medication use that more closely follows recommendations could reduce mortality in this population.

Adrenergic beta-Antagonists

Comparing risk-adjustment methods for provider profiling.

Risk-adjustment and provider profiling have become common terms as the medical profession attempts to measure quality and assess value in health care. One of the areas of care most thoroughly developed in this regard is quality assessment for coronary artery bypass grafting (CABG). Because in-hospital mortality following CABG has been studied extensively, risk-adjustment mechanisms are already being used in this area for provider profiling. This study compares eight different risk-adjustment methods as applied to a CABG surgery population of 28 providers. Five of the methods use an external risk-adjustment algorithm developed in an independent population, while the other three rely on an internally developed logistic model. The purposes of this study are to: (i) create a common metric by which to display the results of these various risk-adjustment methodologies with regard to dichotomous outcomes such as in-hospital mortality, and (ii) to compare how these risk-adjustment methods quantify the 'outlier' standing of providers. Section 2 describes the data, the external and internal risk-adjustment algorithms, and eight approaches to provider profiling. Section 3 then demonstrates the results of applying these methods on a data set specifically collected for quality improvement.

Aged

Relationship between diabetes mellitus and long-term survival after coronary bypass and angioplasty.

BACKGROUND: Recent subgroup analyses of randomized trials have suggested that percutaneous intervention in diabetic patients with multivessel disease results in higher mortality than coronary artery bypass graft surgery (CABG). We studied the relationship between diabetes and survival after revascularization in a large prospective cohort of patients with multivessel coronary artery disease. METHODS AND RESULTS: By analyzing data for 3220 patients (24% diabetic) with symptomatic two- or three-vessel coronary disease who were undergoing percutaneous transluminal coronary angioplasty (PTCA) or CABG at Duke University Medical Center between 1984 and 1990, we found that at 5 years, unadjusted survival in the group of patients undergoing CABG was 74% in diabetics and 86% in nondiabetics. Similarly, 5-year survival among PTCA patients was 76% in diabetics and 88% in patients without diabetes. After adjustment for baseline characteristics, diabetic patients receiving either PTCA or CABG had significantly poorer survival than nondiabetics (chi2=43.56, P<.0001). Unlike previous studies, however, there was no significant differential effect of diabetes on outcome between patients treated with PTCA and those treated with CABG (chi2=0.01, P=.91). CONCLUSIONS: Although diabetes was associated with a worse long-term outcome after both PTCA and CABG in patients with multivessel coronary artery disease, the effect of diabetes on prognosis was similar in both treatment groups. Thus, our findings support the concept that the choice of initial revascularization strategy should not be based exclusively on a history of diabetes but rather should rely on other factors, such as angiographic suitability and clinical status.

Aged

Relationship between physician and hospital coronary angioplasty volume and outcome in elderly patients.

BACKGROUND: With the expectation that physicians who perform larger numbers of coronary angioplasty procedures will have better outcomes, the American College of Cardiology/ American Heart Association guidelines recommend minimum physician volumes of 75 procedures per year. However, there is little empirical data to support this recommendation. METHODS AND RESULTS: We examined in-hospital bypass surgery and death after angioplasty according to 1992 physician and hospital Medicare procedure volume. In 1992, 6115 physicians performed angioplasty on 97,478 Medicare patients at 984 hospitals. The median numbers of procedures performed per physician and per hospital were 13 (interquartile range, 5 to 25) and 98 (interquartile range, 40 to 181), respectively. With the assumption that Medicare patients composed one half to one third of all patients undergoing angioplasty, these median values are consistent with an overall physician volume of 26 to 39 cases per year and an overall hospital volume of 196 to 294 cases per year. After adjusting for age, sex, race, acute myocardial infarction, and comorbidity, low-volume physicians were associated with higher rates of bypass surgery (P < .001) and low-volume hospitals were associated with higher rates of bypass surgery and death (P < .001). Improving outcomes were seen up to threshold values of 75 Medicare cases per physician and 200 Medicare cases per hospital. CONCLUSIONS: More than 50% of physicians and 25% of hospitals performing coronary angioplasty in 1992 were unlikely to have met the minimum volume guidelines first published in 1988, and these patients had worse outcomes. While more recent data are required to determine whether the same relationships persist after the introduction of newer technologies, this study suggests that adherence to minimum volume standards by physicians and hospitals will lead to better outcomes for elderly patients undergoing coronary angioplasty.

Age Factors

Usefulness of serial radionuclide angiography in predicting cardiac death after coronary artery bypass grafting and comparison with clinical and cardiac catheterization data.

This investigation assesses the prognostic value of radionuclide measurements of cardiac function in patients undergoing coronary artery bypass grafting (CABG). Radionuclide angiograms during exercise and at rest were obtained in 182 patients before (< or = 30 days), early (< or = 3 months), and late (< or = 3 years) after CABG. Cox proportional hazard regression analysis was used to identify independent predictors of 44 cardiac deaths that occurred a median 12 years after bypass. Although the exercise ejection fractions before and early after CABG were significantly related to subsequent cardiac death (chi-square = 10.84, p = 0.001, and chi-square = 7.4, p = 0.006, respectively), the late postoperative exercise ejection fraction was the strongest predictor (chi-square = 13.9, p = 0.0002), contributing above and beyond clinical and catheterization data. These data document the validity of the exercise ejection fraction as an important predictor of cardiac death after CABG and suggest the potential clinical application of serial measurements of the exercise ejection fraction as an important noninvasive adjunct to postoperative evaluation of these patients.

Cardiac Catheterization

Risk stratification after myocardial infarction.

PURPOSE: To review the literature on risk stratification after acute myocardial infarction in the reperfusion era and to propose an algorithm for early and continual risk assessment. DATA SOURCES: A MEDLINE search of the English-language literature on humans was done using the terms myocardial infarction, prospective studies, and prognosis. This search was supplemented by narrowed searches for subheadings (such as cardiogenic shock, thrombolytic therapy, and stress testing) and surveys of references cited in review articles and book chapters. STUDY SELECTION: Literature on prognosis and myocardial infarction published from 1981 to 1996 was considered. From the literature on stress testing methods, studies that enrolled patients before 1980, enrolled patients for indications other than myocardial infarction, tested patients more than 6 weeks after infarction, were missing outcome data, or had inadequate follow-up were excluded. DATA EXTRACTION: Because too few randomized trials were available to allow the cross-comparison of risk-stratification methods, the available observational data were synthesized and supplemented with clinical judgments to produce recommendations. DATA SYNTHESIS: Risk stratification must begin when acute myocardial infarction is diagnosed. High-risk patients (such as those with cardiogenic shock) and candidates for reperfusion therapy must be identified quickly if ideal emergency care is to be given. At specific points during hospitalization, specialized tests may be useful if they add incremental information to the results of clinical evaluations. High-risk patients who have complications after infarction or significant left ventricular dysfunction probably benefit from early angiography; patients without these conditions are at low risk for recurrent events and should have noninvasive stress testing for further risk stratification. CONCLUSIONS: Physicians should continually reappraise risk throughout hospitalization to optimize both patient outcomes and cost containment.

Algorithms