Coronary Artery Surgery Study Research Articles

Coronary artery disease and coronary artery bypass grafting in diabetic patients aged ≥65 years (report from the Coronary Artery Surgery Study [CASS] registry)

A cohort of 317 diabetic patients, aged ≥ 65 years, with angiographically proven coronary artery disease, was analyzed and followed for a mean of 12.8 years. Compared with 1,843 age-matched nondiabetic patients, diabetic patients were more likely to (1) have a higher number of coronary occlusions, (2) not be current smokers, (3) have higher systolic but lower diastolic blood pressures, (4) have evidence of peripheral vascular disease, and (5) be women. They did not differ significantly with respect to total cholesterol, family history of coronary artery disease, history of hypertension, or left ventricular hypertrophy. In the total elderly cohort, diabetes was found to be an independent predictor of mortality, conferring a 57.0% increased risk of death. Survival analysis showed that diabetic subjects consistently had higher mortality than nondiabetics. However, the relative survival benefit of coronary artery bypass graft surgery versus medical therapy was comparable in diabetic and nondiabetic patients. Surgical therapy conferred a reduction in mortality of 44%.

Long-term survival in patients with coronary artery disease: Importance of peripheral vascular disease

Objectives. The purpose of this study was to determine the importance of peripheral arterial disease in predicting long-term survival in patients with clinically evident coronary artery disease.Background. Patients in the Coronary Artery Surgery Study (CASS) Registry were followed up for >10 years.Methods. Survival in 2,296 patients with peripheral arterial disease was compared with that of 13,953 patients without peripheral arterial disease using Kaplan-Meier survival curves. All patients had known stable coronary artery disease. Clinical, electrocardiographic (ECG), chest X-ray film and catheterizalion variables of the two groups were compared using the chi-square statistic or the two-sample t test. The independent effect of peripheral arterial disease (as well as other variables) on mortality was determined utilizing a Cox proportional hazards model.Results. Patients with peripheral vascular disease were more likely to have hypertension, diabetes, family history of coronary artery disease, previous angina or myocardial infarction, previous coronary bypass surgery or to have smoked. They also had a higher incidence of congestive heart failure, ECG abnormality and modestly increased frequency of three-vessel disease. Independent correlates of long-term mortality for the entire cohort included age, smoking, diabetes, number of diseased coronary vessels, left ventricular function, hypertension, pulmonary disease, anginal class, previous myocardial infarction and peripheral vascular disease (all p < 0.061). At any point in time, patients with peripheral vascular disease had a 25% greater likelihood of mortality than patients without peripheral vascular disease (multivariate chi-square 25.83, hazard ratio 1.25, 95% confidence interval 1.15 to 1.36, p < 0.0001).Conclusions. Peripheral vascular disease is a strong, independent predictor of long-term mortality in patients with stable coronary artery disease. Aggressive attempts at secondary disease prevention are warranted in this high risk group.

Modifiable risk factors for incident heart failure in the coronary artery surgery study

<h3>Background:</h3> Even with aggressive treatment, heart failure is associated with a substantial morbidity and mortality. This poor prognosis has led to increasing interest in primary prevention, and the identification of modifiable risk factors. Our objective was to determine whether modifiable cardiovascular risk factors, including systolic and diastolic blood pressure, fasting glucose level, cholesterol level, weight, and smoking, were independent risk factors for heart failure in patients with anatomically confirmed coronary artery disease. <h3>Methods:</h3> We studied all patients with documented coronary artery disease eligible for the multicenter, randomized-controlled Coronary Artery Surgery Study. After excluding 79 prevalent cases, we identified incident cases of heart failure using hospital discharge abstracts, mortality records, or self-reported follow-up questionnaires. Criteria for self-reported cases were treatment with digitalis and/or furosemide plus two or more heart failure symptoms, including dyspnea on exertion, orthopnea, paroxysmal nocturnal dyspnea, or edema. Cox regression analysis was used to estimate adjusted relative risks. <h3>Results:</h3> At 12-year follow-up, the cumulative incidence of heart failure was 20.6%. Smoking (relative risk, 1.47) and weight (relative risk, 1.15/10 kg) were independently associated with incident heart failure. Myocardial infarction during follow-up, age, female sex, and baseline left ventricular dysfunction were also risk factors for heart failure. <h3>Conclusions:</h3> Patients with stable coronary artery disease are at high risk for developing heart failure, especially following myocardial infarction. However, interventions aimed at smoking cessation and weight reduction may prevent clinical heart failure in these patients. (Arch Intern Med. 1994;154:417-423)

Modifiable Risk Factors for Incident Heart Failure in the Coronary Artery Surgery Study

Even with aggressive treatment, heart failure is associated with a substantial morbidity and mortality. This poor prognosis has led to increasing interest in primary prevention, and the identification of modifiable risk factors. Our objective was to determine whether modifiable cardiovascular risk factors, including systolic and diastolic blood pressure, fasting glucose level, cholesterol level, weight, and smoking, were independent risk factors for heart failure in patients with anatomically confirmed coronary artery disease. We studied all patients with documented coronary artery disease eligible for the multicenter, randomized-controlled Coronary Artery Surgery Study. After excluding 79 prevalent cases, we identified incident cases of heart failure using hospital discharge abstracts, mortality records, or self-reported follow-up questionnaires. Criteria for self-reported cases were treatment with digitalis and/or furosemide plus two or more heart failure symptoms, including dyspnea on exertion, orthopnea, paroxysmal nocturnal dyspnea, or edema. Cox regression analysis was used to estimate adjusted relative risks. At 12-year follow-up, the cumulative incidence of heart failure was 20.6%. Smoking (relative risk, 1.47) and weight (relative risk, 1.15/10 kg) were independently associated with incident heart failure. Myocardial infarction during follow-up, age, female sex, and baseline left ventricular dysfunction were also risk factors for heart failure. Patients with stable coronary artery disease are at high risk for developing heart failure, especially following myocardial infarction. However, interventions aimed at smoking cessation and weight reduction may prevent clinical heart failure in these patients.

Five-year angiographic follow-up of factors associated with progression of coronary artery disease in the Coronary Artery Surgery Study (CASS)

Objectives. The Coronary Artery Surgery Study (CASS) required participants to undergo follow-up angiography at 5 years to identify clinical and angiographic features associated with progression of coronary artery disease.Background. The CASS randomized 780 patients at 11 participating clinical centers between an initial strategy of medical therapy versus bypass surgery. Five clinical sites accomplished follow-up angiography in >50% of their randomized subjects within a 42- to 66-month period after the entry arteriogram (n = 314).Methods. Qualified clinical site angiographers, using side by side film review, evaluated an average of 13 segments/patient on both arteriograms for initial stenosis severity, morphologic features, lesion location and occurrence of disease progression or occlusion. Progression was defined as further definite narrowing by ≥15% and occlusion as lesion progression to ≥98%. Lesions were subcategorized as to whether they were univariate and had or had not been treated with bypass surgery. Multivariate logistic regression analyses were performed.Results. For nonbypassed segments, right coronary artery and left anterior descending artery proximal and midlocations were associated with disease progression. For stenosis-containing segments, the initial severity, a non-left anterior descending artery location and increased treadmill duration predicted progression. Segment occlusion was associated with initial lesion severity, right coronary artery location and subsequent interval myocardial infarction. There were few predictors of progression or occlusion in bypassed arteries, other than initial lesion severity.Conclusions. Univariate and multivariate associations with lesion progression and occlusion included diabetes, lesion location, elevated cholesterol level, interval infarction and lesion morphology. These angiographic results, collected in a prospective trial, are consistent with known risk factors.

Risk of cardiac surgery in patients with peripheral vascular disease

After reading these articles, I think the evidence is convincing that peripheral vascular disease clearly places the patient at a higher risk for coronary bypass surgery than is the case for patients without peripheral vascular disease. However, in some instances coronary bypass surgery must be performed before peripheral vascular surgery is performed. Perhaps the best way to leave it is to indicate that if there is a clear-cut indication for coronary bypass surgery it should be done independent of vascular disease elsewhere, but one must accept the fact that most reports indicate an increased morbidity and mortality. Thus, I would like to make a final point by quoting Gersh: "The protective shield of prior coronary artery bypass surgery [in patients with peripheral vascular disease] . . . has a price."

Comparison of shortening with timing of wall motion in detecting regional abnormalities of the left ventricle in coronary disease

Clinical observations suggest that ischemic myocardium may demonstrate delayed wall motion while absolute shortening remains normal. Wall motion timing and percent shortening were examined in 25 patients (7 normal, 18 coronary disease) with 35 mm biplane left ventriculograms and coronary arteriography. Mean age was 63 +/- 2.4 years. Of 17 males and 8 females, 13 had 3 vessel, 4 had 2 vessel, and 1 had 1 vessel disease. Left ventricular regions were analyzed using the Coronary Artery Surgery Study nomenclature and quantitative computer-based analysis as well as visual based qualitative analysis. Regional percent shortening and ejection fraction were calculated from end systolic and end diastolic frames. Regional shortening times were related to global ejection time from 30 frame/sec, frame by frame analysis. Feeder arteries were stenosed ( > 70%) in 135 of 225 left ventricular regions analyzed. Computer detection (shortening and timing) identified 97/225 as abnormal (p < 0.01 vs. feeder artery stenosis) while physicians identified 79/225 as abnormal (p < 0.01 vs. feeder artery stenosis). Of the 97 computer detected abnormal regions, shortening alone detected 47, timing alone detected 39, and 11 showed both abnormalities. Timing analysis increased detection of wall motion abnormalities from 58/225 (26%) to 97/225 (43%) (p < 0.001). Timing abnormalities were noted more (92%) in basal segments, while shortening abnormalities dominated (88%) in apical segments (p < 0.001). Use of temporal measurements in wall motion analysis significantly increases the likelihood of detecting abnormal left ventricular regional wall motion when compared to shortening measurements alone.

Significance of silent myocardial ischemia after coronary artery bypass surgery

The prevalence and prognostic significance of transient myocardial ischemia after coronary artery bypass grafting (CABG) were evaluated. In 3 studies, ischemia was found in an average of 24% of patients by ambulatory electrocardiographic monitoring at 3–12 months after CABG. An average of 36% of patients in 3 other studies experienced ischemic ST-segment depression during exercise testing at 4–50 months after CABG. Of the ischemic episodes, 77% were silent during exercise testing. In the Coronary Artery Surgery Study (CASS) randomized patient subsets, survival at 12 years was significantly lower for patients who had either silent or symptomatic ischemia during exercise testing at 6 months after CABG compared with those who had no ischemia.

Effect of smoking on survival and morbidity in patients randomized to medical or surgical therapy in the coronary artery surgery study (CASS): 10-Year follow-up

Objectives. The goal of this study was to ascertain how continued cigarette smoking or smoking cessation related to long-term survival and morbidity in patients with established coronary artery disease managed with medical therapy or coronary bypass surgery.Background. Although the association of cigarette smoking with coronary artery disease is well established, the morbidity and mortality associated with smoking behavior in patients with such disease receiving medical or surgical therapy are less well established.Methods. The 780 patients randomized to medical therapy or coronary bypass surgery in the Coronary Artery Surgery Study (CASS) were subgrouped according to smoking behavior during a mean 11.2-year follow-up interval. Comparisons between smokers and nonsmokers were accomplished by univariate and Cox time-dependent multivariate analyses.Results. Survival at 10 years after entry into the study was 82% among 468 patients who reported no smoking during follow-up (nonsmokers) compared with 77% among the 312 smokers (p = 0.025). Survival was 80% among those who smoked at entry but stopped (quitters) versus 69% among those who continued smoking (p = 0.025). For patients who smoked at baseline and were randomised to bypass surgery, survival at 10 years was 84% among quitters and 68% among nonquitters (p = 0.018); the difference in survival between quitters (75%) and nonquitters (71%) was less among those randomized to medical therapy (p = NS). Among those who smoked at baseline, continued smoking increased the relative risk of death by 1.73. After 10 years, smokers, in comparison with nonsmokers, were less likely to be angina free and more likely to be unemployed and had more activity limitation and more hospital admissions (primarily for chest pain, heart attack, cardiac catheterization, peripheral vascular surgery and stroke).Conclusions. Thus, among patients with documented coronary artery disease, continued cigarette smoking may result in decreased survival—especially among those undergoing bypass surgery. Moreover, smokers have more angina, more unemployment, a greater limitation of physical activity and more hospital admissions.

Stroke in coronary artery bypass graft surgery: an analysis of the CASS experience

An analysis of the Coronary Artery Surgery Registry (CASS) was performed to determine the occurrence of stroke after coronary artery bypass surgery in patients entered into the Coronary Artery Surgery Study Registry. Of the 10,098 patients having coronary artery bypass surgery at the Coronary Artery Surgery Study participating sites during the period July 1974 through May 1979, a total of 348 patients (or 3.4%) sustained a stroke during the first year after coronary bypass surgery. Fifty-nine strokes occurred on the day of surgery, and an additional 129 strokes occurred during hospitalization for coronary bypass surgery. Thus, 188 patients (1.9%) of the entire surgical group sustained a stroke during initial hospitalization for coronary artery bypass surgery. Logistic regression analysis was used to predict stroke on the day of surgery, during the hospitalization for surgery, and during the first year after surgery. The most powerful predictors of stroke on the day of coronary artery bypass surgery were: 1) older age ( n = < 0.0001); 2) use of α-adrenergic drugs after bypass ( n = 0.0001); and 3) longer duration of cardiopulmonary bypass ( n = 0.002). For those strokes occurring at least 1 day after coronary artery bypass but during the initial hospitalization, age and duration of cardiopulmonary bypass were the most powerful predictors of stroke. An analysis of predictors of stroke within 1 yr after hospital dismissal for initial coronary bypass surgery revealed that the most powerful predictor was a history of previous cerebrovascular disease ( n < 0.0001) and a history of hypertension ( n < 0.0001). These data provide a perspective of stroke after coronary bypass surgery and identify predictors of high-risk subgroups of patients for such an event.

Analysis of randomized and nonrandomized patients in clinical trials using the comprehensive cohort follow-up study design

In clinical research, randomized trials are widely accepted as the definitive method of evaluating the efficacy of therapies. The random assignment of patients to their treatment ensures the internal validity of the comparison of new treatment with controls. An assessment of the external validity of trial results can best be achieved by comparing the study population to the population of patients who met the eligibility criteria but did not consent to randomization. A part of the data of the Coronary Artery Surgery Study (CASS), in which coronary artery bypass surgery is compared to conventional medical therapy in patients with coronary artery disease, is used to illustrate a strategy of multivariate analysis of randomized and nonrandomized patients which allows an investigation of both internal and external validity. The method used Cox's proportional hazards regression model with inclusion of covariates for randomization status and corresponding interactions in addition to the usual covariates for treatment and the important prognostic factors.

The relationship between cholesterol level and myocardial infarction or mortality risk in patients with coronary artery disease. A report from the Coronary Artery Surgery Study (CASS) registry.

Using data from the Coronary Artery Surgery Study (CASS) registry, we evaluated the relationship between cholesterol levels measured at enrollment and the following events: all-cause mortality, cardiac death, fatal myocardial infarction (MI), and nonfatal MI. Only patients with a significant coronary artery disease (at least one lesion with stenosis > or = 50%) were considered for this study. Results presented for mortality are for a period of up to 11.5 years and those for MI are for a maximum of 8 years of follow-up. Analyses were performed for each type of event and for each subgroup: women (n = 1861) and men (n = 10,941) under age 65, and women (n = 426) and men (n = 1144) age 65 or older. After adjusting for important covariates, cholesterol level was not associated with cardiac or all-cause mortality. No relationship between cholesterol level and fatal or nonfatal MI could be demonstrated except for men under age 65. However, in this subgroup the risk of MI was highest for those with low or middle cholesterol levels. The data show that in patients with angiographically determined coronary artery disease, cholesterol level is not a statistically significant risk factor for death or MI over the follow-up period in CASS.

Significance of silent myocardial ischemia during exercise testing in patients with diabetes mellitus: A report from the coronary artery surgery study (CASS) registry

To evaluate the significance of ischemic ST depression without anginal chest pain during exercise testing among patients with diabetes mellitus, the data on 45 such patients from the Coronary Artery Surgery Study registry were analyzed. These patients (group 1, silent ischemia) were compared with 37 diabetic patients with both ischemic ST depression and chest pain (group 2, symptomatic ischemia), with 31 diabetic patients without ischemic ST depression or chest pain (group 3, no ischemia), and with 429 patients without diabetes who had silent ischemia during exercise testing. All patients had documented coronary artery disease (CAD) (>70% diameter narrowing). The 6-year survival among patients with silent ischemia was worse in diabetic than nondiabetic patients (59 vs 82%, respectively, p < 0.001). By contrast, the 6-year survival among patients without ischemia was similar among diabetic and nondiabetic patients (93 vs 85%, respectively, p = 0.476). Among diabetic patients, survival at 6 years with medical treatment was 59% for group 1,66% for group 2 and 93% for group 3 (p = 0.008). Survival among subsets of patients with diabetes and silent ischemia (group 1) based on the extent of CAD and left ventricular function ranged from 100 to 32% (p = 0.093). The survival of the 45 patients with diabetes mellitus and silent ischemia (group 1) treated medically was compared with that of 28 patients receiving coronary artery graft bypass surgery. Survival at 6 years was enhanced by surgery compared with medical treatment among group 1 diabetic patients with 3-vessel CAD and either preserved left ventricular function (85 vs 52%, respectively, p = 0.080) or impaired left ventricular function (100 vs 32%, respectively, p = 0.015). These data suggest that, among patients with diabetes and CAD, silent myocardial ischemia during exercise testing adversely affects survival, and that coronary artery bypass graft surgery improves the survival of diabetic patients with silent myocardial ischemia and 3-vessel CAD.

Prevalence and prognostic significance of silent and symptomatic ischemia after coronary bypass surgery: A report from the Coronary Artery Surgery Study (CASS) randomized population

The prevalence and prognostic significance of postoperative myocardial ischemia, as detected by exercise testing, were prospectively assessed in 174 patients from the Coronary Artery Surgery Study (CASS) randomized surgical population who had exercise testing before and 6 months after coronary artery bypass graft surgery. Whereas the prevalence of symptomatic ischemia significantly decreased postoperatively (52% vs. 6%, p < 0.001), the frequency of silent myocardial ischemia did not change (30% vs. 29%).Survival at 12 years after bypass surgery based on the 6-month postoperative exercise, test results was significantly better for the 112 patients with no ischemia (80%) than for the 51 patients with silent ischemia (68%) or the 11 patients with symptomatic ischemia (45%).These data show that coronary artery bypass graft surgery diminishes the overall prevalence of symptomatic but not silent ischemia and that both silent and symptomatic ischemia adversely affect the postoperative prognosis of these patients.

Congestive heart failure symptoms in patients with preserved left ventricular systolic function: Analysis of the CASS registry

The clinical characteristics and long-term survival of 284 patients from the Coronary Artery Surgery Study (CASS) registry data base who had moderate to severe congestive heart failure symptoms and a left ventricular ejection fraction ≥0.45 were studied. A control group consisting of registry patients with an ejection fraction ≥0.45 who did not have heart failure was used for comparison. Patients who had heart failure were older and more likely to be female and to have a higher incidence of hypertension, diabetes and chronic lung disease than registry patients who did not have heart failure. As a group, patients with heart failure had more severe angina and were more likely to have had a prior myocardial infarction than were registry patients without heart failure.At 6 year follow-up, 82% of patients in the heart failure group survived compared with 91% of patients in the control group (p < 0.0001). Multivariate analysis using the Cox proportional hazards model identified the following independent predictors of mortality: regional ventricular systolic dysfunction, number of diseased coronary arteries, advanced age, hypertension, lung disease, diabetes, increased left ventricular end-diastolic pressure and heart failure symptoms. Among patients with heart failure, the 6-year survival rate of those who had three-vessel coronary artery disease was 68% compared with 92% for the group without coronary artery disease. However, the 6-year survival rate for patients with heart failure who underwent surgical revascularization of diseased coronary arteries was not significantly improved compared with that of patients treated medically.It appears from these data that the presence of moderate to severe heart failure symptoms in patients with an ejection fraction ≥0.45 is a clinical marker for a distinct patient group characterized by increased age, more severe clinical coronary artery disease, hypertension and an increased incidence of additional medical illnesses that have independent value in predicting long-term survival. As a result of the high incidence of concurrent illnesses, this patient group has a significantly reduced 6-year survival rate compared with a CASS registry patient group that did not have heart failure, and the additional presence of coronary artery disease dramatically reduces their survival. However, surgical treatment of coronary artery disease is not associated with improved survival over a 6-year follow-up period in this CASS registry subgroup.

Survival did not differ for patients whether they were in or out of the Coronary Artery Surgery Study (CASS)

Source Citation Chaitman BR, Ryan TJ, Kronmal RA, et al., and the CASS Investigators Coronary Artery Surgery Study (CASS): comparability of 10 year survival in randomized and randomizable patients....

Coronary artery bypass graft surgery improved survival in asymptomatic and mildly symptomatic patients with extensive coronary artery disease and LV dysfunction, but conferred no prognostic benefit in patients with preserved left ventricular function - 10 year follow-up of the Coronary Artery Surgery Study (CASS)

TherapeuticsMarch 1, 1991Coronary artery bypass graft surgery improved survival in asymptomatic and mildly symptomatic patients with extensive coronary artery disease and LV dysfunction, but conferred no prognostic benefit in patients with preserved left ventricular function - 10 year follow-up of the Coronary Artery Surgery Study (CASS)Robert J. Goldberg, PhDRobert J. Goldberg, PhDUniversity of Massachusetts Medical School, Worcester, Massachusetts, USA (R.J.G.)Search for more papers by this authorAuthor, Article, and Disclosure Informationhttps://doi.org/10.7326/ACPJC-1991-114-2-037 SectionsAboutFull Text ToolsAdd to favoritesDownload CitationsTrack Citations ShareFacebookTwitterLinkedInRedditEmail Source CitationAlderman EL, Bourassa MG, Cohen LS, et al. Ten-year follow-up of survival and myocardial infarction in the randomized Coronary Artery Surgery Study. Circulation. 1990; 82:1629-46.Reference1 Califf RM, Harrell FE Jr, Lee KL, et al. JAMA. 1989;261:2077-86 Google Scholar Author, Article, and Disclosure InformationAffiliations: University of Massachusetts Medical School, Worcester, Massachusetts, USA (R.J.G.) PreviousarticleNextarticle Advertisement FiguresReferencesRelatedDetails March 1, 1991Volume 114, Issue 2Page: 37KeywordsAnginaAngioplastyCardiovascular disease riskCoronary angioplastyCoronary arteriesCoronary heart diseaseCoronary revascularizationEjection fractionExtrapolationHeart failureIschemiaLesionsMedical risk factorsMyocardial infarctionMyocardiumRevascularizationStable coronary artery diseaseSurgery ePublished: 9 March 2020 Issue Published: March 1, 1991 Copyright & PermissionsCopyright © 1991 by American College of Physicians. All Rights Reserved.Loading ...

Initial medical therapy did not adversely affect long-term quality of life in the Coronary Artery Surgery Study (CASS)

Source Citation Rogers WJ, Coggin CJ, Gersh BJ, et al. Ten-year follow-up of quality of life in patients randomized to receive medical therapy or coronary artery bypass graft surgery. The Coronary ...

Technology Assessment in the Coronary Artery Surgery Study

The majority of the 26 technology assessment articles from the Coronary Artery Surgery Study (CASS) follow the original purpose of the registry and evaluate the therapeutic capabilities of coronary artery bypass graft surgery. However, these registry data have also been used to identify risk factors for cardiovascular disease, to test diagnostic technologies, and to evaluate technological processes. Consideration of quality of life issues and the availability of cost data provide valuable additions to the continued use of the CASS for technology assessment.

Decision Analysis in the Evaluation of Revascularization

Editorials1 December 1990Decision Analysis in the Evaluation of RevascularizationRolf M. Gunnar, MDRolf M. Gunnar, MDSearch for more papers by this authorAuthor, Article, and Disclosure Informationhttps://doi.org/10.7326/0003-4819-113-11-817 SectionsAboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinkedInRedditEmail ExcerptIn this issue, Dr. Wong and colleagues (1) evaluate the effects of revascularization for chronic stable angina, using a mathematical model to simulate clinical strategies. The model, however, is only as good as the database. A great deal of uncontrolled data on the outcome of patients treated with percutaneous transluminal coronary angioplasty (PTCA) and coronary artery bypass graft surgery (CABG) are available. Reliable information about the natural history of angina pectoris without mechanical intervention, however, is difficult to find.Wong and colleagues (1) rely quite heavily on data from the Coronary Artery Surgery Study (CASS) (2) as well as on...