All-artery multigraft coronary artery bypass grafting with only internal thoracic arteries possible and safe: a randomized trial.

BACKGROUND: The internal thoracic artery (ITA) bypass to the left anterior descending coronary artery is of proven benefit in multigraft coronary artery bypass. Total ITA grafts, if reoperation is averted by avoiding saphenous vein grafts (SVGs), are attractive. The safety of the total ITA graft operation (all-ITA) is a concern. METHODS: A randomized trial of multiple-ITA bypass graftings with the use of bilateral sequential ITA without SVGs was performed. Control patients received 1 ITA plus SVG. Inclusion criteria were those used in the Coronary Artery Surgery Study, extended to age 76 years, and any angina class, except emergent. One hundred sixty-two patients were randomized (81 patients per group) from January 1, 1990, to December 31, 1994. RESULTS: Baseline traits were similar as were cross-clamp times, pump times, and number of arteries bypassed (average, 4.3 arteries). Patients who received multiple ITA grafts had no myocardial infarctions, per reference laboratory. One patient died, and 2 patients returned for bleeding. The ITA-SVG group had similar results. The all-ITA group experienced successful completion in 93% of cases. Complications did not differ from control patients. CONCLUSIONS: Early and 5-year outcomes were not different between the all-ITA group and the ITA with SVGs group. We believe experienced surgeons can safely extend the ITA to multibypass coronary artery bypass without use of SVG to achieve an all-ITA operation.

CASS Registry long term surgical survival. Coronary Artery Surgery Study.

OBJECTIVES: To show the effect of clinical, angio and demographic traits on late survival of Coronary Artery Surgery Study (CASS) patients following coronary artery bypass grafting (CABG) and introduce Hazard Function analysis to CASS survival data. METHODS: Patients were reached by mail survey with 94% response. By National Death Index, vital status was obtained in 99.7% (n = 8221) with a mean follow up of 15 years. Cox proportional hazard and Blackstone Hazard Function regressions were used to assess effects of preoperative traits. RESULTS: Ninety percent of patients were alive at 5, 74% at 10 and 56% at 15 years. Of those age 65 and age 75 at operation, 74% and 59% were living at 10 years and 54% and 33% at 15 years (now age 90), survival exceeding the matched U.S. population. Hazard Function falls rapidly after CABG to 9 to 12 months, then rises, doubling by 15 years. Young patients, below age 35, had lower late survival. The time-segmented Cox model (divided at time suggested by the Hazard Function) identified traits showing predictive power early, throughout and late. Female sex, small body surface, ischemic symptoms and emergency status affected survival early. Heavier weight, infarct(s), diuretics, diabetes, smoking, left main and LAD stenosis and use of vein grafts only increased hazard late only. CONCLUSIONS: There are still lessons from the CASS database. CABG in the elderly is supported by the survival pattern of our patients age 75 at operation. Time-segmented Cox analysis and Hazard Function analysis separate baseline variables into those that predict early mortality and those that predict long survival.

Stroke in coronary artery bypass graft surgery: an analysis of the CASS experience. The participants in the Coronary Artery Surgery Study.

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 = less than 0.0001); 2) use of alpha-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 less than 0.0001) and a history of hypertension (n less than 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Effects 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. CASS Investigators.

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 randomized 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.

Effect of completeness of revascularization on long-term outcome of patients with three-vessel disease undergoing coronary artery bypass surgery. A report from the Coronary Artery Surgery Study (CASS) Registry.

BACKGROUND: Complete revascularization after coronary artery bypass surgery is a logical goal and improves symptomatic outcome and survival. However, the impact of complete revascularization in patients with three-vessel coronary disease with varying severities of angina and left ventricular dysfunction has not been clearly defined. METHODS AND RESULTS: The study was performed as a retrospective analysis of 3,372 nonrandomized surgical patients from the Coronary Artery Surgery Study (CASS) Registry who had three-vessel coronary disease. Group 1 (894 patients) had class I or II angina (Canadian Cardiovascular Society criteria) and group 2 (2,478 patients) had class III or IV angina. In group 1, adjusted cumulative 4-year survivals according to the number of vessels bypassed were 85% (one vessel), 94% (two vessels), 96% (three vessels), and 96% (more than three vessels) (log rank, p = 0.022). Adjusted event-free survival (death, myocardial infarction, definite angina, or reoperation) was not influenced by the number of vessels bypassed, nor was the anginal status among patients remaining alive after 5 years. In group 2, adjusted cumulative 5-year survivals were 78% (one vessel), 85% (two vessels), 90% (three vessels), and 87% (more than three vessels) (log rank, p = 0.074). Adjusted event-free survivals after 6 years were 23% (one vessel), 23% (two vessels), 29% (three vessels), and 31% (more than three vessels) (p = 0.025); at 5 years, those with more complete revascularization were more likely to be asymptomatic or free of severe angina. Among group 2 patients with ejection fractions less than 0.35, 6-year survival was 69% for those with grafts to three or more vessels versus 45% for those with grafts to two vessels (p = 0.04). Placing grafts to three or more vessels was independently associated with improved survival and event-free survival in group 2 but not group 1 patients. The case-fatality rates among 529 patients experiencing a myocardial infarction during follow-up was significantly higher for patients with less complete revascularization. CONCLUSIONS: Complete revascularization (grafts to three or more vessels) in patients with three-vessel coronary disease appears to most benefit those with severe angina and left ventricular dysfunction.

Ten-year follow-up of quality of life in patients randomized to receive medical therapy or coronary artery bypass graft surgery. The Coronary Artery Surgery Study (CASS)

Quality of life indexes were assessed in 780 patients 10 years after randomization to medical therapy (n = 390) or coronary artery bypass graft surgery (n = 390) in the Coronary Artery Surgery Study. At 10 years, mortality was 21.8% in the medical group and 19.2% in the surgical group (p = NS), and 144 (37%) of the medical group had undergone surgery because of increasing chest pain. At study entry, 22% of medical and surgical patients were angina free; at 1 and 5 years after entry, the frequency of asymptomatic patients was 66% and 63% in the surgical group and 30% and 38% in the medical group. However, by 10 years after entry, the proportion of patients free of angina had fallen to 47% in the surgical group and to 42% in the medical group. Activity limitation and use of beta-blockers and long-acting nitrates were less in the surgical than the medical group at 1 and 5 years after entry but little different from the medical group at 10 years after entry. Throughout follow-up, recreational status, employment status, frequency of heart failure, use of other medications, and hospitalization frequency were similar between the two groups. Thus, indexes of quality of life such as angina relief, increased activity, and reduction in use of antianginal medications initially appear superior in patients with stable manifestations of ischemic heart disease assigned to surgery, but by 10 years after entry, these advantages are much less apparent. Although the observed similarities of the medically and surgically assigned groups at 10 years reflect return of symptoms in the surgical group to some extent, a more important explanation is the performance of late surgery in a large proportion of the medically assigned patients, rendering them asymptomatic.

Improved survival of surgically treated patients with triple vessel coronary artery disease and severe angina pectoris. A report from the Coronary Artery Surgery Study (CASS) registry.

We examined survival rates during a 6-year follow-up of patients in the registry of the Coronary Artery Surgery Study who had three vessel coronary artery disease and Canadian Cardiovascular Society class III-IV angina pectoris. All patients had a stenosis of 70% or greater in either the mid or proximal segment of all three coronary arteries. There were 679 medically treated patients and 1921 surgically treated patients in this nonrandomized comparison. Patients were stratified by left ventricular wall motion score and number of proximal coronary artery stenoses; after adjustment for these variables, the estimated probability of being alive at 6 years was 82% for surgically treated patients and 59% for medically treated patients (p less than 0.0001). Among patients with the most severe left ventricular dysfunction (left ventricular wall motion score of 16 to 30), the 6-year survival rate was 63% for surgically treated patients and 30% for medically treated patients (p less than 0.0001). Those with three proximal lesions (all gradations of left ventricular score) had an 81% 6-year survival rate with surgical treatment and 40% with medical treatment (p less than 0.0001). Ninety percent of surgically treated patients with normal ventricular function were living at 6 years and 78% of medically treated patients (p less than 0.0001). Among these patients, the survival rate was significantly better after surgical treatment than after only medical treatment if two or three proximal stenoses were present. If no proximal lesions were present (all categories of left ventricular function), 84% of surgically treated patients and 67% of medically treated patients were alive at 6 years (p less than 0.0001). In a multivariate (Cox) analysis of preoperative clinical, hemodynamic, and angiographic factors, early operation was a strong predictor of survival (estimated relative risk 0.38).

Comparison of effects of medical and surgical therapy on survival in severe angina pectoris and two-vessel coronary artery disease with and without left ventricular dysfunction: a Coronary Artery Surgery Study Registry Study.

This nonrandomized study compared the results of early coronary artery bypass grafting to those of initial medical therapy in a group of 2,023 patients with severe angina pectoris and 2 major epicardial coronary arteries having greater than or equal to 70% diameter luminal narrowing. Medical therapy was selected for 706 patients, and 1,317 patients were treated by coronary artery bypass grafting. The 6-year survival rate was 76% for patients treated medically and 89% for patients treated surgically (p less than 0.0001). Cox multivariate analysis showed that surgical treatment was a beneficial independent predictor of survival (p less than 0.001). For patients with 2-vessel coronary artery disease who had Canadian Heart Association class III and IV angina at presentation, surgical therapy provided a survival advantage for patients with impaired left ventricular function and proximal narrowing of 1 or more coronary arteries.

Clinical implications of internal mammary artery bypass grafts: the Coronary Artery Surgery Study experience.

From the Coronary Artery Surgery Study Registry, all patients undergoing initial bypass surgery procedures with independent vein grafts were identified. The 950 patients receiving an internal mammary artery bypass graft were compared with the 6027 patients receiving vein graft alone. Improved survival rates with internal mammary artery grafts were noted at hospitals in which these grafts were performed infrequently as well as those in which the internal mammary artery graft was used frequently. The improved survival was noted in patients with normal (p = .004) as well as impaired (p = .004) ventricular function, in men (p = .0001) as well as women (p = .005), in patients over age 65 (p = .01) as well as younger patients (p less than .0001), and in those with (p = .05) or without (p less than .0001) critical stenosis of the left main coronary artery. The internal mammary artery bypass graft was an independent predictor of survival (p = .0004) and reduced the risk of dying by a factor of 0.64. It was concluded that the internal mammary artery graft is the bypass vessel of choice and should not be denied any subgroup.

Time to first new myocardial infarction in patients with severe angina and three-vessel disease comparing medical and early surgical therapy: a CASS registry study of survival.

We compared time to first new myocardial infarction during a 6-year follow-up in patients in the registry of the Coronary Artery Surgery Study who had three-vessel coronary artery disease and Canadian Cardiovascular Society Class III-IV angina pectoris. There were 679 medically treated patients and 1921 surgically treated patients in this nonrandomized comparison. A broad definition of myocardial infarction incorporating electrocardiographic and clinical criteria was used to include as many new infarctions as possible. Patients were stratified by left ventricular wall motion score and number of proximal coronary artery stenoses; after adjustment for these variables, 86% of surgical and 73% of medical patients were free of new myocardial infarction at 6 years (p less than 0.0001). This advantage of surgical treatment was observed in subgroups of patients with at least one proximal 70% (or greater) stenosis in the left anterior descending coronary artery and moderate or severe impairment of left ventricular function, as well as those patients with two proximal coronary artery narrowings. In a multivariate (Cox) analysis of preoperative clinical, hemodynamic, and angiographic factors, early operation was the strongest predictor of freedom from new myocardial infarction.

Medical versus early surgical therapy in patients with triple-vessel disease and mild angina pectoris: a CASS registry study of survival.

Results of coronary artery bypass grafting were evaluated in 856 nonrandomized patients in the Coronary Artery Surgery Study (CASS) registry with mild angina (Canadian Cardiovascular Society Classes I and II) and three-vessel disease, defined as 70% or more stenosis in the proximal or middle segment of the three major coronary arteries. There were 413 patients with medical therapy and 443 with early operation. Patients with delayed operation were kept in the medical group for analysis. Six-year survival adjusted for left ventricular (LV) function and number of proximal stenoses was 67% for medical and 84% for surgical patients (p less than 0.0001). Patients with normal LV function had equal survival with medicine or surgical intervention. Those with mild or moderate LV dysfunction (CASS LV wall motion score 6 to 9 and 10 to 15, respectively) and at least one proximal stenosis (the dominant right coronary artery) had increased probability of being alive at six years with surgical treatment. In patients with severe LV impairment (LV score higher than 15) and in those whose only proximal stenosis of 70% or more (in three-vessel disease) was located in the left anterior descending coronary artery, increased survival with surgical treatment could not be demonstrated. This is a nonrandomized observational study with the limitations of such studies: the need to adjust for differences in baseline traits between medical and surgical groups and the possibility of an unrecognized imbalance in baseline characteristics. In a Cox analysis of variables influencing outcome, early surgical treatment was an independent predictor of survival with 43% the risk of medical treatment (95% confidence range: 29 to 62%). Adjustment by propensity analysis to reduce selection bias from known differences in baseline variables did not alter results.

Time to first new myocardial infarction in patients with mild angina and three-vessel disease comparing medicine and early surgery: a CASS registry study of survival. Coronary Artery Surgery Study.

Two categories--patients alive and free from new myocardial infarction (MI) and time to first new MI (nonfatal and fatal)--were compared in medical and early surgical groups in the Coronary Artery Surgery Study (CASS) registry with Class I or II angina and three-vessel disease in a six-year follow-up. There were 413 in the medical group and 443 in the early surgical group. A broad definition of MI using ECG and clinical criteria on hospital discharge and follow-up was used to include as many new MIs as possible, including perioperative MIs. Stratification was by left ventricular wall motion score and number of proximal segment stenoses and by quintile of propensity score to reduce selection bias in therapy groups. Adjusted by propensity analysis, 79% of medical and 88% of surgical patients (p = .005) were free from new MI; death without diagnosis of new MI was censored. Similarly adjusted, 57% of medical and 76% of surgical patients (p less than .0001) were alive and free from new MI at six years. For patients with previous MI, surgery offered the probability of protection from new MI: with multiple prior MIs, 66% of medical and 88% of surgical patients were free from new MI at six years (p = .0019). This is a nonrandomized, observational study with the limitations of such studies: the need to adjust for differences in baseline traits in medical and surgical groups and the unknown effects of unobserved variables. Fifty-one variables, including therapy, were tested by Cox model with time to new MI as the end point. Early surgery was the strongest independent predictor of freedom from new MI (p = .002) with a relative risk of 51% compared with medical therapy (95% confidence limits of 33 to 78%). In patients with multiple prior MIs, the new MI risk with early surgery was 24% of that for medicine, with an upper 95% confidence point of 64%.

The influence of surgery on the natural history of angiographically documented left ventricular aneurysm: the Coronary Artery Surgery Study.

Coronary artery bypass surgery with or without aneurysmectomy has been used to treat patients with angiographically defined left ventricular aneurysm. To evaluate whether surgery benefits such patients, we analyzed the data from 1131 patients who were enrolled in the registry of the Coronary Artery Surgery Study. Four hundred sixty-seven patients underwent bypass surgery, of which 238 also had left ventricular resection, and 30 had resection alone. The overall operative mortality was 7.9%; the operative mortality was 7% for bypass alone compared with 9% for bypass surgery plus left ventricular resection (NS). Long-term survival by life-table analysis was similar for both medically and surgically treated patients (69% vs 67%, respectively). Cox survival analysis identified congestive heart failure score, duration of chest pain, extent of coronary disease, left ventricular end-diastolic pressure, age, and surgical therapy as important predictors of outcome. Patient subsets that showed improved survival with surgical therapy after adjustment for inequities in baseline characteristics were patients with three-vessel disease and those patients in moderate- and high-risk subgroups. Surgical therapy significantly reduced symptoms of angina and use of cardiac medications but the incidence of recurrent infarction was similar for both therapies.

Surgical survival in the Coronary Artery Surgery Study (CASS) registry.

The overall surgical survival data in the Coronary Artery Surgery Study (CASS) registry have not been published to date, pending the report of the randomized medical-surgical comparison (CASS randomized trial). Non-randomized surgical survival data from the CASS registry are given in this article. The overall medical survival data from the registry were reported previously as a natural history study. There were 8,991 patients in the registry portion of CASS who had primary isolated coronary artery bypass grafting and 8,971 with follow-up of more than 30 days. The 5-year survival for all 8,971 patients was 90%, and the operative mortality was 2.37%. Patients with left main coronary artery disease had an operative mortality of 3.84% and a 5-year survival of 85%, while patients with lesions in other vessels had an operative mortality of 2.12% and a 5-year survival of 91%. Among patients without left main coronary disease, the 5-year survival was 93% in those with single-vessel and 92% in those with double-vessel disease (operative mortality was 1.50% and 1.92%, respectively) and 88% in patients with triple-vessel disease (operative mortality was 2.62%; p = 0.009). When results for patients with left main coronary artery obstruction were compared with those for triple-vessel disease, the 5-year survival figures were 85% and 88%, respectively (p = 0.02) and the operative mortality, 3.84% and 2.62%, respectively (p = 0.03). Patients with normal or nearly normal left ventricular (LV) function (i.e., LV segmental wall motion scores ranging from 5 through 11) had a 5-year survival of 92% and an operative mortality of 1.97%. Patients with moderate impairment (LV score range, 12 through 16) had a 5-year survival of 80% and an operative mortality of 4.21%. In those with poor ventricular function (LV score of 17 or greater), the 5-year survival was 65% and the operative mortality was 6.21%. The difference in survival among the three groups was significant (p less than 0.0001). Of 29 variables used in a stepwise Cox regression analysis, LV wall motion score, congestive heart failure score, age, number of operable vessels, smoking history, LV end-diastolic pressure, and percent of left main coronary artery stenosis were found to have a significant effect on long-term survival (excluding 30-day mortality), and these variables plus surgical priority and height influenced surgical mortality. When height was used in the Cox proportional hazards model, female sex was no longer a significant variable.

Local intra-arterial streptokinase therapy for acute peripheral arterial occlusions. Should thrombolytic therapy replace embolectomy?

Locally administered low-dose streptokinase was used in 13 patients with acute arterial occlusions. Systemic fibrinolytic effects were noted in each of 11 patients in whom some effective thrombolysis was demonstrated. In the two patients with no angiographically demonstrable thrombolysis, a systemic lytic effect was absent. Bleeding complications were frequent (31%). Three patients required amputations and one patient died. The systemic lytic effects of streptokinase appear to be necessary for complete clot lysis. Locally administered streptokinase appears to have no significant benefit compared to high-dose systemic administration. Occlusions accessible to balloon embolectomy should probably be treated surgically, reserving fibrinolytic therapy for inaccessible lesions. More research is needed to clarify the specific indications, as well as to determine optimal methods of administration and dosage.

Comparison of coronary artery bypass surgery and medical therapy in patients 65 years of age or older. A nonrandomized study from the Coronary Artery Surgery Study (CASS) registry.

We compared the results of coronary artery bypass surgery with those of medical therapy alone in 1491 nonrandomized patients 65 years of age or older. Cumulative survival at six years (adjusted for major differences in important base-line characteristics) was 79 per cent in the surgical group and 64 per cent in the medical group (P less than 0.0001). At five years, chest pain was absent in 62 per cent of the surgical group and 29 per cent of the medical group (P less than 0.0001). Analysis by the Cox proportional-hazards model suggested an independent beneficial effect of surgery on survival (P less than 0.0001). Patients were divided into risk quartiles on the basis of preoperative predictors of survival identified by the Cox model. Surgical benefit was greatest in "high-risk" patients (those in the two quartiles containing patients with the poorest prognosis). Among 234 "low-risk" patients with mild angina, relatively good ventricular function, and no left main coronary artery disease, there was no survival difference between those treated medically and those treated surgically. We conclude that in specific higher-risk subsets of non-randomized patients 65 years of age or older, coronary bypass surgery appeared to improve survival and symptoms in comparison with medical therapy alone. These conclusions must be tempered by consideration of the limitations of nonrandomized studies, particularly since patients in the two treatment groups differed substantially with regard to important base-line characteristics.

Clinical experience with preoperative myocardial nutrition management.

Three hundred and twelve elective adult coronary artery surgery patients were divided into five groups differing as to preoperative glucose or fat loading. The control group (n = 54) had a mean myocardial glycogen level of 880 mg/100 gram heart weight, a 18.5% incidence of serious ventricular arrhythmias, 24.2% dependence on vasopressors, a mean peak postoperative SGOT level of 100 IU, and a 3.7% perioperative transmural myocardial infarction rate. The 10% glucose loading group (n = 67) had elevated myocardial glycogen of 1180 mg/100 gram heart, 14.9% serious ventricular arrhythmias but a lessened dependence on vasopressors (17.9%), a peak post bypass SGOT of 74 IU, and 2.9% transmural infarction rate. A 20% glucose overnight loading group (n = 65) had myocardial glycogen level of 1270 mg/100 gram heart, a 23.0% incidence of serious ventricular arrhythmias, a significant reduction in vasopressor dependence (3.1%), no transmural myocardial infarctions, and peak post bypass SGOT of 53 IU. The intravenous fats (10% Intralipid) group (n = 57) had the highest glycogen level of 1509 mg/100 gram heart, the lowest peak SGOT of 51 IU, no infarctions, a low vasopressor dependence (5.2%), but high rate of serious ventricular arrhythmias (22.8%). The oral fat and 20% glucose loading group (n = 69) had a myocardial glycogen of 1486 mg/100 gram heart, a low vasopressor dependence rate of 4.3%, no infarctions, a peak SGOT of 66 IU, and the lowest serious ventricular arrhythmia rate of 4.3%. These results suggest that it is possible to alter prebypass myocardial substrate levels against the stresses of cardiac surgery with fat and/or glucose loading and that myocardial protection is evident.(ABSTRACT TRUNCATED AT 250 WORDS)

Survival following coronary artery bypass grafting in patients with severe angina pectoris (CASS). An observational study.

This observational study evaluates the effects of the severity of angina pectoris and the treatment method upon the survival of 4,209 patients in the Coronary Artery Surgery Study registry. In this nonrandomized study, these patients met the criteria used in the Coronary Artery Surgery Study randomized trial, except for the degree of angina pectoris and the method of selection of treatment. The 5 year survival rate was greater than or equal to 93% in patients with Class I and II angina pectoris and normal left ventricular function, regardless of the number of involved vessels or treatment received. Late survival of surgically treated patients with Class III and IV angina pectoris and normal left ventricular function was similar, regardless of the number of vessels involved (greater than or equal to 92% at 5 years). Nonoperatively treated patients with Class III and IV angina pectoris and normal left ventricular function had poorer 5 year survival rates, lowest (74%) in patients with three vessel disease (p less than 0.0001). This difference was also observed in patients with abnormal left ventricular function, three vessel disease, and Class III and IV angina pectoris; the 5 year survival rates were 82% for the operative group and 52% for the nonoperative group (p less than 0.0001). These data confirm the importance of clinical as well as anatomic factors in determining the prognosis of patients with ischemic heart disease and indicate that coronary artery bypass grafting can improve late survival in patients with triple vessel disease and severe angina pectoris.