Evidence from a nonrandomized study that coronary surgery prolongs survival in patients with two-vessel coronary disease

Routine coronary angiography for effort angina

OBJECTIVE

To compare the value of exercise testing and coronary angiography in the management of patients with effort angina.

DESIGN

A retrospective follow-up study.

SETTING

A university teaching hospital.

PATIENTS

Four hundred and thirty-four patients with a history of angina, who developed pain or ST segment changes during an exercise test and who were followed-up at up to nine years after their exercise test.

INTERVENTIONS

Coronary angiography was offered to patients for disabling angina only. Bypass surgery was generally offered to patients with multiple vessel coronary artery obstruction.

MAIN OUTCOME MEASURE

Patient survival.

RESULTS

Stepwise regression analysis based on the Cox proportional hazards model indicated that the decision to perform coronary angiography (P less than 0.001) and the amount of ST segment depression on exercise testing (P less than 0.01) were predictors of survival. With ST segment depression set at 1 mm and age set at 53.5 years (both sample median values) the probability of survival at five years was 86% in patients who did not undergo coronary angiography compared with 96% in patients who did undergo angiography. There were eight deaths in 59 patients who did not show any ST segment depression during the exercise test and who were treated medically without coronary angiography.

CONCLUSIONS

Coronary angiography is a superior technique to exercise testing for detecting patients with effort angina who are at high risk of premature mortality. Coronary bypass surgery makes a big improvement in the chance of five-year survival in such patients.

Effect of aortocoronary bypass surgery on coronary circulation and myocardial metabolism during atrial pacing

Eleven patients with coronary heart disease, in whom at least one of several bypass grafts to the left coronary artery was patent, were selected for the study. The hemodynamics, coronary sinus blood flow, myocardial oxygen consumption, and myocardial lactate metabolism were evaluated at rest and during atrial pacing stress test before and after surgery. There were no significant improvements in the cardiac index, pulmonary arterial end-diastolic pressure, and left ventricular ejection fraction after aortocoronary bypass surgery. However, significant improvement of coronary sinus blood flow, myocardial oxygen consumption, and myocardial lactate extraction and consumption were found during postoperative atrial pacing compared with the preoperative findings. These results suggest that successful bypass grafting may improve myocardial lactate metabolism in ischemic lesions and contribute to the postoperative relief of angina.

Exercise radionuclide assessment of left ventricular function before and after coronary bypass surgery

The effects of elective saphenous vein coronary artery bypass surgery on left ventricular ejection fraction were assessed by using exercise first-pass radionuclide angiography in 66 consecutive patients. All patients with left main coronary artery or concomitant valvular disease were eliminated from the study. Before surgery, 7 patients had normal postexercise left ventricular function (Group 1), 33 had normal resting left ventricular function with an abnormal response to exercise (Group 2), and 26 had an abnormal resting left ventricular ejection fraction with an abnormal response to exercise (Group 3). Following surgery, patients in all three groups had no change in mean resting left ventricular ejection fraction; however, patients in Groups 2 and 3 had significant improvement in mean postexercise left ventricular ejection fraction (p less than 0.0001 and p less than 0.0054 respectively), whereas patients in Group 1 did not. Previous studies reported improvement in postexercise ejection fraction in patients with reduced resting left ventricular function and with an ischemic response to exercise (Group 3). But this is the first study to confirm improvement in postexercise function in patients with normal resting function and an ischemic response to exercise (Group 2).

Assessment of the impact of coronary artery surgery on mortality after recovery from myocardial infarction

Death rates over a nine year period were studied in 1,232 survivors of myocardial infarction. From 1973 to 1981, the 29 to 365 day case fatality rate in 28 day survivors dropped from 13.3% to 3.2%. This down-trend in case fatality was highly significant, averaging 14.3% in each year. After adjustment for changes in age and severity of infarction, using a prognostic score derived from the Perth Coronary Register (the PCR score), the estimated decline was still 12.2% in each year. During the nine years, the rate of coronary surgery in the post-infarction year rose from 1.5% to 12.0%. Overall, the surgically treated cases had a lower case fatality rate (1.6%) than the medically treated cases (7.7%). However, the surgical cases had a better prognosis at the time of infarction than the medical cases. When the severity of infarction (PCR score) and year of admission were considered, coronary surgery in the post-infarction year had no independent effect on outcome.

Twelve years of coronary artery surgery in South Australia

Twelve years' results of coronary artery bypass surgery in South Australia have been reviewed. The preoperative assessment parameters and operative profiles of 4001 patients who underwent isolated coronary artery grafting between 1970 and 1982 have been examined. In addition, all surviving patients received a follow-up questionnaire; only 48 patients have remained untraced. Survival curves for the patient group have been calculated and compared with those for the Australian population. The risk factors which influenced long-term survival have been identified. Surviving patients described their anginal symptoms as diminished in 93% of cases at the time of review. When recurrent angina was described, 58% of patients experienced it within 12 months of the operation. Postoperative activity was improved in 71% of patients; 8% described a deterioration. A second operation was performed in 2.1% of patients. This study provides a comprehensive review of the efficacy of coronary artery bypass surgery both in the short and in the medium term.

Effect of coronary artery bypass grafting on subsequent hospitalization

The rates of hospitalization during follow-up for a matched pair cohort of medically and surgically treated patients from the Angiography Registry of Seattle Heart Watch were compared. Medically and surgically treated patients were matched according to extent of disease, left ventricular ejection fraction, age, and 3 other survival rate-related characteristics. There was a 26% reduction in cardiovascular hospitalizations in the surgically treated patients (19%/year) compared with the medically treated patients (26%/year). This was due to a significant reduction in hospitalization rate for myocardial infarction (surgically treated patients 1.1%/year, medically treated patients 2.6%/year), and for other cardiovascular reasons (surgically treated patients 12.5%/year, medically treated patients 15.7%/year). No significant (p = 0.146) reduction occurred in hospitalization rate for chest pain not due to myocardial infarction (surgically treated patients 5.6%/year, medically treated patients 7.7%/year). When the perioperative infarctions are included for the surgical cohort, the overall myocardial infarction rate is not significantly different (p = 0.173) between the 2 treatment groups (surgically treated patients 1.9%/year, medically treated patients 2.6%/year). Acute myocardial infarction was an uncommon reason for hospitalization, accounting for only 8% (55 of 685) of all cardiovascular hospitalizations, and was not related to the number of stenotic vessels in medically treated patients.

Clinical evaluation of the relative effectiveness of multidose crystalloid and cold blood potassium cardioplegia in coronary artery bypass graft surgery: a nonrandomized matched-pair analysis

Controversy exists concerning the most effective method of myocardial protection during coronary artery bypass graft operations. Accordingly, we performed a matched-pair analysis between 25 patients receiving multidose hypothermic potassium crystalloid cardioplegia and 25 other patients receiving cold blood potassium cardioplegia. Patients were matched on the basis of preoperative ejection fraction (EF) and the number of anatomically similar stenotic coronary arteries. The adequacy of myocardial protection was assessed by serial perioperative determinations of radionuclide ventriculography, hemodynamic measurements, analyses of electrocardiograms and serum levels of MB-CK. We found that the level of myocardial protection was similar between unstratified groups. However, when subgroups were selected on the basis of prolonged aortic cross-clamp time (greater than ninety minutes) or impaired preoperative left ventricular function (EF less than 40%), there was a suggestion that cold blood cardioplegia may be advantageous.

Coronary artery graft surgery

The last decade has seen significant technical advances in equipment for the procedure of, and the surgeon's operating skill in coronary artery by pass surgery. Such surgery is indicated when, despite medical treatment, angina is disabling; although evidence is increasing that patients whose pain is controlled should be considered for surgery. Late operations are more complex and expensive, and patients are exposed to a higher risk of sudden death in the intervening period. Delay may also allow the disease to progress to an inoperable state. Patients unlikely to benefit from medical treatment should be offered surgery as soon as their disease is identified by angiography. Intensive medical treatment, with its poorer control of symptoms, leads to an increasing dependence on the State of medicine, hospital facilities and sickness benefits. The reputedly expensive coronary artery bypass operation is cheaper both to the State and to the patient tha unoperated invalidism.

Nonrandomized matched pair analysis of intermittent ischemic arrest versus potassium crystalloid cardioplegia during myocardial revascularization

The quest for the ideal method of myocardial preservation during coronary artery bypass graft (CABG) surgery continues at a rapid pace. Nevertheless, in the present clinical practice of cardiac surgery, the choice is chiefly between hypothermic intermittent ischemic arrest and hypothermic potassium cardioplegia. This study applies newer technics in radionuclear cardiology, as well as more conventional enzymatic, electrocardiographic, and hemodynamic determinations, to the evaluation of the effectiveness of the previously mentioned modes of myocardial protection. Serial assessments are made preoperatively as well as during the first ten days postoperatively. We find that the perioperative incidence of myocardial damage and changes in left ventricular performance are almost identical using either method in patients with relatively normal preoperative left ventricular performance who do not have severe preoperative refractory ischemia or necrosis.

Arteriography of coronary disease at clinical onset

The coronary arteriographic anatomic findings in 491 male patients clinically symptomatic for less than six months are described. Single and multiple vessel disease was noted, respectively, in 40 and 60 percent with 6.5 percent also manifesting left main coronary disease. Our findings indicate that severe coronary artery disease is present early in the symptomatic phase and that patients presenting with initial inferior myocardial infarctions may represent a select group having an excessive frequency of severe coronary disease suitable for early angiographic detection and surgical bypass therapy.

Effect of surgical versus medical therapy on return to work in patients with coronary artery disease

The proportion of medically and surgically treated patients with coronary artery disease working full time 1 year after cardiac catheterization or surgery, respectively, was assessed by questionnaire in a registry of patients who had had coronary angiography. The proportion of medically and surgically treated patients working 3 months before catheterization or surgery was 74 percent (148 of 201) and 75 percent (899 of 1,198), respectively, whereas 62 percent (125 of 201) and 62 percent (747 of 1,198), respectively, were working full time 1 year after catheterization or surgery. Multivariate analysis identified five variables predictive of return to work. In order of significance these were: working status 3 months before surgery or catheterization, years of education, age, functional class before surgery or catheterization and period of not working before surgery or catheterization. Work status 3 months before surgery or catheterization was clearly the best predictor of continued employment 15 months later. Surgical therapy was not more effective than medical therapy in maintaining full-time employment in this registry of patients with coronary artery disease.