Preinfarctional (unstable) angina--a prospective study--ten year follow-up. Prognostic significance of electrocardiographic changes

Unstable angina pectoris: national cooperative study group to compare medical and surgical therapy. I. Report of protocol and patient population

A preliminary report is presented of a prospective randomized trial conducted by eight cooperative institutions under the auspices of the National Heart and Lung Institute to compare the effectiveness of medical and surgical therapy in the management of the acute stages of unstable angina pectoris. To date 150 patients have been included in the randomized trial, 80 assigned to medical and 70 to surgical therapy; the clinical presentation, coronary arterial anatomy and left ventricular function in the two groups are similar. Some physicians have been reluctant to prescribe medical or surgical therapy by a random process, and the eithical basis of the trial has been questioned. Since there are no hard data regarding the natural history and outcome of therapy for unstable angina pectoris, randomization appears to provide a rational way of selecting therapy. Furthermore, subsets of patients at high risk may emerge during the process of randomization. The design of this randomized trial is compared with that of another reported trial. Thus far, the study has shown that it is possible to conduct a randomized trial in patients with unstable angina pectoris, and that the medical and surgical groups have been similar in relation to the variables examined. The group as a whole presented with severe angina pectoris, either as a crescendo pattern or as new onset of angina at rest, and 84 percent had recurrence of pain while in the coronary care unit and receiving vigorous medical therapy. It is anticipated that sufficient patients will have been entered into the trial within the next 12 months to determine whether medical or surgical therapy is superior in the acute stages of unstable angina pectoris.

Ventriculography and coronary arteriography in the acutely III patient. Complications, extent of coronary arterial disease, and abnormalities of left ventricular function

Of 99 patients who underwent "emergency" diagnostic studies, 82 had "unstable angina" (group A), 15 had recent myocardial infarction (group B), and two had intractable congestive heart failure due to acute mitral regurgitation (group C). Two cardiac and two local complications occurred either during the procedure or during the following 48 hours. There were no deaths or myocardial infarctions. Ten (12 percent) patients of group A had "normal" coronary arteries and normal left ventricular function; 13, 26 and 33 patients had one, two, and three coronary arteries involved, respectively. Those with three-vessel disease had a significantly higher left ventricular end-diastolic pressure (LVEDP) and lower ejection fraction (EF) than those with one- and two-vessel disease. Those with previous myocardial infarction had a significantly higher incidence of reduced EF and of wall motion abnormalities than those without a previous myocardial infarction. All patients in group B had significant coronary arterial disease, and 80 percent (12) had abnormal left ventricular function. Their mean LVEDP and EF were significantly higher and lower, respectively, than those found in group A. In conclusion, acutely ill patients were studied with low risk. Most patients had three- or two-vessel disease. Abnormal left ventricular function was related to three-vessel disease and to recent and old myocardial infarction.

Aortocoronary bypass surgery for ischemic heart disease: indications based on controlled trials

One- and two-year results of aortocoronary bypass for ischemic heart disease indicate that in stable angina pectoris, at least, the operation can be beneficial, ie, superior to intensive medical therapy, in achieving certain objectives. The operation is clearly a technical success, and prospects for very long-range patency of the grafts appear to be good. An observation of great interest is symptomatic improvement in some patients with occluded grafts. The greatest success of aortocoronary bypass is improvement in quality of life for certain patients.

Duration of hospitalization in "uncomplicated completed acute myocardial infarction". An Ad Hoc Committee review

The clinical and laboratory findings diagnostic of acute myocardial infarction include at least two of the following: (1) a history of pain consistent with myocardial ischemia, (2) electorcardiographic findings consistent with infarction, and (3) a rise in the serum level of specific cardiac enzymes. By the 4th or 5th day of illness, specific criteria can be applied to assign certain patients to a subset with "uncomplicated completed acute myocardial infarction." These criteria include the absence of evidence of (1) continuing cardiac ischemia, (2) left ventricular failure, (3) shock, (4) important cardiac arrhythmias, (5) conduction disturbances, and (6) other serious illnesses in patients with an established acute myocardial infarction. In terms of prognosis and management, patients in this subset should be regarded as substantively different from patients in other subsets. They should respond favorably to short periods of immobilization and hospitalization than those generally used. They may remain at bed rest (modified in regard to sitting and the use of a commode) for 4 days. Subsequently, mobilization with a program of progressive activity over the ensuing 5 to 10 days should reduce the duration of hospitalization to less than the current average of 17.5 to 20.8 days for patients with acute myocardial infarction. Nine to 14 days should suffice in most instances. Current and future trials may indicate that still earlier mobilization and shorter hospitalization periods can be applied to certain patient groups, but the evidence on this point is incomplete. For the individual patient, many factors will determine the optimal duration of bed rest and hospital stay. The patient's physician must consider the therapeutic benefits that may attend earlier mobilization and shorter hospitalization while weighing potential disadvantages. When the responsible physician does not regularly care for the patient, consultation with an experienced cardiologist is desirable. Patients whose condition is classified as "uncomplicated" may manifest deterioration during their illness and require assignment to a subset with a different prognosis and requiring different forms of treatment. For patients with uncomplicated acute myocardial infarction, as well as those in other subsets, absolute rules for therapy are unwise and application of broader principles by the alert physician is more likely to be beneficial.

Detection of unstable angina by 99m technetium pyrophosphate myocardial scintigraphy

99mTechnetium stannous pyrophosphate has been shown to accumulate in acutely infarcted myocardium. To determine if the isotope is also taken up by severely ischemic, but not necrotic myocardium, we performed myocardial scintigraphic studies in 17 patients with chest pains. Seven of the patients satisfied conventional clinical, electrographic, and laboratory criteria for the diagnosis of unstable angina and showed no electrocardiographic or enzymatic evidence of myocardial necrosis. Five of these seven patients with unstable angina demonstrated abnormal localized patterns, and one showed a borderline picture. Myocardial scintiscans were normal in all of a control group of ten patients with stable angina. Thus, scanning with 99mtechnetium stannous pyrophosphate is shown to be of value in the objective demonstration of myocardial abnormality in unstable angina.

Complication rate of coronary arteriography. A review of 5250 cases studied by a percutaneous femoral technique

Distressing rates of embolic complications from coronary arteriography performed by the percutaneous femoral approach have been reported since 1972. From 1970-1974, 5250 patients underwent coronary arteriography in our laboratory by the same percutaneous femoral technique with preformed polyethylene catheters and no systemic heparinization. Data were recorded during and for 24 hours postcatheterization. The annual mortality rate averaged 0.23% and remained relatively stable. Our incidence of embolic complications was very low. In patients with normal coronary arteries, no fatal or serious nonfatal complications occurred. Left main coronary artery disease was present in all cases of mortality and greater than or equal to 60% stenosis was shown in nine of 12 instances. Thus major risk was proportional to the severity of disease in the left coronary system. The use of more aggressive supportive measures in these high-risk cases appears essential to reduce the total complication rate from coronary arteriography significantly.

Medical versus surgical therapy for acute coronary insufficiency. A randomized study

Forty patients with acute coronary insufficiency, including continued angina at rest and reversible ischemic electrocardiographic changes after hospitalization ("high-risk" subgroup), were randomly allotted to medical therapy or urgent surgical coronary bypass groups. In four months there were no deaths and two myocardial infarctions in 19 medical patients and one death and three myocardial infarctions in 21 surgical patients. Left ventricular ejection fraction did not change significantly in either group. The surgical patients had significantly higher functional capacities at four months as judged by lower symptomatic functional class (P less than 0.01), higher exercise angina threshold (P less than 0.001), higher pacing angina threshold (P less than 0.0001), and higher myocardial lactate extraction during pacing (P less than 0.0001). Initial medical management of patients with acute coronary insufficiency followed by elective coronary bypass in patients with continued disabling angina pectoris is a reasonable alternative to emergency bypass.

Unstable angina. The problem of definition

Unstable angina is used interchangeably with a variety of other terms to refer to a clinical situation intermediate in severity between chronic effort angina and myocardial infarction. In most reports dealing with this syndrome, the patients were selected according to a number of criteria which varied from one study to another. Some authors recognized subgroups of patients with variable severity while others looked at unstable angina as one single group. This resulted in conflicting observations and consequent dilemmas in the management of these patients. Accurate definitions are, therefore, necessary. It is proposed to divide unstable angina into two main clinical categories. Type I: This includes three subgroups. (A) Patients with known chronic angina and sudden or accelerated progression of symptoms; (B) patients with chronic angina and onset of recurrent attacks at rest; and (C) patients with angina of recent onset and rapid progression into a severe condition. Type II: (severe unstable angima). Any of the subgroups described under unstable angina Type I will qualify for this classification if the patient develops recurrent episodes of prolonged ischaemic chest pains resistant to nitroglycerin lasting for 15 minutes or more. Accurate measurement of symptoms and laboratory criteria are suggested to qualify for the different subgroups of unstable angina.

Results of direct coronary artery graft reconstruction. A five-year clinical and arteriographic appraisal

Three hundred thirty-six patients with severe coronary artery disease were operated upon between June, 1969, and December, 1974. All were followed from 1 to 66 months (average, 37 months) with respect to survival and late myocardial infarction. The patients operated upon were compared statistically with a group of unoperated patients, and this evaluation demonstrated significantly better late survival in the surgically treated patients who had double- and triple-vessel disease. Two hundred thirty-six consecutive patients had clinical and late arteriographic reevaluation more than 6 months postoperatively; 78% were asymptomatic. Factors affecting graft patency are reviewed in detail. Late graft patency is determined by preoperative selection of vessels for grafting. Patency is not an index of success for this procedure. Surgical therapy appears to be the treatment of choice for patients with two- three-vessel coronary occlusive disease.

Acute coronary insufficiency. An urgent surgical condition

In 41 of 220 consecutive patients who had a coronary artery bypass operation between July 1973 and March 1974 the operation was for acute coronary insufficiency (recurrent chest pain with transient electrocardiographic changes persisting after admission to hospital). Their mean age was 54 (range 33-70 years). Eleven patients had had angina before, 14 had had at least one myocardial infarction, and 16 presented de novo. Eight of the latter 16 patients required only a single graft, usually to the left anterior descending artery, a significantly greater number than the two of the other 25 patients (P less than 0.01). Fourteen of these 16 patients had normal ventricular contraction, a significantly higher proportion than the 13 of the remaining 25 (p less than 0.05). No collaterals were seen in any of the 10 with single-vessel disease, which was significantly fewer than five out of 18 with double- and nine out of 13 with triple-vessel disease (P less than 0.005). Patients with rapidly developing obstruction, especially in the proximal left anterior descending artery, may not have time to develop collaterals, present acutely with good ventricular function, and may be particularly at risk. There was no operative mortality. The patients had a perioperative myocardial infarction, and there was one late death. At follow-up averaging 9-7 months (range 5-14 months) 32 (80%) patients were angina-free, no myocardial infarctions had occurred, and 85% were fully employed. Urgent coronary artery bypass grafting is a safe and effective treatment for acute coronary insufficiency.

Coronary artery bypass in patients over 70 years of age: indications and results

With recent advances in all phases of coronary care and the increasing success of coronary arterial surgery, operative treatment of coronary artery disease is more readily recommended, even for patients over 70 years of age. In a series of 3,730 patients who underwent aortocoronary bypass from November 1969 through June 1974, there were 95 patients who were 70 years of age or older. The primary indication for surgery was severe angina, which was present in 88 patients. The mean coronary arterial score was 9.51. Associated valvular lesions were treated surgically in 21 patients, and a left ventricular aneurysm was resected in 7. Improvements in surgical technique and postoperative care are responsible for the hospital mortality rate of only 4.8 percent in the 21 patients operated upon during the first 6 months of 1974 compared with the overall mortality rate of 22.1 percent in all 95 patients. Long-term follow-up among the 95 patients includes data from 33 patients: 9 patients whose condition improved, 21 who were asymptomatic and 1 "coronary death".

Improved long-term survival after aortocoronary bypass for advanced coronary artery disease

Three hundred thirty patients undergoing coronary bypass grafts for disabling angina, "preinfarction" angina, or coronary occlusion without cardiogenic shock have undergone coronary revascularization from July 1970 to March 1974. The operative mortality was 1.2 per cent and the long-term mortality, 4 per cent. Patients were subjected to life table analysis, and the figures suggest that in patients with two- and three-vessel coronary artery disease who received complete revascularization, there was a significant prolongation of life when compared with data from a large series of medically treated patients with angiographically documented coronary artery disease. Longer follow-up data will be important in definitively ascertaining the favorable effect of coronary revascularization on longevity.

Correlation of "critical" left coronary artery lesions with positive submaximal exercise tests in patients with chest pain

This study correlates the anatomic pathologic coronary anatomy found by arteriography in each of three groups of symptomatic patients, all with coronary artery disease, divided according to the magnitude of ST-segment depression after an adequate submaximal treadmill exercise test. Group I consists of 45 patients with ST-segement depression of 2 mm. or more, Group II of 31 patients with ST-segment depression between 1.0 and 1.9 mm., and Group III, 30 patients with 0 to 0.9 mm. ST-segment depression. Seventy-five per cent of the patients in Group I had critical lesions defined as (1) 75 per cent or greater narrowing of left main coronary artery (LMCA), (2) 75 per cent or greater obstructive left anterior descending and left circumflex coronary artery both proximal to any major branching, the so-called left main equivalent (LME) lesions, and (3) 90 per cent or more obstruction of the left anterior descending coronary proximal to any major branches. Of patients in Group I, 24 PER CENT Had LMCA lesions, 29 per cent had LAD lesions. Eight-two per cent of Group I patients had two- or three-vessel disease. All patients with LMCA lesions had 2 mm. or more ST-segment depression. Over 95 per cent of patients with "critical" lesions is less than 5 per cent in the presence of an adequate aubmaximal treadmill test that shows less than 1 mm. of ST-segment depression, it is concluded that in such patients with medically controllable angina, coronary arteriography is not necessary.

Coronary bypass surgery for unstable angina pectoris. Clinical follow-up and results of postoperative treadmill electrocardiograms

The first 81 patients who underwent coronary artery bypass surgery at Stanford University Hospital for unstable angina pectoris have been followed up for an average of 18 months. The over-all surgical mortality was 8.6 per cent (seven patients). There have been no operative deaths in last 32 patients, which may be due to over 75 per cent of these patients being stabilized on intensive medical therapy from 24 to 72 hours before study or surgery. There was a 16 per cent (13 patients) perioperative and 15 per cent (12 patients) late incidence of myocardial infarction. Of 74 patients who survived the initial operation 2 died 2 and 3 months postoperatively. Good or complete relief from pain was obtained in 94 per cent (70 patients) of the survivors. Of 57 longterm survivors tested, 49 per cent (28 patients) had a definite ischemic response to treadmill exercise testing. This may reflect the severe nature of the occlusive coronary disease or mechanisms other than increased coronary flow being responsible for the relief of pain. Although coronary bypass surgery appears to be effective in relieving the pain of patients with unstable angina pectoris, the 18 month average follow-up indicates that the incidence of myocardial infarction in surgically treated patients is comparable to that in medically treated patients.