Surgical versus non-surgical management of patients soon after acute myocardial infarction.

Of 510 patients admitted to hospital with acute myocardial infarction, 34 had coronary artery bypass grafting before discharge (6-43 days (median 20) after infarction). The patients who were given grafts generally had a smaller infarction with less functional impairment than the 476 patients who were not. The outcome of coronary artery bypass grafting was investigated in a retrospective matched pair study. Patients were matched on the basis of the presence of postinfarction angina, left ventricular ejection fraction, location of the infarction, peak creatine kinase activity, Killip clinical class, and severity of coronary disease with 34 patients who were given medical treatment only. At one year follow up fewer of the operated patients had symptoms than did the matched non-operated patients. Survival at one year in the operated and non-operated groups respectively was 94% vs 91%; angina within one year occurred in 3% vs 68%; congestive heart failure in 3% vs 6%; and 0% vs 32% were referred for later bypass grafting or coronary angioplasty. It is concluded that coronary artery bypass grafting can be performed safely soon after myocardial infarction provided that left ventricular function is not seriously compromised. Such treatment is more effective than medical treatment for relief of angina during the first year after infarction.     

Stepwise risk stratification soon after acute myocardial infarction

A stepwise rise stratification procedure sequentially combining historical and clinical characteristics and treadmill exercise test results was applied to 702 consecutive men aged ≤70 years who were alive 21 days after acute myocardial infarction (Ml). Historical characteristics alone (prior Ml and prior angina or recurrence of pain in the coronary care unit) identified 10% of patients with the highest rate of reinfarction and death within 6 months (18%). Clinical contraindications to exercise testing identified another 40% of patients with an intermediate rate of cardiac events (6.4%). In the 50% of patients who underwent treadmill testing 3 weeks after Ml, the rate of cardiac events within 6 months was 4.4%: 3.9% in patients with a negative test and 9.7% in patients with a positive test (ischemic ST-segment depression ≥0.2 mV and a peak heart rate ≤135 beats/min). Patients with negative treadmill tests, who comprised 46% of patients ≤70 years and 53% of patients ≤60 years, had a cardiac death rate of <2% in the 6 months after Ml. The stepwise classification procedure correctly classified 72% of patients with hard medical events within 6 months. Thus, most patients who experience subsequent cardiac events are correctly classified on the basis of historical and clinical risk characteristics. In patients without these risk characteristics, early treadmill testing is useful for further discriminating high-risk from very low risk patients.     

Exercise training soon after myocardial infarction

To assess the cardiovascular effects of exercise training soon after clinically uncomplicated myocardial infarction, 70 men (mean age 54 years) underwent gymnasium training (no. = 28), home training (no. = 12) or no training (no. = 30) 3 to 11 weeks after the acute event. During this 8 week interval functional capacity increased significantly (P < 0.001) in all three groups: gymnasium training, 66 percent; home training, 41 percent; and no training, 34 percent. Peak functional capacity at 11 weeks was 11.0 ± 1.6, 10.3 ± 1.4 and 9.4 ± 1.8 (mean ± standard deviation) multiples of resting energy expenditure (METs) in the three groups—values approximating those of sedentary men of similar age without coronary heart disease. Functional capacity increased more in the gymnasium training group than in the no training group, but this difference was statistically significant only in patients without exercise-induced ischemie S-T segment depression or angina pectoris (P < 0.01). Another “training effect”—diminished heart rate response to submaximal work—was also observed in all three groups. It is concluded that (1) symptom-limited treadmill exercise testing performed soon after clinically uncomplicated myocardial infarction is feasible and safe and provides useful guidelines for physical reconditioning. (2) Patients who demonstrate nonischemic responses to treadmill exercise testing soon after infarction may safely undergo unsupervised exercise training at home. (3) Formal exercise training may not be required to restore functional capacity to nearly normal values soon after clinically uncomplicated myocardial infarction.     

Exercise testing soon after myocardial infarction.

Forty-six men under age 70, without clinical congestive heart failure or unstable angina pectoris, performed treadmill tests 3, 5, 7, 9 and 11 weeks after myocardial infarction. Patients were more frequently able to perform moderate exertion (2 mph, 14% grade) at 7 and 11 weeks than at 3 weeks following infarction. Ischemic ST-segment depression, usually unaccompained by angina pectoris, occurred in 45% of patients and was associated with a significantly increased incidence of subsequent coronary events. The presence of exercise-induced ventricular ectopic activity provided little independent prognostic information. No serious complications occurred in 210 tests. Exercise testing soon after myocardial infarction provides objective information concerning the capacity to resume physical activity, including return to work. Two tests, at 3-5 weeks and at 7-11 weeks, appear to provide most of the information contined in five tests performed during this time.     

Clinical implications of coronary arteriographic findings soon after non-Q-wave acute myocardial infarction

A significant incidence of death and myocardial infarction after non-Q-wave infarction belies the earlier impression that it is less serious than Q-wave infarction. Coronary angiography in the early stages after non-Q-wave infarction shows a progressive increase in the number of totally occluded vessels. This is paralleled by an increase in number of collateral vessels. Thrombus also becomes increasingly prevalent over the week after non-Q-wave infarction, and plays a role in 30 to 40% of infarctions.     

ST-segment re-elevation and left ventricular expansion soon after acute anterior myocardial infarction.

The sum of ST-segment elevation (sigma ST on V2-4) was measured to evaluate ST-segment re-elevation during early convalescence in 57 patients with acute myocardial infarction. Following rapid ST-segment elevation resolution during the first 12 h, sigma ST again increased in many patients without signs of reinfarction or pericarditis, reaching a maximum approximately 5 days after onset. The magnitude of this re-elevation (delta sigma ST) was less than 0.3 mV in 30 patients (group A), and 0.3 mV or more in another 27 (group B). Based upon left ventriculography, the global ejection fraction in group B decreased significantly from 51 +/- 10% at the acute phase to 46 +/- 10% at the chronic phase. No such decreases were seen for group A. Regional ejection fraction in the infarcted portion improved significantly from 28 +/- 13% at the acute phase to 35 +/- 14% at the chronic phase in group A, but did not improve in group B. In addition, the non-infarcted portion in group B showed a significantly reduced regional ejection fraction. These results suggest that myocardial expansion of the infarcted portion may contribute to ST-segment re-elevation, an ominous sign of left ventricular dysfunction soon after acute myocardial infarction.     

The safety of static-dynamic effort soon after myocardial infarction

Many activities of daily living require static-dynamic effort. To evaluate the safety of such effort 3 weeks after myocardial infarction, 27 male patients underwent a weight-carrying test requiring 5 minutes of treadmill ambulation with graded weight loads of 10 to 30 pounds. The hemodynamic responses with weight carrying were compared to that of a predischarge graded dynamic exercise test. The peak heart rate was significantly lower (p less than 0.01) with weight carrying, the peak systolic blood pressure did not differ, and the diastolic pressure was significantly higher (P less than 0.01). ST segment depression and angina pectoris occurred less frequently with weight carrying. The type and frequency of ventricular arrhythmias were similar between the two tests. We conclude that many men are capable of performing static-dynamic activity equivalent to carrying up to 30 pounds by 3 weeks after myocardial infarction.     

Surgical therapy of acute myocardial infarction

All over the world the therapy of acute myocardial infarction has concentrated upon saving the ischaemically injured, but still viable cells of the myocardium. Also the acute coronary surgery, which among our groups of coronary-surgical patients has a proportion of 3.5% with 41 patients, answers this purpose. The preferred indication groups for acute coronary-surgical operations are the occlusion of the vessel after coronary dilation and the condition after intracoronary fibrinolysis. In these 22 patients the hospital lethality was only 4.5%. The reasonable active approach in acute myocardial infarction, particularly the combination fibrinolysis - acute coronary surgery, is a hopeful enlargement of the previous therapy for the highly imperilled patients with myocardial infarction.     

Surgical treatment of acute myocardial infarction

In 1989 the following indications for surgical treatment of acute myocardial infarction are: (1) acute evolving myocardial infarction less than 6 h from onset, in patients in whom percutaneous transluminal coronary angioplasty (PTCA) or streptokinase (SK), depending on the coronary anatomy, has been unsuccessful; if single vessel disease, coronary artery bypass grafting (CABG) is unlikely; if multiple vessel disease, CABG is preferable to SK/PTCA unless a very major 'culprit' lesion can be identified with certainty; (2) postinfarction angina hours to days after a transmural myocardial infarction unyielding to maximal medical therapy and in patients with a coronary artery obstruction not amenable to PTCA; (3) occlusion of a coronary artery during cardiac catheterization that cannot be fixed by PTCA and/or SK; (4) occlusion of a coronary artery during PTCA causing hemodynamic obstruction and a threatened myocardium subtended by the obstructed coronary artery; (5) balloon-dependent patients in cardiogenic shock without mechanical defects who have adequate residual left ventricular function as determined by regional wall motion studies; (6) ventricular septal defect secondary to myocardial infarction unless there is terminal organ damage; (7) mitral valve replacement with coronary bypass for acute papillary muscle rupture; (8) semi-emergency cardiac transplantation, either with or without a mechanical bridge to transplant in young individuals (less than 50 years) who have suffered massive destruction of left ventricular myocardium by an acute coronary occlusion with or without recurring ventricular tachyarrhythmias. Ejection fraction in this clinical category is always under 0.20 and usually under 0.15.     

The management of patients with acute myocardial infarction after successful reperfusion with streptokinase

Intracoronary streptokinase administration has been an effective procedure for establishing reperfusion of an evolving myocardial infarction by lysing the thrombus that is usually responsible for the infarction. After reperfusion is accomplished, appropriate management of the patient must be planned to provide the best chance for assuring continued vessel patency, and appropriate management of the patient's residual coronary artery disease also must be considered. In selected patients, percutaneous transluminal coronary angioplasty of the residual coronary lesion has been performed successfully immediately following reperfusion with streptokinase. Early coronary artery bypass graft surgery has been performed with good results in other patients. The appropriate management of the patient with acute myocardial infarction is still evolving, and only with additional study and experience will the "best" approach in the management of these patients be defined.     

Surgical intervention in acute myocardial infarction

The goal of surgical reperfusion during the first hours of acute evolving myocardial infarction is to limit the extent of the infarction. This should be reflected by improved ventricular function and low mortality. Over the past 10 years, 440 patients with transmural myocardial infarction and 261 patients with nontransmural myocardial infarction underwent coronary artery bypass graft surgery within 24 hours of peak symptoms. The in-hospital mortality was 5.2% in the transmural group and 3% in the non-transmural group. In a 10-year study period, the mortality in the transmural group rose to 12.5%, while the mortality in the nontransmural group, followed for an 8-year period, rose to a total of 6.5%. The transmural myocardial infarctions in patients revascularized within 6 hours, showed a significantly improved in-hospital mortality of 3.8% compared to an in-hospital mortality of 12% for reperfusion after 6 hours. Anterior transmural areas of myocardial infarctions were reperfused within 6 hours of symptom onset, and demonstrated improved global ejection fraction and regional wall motion. Little improvement was seen if revascularization was instituted later than 6 hours from symptoms except in patients with adequate collateral perfusion of non-total left anterior descending coronary occlusion. Long-term follow-up of patients revascularized for acute myocardial infarction shows a low rate of subsequent reinfarction, incapacitating angina and sudden death. Left ventricular function at the time of cardiac catheterization correlates well with subsequent long-term mortality.     

Prognostic significance of angina pectoris recurring soon after myocardial infarction

The prognostic significance of an early occurrence, or recurrence,of angina pectoris after myocardial infarction was studied in254 patients (221 male, 33 female; mean age 58±11 years).During the in-hospital rehabilitation program, 41 patients (16%)had anginal pain. The mean follow-up was 21 months (range 12–33months). Among the 254 patients, 21 died, five had recurrentmyocardial infarction, 13 had unstable angina, and 22 underwentaortocoronary bypass surgery. An early recurrence of anginapectoris was predictive of combined (medical+surgical) events(21 patients, P<0.05), medical events (11 patients, P<0.05)and surgical events (10 patients, P<0.001), but failed topredict individual death (six patients), recurrent myocardialinfarction (two patients) or unstable angina (three patients).Of the events that occurred in the 254 patients, 34% were predictedby the early recurrence of angina pectoris. Early post-infarctionangina was observed more frequently in older patients and patientswith previous history of angina pectoris. This represents animportant prognostic factor after myocardial infarction, whichdefines a high-risk group of patients requiring further investigationand appropriate therapeutic approaches.     

Diabetic patients and beta-blockers after acute myocardial infarction

Whether diabetic patients may benefit, compared with non-diabetic patients, from beta-blocker therapy following acute myocardial infarction was examined in a large multicentre cohort of 2024 patients, including 340 diabetics, 281 of whom survived hospitalization. One-year mortality following discharge was 17% for diabetics compared with 10% for non-diabetics (P less than 0.001). However, diabetics discharged on beta-blockers had a 1-year mortality of only 10%, compared with 23% for diabetics not on beta-blockers. In non-diabetics, mortality rates were 7% and 13% for those taking and not taking beta-blockers, respectively. Bias in patient selection for beta-blocker therapy might be responsible for the trends exhibited in our population since patients were not randomized to treatment. In diabetics, evidence of pulmonary congestion on X-ray was more prevalent than in non-diabetics; this appeared to be true both for patients taking beta-blockers and for those not taking beta-blockers. However, even in diabetics without evidence of pulmonary congestion on X-ray, 1-year mortality was 7% vs 17% for those with and without beta-blocker therapy, respectively (P less than 0.04). In multivariate analysis, beta-blocker use was an independent predictor of 1-year cardiac survival following hospital discharge for all diabetics, even those without evidence for pulmonary congestion on X-ray, but not for non-diabetics. These data suggest a beneficial effect, but a definitive answer regarding the benefit of beta-blockade in diabetic patients after acute myocardial infarction would require a prospective, randomized study.     

Coronary arteriographic findings soon after non Q wave myocardial infarction

We performed early coronary arteriography in 27 patients (23 males, 4 females) having non Q wave MI. Infarct related vessel (IRV) was totally blocked in 25.9%, whereas 66.7% had severe residual stenosis (greater than or equal to 70%). Left main was involved in 7.5%, and at least 2 major coronary arteries were involved in 51.8%. Visible collaterals were seen in 11%. We feel, as compared to transmural MI, where total occlusion of IRV is common, the higher incidence of subtotal occlusion of IRV with severe residual stenosis, poor collaterals and significant involvement of at least one other major coronary artery may be responsible for observation of early recurrent ischemic episodes in non Q wave MI.     

Proinflammatory cytokines and myocardial viability in patients after acute myocardial infarction

BACKGROUND: Proinflammatory cytokines such as tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) can potentiate heart muscle damage during acute myocardial infarction (AMI). Whether changes in their plasma levels after AMI are dependent on the presence of myocardial viability is unclear. The aim of the study was to estimate the relation of time course of plasma TNF-alpha and IL-6 and the presence of reversible and irreversible myocardial dysfunction in patients early after AMI treated thrombolytically. MATERIAL AND METHODS: Patients (54; mean age 60.4 +/- 11.7 years) with AMI plasma TNF-alpha and IL-6 were evaluated on the 2nd, 10th and 30th day after thrombolysis. Based on the response of dysfunctional segments of myocardium during dobutamine stress echocardiography performed on the 10th day, patients were divided into four groups: A, sustained improvement in contractility; B, biphasic (improvement followed by worsening); C, only worsening; D, no change. Twenty-two healthy persons served as controls. RESULTS: On the 2nd day, all four groups of patients demonstrated increased levels of TNF-alpha and IL-6 and did not differ among one another regarding both cytokines. On the 10th day, plasma TNF-alpha and IL-6 decreased in each group and were the lowest in group A, intermediate in group B and the highest in groups C and D. On the 30th day, both cytokines were not different among all studied groups. CONCLUSION: Elevated plasma TNF-alpha and IL-6 early after AMI decreased more quickly in patients with dysfunctional myocardium comprising not only necrotic but also viable segments. This decline is attenuated by the presence of residual ischemia.