Predictors of late hospital death in acute myocardial infarction

Risk Factors in Patients with Non-ST Segment Elevation Myocardial Infarction

Introduction:

The most common cause of myocardial ischemia is atherosclerotic epicardial coronary artery disease, present in 90% of patients. Risk factors positively correlate with the onset, development and subsequent complications of atherosclerotic disease.

Aim:

Determine the percentage frequency of classic risk factors for coronary disease in patients with non-ST segment elevation myocardial infarction (NSTEMI), with regard to gender.

Methods:

A retrospective study was conducted on 600 respondents, treated for NSTEMI at the Clinic for Internal Medicine of the University Clinical Center (UKC) Tuzla, in the period from June 2016 to December 2019.

Results:

Overall, smoking was the leading risk factor (65%), followed by hypertension (58%), hyperlipoproteinemia (39%), overweight (33%), positive family burden (30%) and diabetes mellitus (19%). In male patients, the leading risk factor was smoking, rating at 74%, while in female patients – it was hypertension at 67%. In younger groups of patients leading risk factors were smoking and a positive family burden.

Conclusion:

With adequate prevention and treatment measures, a significant reduction in the prevalence of the cardiovascular disease can be achieved, since the risk factors for its development have long been known. Quitting smoking is one of the most effective secondary prevention measure since it reduces the reinfarction risk rate by 50%. Knowledge of coronary risks, as well as success in reducing them, can greatly contribute to patients’ overall sense of contentment and significantly raise their self-confidence.

Acute myocardial infarction and complete bundle branch block at hospital admission: clinical characteristics and outcome in the thrombolytic era. GUSTO-I Investigators. Global Utilization of Streptokinase and t-PA [tissue-type plasminogen activator] for Occluded Coronary Arteries

OBJECTIVES

We sought to assess the outcome of patients with acute myocardial infarction (MI) and bundle branch block in the thrombolytic era.

BACKGROUND

Studies of patients with acute MI and bundle branch block have reported high mortality rates and poor overall prognosis.

METHODS

The North American population with acute MI and bundle branch block enrolled in the Global Utilization of Streptokinase and t-PA [tissue-type plasminogen activator] for Occluded Coronary Arteries (GUSTO-I) trial was matched by age and Killip class with an equal number of GUSTO-I patients without conduction defects.

RESULTS

Of all 26,003 North American patients in GUSTO-I, 420 (1.6%) had left (n = 131) or right (n = 289) bundle branch block. These patients had higher 30-day mortality rates than matched control subjects (18% vs. 11%, p = 0.003, odds ratio [OR] 1.8) and were more likely to experience cardiogenic shock (19% vs. 11%, p = 0.008, OR 1.78) or atrioventricular block/asystole (30% vs. 19%, p < 0.012, OR 1.57) and to require ventricular pacing (18% vs. 11%, p = 0.006, OR 1.73). Bundle branch block also carried an independent 53% higher risk for 30-day mortality. Thirty-day mortality rates for patients with complete, partial and no reversion of the bundle branch block were 8%, 12% and 20%, respectively (two-tailed chi-square test for trend 5.61, p = 0.02, OR 0.34 for complete reversion, OR 0.55 for partial reversion).

CONCLUSIONS

Bundle branch block at hospital admission in patients with acute MI predicts in-hospital complications and poor short-term survival.

Cardiac free wall rupture in acute myocardial infarction: ameliorative effect of coronary reperfusion

To investigate the pathophysiology of cardiac free wall rupture (cardiac rupture) following acute myocardial infarction (AMI), and to clarify whether reperfusion therapy prevents cardiac rupture, 1,329 cases of AMI (conventional therapy group: 807 cases and reperfusion therapy group: 533 cases) were studied retrospectively. The overall incidence of cardiac rupture was 2.3% (2.7% in the conventional therapy group vs. 1.7% in the reperfusion therapy group). Patients with cardiac rupture were divided into two subgroups according to the time interval from the onset of AMI to cardiac rupture (early rupture less than or equal to 72 h and late rupture greater than or equal to 4 days). The indices of initial evolution of AMI was a significant risk of early cardiac rupture. The reperfusion therapy group showed significantly lower incidence of late rupture (0.4 vs. 1.5% in conventional therapy group; p less than 0.05). The incidence of cardiac rupture in the unsuccessful reperfusion therapy group was higher than that of the successful group (5.9% of 118 cases vs. 0.5% of 404 cases; p less than 0.05). It is concluded that the etiology of cardiac rupture following AMI cannot be explained by any single factor. Early rupture depends on the initial evolution of AMI, and early reperfusion and collateral flow prevent the late onset cardiac rupture.

Conduction defects in acute myocardial infarction in the Chinese in Hong Kong

In order to delineate the conduction defects complicating acute myocardial infarction in the Chinese, 636 Chinese patients admitted into one of the three medical units of a general hospital in Hong Kong in the period 1973-80 were reviewed. A relatively high incidence of conduction defects was observed, including atrioventricular block (11.3%), right bundle branch block (12.7%) and left bundle branch block (3.3%). Right bundle branch block (whether isolated or combined with left fascicular block) and atrioventricular block complicating anterior Q-wave infarction were ominous, with a high incidence of pump failure, cardiogenic shock and cardiac arrhythmias. These are markers of massive infarction. Atrioventricular and bundle branch blocks complicating inferior Q-wave infarction were benign. Left bundle branch block appeared to be a more chronic lesion, with moderate mortality, and isolated left anterior hemiblock did not adversely affect the short-term outcome. These results conform well to the patterns seen in Western series. The high incidence of conduction defects, in particular right bundle branch block and atrioventricular block complicating anteroseptal infarction, indicates a more serious clinical spectrum of acute myocardial infarction in the Chinese, and could have contributed to a higher hospital mortality in the Chinese series.

Validation of a coronary prognostic index for the Chinese--a tale of three cities

In order to confirm the efficacy of a new coronary prognostic index for the prediction of mortality of acute myocardial infarction in the Chinese in general, this index was applied to 886 patients from six general hospitals in Hong Kong (435 patients), Guangzhou (212 patients) and Shanghai (239 patients), respectively. They could be successfully stratified into seven clinical subsets with stepwise increasing mortality. The overall mortality tallied with that predicted by the original coronary prognostic index. The efficacy of this prognostic index for the prediction of mortality from acute myocardial infarction among the Chinese is verified and its application in the objective assessment of patients with acute myocardial infarction is recommended.

The size of infarction as judged enzymatically in 1974 patients with acute myocardial infarction. Relation with symptomatology, infarct localization and type of infarction

A common data base of six coronary care units containing personal and clinical data of 17462 patients was used to investigate the relation between clinical symptoms of patients with acute myocardial infarction and size of infarction. In 1974 of the 5110 patients, in whom a final diagnosis of infarction was made, size of infarction was determined according to serially measured levels of serum alpha-hydroxybutyrate dehydrogenase. The episode of infarction was the first in 1396 patients, was recurrent in 497, and undetermined in 81 patients. We calculated the size factor (defined as the mean size of infarction of patients with a particular symptom divided by the mean size of infarction of patients without that symptom) to evaluate the role of the size of infarction to manifestation of certain clinical symptoms. Bradycardia, shock and right-sided failure when noted on admission to the coronary care unit, had factors for size of infarction significantly greater than 1.0 (1.15, 1.79 and 1.30, respectively) in patients suffering an initial infarction, but not significantly different from 1.0 in patients with recurrent infarction. The occurrence of primary and secondary ventricular tachycardia and/or fibrillation, left heart failure (Killip class II-IV), symptomatic supraventricular tachycardia, high-degree atrioventricular blocks, ruptures and death in the coronary care unit was associated with factors significantly greater than 1.0 in those patients having both initial and recurrent infarctions. The size of infarction as judged enzymatically was significantly larger in patients with anterior than inferior and lateral infarction. The size of infarctions without Q waves was judged to be generally 35% smaller than infarctions producing Q waves. It is concluded that the size of infarction determines the occurrence of several symptoms and complications diagnosed at admission or during stay in the coronary care unit.

Therapeutic trials in coronary thrombosis should measure left ventricular function as primary end-point of treatment

Clinical trials in coronary thrombosis can record as end-points either death or an index of left ventricular function (ejection fraction or end-systolic volume) which can be used as a surrogate for long-term mortality. Hospital mortality for patients under 70 years of age in whom effective thrombolysis is achieved should now be no more than about 5%. To show a 20% reduction (to 4%) in mortality with an alpha error (two-sided) of 0.05 and a beta error of 0.2 requires 15,000 patients. By contrast, a 25% improvement towards normal in ejection fraction (from about 59% to about 62%) requires only 384 patients. Since it is likely that one of several thrombolytic agents will be effective in conjunction with one or more myocardial protective agents, many trials will be required, and it may be more appropriate in future studies to measure left ventricular function rather than mortality as the principal end-point.

Differences in mortality from acute myocardial infarction between coronary care unit and medical ward: treatment or bias?

To analyse the effectiveness of coronary care units in reducing mortality from myocardial infarction 18 hospitals ranging from large urban teaching hospitals to small country hospitals were stratified into four levels of care. Previous analysis had failed to show significant differences in the overall mortality in hospital among levels. There were significant differences in mortality, however, between those patients allocated to be cared for in the coronary care unit and those in the medical wards in the more advanced hospitals. The differences were largest in the hospitals with the most elaborate facilities (level 1) and non-existent in those with the least (level 4). Several analytical approaches to these observed differences indicated that they were: (a) reduced by adjustment for age and severity of infarction; (b) paralleled by differences in coexisting disease recorded on death certificates; (c) no longer significant at level 1 after allowing for differences in coexisting disease; and (d) not significant at any level after exclusion of patients first diagnosed at necropsy. These findings suggest that the observed differences in mortality between coronary care units and medical wards are largely due to bias in selection and diagnosis.

Coronary prognostic index for the Chinese

A coronary prognostic index (CPI) for the prediction of mortality of patients with acute myocardial infarction (AMI) has been constructed with data from 644 Chinese patients in Hong Kong. According to this CPI, patients with AMI could be divided into subgroups with increasing hospital mortality from 1.6% to 100%, depending on their ages, blood pressure, heart size, serum urea level, positions and types of infarcts, the presence of pulmonary congestion and cardiac dysrhythmia in the initial three days. This simple and convenient CPI could be useful for the objective assessment and stratification of AMI in the Chinese, as well as in many other developing countries in the Asian-Pacific region.

Effects of early intracoronary streptokinase on infarct size estimated from cumulative enzyme release and on enzyme release rate: a randomized trial of 533 patients with acute myocardial infarction

The effects of early intracoronary streptokinase (SK) on enzymatic infarct size and rate of enzyme release were studied in a randomized multicenter trial. A total of 533 patients with acute myocardial infarction (AMI) were allocated to either the SK treatment group (n = 269) or the conventional (control) treatment group (n = 264). Enzymatic infarct size was represented by the cumulative quantity of alpha-hydroxybutyrate dehydrogenase (HBDH) released by the heart per liter of plasma in the first 72 hours. Rate of enzyme release was represented by the ratio of HBDH quantities released in 24 hours and 72 hours. On an "intention to treat" basis, the SK group had a smaller (by 30%; p = 0.0001) median enzymatic infarct size and a higher (by 35%; p = 0.0001) median rate of enzyme release than the control group. Limitation of infarct size was less apparent in patients treated with intracoronary SK only (25%) than in patients treated with intravenous plus intracoronary SK (34%). Compared to the control group, the enzyme release rate in patients treated with intracoronary SK only was slightly less (34%) than that in patients treated with intravenous plus intracoronary SK (38%). Patients with a patent infarct-related coronary artery at acute angiography had a median infarct size which was 55% (p = 0.0001) smaller than the median infarct size of the control group, and the median rate of enzyme release was 38% (p = 0.001) higher than the median release rate of the control group. Patients with successful recanalization during intracoronary SK infusion had a median infarct size which was 31% (p = 0.002) smaller than the median infarct size of the control group and a median rate of enzyme release which was 42% (p = 0.0001) higher than the median release rate of the control group. Patients with persistent coronary occlusion in spite of thrombolytic therapy had a median infarct size which was 11% (NS) higher than the median infarct size of the control group, although the median rate of enzyme release was still 23% (p = 0.02) higher than the median release rate of the control group. It is concluded that thrombolysis in the early phase of AMI limits infarct size and that intracoronary SK treatment itself accelerates the process of enzyme release from infarcted myocardium, independent of the angiographic result.

Incidence and significance of pericardial effusion in acute myocardial infarction as determined by two-dimensional echocardiography

To determine the incidence and clinical significance of pericardial effusion after acute myocardial infarction, two-dimensional echocardiography was serially performed in 66 consecutive patients. Pericardial effusion was observed in 17 (26%); the effusion was small in 13 patients, moderate in 3 and large with signs of cardiac tamponade in 1. In this patient, two-dimensional echocardiography strongly suggested myocardial rupture. The observation of pericardial effusion was not associated with age, sex, previous myocardial infarction, atrial fibrillation or treatment with heparin. It was more often a complication of anterior than of inferior acute infarction. Patients with pericardial effusion had higher peak levels of creatine kinase and lactic dehydrogenase and a higher wall motion score index. More patients with pericardial effusion had congestive heart failure or ventricular arrhythmias, developed a ventricular aneurysm or died within 1 year after their infarction. In conclusion, pericardial effusion is frequently visualized by two-dimensional echocardiography after acute myocardial infarction and its presence is associated with an increased occurrence of complications and cardiac death.

Metabolism and blood flow as new markers of myocardial viability in the evolution of myocardial infarction

Animal studies have shown that increased regional 18F-deoxyglucose (FDG) uptake as demonstrated by positron emission tomography (PET) in ischemic and reperfused myocardium reflects reversible tissue injury. Therefore, we studied patients with acute myocardial infarction to define the extent and severity of injury. Left ventricular segments with reduced blood flow and metabolism, as demonstrated by matching defects of flow and FDG uptake, revealed irreversible injury as evidenced by lack of functional recovery. In contrast, segments with reduced flow but maintained FDG uptake showed variable functional outcome with improvement of the average wall motion score. Thus, PET may be useful in identifying myocardium at risk which may benefit from therapeutic interventions.

The development and progression of myocyte injury at the margins of experimental myocardial infarcts

Distinct differences in the extent and progression of the lateral and epicardial boundaries of evolving regional infarcts were demonstrated in isolated rabbit hearts. Ischemia was produced by interrupting (0-240 minutes) flow in the ventral interventricular branch of the left coronary artery, whilst the remainder of the heart was continuously perfused with oxygenated Krebs-Henseleit bicarbonate buffer. Perfusion fixed blocks were freeze-fractured then examined using back-scattered electron imaging in a scanning electron microscope. Control myocytes showed relatively smooth, continuous internal fracture faces. After 30 min of ischemia myocytes showed evidence of mild, probably reversible, injury in the form of prominence of pits and channels. Severe injury, characterized by separation of organelles and prominent intracellular spaces, developed after 60 or more min of ischemia, first in the subendocardial two thirds, and after 120 min across the full thickness of the ventricular wall. At the lateral margins of infarcts there was a distinct cell-to-cell boundary between control and severely injured myocytes, with only a few scattered mildly injured cells within 30 mu of the infarct. Although transmural progression of necrosis provides the potential for recovery of the external aspect of the myocardium in the ischemic zone by reperfusion, corresponding regions of salvageable myocytes at lateral infarct margins are very narrow.

Myocardial ischemia. Towards better use of the coronary care unit

The coronary care unit is an expensive facility. Attempts to prove its value have not been successful, and the difficulty of doing so is considerable. In the absence of proof, it is nevertheless still necessary to establish a reasonable approach to the use of this facility. Such an approach and the evidence in its support are summarized. Pending the acquisition of more accurate predictors of risk, the following arbitrary guidelines are suggested. The coronary care unit is an appropriate environment for the management of dangerous arrhythmias and the major complications of infarction, for the management of resting angina until asymptomatic for 24 hours, and for the management of uncomplicated infarction in the absence of all predictors of risk for a period of 24 hours after the last episode of ischemic pain. Longer observation may be desirable for patients with certain predictors of short-term risk.

Incidence of pericardial effusions in acute myocardial infarctions

To study the incidence of pericardial effusions in the first 72 hours after myocardial infarction, M-mode echocardiograms were performed on 90 of 100 consecutive patients with acute myocardial infarctions. Pericardial effusions were documented in five patients (5.6 percent), four of which resolved without sequelae by the time of discharge. The remaining patient died of presumed myocardial rupture. Pericardial effusions tended to be more common in patients with anterior or anterolateral infarcts and in those who had received intracoronary streptokinase (p less than .10). No patient with postinfarction pericarditis had an effusion.

Early recognition of the patient at late high risk: incomplete infarction and vulnerable myocardium

The process of identifying patients with myocardial infarction (MI) at high risk after hospital discharge should begin at admission. By using basic clinical and laboratory information, enhanced by a wide variety of noninvasive tests, not only can individual patients at risk be recognized, but also the processes that determine risk can, at least in part, be appreciated. Outcome is affected by the extent of damaged tissue and, apparently, by the amount of potentially ischemic muscle. MI may change the coronary circulation such that a new and fragile balance between supply and demand results, both within and outside the infarct zone; that is, the infarct may be incomplete and the viable muscle within it may then be vulnerable to later ischemia. Muscle outside the infarct zone may be left in much the same precarious state. Also, coronary spasm may not be infrequent in the weeks after MI. These factors together may underlie recurrent post-MI myocardial ischemia.

Myocardial rupture after acute myocardial infarction. Ten year review

Forty-nine patients with myocardial rupture complicating acute myocardial infarction were managed in our coronary care unit from 1972 to 1981: 33 patients with post-infarction ventricular septal defect, 12 patients with isolated rupture of the free wall of the left ventricle, and four patients with papillary muscle rupture. Nine of 19 patients (47%) who underwent surgical repair of a post-infarction ventricular septal defect survived. The major determinant of survival was the preoperative haemodynamic status. Ten of 13 patients (77%) who developed cardiogenic shock preoperatively died, while none of the six patients who were not in cardiogenic shock died. Survival was not related to the site or size of infarction, extent of coronary artery disease, or magnitude of the left to right shunt. There were no survivors among the 14 patients with post-infarction ventricular septal defect managed without surgical intervention. Seven of the 12 patients with isolated rupture of the free wall of the left ventricle developed mechanical cardiac arrest and died at the onset of rupture, but five patients developed subacute heart rupture and two of these patients survived after urgent surgical repair. Two of the four patients with papillary muscle rupture underwent mitral valve replacement, but both died in the early postoperative period; both patients who were not operated on died. Early detection and early surgical intervention are essential in the management of myocardial rupture complicating acute myocardial infarction.