A comparison of thrombolytic therapy with primary coronary angioplasty for acute myocardial infarction. Myocardial Infarction Triage and Intervention Investigators

BACKGROUND: Several relatively small randomized trials have shown that primary angioplasty results in a better short-term outcome than thrombolytic therapy in patients with acute myocardial infarction. These results, however, have not been duplicated other than in investigational trials. METHODS: We compared mortality during hospitalization and long-term mortality, as well as the use of resources, among 1050 patients in a primary-angioplasty group and 2095 patients in a thrombolytic-therapy group. Patients were selected from the Myocardial Infarction Triage and Intervention Project Registry cohort of 12,331 consecutive patients admitted with acute myocardial infarction to 19 Seattle hospitals between 1988 and 1994. Because of the potential for selection bias, several subgroup analyses were performed that included patients eligible for thrombolysis, high-risk patients, and patients in the primary-angioplasty group who were treated at hospitals with high volumes of angioplasty. RESULTS: There was no significant difference in mortality during hospitalization or long-term follow-up between patients in the thrombolytic-therapy group and those in the primary-angioplasty group (mortality during hospitalization, 5.6 percent and 5.5 percent, respectively; P=0.93; adjusted hazard ratio for the risk of death within three years after primary angioplasty, 0.95; 95 percent confidence interval, 0.8 to 1.2). There was also no significant difference in mortality between high-risk subgroups of patients in the two treatment groups. The rates of procedures and costs were lower among patients in the thrombolytic-therapy group both at the time of hospital discharge and after three years of follow-up (30 percent fewer coronary angiograms, 15 percent fewer coronary angioplasties, and 13 percent lower costs after three years of follow-up). CONCLUSIONS: In a community setting, we observed no benefit in terms of either mortality or the use of resources with a strategy of primary angioplasty rather than thrombolytic therapy in a large cohort of patients with acute myocardial infarction.     

Admission to hospitals with on-site cardiac catheterization facilities :impact on long-term costs and outcomes

BACKGROUND: Admission to a hospital with a capability for cardiac procedures is associated with a higher likelihood of referral for a cardiac procedure but not with a better short-term clinical outcome. Whether there are differences in long-term mortality and resource consumption is not clear. We sought to determine whether elderly Medicare patients with acute myocardial infarction admitted to hospitals with on-site cardiac catheterization facilities have lower long-term hospital costs and better outcomes than patients admitted to hospitals without such facilities. METHODS AND RESULTS: As part of the Cooperative Cardiovascular Project pilot in Connecticut, we conducted a retrospective cohort study using data from medical charts and administrative files. The study sample included 2521 patients with acute myocardial infarction covered by Medicare from 1992 to 1993. The cardiac catheterization rate was higher in the hospitals with facilities (38.6% versus 26.9%; P<0.001), but the revascularization rate was similar (20.5% versus 19.5%) during the initial episode of care and at 3 years (29.7% versus 29.7%). Mortality rates were similar for patients admitted to the 2 types of hospitals at 30 days (OR, 1.08; 95% CI, 0.83 to 1.42) and at 3 years (OR, 1.02; 95% CI, 0.83 to 1.26). The adjusted readmission rates were significantly lower among patients admitted to hospitals with cardiac catheterization facilities (OR, 0.76; 95% CI, 0.61 to 0.94). However, the overall mean days in the hospital for the 3 years after admission was 25.9 for patients admitted to hospitals with facilities and 24.6 for the other patients (P=0.234). Adjusting for baseline patient characteristics, there was no significant difference in the 3-year costs between patients admitted to the 2 types of hospitals. CONCLUSIONS: With higher rates of cardiac catheterization and lower readmission rates, patients admitted to hospitals with on-site cardiac catheterization facilities did not have significantly different hospital costs compared with patients admitted to hospitals without these facilities. There was also no significant difference in short- or long-term mortality rates.     

Bundle-branch block and in-hospital mortality in acute myocardial infarction. National Registry of Myocardial Infarction 2 Investigators

BACKGROUND: Left bundle-branch block (BBB) is considered an important predictor of poor outcome in patients with acute myocardial infarction, but the consequences of right BBB are not well understood. OBJECTIVES: To 1) estimate the prevalence of left and right BBB in patients with myocardial infarction; 2) compare the clinical characteristics of and treatments received by patients with left, right, or no BBB; and 3) determine the independent association of left BBB and right BBB with in-hospital death. DESIGN: Retrospective cohort study. SETTING: Multicenter registry of 1571 U.S. hospitals. PATIENTS: 297,832 patients with acute myocardial infarction who had left, right, or no BBB on initial electrocardiography. MEASUREMENTS: Presence and type of BBB, clinical characteristics of patients, therapies given, and in-hospital death. RESULTS: Patients with left BBB (n = 19,967; 6.7%) or right BBB (n = 18,354; 6.2%) were older and had more comorbid illness and congestive heart failure than patients with no BBB. Among patients for whom thrombolytic therapy was clearly indicated, fewer patients with left or right BBB (16.6% and 32.0%, respectively) than patients with no BBB (66.5%) received this therapy (P < 0.001). Fewer patients with left or right BBB (60.6% and 67.3%, respectively) than patients with no BBB (75.6%) received aspirin within the first 24 hours (P < 0.001), and fewer patients with left or right BBB (23.9% and 31.8%, respectively) than patients with no BBB (40.4%) received beta-blockers within the first 24 hours (P < 0.001). Unadjusted in-hospital mortality rates were almost twice as high for patients with left or right BBB (22.6% and 23.0%, respectively) as for patients with no BBB (13.1%) (P < 0.001). Compared with no BBB and no ST-segment elevation, left BBB was associated with a 34% increase (odds ratio, 1.34 [95% CI, 1.28 to 1.39]) and right BBB was associated with a 64% increase (odds ratio, 1.64 [CI, 1.57 to 1.71]) in the risk for in-hospital death, after adjustment for potential confounders. CONCLUSIONS: In patients with acute myocardial infarction, prevalences of right and left BBB are similar. Patients with BBB have more comorbid conditions, are less likely to receive therapy, and have an increased risk for in-hospital death compared with patients with no BBB. Compared with left BBB, right BBB seems to be a stronger independent predictor of in-hospital death.     

Management and outcomes for black patients with acute myocardial infarction in the reperfusion era. National Registry of Myocardial Infarction 2 Investigators

Data from a national registry of myocardial infarction patients from June 1994 to April 1996 were analyzed to compare the presenting characteristics, acute reperfusion strategies, treatment patterns, and clinical outcomes among black and white patients. Blacks presented much later to the hospital after the onset of symptoms (median 145 vs 122 minutes, p <0.001), were more likely to have atypical cardiac symptoms (28% vs 24%, p <0.001), and nondiagnostic electrocardiograms during the initial evaluation period compared with whites (37% vs 31%, p <0.001). Also, blacks were less likely to receive intravenous thrombolytic therapy (adjusted odds ratio [OR] 0.76, 95% confidence intervals [CI] 0.71 to 0.80), coronary arteriography (adjusted OR 0.85, 95% CI 0.77 to 0.95), other elective catheter-based procedures (adjusted OR 0.87, 95% CI 0.78 to 0.96), and coronary artery bypass surgery (adjusted OR 0.66, 95% CI 0.58 to 0.75) than their white counterparts. Despite these differences in treatment, there were no significant differences in hospital mortality between blacks and whites.     

Triggering of acute myocardial infarction onset by episodes of anger. Determinants of Myocardial Infarction Onset Study Investigators

PURPOSE: We performed this study to identify prognostic factors in a subgroup of patients with carcinoma of unknown primary site treated with cisplatin combination chemotherapy. PATIENTS AND METHODS: Seventy-nine patients with poorly differentiated adenocarcinoma or undifferentiated carcinoma of unknown primary site were treated on two consecutive phase II chemotherapy protocols. The first protocol consisted of treatment with 3-week courses of cisplatin, etoposide, and bleomycin (BEP). In the second protocol, cisplatin was administered weekly combined with oral administration of etoposide (DDP/VP). To identify prognostic factors, univariate and multivariate analyses were conducted. RESULTS: In the univariate analysis, performance status, histology, liver or bone metastases, and serum levels of alkaline phosphatase and AST were significant variables to predict survival. In the multivariate analysis, performance status and alkaline phosphatase were the most important prognostic factors. CONCLUSION: Good-prognosis patients had a performance score of 0 (World Health Organization [WHO]) and an alkaline phosphatase serum level less than 1.25 times the upper limit of normal (N). These patients had a median survival duration greater than 4 years. Intermediate-prognosis patients were characterized by either a WHO performance status < or = 1 or an alkaline phosphatase level > or = 1.25 N. These patients had a median survival duration of 10 months and a 4-year survival rate of only 15%. The poor-prognosis group had both a WHO performance status > or = 1 and an alkaline phosphatase level > or = 1.25 N. These patients had a median survival duration of only 4 months and none survived beyond 14 months. Treatment strategies for these three groups are discussed. It is suggested that this prognostic model be validated in other patients series.     

Effect of reperfusion modality on outcome in nonsmokers and smokers with acute myocardial infarction (a Primary Angioplasty in Myocardial Infarction [PAMI] substudy). PAMI Investigators

BACKGROUND: We present our experience with laparoscopic cholecystectomy in pregnant patients, with consideration of the physiological changes of pregnancy affecting anesthetic and surgical management. METHODS: We reviewed the medical records of all pregnant patients undergoing laparoscopic surgery at Brigham and Women's Hospital between January 1, 1991 and April 30, 1995. RESULTS: Laparoscopic cholecystectomy was performed without complication in ten patients (gestational age 9-30 weeks). Details of anesthetic and surgical management are described. The anesthetic and surgical implications of pregnancy-associated physiological changes in the gastrointestinal, respiratory, cardiovascular, and central nervous system are reviewed. CONCLUSIONS: With appropriate attention to the altered physiology of pregnancy, laparoscopic cholecystectomy can be performed safely and effectively during pregnancy.     

Can ECG changes predict the long-term outcome in patients admitted to hospital for suspected acute myocardial infarction?

SETTING: The activity of KRM 1648 (KRM), a new benzoxazinorifamycin, and rifabutin (RBT), alone or in combination with clarithromycin (CLA), was evaluated against Mycobacterium avium complex (MAC) that multiplied in human alveolar macrophages (AM). DESIGN: AM were recovered by bronchoalveolar lavage, incubated in RPMI 1640 medium with 10% human AB serum, infected with four strains of MAC (of non-acquired immune deficiency syndrome [AIDS] origin), and then treated with each drug alone or in combination. After incubation for 7 days, colony forming units in each well were counted on 7H10 agar. RESULTS: Although concentrations between 0.2 microgram/ml and 20 micrograms/ml of both rifamycins showed clear dose-dependent activities against all MAC strains tested, only 20 micrograms/ml of each drug had modest bactericidal effect. In combination with 2.0 micrograms/ml of CLA, however, 0.2 microgram/ml of both drugs caused a bactericidal response against two of the four MAC strains examined. CONCLUSION: According to this human alveolar macrophage model of MAC infection, KRM and RBT in combination with CLA was found to be a promising candidate against human pulmonary MAC infection, and deserves clinical evaluation.     

Effect on outcome of the presence or absence of chest pain at initiation of recombinant tissue plasminogen activator therapy in acute myocardial infarction. The Thrombolysis in Myocardial Infarction Investigators

To ascertain whether the outcome of patients with suspected myocardial infarction differs when chest pain is still present at initiation of thrombolytic therapy, participants in the Thrombolysis in Myocardial Infarction Phase II study, all of whom presented within 4 hours of symptoms onset, were retrospectively divided into 2 groups: (1) those with chest pain present at onset of intravenous thrombolysis, n = 3,000; and (2) those who were free of chest pain on beginning intravenous thrombolytic therapy, n = 337. Patients free of chest pain were older (58 vs 57 years, p = 0.01), more often women (23 vs 17%, p = 0.01), had fewer electrocardiographic leads with ST elevation (3.8 vs 4.1, p < 0.001), and the presenting event was confirmed less often as myocardial infarction than as chest pain without infarction (88 vs 96%, p < 0.001). There were no significant differences between the 2 groups for in-hospital death, reinfarction, recurrent ischemic events, stroke, overall hemorrhagic complications, coronary angioplasty or bypass surgery. At 6-weeks follow-up, more pain-free patients had resting ejection fraction > 0.55 (35 vs 31%, p = 0.001) and fewer developed congestive heart failure (12 vs 20%). At 1-year follow-up, fewer pain-free patients developed congestive heart failure (15 vs 21%, p = 0.009), but no differences existed between the 2 groups in frequency of death, reinfarction, coronary angioplasty, bypass surgery or anginal class. Thus, there are several observations in patients who were free of chest pain at onset of lytic therapy. (1) The majority developed enzymatic or electrocardiographic evidence of acute myocardial infarction.(ABSTRACT TRUNCATED AT 250 WORDS)     

The 60 Minutes Myocardial Infarction Project. Characteristics on admission and clinical outcome in patients with reinfarction compared to patients with a first infarction

PURPOSE: The purpose of the study was to evaluate parameters that characterize patients with myocardial reinfarction as compared to patients with a first infarction in clinical practice, and possibly to determine their clinical outcome. METHODS: The 60 minutes Myocardial Project is a German multicentre prospective observational study in which 136 hospitals are participating. Fourteen thousand, nine hundred and eighty consecutive patients with acute Q wave myocardial infarction were included from July 1992 to September 1994. RESULTS: Out of these 14,980 patients, there were 2854 (19%) with reinfarction and 12,126 (81%) with a first infarction. Patients with a reinfarction arrived at the hospital 24 min earlier than patients with a first infarction (pre-hospital delay 156 vs 180 min; P < 0.001); the door-to-needle time with reinfarction was longer (38 vs 30 min; P < 0.001); however, patients with reinfarction were older (69 vs 66 years; P < 0.001), had a lower rate of a diagnostic first ECG (54 vs 71%; P < 0.001) and received thrombolytic therapy less frequently than patients with a first infarction (46 vs 52%; P < 0.001). A low number of patients received primary PTCA ( n = 205) since only a few hospitals offered a primary PTCA service at the time the study was performed. In patients with reinfarction, there were more reasons as to why thrombolytic therapy was not given (24 vs 21%; P < 0.001). Left bundle branch block occurred more frequently in patients with reinfarction (15 vs 8%; P < 0.001). The intra-hospital course in patients with reinfarction was associated with an increase of complications and intra-hospital death (23 vs 15%; P < 0.001. CONCLUSIONS: Although reinfarction patients arrived earlier at hospital than patients with a first infarction, the former received thrombolytic therapy less frequently than the latter. Patients with reinfarction were older, more frequently had a non-diagnostic ECG on admission and had a higher rate of contraindications against thrombolytic therapy.     

Beneficial effects of captopril on prognosis in patients with acute myocardial infarction. Shanghai Secondary Prevention of Acute Myocardial Infarction Study Group

OBJECTIVES: To assess the effects of early and long-term angiotensin-converting enzyme inhibitor treatment with captopril on clinical outcome in patients with acute myocardial infarction (AMI). METHODS: Eight hundred and twenty-two patients with AMI who were hospitalised within 72 hours of symptoms and had no cardiogenic shock were randomly allocated to captopril (n = 478, Group I) and conventional treatment (n = 344, Group II). Cardiac events including congestive heart failure, reinfarction, severe arrhythmias and cardiac death during hospitalization and follow-up period (average 20 months) were determined. RESULTS: The overall mortality rate during hospitalization was lower in group I than in group II (P = 0.0001), this was true for patients with anterior (P = 0.0003), inferior (P = 0.0411) and anterior inferior AMI (P = 0.0232). During follow-up, despite similar occurrence rate of reinfarction and severe arrhythmias in the two groups, the mortality rate (P = 0.0324) and total cardiac event rate (P = 0.055) were lower in group I than in group II. CONCLUSIONS: After AMI, early and long-term treatment with captopril exerts a beneficial effect on the prognosis of patients.     

Educational attainment, anger, and the risk of triggering myocardial infarction onset. The Determinants of Myocardial Infarction Onset Study Investigators

BACKGROUND: While it has recently been shown that anger may trigger the onset of acute myocardial infarction, there has been no study of the role of socioeconomic factors in such triggering. Socioeconomic factors, such as educational attainment, may modulate the risk of triggering because of their influence on individual reactivity to external stressors and on the prevalence of traditional cardiac risk factors. OBJECTIVE: To evaluate the influence of educational attainment on the relative risk of myocardial infarction onset following episodes of anger. METHODS: We interviewed 1623 patients (501 women) an average of 4 days following a myocardial infarction. Data were collected on standard demographic variables as well as risk factors for coronary artery disease. Educational attainment was categorized into 3 levels: less than high school, completed high school, and at least some college. Anger was assessed by the Onset Anger Scale, a single-item, 7-level, self-report scale. Occurrence of anger in the 2 hours preceding the onset of myocardial infarction was compared with its expected frequency using self-matched control data based on the case-crossover study design. RESULTS: The risk of having a myocardial infarction triggered by isolated episodes of anger declined consistently and significantly with increasing levels of educational attainment (P = .03). The relative risk was twice as high among those with less than high school education (relative risk, 3.3; 95% confidence interval, 2.0-5.4) compared with patients with at least some college education (relative risk, 1.6; 95% confidence interval, 0.9-2.9). CONCLUSIONS: These findings indicate that socioeconomic factors are potent modulators of the risk of triggering acute cardiovascular disease onset. A better understanding of the physiological mechanisms underlying this association may lead to novel approaches to prevent acute cardiovascular events.     

TNK-tissue plasminogen activator compared with front-loaded alteplase in acute myocardial infarction: results of the TIMI 10B trial. Thrombolysis in Myocardial Infarction (TIMI) 10B Investigators

BACKGROUND: Bolus thrombolytic therapy is a simplified means of administering thrombolysis that facilitates rapid time to treatment. TNK-tissue plasminogen activator (TNK-tPA) is a highly fibrin-specific single-bolus thrombolytic agent. METHODS AND RESULTS: In TIMI 10B, 886 patients with acute ST-elevation myocardial infarction presenting within 12 hours were randomized to receive either a single bolus of 30 or 50 mg TNK-tPA or front-loaded tPA and underwent immediate coronary angiography. The 50-mg dose was discontinued early because of increased intracranial hemorrhage and was replaced by a 40-mg dose, and heparin doses were decreased. TNK-tPA 40 mg and tPA produced similar rates of TIMI grade 3 flow at 90 minutes (62.8% versus 62.7%, respectively, P=NS); the rate for the 30-mg dose was significantly lower (54.3%, P=0.035) and was 65. 8% for the 50-mg dose (P=NS). A prespecified analysis of weight-based TNK-tPA dosing using median TIMI frame count demonstrated a dose response (P=0.001). Similar dose responses were observed for serious bleeding and intracranial hemorrhage, but significantly lower rates were observed for both TNK-tPA and tPA after the heparin doses were lowered and titration of the heparin was started at 6 hours. CONCLUSIONS: TNK-tPA, given as a single 40-mg bolus, achieved rates of TIMI grade 3 flow similar to those of the 90-minute bolus and infusion of tPA. Weight-adjusting TNK-tPA appears to be important in achieving optimal reperfusion; reduced heparin dosing appears to improve safety for both agents. Together with the safety results from the parallel Assessment of the Safety of a New Thrombolytic: TNK-tPA (ASSENT I) trial, an appropriate dose of this single-bolus thrombolytic agent has been identified for phase III testing.     

Physical exertion as a trigger of acute myocardial infarction. Triggers and Mechanisms of Myocardial Infarction Study Group

BACKGROUND: It is controversial whether the onset of myocardial infarction occurs randomly or is precipitated by identifiable stimuli. Previous studies have suggested a higher risk of cardiac events in association with exertion. METHODS: Consecutive patients with acute myocardial infarction were identified by recording all admissions to our hospital in Berlin and by monitoring a general population of 330,000 residents in Augsburg, Germany. Information on the circumstances of each infarction was obtained by means of standardized interviews. The data analysis included a comparison of patients with matched controls and a case-crossover comparison (one in which each patient serves as his or her own control) of the patient's usual frequency of exertion with the last episode of exertion before the onset of myocardial infarction. RESULTS: From January 1989 through December 1991, 1194 patients (74 percent of whom were men; mean age [+/- SD], 61 +/- 9 years) completed the interview 13 +/- 6 days after infarction. We found that 7.1 percent of the case patients had engaged in physical exertion (> or = 6 metabolic equivalents) at the onset of infarction, as compared with 3.9 percent of the controls at the onset of the control event. For the patients as compared with the matched controls, the adjusted relative risk of having engaged in strenuous physical activity at the onset of infarction or the control event was 2.1 (95 percent confidence interval, 1.1 to 3.6). The case-crossover comparison yielded a similar relative risk of 2.1 (95 percent confidence interval, 1.6 to 3.1) for having engaged in strenuous physical activity within one hour before myocardial infarction. Patients whose frequency of regular exercise was less than four and four or more times per week had relative risks of 6.9 and 1.3, respectively (P < 0.01). CONCLUSIONS: A period of strenuous physical activity is associated with a temporary increase in the risk of having a myocardial infarction, particularly among patients who exercise infrequently. These findings should aid in the identification of the triggering mechanisms for myocardial infarction and improve prevention of this common and serious disorder.     

Influence of payor on use of invasive cardiac procedures and patient outcome after myocardial infarction in the United States. Participants in the National Registry of Myocardial Infarction

OBJECTIVES: We sought to determine the influence of payor status on the use and appropriateness of cardiac procedures. BACKGROUND: The use of invasive procedures affects the cost of cardiovascular care and may be influenced by payor status. METHODS: We compared treatment and outcomes of myocardial infarction among four payor groups: fee for service (FFS), health maintenance organization (HMO), Medicaid and uninsured. Multivariate comparison was performed on the use of invasive cardiac procedures, length of hospital stay and in-hospital mortality in 17,600 patients <65 years old enrolled in the National Registry of Myocardial Infarction from June 1994 to October 1995. To determine the appropriateness of coronary angiography, we compared its use in patients at low and high risk for cardiac events. RESULTS: Angiography was performed in 86% of FFS, 80% of HMO, 61% of Medicaid and 75% of uninsured patients. FFS patients were more likely to undergo angiography than HMO (odds ratio [OR] 1.27, 95% confidence interval [CI] 1.13 to 1.42), Medicaid (OR 2.43, 95% CI 2.11 to 2.81) and uninsured patients (OR 1.99, 95% CI 1.76 to 2.25). Similar patterns for the use of coronary revascularization were found. Among those at low risk, FFS patients were as likely to undergo angiography as HMO patients but more likely than Medicaid and uninsured patients. For those at high risk, FFS patients were more likely to undergo angiography than patients in other payor groups. Adjusted mean length of stay (7.3 days) was similar among all payor groups, but adjusted mortality was higher in the Medicaid group (Medicaid vs. FFS: OR 1.55, 95% CI 1.19 to 2.01). CONCLUSIONS: Payor status is associated with the use and appropriateness of invasive cardiac procedures but not length of hospital stay after myocardial infarction. The higher in-hospital mortality in the Medicaid cohort merits further study.     

In-hospital outcome of elderly patients with acute inferior myocardial infarction and right ventricular involvement

BACKGROUND: There are some specific high-risk subgroups of patients with acute inferior myocardial infarction, such as older patients and those with right ventricular involvement. However, the clinical implications of right ventricular infarction in elderly subjects have not been studied previously. METHODS AND RESULTS: To determine the clinical impact of right ventricular involvement in elderly patients with inferior myocardial infarction, we studied the in-hospital outcome of 198 consecutive patients > or = 75 years of age with a first acute inferior myocardial infarction according to the presence of ECG or echocardiographic criteria of right ventricular infarction. In patients with right ventricular involvement (41%), in-hospital case fatality rate was 47% (mainly because of nonreversible low cardiac output cardiogenic shock) compared with 10% in patients without right ventricular involvement (P<.001). Patients with right ventricular involvement also had a significantly higher incidence of cardiogenic shock (32% versus 5%), which was independent of left ventricular ejection fraction, complete AV block (33% versus 9%), and interventricular septal rupture (9% versus 0%). After adjustment for age, sex, diabetes, shock on admission, left ventricular systolic dysfunction, and complete AV block, right ventricular infarction remained a powerful independent predictor of in-hospital death (adjusted odds ratio, 4.0; 95% confidence interval, 1.3 to 14.2). CONCLUSIONS: Elderly patients with acute inferior myocardial infarction have a substantially increased risk of death during hospitalization when right ventricular involvement is present. The poorer outcome is due mainly to the high incidence of cardiogenic shock and its infrequent reversibility.     

Myocardial contrast echocardiography in acute myocardial infarction. Pathophysiological background and clinical applications

Myocardial contrast echocardiography is a technique used in experimental and clinical settings in order to visualize the pattern of intramyocardial perfusion. In the acute phase of myocardial infarction, regional absence of flow during myocardial contrast echocardiography delineates the area at risk of necrosis, while the definitive non-perfused area expresses infarct size. Reopening the infarct-related artery, which may be achieved spontaneously by thrombolysis or percutaneous transluminal coronary angioplasty, is not a reliable indicator of intramyocardial reperfusion. If myocardial ischaemia due to coronary occlusion has been sufficiently prolonged and severe, not only myocyte viability, but also microvascular integrity is lost. Myocardial contrast echocardiography, using intracoronary injection of sonicated contrast medium, gives information about microvascular integrity and the effective presence of intramyocardial reflow. Anatomical integrity of microvasculature does not necessarily imply preserved function, and thus the microvessel vasodilating reserve may also be impaired. Myocardial contrast echocardiography has the potential to assess alterations in microvascular function, showing, in the myocardial area with reduced coronary reserve, a relatively reduced increase in echocontrast signal intensity when an intravenous vasodilator agent is administered.     

Clinical profile of patients admitted to the coronary care unit with possible myocardial infarction without diagnostic ECG and/or enzyme changes

Concern has been expressed about the cost-effectiveness of the Coronary Care Unit (CCU) and solution options offered on account of the large number of patients admitted to the CCU who turn out not to have acute myocardial infarction. In a prospective study over four years, we studied a group of patients admitted to the CCU with suspected myocardial infarction but who did not have diagnostic ECG and/or enzyme changes for the causes of their chest pain. We compared the clinical profile of these patients (Group A) with that of a random sample of patients with confirmed myocardial infarction (Group B). Gastrointestinal disorders, musculoskeletal chest pain, panic and anxiety disorders were the major causes of chest pain in Group A patients. A normal ECG and a normal creatine phosphokinase (CPK) within the first 24 hours, a normal initial random blood sugar, a younger age and absence of coronary risk factors effectively separated Group A patients as low risk from Group B patients as high risk for acute myocardial infarction. These simple parameters will assist physicians providing CCU care in most hospitals in early decision making and in the judicious use of the CCU.     

Variations between countries in invasive cardiac procedures and outcomes in patients with suspected unstable angina or myocardial infarction without initial ST elevation. OASIS (Organisation to Assess Strategies for Ischaemic Syndromes) Registry Investigators

BACKGROUND: There are wide variations between countries in the use of invasive cardiac catheterisation and revascularisation procedures for patients with acute ischaemic syndromes. We studied the relation between rates of such procedures and rates of cardiovascular death, myocardial infarction, stroke, refractory angina, and major bleeding in a prospective, registry-based study in six countries with widely varying intervention rates. METHODS: 7987 consecutive patients presenting with unstable angina or suspected myocardial infarction without ST-segment elevation were recruited prospectively from 95 hospitals in six countries and followed up for 6 months. FINDINGS: The rates of all procedures were highest in patients in Brazil and the USA, intermediate in Canada and Australia, and lowest in Hungary and Poland. There were no significant differences in rates of cardiovascular death or myocardial infarction among these countries (4.7% overall [range 3.7-5.6] at 7 days; 11% overall [9-12] at 6 months). For the countries with the highest rates of invasive procedures (59%) versus the rest (21%) there was no difference in rate of cardiovascular death or myocardial infarction (adjusted odds ratio 0.88 at 7 days and 1.0 at 6 months). Rates of stroke were higher in Brazil and the USA than in the countries with lower intervention rates (adjusted odds ratio at 7 days 3.0, p=0.012; at 6 months 1.8, p=0.004) but rates of refractory angina at 7 days (0.7, p<0.001) and readmission for unstable angina at 6 months were lower (0.70, 0.63; both p<0.001). Comparison of results for hospitals without cardiac-catheterisation facilities and for those with such facilities gave adjusted odds ratios for cardiovascular death, myocardial infarction, or stroke at 6 months of 0.83 (10.6% vs 12.5%, p=0.05) and for refractory angina of 1.25 (19.3% vs 16.1%, p=0.09). INTERPRETATION: Higher rates of invasive and revascularisation procedures were associated with lower rates of refractory angina or readmission for unstable angina, no apparent reduction in cardiovascular death or myocardial infarction, but with higher rates of stroke. Randomised trials should assess the relative impact of conservative and more aggressive approaches to invasive cardiac procedures and revascularisations in patients with unstable angina.