Prognostic significance of early ischemia after acute myocardial infarction in low-risk patients. IRES (Ischemia Residua) Study Group

Long-term prognosis of patients with early post-infarction angina

BACKGROUND

Most studies have shown that early post-infarction angina (EPA) implies an unfavorable long-term prognosis among patients with acute myocardial infarction (AMI). However, some studies have failed to establish a link between the occurrence of EPA and increased mortality and recurrent infarction rates.

METHODS AND RESULTS

In order to evaluate a long-term prognosis in patients with EPA, we assessed the 5-year prognosis of 80 patients with AMI by the presence or absence of EPA. During the 5-year follow up, the occurrence of death, cardiac death, recurrent infarction, unstable angina, heart failure, revascularization and cardiac events were recorded. A cardiac event was defined as an occurrence of any of the following events: cardiac death, recurrent infarction, unstable angina, heart failure and revascularization. Survival analysis showed no differences between patients with and without EPA in the probability of death (p=NS), cardiac death (p=NS), recurrent myocardial infarction (p=NS) and unstable angina (p=NS). Patients with EPA had a higher probability of developing cardiac events (p=0.0285) and undergoing revascularization procedures (p=0.0188).

CONCLUSIONS

EPA increases the risk of patients developing cardiac events and undergoing revascularization procedures, and thereby implies a poor long-term prognosis for patients with AMI.

Prediction of infarction-related artery occlusion and multivessel disease in postinfarction angina

CONDENSED ABSTRACT

To investigate the predictive value of clinical data for infarction-related artery (IRA) occlusion and multivessel coronary disease in postinfarction angina (PIA), we studied 181 consecutive patients presenting PIA following a first uncomplicated ST elevation AMI. Multivariate analysis showed ECG changes during PIA and the absence of thrombolytic therapy as independent predictors of IRA occlusion. Independent clinical predictors of multivessel coronary disease were age, previous history of angina and the number of cardiovascular risk factors. We conclude that reversible ECG changes during PIA correlated to IRA occlusion but failed to predict a multivessel coronary disease.

AIM

To identify clinical variables predictive of infarction-related artery (IRA) occlusion and multivessel coronary disease in patients with postinfarction angina pectoris (PIA) after a first uncomplicated acute myocardial infarction (AMI).

METHODS

We studied 181 consecutive patients with PIA following a first uncomplicated AMI. Clinical variables included cardiovascular risk factors, clinical history of angina before the event of inclusion, use of thrombolytic therapy in the previous AMI, ST-T changes during PIA, time to onset, number of episodes and delay to angiography after PIA. Angiographic variables were IRA TIMI flow, number of diseased vessels and ventricular function.

RESULTS

The IRA was occluded in 67 patients with PIA (37.0%). Reversible ECG changes during PIA were detected in 121 patients (67.0%): 79 cases (43.6%) with ST/T elevation and 42 cases (23.2%) with ST/T depression. Multivariate logistic regression analysis showed ECG changes during PIA (OR 3.12 CI 95% 1.48-6.54, p<0.01) and the absence of thrombolytic therapy (OR 2.21 95% CI 1.11-4.43, p<0.05) as independent predictors of IRA occlusion. We found multivessel coronary disease in 89 patients (49.2%) without any correlation to ECG changes during PIA. Independent clinical predictors of multivessel coronary disease were age (OR 1.03 95% CI 1.01-1.06, p<0.05), previous history of angina (OR 2.37 95% CI 1.06-5.28, p<0.05) and the number of cardiovascular risk factors (OR 1.37 95% CI 0.97-1.92, p=0.07).

CONCLUSIONS

ECG changes during PIA was correlated to IRA occlusion in spite of previous thrombolytic therapy but failed to predict a multivessel coronary disease in our patients.

[Prognostic value of early post-infarction angina in elderly patients]

Although numerous studies have shown that early post-infarction angina was a predictor of poor prognosis in patients with acute myocardial infarction, not a single study has considered this issue in the elderly. The goal of this study, based on a five-year follow-up of elderly patients with acute myocardial infarction, was to determine whether early post-infarction angina in the elderly had any influence on mortality and the incidence of additional coronary events. The study population consisted of 51 patients, aged 60 years or more, with acute myocardial infarction. Early post-infarction angina occurred in 31 subjects (Group 1), while it did not in 20 subjects (Group 2). Patients were monitored for five years and the incidences of death and new coronary events were recorded. A survival analysis was carried out using the Kaplan-Meier method. The survival analysis showed no difference between the observed groups concerning the following probabilities: death (p = 0.9459), cardiac death (p = 0.8253), myocardial reinfarction (p = 0.7405), new coronary events (p = 0.1708), unstable angina (p = 0.1788), myocardial revascularisation (p = 0.0691), and heart failure (p = 0.7047). In contrast to the younger population, where numerous studies have confirmed the link between early post-infarction angina and poor long-term prognosis, such findings could not be replicated in this study of the elderly population.

Determinants of left ventricular systolic function after acute myocardial infarction: the role of residual myocardial ischaemia

BACKGROUND

Left ventricular systolic function (LVSF) is one of the major determinants of survival after acute myocardial infarction (AMI). Some factors such as the infarct size and localization, and the patency of the infarct-related artery are known determinants of LVSF. However, the long-term effect of myocardial ischaemia on LVSF has been poorly studied in clinical settings.

OBJECTIVES

To assess the acute and long-term effects of myocardial ischaemia on LVSF in patients recovering from an AMI.

METHODS

A cohort of 74 patients recovering from AMI was studied. Myocardial ischaemia was detected by means of ambulatory electrocardiogram (ECG) monitoring at recruitment (4+/-2 days after AMI), exercise ECG test and stress echocardiography at discharge (7+/-4 days after AMI). LVSF was studied by means of two-dimensional echocardiography at recruitment, at discharge, and at 1, 3, 6 and 12 months after AMI.

RESULTS

Patients with myocardial ischaemia on ambulatory ECG monitoring and stress echocardiography had worse LVSF at recruitment than those without ischaemia. The presence of myocardial ischaemia on ambulatory ECG monitoring was an independent determinant of LVSF at recruitment together with infarct localization and size (assessed by creatine kinase MB isoenzyme (CK-MB) levels). Patients with signs of myocardial ischaemia on ambulatory ECG monitoring and stress echocardiography had a progressive left ventricular dysfunction compared with those without ischaemia.

CONCLUSIONS

Residual ischaemia is an independent determinant of LVSF after AMI and its presence implied a progressive worsening of the LVSF. Because left ventricular systolic dysfunction is a major determinant of survival after AMI, its precursors, among them residual myocardial ischaemia, should be identified. Treatment of ischaemia is known to be associated with improved prognosis and improved LVSF.

Three-year follow-up of patients with silent ischemia in the subacute phase of myocardial infarction after thrombolysis and early coronary intervention

In order to assess the prognostic value of silent myocardial ischemia in acute myocardial infarction after thrombolysis and early coronary angiography (14-48 h after start of thrombolysis) including percutaneous transluminal coronary angioplasty, if indicated, 126 patients underwent 24 h-Holter-monitoring in the early postinfarction period. The 24 h-Holter-recording was initiated directly after early coronary intervention (40+/-11 h after onset of symptoms). Of the 126 patients initially eligible for the study 29 had to be excluded from further analysis for clinical or methodical reasons. Of the remaining 97 patients, 10 (10%) had silent ischemia (group A) and 87/97 (90%) patients showed no significant ST-segment alterations. Both groups did not significantly differ from each other with regard to baseline clinical characteristics, severity of coronary artery disease and frequency of successful percutaneous transluminal coronary angioplasty. The left ventricular ejection fraction showed a trend towards lower values in patients with than in those without silent ischemia (47+/-15% vs. 55+/-13%, p=0.07). When both silent ischemia and left ventricular ejection fraction <40% were present, a subset of patients at high risk for cardiac death could be identified (specificity: 98%, positive predictive accuracy: 75%). By Kaplan-Meier analysis, significantly more cardiac deaths occurred in group A than in group B (30% vs. 6%, p<0.01) during the three-year follow-up (950+/-392 days) after acute myocardial infarction. Regarding the cardiac events during long-term follow-up (emergency percutaneous transluminal coronary angioplasty, coronary artery bypass grafting, non-fatal reinfarction, and cardiac death) there was no significant difference between both groups (30% vs. 18%, NS). In conclusion, Holter monitor-detected silent ischemia in the subacute phase of myocardial infarction after thrombolysis followed by early delayed coronary intervention occurs in 10% of the patients indicating either a residual ischemia in the infarcted zone despite a combined reperfusion strategy or a remote ischemic potential in case of multivessel disease. In this small selected group of infarct patients too, silent ischemia is to be considered as an important non-invasive parameter to predict cardiac death during long-term follow-up and provides valuable complementary information to left ventricular dysfunction, a well established prognostic marker in the postinfarction period.

Acute coronary syndromes in the GUSTO-IIb trial: prognostic insights and impact of recurrent ischemia. The GUSTO-IIb Investigators

BACKGROUND

Recurrent ischemia after an acute coronary syndrome portends an unfavorable outcome and has major resource-use implications. This issue has not been studied systematically among the spectrum of patients with acute coronary presentations, encompassing those with and without ST-segment elevation.

METHODS AND RESULTS

We assessed the 1-year prognosis of the 12 142 patients enrolled in the GUSTO-IIb trial by the presence (n=4125) or absence (n=8001) of ST-segment elevation. This latter group was further categorized into those with baseline myocardial infarction (n=3513) or unstable angina (n=4488). We also assessed the incidence of recurrent ischemia and its impact on outcomes. Recurrent ischemia was significantly rarer in those with ST-segment elevation (23%) than in those without (35%; P<0.001). Mortality at 30 days was greater among patients with ST-segment elevation (6.1% versus 3.8%; P<0.001) but less so at 6 months; by 1 year, mortality did not differ significantly (9.6% versus 8.8%). Patients with non-ST-segment-elevation infarction had higher rates of reinfarction at 6 months (9.8% versus 6.2%) and higher 6-month (8.8% versus 5.0%) and 1-year mortality rates (11.1% versus 7.0%) than such patients who had unstable angina.

CONCLUSIONS

Refractory ischemia was associated with an approximate doubling of mortality among patients with ST-segment elevation and a near tripling of risk among those without ST elevation. This study highlights not only the substantial increase in late mortality and reinfarction with non-ST-segment-elevation infarction but also the opportunities for better triage and application of therapeutic strategies for patients with recurrent ischemia.

[Results of primary angioplasty in patients with multivessel disease]

INTRODUCTION

In patients with acute myocardial infarction treated with primary angioplasty, multivessel disease is associated with a higher mortality. However, if higher mortality is simply due to a higher prevalence of cardiogenic shock or if multivessel disease is an independent risk factor remains unclear.

OBJECTIVES

To study if multivessel disease constitute an independent prognostic factor in patients with acute myocardial infarction treated with primary angioplasty, and to ascertain possible mechanisms contributing to the worse prognosis found in these patients.

PATIENTS AND METHODS

Between august 1991 and october 1996, 312 patients with acute myocardial infarction were treated with primary angioplasty in our center. Characteristics and in-hospital outcome of patients with or without multivessel disease were compared.

RESULTS

Patients with multivessel disease (n = 158; 51%) were older (64 +/- 11 vs 61 +/- 13 years; p = 0.017), less often smokers (60% vs. 76%; p = 0.006) and had a higher prevalence of diabetes (35% vs. 20%; p = 0.007), hypertension (54% vs. 39%; p = 0.012), prior acute myocardial infarction (29% vs. 5%; p < 0.001), prior coronary bypass (2% vs. 0%; p = 0.042) and Killip class IV at admission (19% vs. 8%; p < 0.001). Angiographic success rate was not different in patients with or without multivessel disease (89% vs. 92%; NS). Patients with multivessel disease had a higher in-hospital mortality (21% vs. 7%; p < 0.001), need of revascularization (17% vs. 3%; p < 0.001) and incidence of severe mitral regurgitation, (5% vs. 0%; p < 0.001), second or third atrioventricular blockade (10% vs. 1%; p < 0.001) and severe bleeding (4% vs. 1%; p = 0.089). After excluding patients with Killip class III or IV at admission, mortality was also higher in patients with multivessel disease (9% vs. 2%; p = 0.009). Multivariate analysis showed the following independent risk factors for mortality: age > 65 years, Killip class IV and multivessel disease.

CONCLUSIONS

In patients with acute myocardial infarction treated with primary angioplasty, multivessel disease is associated with higher mortality. This is due not only to a higher prevalence of cardiogenic shock at admission, but also to a worse baseline profile, a higher incidence of complications and a more frequent need of revascularization.

Prognostic significance of ST segment shift early after resolution of ST elevation in patients with myocardial infarction treated with thrombolytic therapy: the GUSTO-I ST Segment Monitoring Substudy

OBJECTIVES

We sought to study the relation between recurrent ST segment shift within 6 to 24 h of initial resolution of ST elevation after thrombolytic therapy and 30-day and 1-year mortality.

BACKGROUND

Rapid and stable resolution of ST segment elevation in relation to thrombolytic therapy in patients with an acute myocardial infarction is an indicator of culprit artery patency. Whether recurrence of ST segment shift during continuous ST monitoring after initial resolution is related to poor prognosis has not been studied.

METHODS

ST segment monitoring was performed within 30 min after thrombolytic therapy for acute myocardial infarction. The predictive value of a new ST segment shift (assessed as > or = 0.1-mV deviation from the baseline) 6 to 24 h after thrombolytic therapy was studied with respect to 30-day and 1-year mortality.

RESULTS

Of 734 patients, 243 had a new ST segment shift (33%). The 30-day mortality rate in patients with an ST shift (7.8%) was significantly higher than that in patients without an ST shift (2.25%, p = 0.001), as was the 1-year mortality rate (10.3% vs. 5.7%, respectively, p = 0.025). Multivariable analysis revealed an independent predictive value of ST shift with respect to 30-day mortality (p = 0.008), even after consideration of multiple clinical risk factors in the overall Global Utilization of Streptokinase and TPA for Occluded Coronary Arteries (GUSTO)-I mortality model (p = 0.0001). Moreover, the duration of the ST shift bore a direct relation with 1-year mortality (p = 0.008).

CONCLUSIONS

Detection of ST segment shift early after thrombolytic therapy for acute myocardial infarction is a simple, noninvasive means of identifying patients at high risk and is superior to other commonly assessed clinical risk factors. Thus, patients with a new ST shift after the first 6 h, but within 24 h, represent a high risk group that may benefit from more aggressive intervention, whereas patients without evidence of an ST shift represent a low risk subgroup.

Recurrent ischemia after thrombolysis: importance of associated clinical findings. GUSTO-I Investigators. Global Utilization of Streptokinase and t-PA [tissue-plasminogen activator] for Occluded Coronary Arteries

OBJECTIVES

We sought to assess the incidence and clinical relevance of examination data to recurrent ischemia within an international randomized trial.

BACKGROUND

Ischemic symptoms commonly recur after thrombolysis for acute myocardial infarction.

METHODS

Patients (n = 40,848) were prospectively evaluated for recurrent angina and transient electrocardiographic (ECG) or hemodynamic changes. Five groups were developed: Group 1, patients with no signs or symptoms of recurrent ischemia; Group 2, patients with angina only; Group 3, patients with angina and ST segment changes; Group 4, patients with angina and hemodynamic abnormalities; and Group 5, patients with angina, ST segment changes and hemodynamic abnormalities. Baseline clinical and outcome variables were compared among the five groups.

RESULTS

Group 1 comprised 32,717 patients, and Groups 2 to 5 comprised 20% of patients (4,488 in Group 2; 3,021 in Group 3; 337 in Group 4; and 285 in Group 5). Patients with recurrent ischemia were more often female, had more cardiovascular risk factors and less often received intravenous heparin. Significantly more extensive and more severe coronary disease, antianginal treatment, angioplasty and coronary bypass surgery were observed as a function of ischemic severity. The 30-day reinfarction rate was 1.6% in Group 1, 6.5% in Group 2, 21.7% in Group 3, 13.1% in Group 4 and 36.5% in Group 5 (p < 0.0001); in contrast, the 30-day mortality rate was significantly lower (p < 0.0001) in Groups 1, 2 and 3 (6.6%, 5.4% and 7.7%, respectively) than in Groups 4 and 5 (21.8% and 29.1%).

CONCLUSIONS

Postinfarction angina greatly increases the risk of reinfarction, especially when accompanied by transient ECG changes. However, mortality is markedly increased only in the presence of concomitant hemodynamic abnormalities.

[Clinical prediction of the early prognosis in acute myocardial infarct]

Several clinical factors can influence the pathophysiology, clinical course and prognosis of acute myocardial by different means. Some of them may be easily detected through the history, physical examination or ECG in an early phase. The knowledge of these factors may help the therapeutic decision making of patients with myocardial infarction. The influence for the main clinical factors (age, sex, risk factors, cardiologic antecedents and evolutive findings) on the short-term prognosis of acute myocardial infarction is reviewed. An analysis of the likely mechanisms of the influence of these factors on infarct prognosis is also performed.

Early and six-month outcome in patients with angina pectoris early after acute myocardial infarction (the GISSI-3 APPI [angina precoce post-infarto] study)

There is conflicting evidence whether or not early postinfarction angina implies an unfavorable prognosis. This prospective study assessed the significance and natural history of early angina in a broad population of patients conservatively managed after acute myocardial infarction (AMI) and enrolled in the third Gruppo Italiano per lo Studio della Sopravvivenza nel Infarto Miocardico (GISSI-3) trial. Out of 2,363 consecutive patients (age 63 +/- 11; first AMI in 86%; thrombolysis in 74%) admitted in 31 centers lacking on-site revascularization facilities, early angina associated with transient electrocardiographic (ECG) changes was documented in 332 (14%). At multivariate analysis, preinfarction angina, age > or = 70 years, female gender, and history of infarct were significant predictors of early angina. Though the in-hospital course was free from major cardiac events in 78% of patients after the first anginal episode, reinfarction was more common after early angina (7% vs 2% in patients without, RR 3.1, 95% confidence interval [CI] 1.9 to 5.6; p <0.001), and death occurred in 7% of patients with early angina (vs 5% of patients without, RR 1.4, CI 0.9 to 2.4, p = NS). No demographic or clinical characteristics identified patients who suffered nonfatal reinfarction after angina, and neither the ECG location (infarct zone or remote) nor patterns of ECG changes during angina proved significant predictors of in-hospital reinfarction or death. Early angina emerged as the sole independent predictor of 6-month cumulative reinfarction (12% vs 5% of patients without, RR 2.9, CI 2.0 to 4.4; p <0.0001) and an independent predictor of death (13% vs 7% of patients without early angina, RR 2.3, CI 1.6 to 3.3; p <0.0001). Early postinfarction angina is a powerful prognostic marker. Patients with early postinfarction angina had an unfavourable in-hospital outcome, but the prospective identification of patients at greater risk of major events after angina remains elusive. Although in-hospital stabilization was achieved by medical treatment in the majority of patients with early angina, their increased 6-month risk of reinfarction and death suggests that a more aggressive management is warranted.

Unstable angina pectoris

Preview Patients with angina that occurs increasingly often, for longer periods, with less and less exertion, or during periods of rest are of particular concern. These traits are all characteristic of unstable angina. Unlike stable angina, which has a relatively benign course, unstable angina has the capability of progressing to acute myocardial infarction or death. The authors summarize patient evaluation, with emphasis on identification of those at risk.

Frequency, significance, and cost of recurrent ischemia after thrombolytic therapy for acute myocardial infarction. TAMI Study Group

Early postinfarction angina implies an unfavorable prognosis. Most published information on this outcome represents data collected in the prethrombolytic era, in which definitions and populations differed considerably. Our purpose was to evaluate the incidence and importance of recurrent ischemia after administration of thrombolytic therapy. We studied patients enrolled in the Thrombolysis and Angioplasty in Myocardial Infarction studies. Patients were enrolled into 5 studies with similar entry criteria; 552 patients were treated with tissue plasminogen activator (t-PA), 293 were treated with urokinase, and 385 received both thrombolytic agents. Recurrent ischemia was defined as symptoms in association with electrocardiographic changes; reinfarction was defined as a reelevation of creatine kinase myocardial band isoenzyme in an appropriate clinical setting. Both recurrent ischemia and reinfarction occurred in 42 patients (3.4%), recurrent ischemia alone occurred in 226 (18%), whereas neither occurred in 964 (78%). Although baseline characteristics were similar among the 3 groups, in-hospital cardiac events (total 73 deaths, 253 heart failure episodes) were not: in-hospital mortality in patients with reinfarction was 21%; with recurrent ischemia, 11%; and with neither event, 4% (p < 0.0001). The in-hospital heart failure rate of patients with reinfarction was 50%; with recurrent ischemia alone, 31%; and with neither event, 17% (p < 0.0001). As expected, median in-hospital costs were highest in patients with reinfarction ($26,802), intermediate for those with recurrent ischemia alone ($18,422), and lowest in patients with neither event ($15,623). Recurrent myocardial ischemia after thrombolytic therapy is a frequent, important, and expensive adverse clinical outcome, making it a critical target for therapeutic intervention.

Residual exertional ischemia and unfavorable left ventricular remodeling in patients with systolic dysfunction after anterior myocardial infarction

OBJECTIVES

This study investigated whether exercise-induced myocardial ischemia influences left ventricular remodeling after anterior myocardial infarction.

BACKGROUND

The effects of acute and recurrent ischemia on ventricular function are well established. However, to our knowledge the role of exertional ischemia in the remodeling response after infarction has not been investigated.

METHODS

Ninety-one patients with a first anterior Q wave myocardial infarction were studied at 5 weeks by rest echocardiography and exercise scintigraphy. The echocardiographic examination was repeated 6 months later. On the basis of the presence and extent of reversible perfusion defects on exercise scintigraphy, patients were assigned to groups with no exertional ischemia (group 1, n = 20 [22%], mild to moderate ischemia (group 2, n = 45 [49%]) and severe exertional ischemia (group 3, n = 26 [29%]).

RESULTS

Initial left ventricular volumes were similar, and no differences were found among the three groups in the remodeling response over the 6-month period of the study. However, patients in groups 2 and 3 with an ejection fraction < or = 40% showed significant (p < 0.01) ventricular enlargement over time, which was similar between the two groups (end-diastolic volume [mean +/- SD] from 74 +/- 13 to 80 +/- 17 ml/m2 in group 2 and from 72 +/- 11 to 81 +/- 19 ml/m2 in group 3; regional dilation from 42 +/- 16% to 52 +/- 22% in group 2 and from 38 +/- 18% to 46 +/- 27% in group 3). In contrast, ventricular dimensions did not change in group 1 patients with an ejection fraction < or = 40% as well as in patients in all three groups with an ejection fraction > 40%.

CONCLUSIONS

Exercise-induced myocardial ischemia may contribute to progressive ventricular enlargement in patients with poor left ventricular function after a large anterior myocardial infarction.

Silent ischemia after uncomplicated myocardial infarction: lack of incremental clinical significance

To determine the potential utility of the detection of silent myocardial ischemia after acute myocardial infarction for clinical decision making, we investigated the hypothesis that the occurrence of silent myocardial ischemia on ambulatory electrocardiographic (EGG) monitoring after acute myocardial infarction is independently predictive of adverse outcome in patients in whom conventional clinical and investigative parameters indicate favourable prognosis on medical therapy. Among 465 consecutive patients admitted to our Coronary Care Unit with acute myocardial infarction, 42 patients (39% of those eligible) were randomly selected for study. Twenty-four hour ambulatory ECG monitoring was carried out 13 +/- 10 (standard deviation) days post-acute myocardial infarction. Ninety-eight percent of patients were receiving prophylactic anti-ischemic medications and 81% on aspirin. Silent myocardial ischemia was detected in 14%. During the follow-up period of 16 +/- 3 months, acute ischemic events occurred in 33% of those with silent myocardial ischemia and 19% of those without previous silent myocardial ischemia (P = 0.59). The sensitivity of the test for prediction of future acute ischemic events was 22% (95% confidence interval: 3-60%), specificity 87% (95% confidence interval: 72-97%), positive predictive value 33% (95% confidence interval: 4-78%) and negative predictive value 81% (95% confidence interval: 64-92%). Therefore the detection of ambulatory silent myocardial ischemia after acute myocardial infarction is not of sufficient incremental value as a predictor of the occurrence of adverse cardiac events to justify its routine clinical use in this subgroup of patients.