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Prognosis

Early postinfarction angina with ST-T changes was associated with poorer clinical outcomes

ACP J Club. 1992 Mar-April;116:57. doi:10.7326/ACPJC-1992-116-2-057


Source Citation

Bosch X, Théroux P, Pelletier GB, et al. Clinical and angiographic features and prognostic significance of early postinfarction angina with and without electrocardiographic signs of transient ischemia. Am J Med. 1991 Nov;91: 493-501.


Abstract

Objective

To determine the clinical correlates and prognostic significance of early postinfarction angina with and without electrocardiographic (ECG) changes.

Design

An inception cohort of patients with acute myocardial infarction.

Setting

Tertiary coronary care unit.

Patients

631 consecutive patients with myocardial infarction were considered for enrollment. Patients were excluded if they died in the acute phase (n = 69), had severe congestive heart failure (n = 23), had contraindications to coronary angiography (n = 23), or if they refused (n = 67). 449 patients were enrolled (84% men), mean age 54 ± 9 years, with acute myocardial infarction defined by ≥ 2 acute episodes of chest pain lasting ≥ 30 minutes, a diagnostic increase in serum creatine kinase, and new Q waves on serial ECGs. 291 patients (65%) had a Q-wave myocardial infarction. 136 patients had a past history of hypertension; 158, angina; and 103, myocardial infarction.

Assessment of prognostic factors

Postinfarction angina was defined as chest pain occurring ≥ 24 h after admission, judged as ischemic in origin by 2 independent assessors. ECGs were done during and after chest pain episodes. Changes were defined as transient ST-segment depression or elevation, transient inversion, or pseudonormalization of a negative T-wave. Follow-up after angiography was for a mean of 14 months.

Main outcome measures

Mortality, infarct extension, and angina.

Main results

3 groups of patients were identified: Group 1 had no angina (n = 285, 63%); group 2 had angina without ST-T changes (n = 85, 19%); group 3 had angina with ST-T changes (n = 79, 18%). The groups were similar for smoking, sex, infarct site, and Killip class. Groups 1 to 3 showed gradients (all P < 0.05) for history of previous angina (28% vs 42% vs 53%), number of diseased coronary arteries (1.6 vs 1.9 vs 2.1), and myocardial segments jeopardized by stenotic lesions (1.2 vs 1.5 vs 1.9). Group 1 and 2 patients had similar and better early and late outcomes than group 3 patients: For groups 1, 2, and 3, infarct extension occurred during hospitalization in 2%, 3.5%, and 28% of patients, respectively (P < 0.001). The 2-year survival rates were 96%, 90%, and 83%, respectively (P = 0.02); rates for survival without recurrent myocardial infarction were 80%, 78%, and 67%, respectively (P = 0.004).

Conclusions

Patients with early postinfarction angina and ST-T changes during pain had a poorer prognosis than patients with angina alone, whose prognosis was similar to that of patients without angina.

Source of funding: Not stated.

Address for article reprint: Dr. P. Théroux, Montreal Heart Institute, 5000 East Bélanger Street, Montreal, Quebec H1T 1C8, Canada.


Commentary

This study and others show that patients with recent myocardial infarction fall along a continuum of risk and that clinical assessment and laboratory data provide complementary information about outcome (1).

Angina with ECG changes carries a worse prognosis than angina without ECG changes, whether in patients with stable, unstable, or postinfarction angina. Possible explanations are that myocardial ischemia associated with ECG changes is more extensive or severe or that patients with ECG changes have more severe underlying disease. Bosch and colleagues did not do a multivariate analysis to test whether ECG changes add prognostic information to clinical and angiographic factors, but this has been shown in other studies.

Current guidelines from the American College of Cardiology/American Heart Association state that coronary angiography is "usually indicated" in patients with postinfarction angina, "particularly if accompanied by ECG changes" (2). This study supports this aggressive approach. The favorable outcome of patients with angina unaccompanied by ECG changes raises the issue of whether angiography should be routinely done in such patients. The Bosch study does not provide strong evidence to answer this question because it was of relatively small size and every patient had angiography, which was often followed by coronary revascularization. Thus, equally favorable outcomes might not result from a noninvasive evaluation strategy in patients with ECG changes. I continue to recommend angiography for most patients with postinfarction angina.

Mark A. Hlatky, MD
Stanford University School of MedicineStanford, California, USA


References

1. Califf RM, Mark DB, Harrell FE Jr, et al. Importance of clinical measures of ischemia in the prognosis of patients with documented coronary artery disease. J Am Coll Cardiol. 1988;11:20-6.

2. Gunnar RM, Bourdillon PD, Dixon DW, et al. ACC/AHA guidelines for early management of patients with acute myocardial infarction. Circulation. 1990;82:664-707.