Clinical study
Effects of an early invasive strategy on ischemia and exercise tolerance among patients with unstable coronary artery disease☆

https://doi.org/10.1016/j.amjmed.2003.06.003Get rights and content

Abstract

Background

An early invasive approach after an episode of unstable coronary artery disease has beneficial effects on mortality and myocardial infarction, but its effects on exercise capacity and ischemia have not been investigated.

Methods

In the Fast Revascularisation during InStability in Coronary disease (FRISC) II trial, 2457 patients with unstable coronary artery disease were assigned randomly to an early invasive or noninvasive strategy. A symptom-limited bicycle exercise test was performed before discharge in the noninvasive group and after 3 months in both groups.

Results

At 3 months, 86% (1046/1222) of the patients in the invasive group and 81% (995/1235) in the noninvasive group performed the exercise test. Before the test, revascularization had been performed in 78% (n = 819) of these patients in the invasive group compared with 28% (n = 281) of those in the noninvasive group. The mean (± SD) exercise capacity was higher (6.4 ± 1.9 vs. 6.2 ± 1.9 metabolic equivalents [METS], P <0.01), and the occurrence of ischemia lower (23% [229/1004] vs. 36% [352/966], P <0.001) in the invasive group. In the noninvasive group, 882 patients performed an exercise test both predischarge and at 3 months. If a revascularization procedure was performed (n = 210), exercise tolerance increased from 5.1 ± 1.4 to 6.0 ± 1.8 METS (P <0.001) and the number of patients with ST depression decreased from 65% (131/203) to 31% (63/203) (P <0.001). Without revascularization (n = 670), exercise tolerance increased from 5.9 ± 2.2 to 6.3 ± 1.9 METS (P <0.001), and there were no differences in the occurrence of ischemia.

Conclusion

In unstable coronary artery disease, an invasive strategy improves exercise tolerance and reduces exercise-induced ischemia.

Section snippets

Patients

FRISC II was a multicenter study that randomly assigned patients with unstable angina or non–ST-elevation myocardial infarction to an early invasive (coronary angiography/revascularization within 7 days) or noninvasive regimen (4). Inclusion criteria were symptoms of cardiac ischemia associated with either ST depression ≥0.1 mV or T-wave inversion ≥0.1 mV in at least one lead, or elevation of biochemical markers of myocardial damage. Major exclusion criteria were increased risk of bleeding

Results

The characteristics of the patients who performed an exercise test at 3 months were similar in the two groups (invasive vs. noninvasive), except that there were more women in the noninvasive group (Table 1). In the invasive group, a 3-month exercise test was performed in 86% (1046/1222) of patients, compared with 81% (995/1235) in the noninvasive group (P = 0.001). Revascularization had been performed in 78% (n = 819) of these patients in the invasive group compared with 28% (n = 281) of these

Discussion

When comparing different treatments in unstable coronary artery disease, most trials have used the composite of death and myocardial infarction as the primary endpoint 4, 15, 16. Urgent revascularization (17), refractory ischemia (18), or rehospitalization (6) have also been used as additional outcomes. Our findings, based on the results of an exercise test at 3 months, provide information on the functional status of the patient and on the occurrence of ischemia.

Among patients with stable

Acknowledgements

We gratefully acknowledge the invaluable contribution of all patients who agreed to participate and the dedicated work of the research nurses, monitors, investigators, coordinators, core laboratories, end-point committee, and data safety monitoring board.

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    • Cited by (0)

    ☆

    The study was supported by and organized in collaboration with the Pharmacia-Upjohn Company, Stockholm, Sweden. The project organization within the research group was also supported by the Swedish Heart-Lung Foundation.

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