Ten-year mortality rate in relation to observations at a bicycle exercise test in patients with a suspected or confirmed ischemic event but no or only minor myocardial damage: influence of subsequent revascularization.

AIM

Our purpose was to describe symptoms and electrocardiographic findings at a bicycle exercise test 4 weeks after hospitalization for a suspected or confirmed acute ischemic event but either no or only minor myocardial necrosis and its relationship to long-term prognosis and subsequent revascularization.

METHODS

In all patients a symptom-limited bicycle exercise test was performed 4 weeks after discharge from the hospital. The total mortality rate over 10 years was registered.

RESULTS

In all, 770 patients participated in the evaluation. The median age was 63 years, and 34% were women. The most frequent reason for stopping the exercise test was fatigue (69%) followed by dyspnea (33%) and angina pectoris (15%). Angina pectoris was observed in 24% of the patients. ST-segment depression >or=1 mm was observed in 50% and ST-segment depression >or=2 mm was observed in 15% of the patients. The 10-year mortality rate in patients with ST-segment depression >or=2 mm was 24.7%, in patients with ST-segment depression 1.0 to 1.9 mm 33.5%, and in patients with ST-segment depression <1 mm 26.9% (not significant [NS]). Patients with symptoms of angina pectoris had a 10-year mortality rate of 29.4% compared with 27.9% among patients without such symptoms (NS). Patients who had either a drop in systolic blood pressure or failure to raise systolic blood pressure (13%) had a 10-year mortality rate of 36.2% compared with 27.2% among patients without such signs (NS). However, there was a significant association between maximum exercise capacity (in watts) and mortality (P < .0001): 53.8% in the lowest quartile (30-70 W) and 10.2% in the highest (>120 w). When clinical history was considered simultaneously, a low exercise capacity remained as a strong independent predictor of death together with age and a history of either acute myocardial infarction, smoking, or diabetes mellitus. Mechanical revascularization during the subsequent 5 years interacted only with angina pectoris and prognosis; thus patients who had angina during the exercise test had a worse prognosis than those without if they were not being revascularized.

CONCLUSION

Among patients hospitalized with a suspected or confirmed acute ischemic event but either no or only minor myocardial necrosis, we found the maximum working capacity at a symptom-limited bicycle exercise test to be independently associated with the long-term prognosis but not other signs of myocardial ischemia. Further predictors for long-term prognosis were age, a history of acute myocardial infarction, current smoking, and diabetes mellitus. Mechanical revascularization during the subsequent 5 years interacted with the influence of symptoms of angina during test and prognosis.