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Painless exercise ST deviation on the treadmill: long-term prognosis
D B Mark1, M A Hlatky, R M Califf
1Department of Medicine, Duke University Medical Center, Durham, North Carolina.
Insights
Silent ischemia during exercise testing in coronary artery disease patients is not benign but indicates an intermediate risk. These patients have less severe disease and a better prognosis than those with symptomatic ischemia.
Area of Science:
- Cardiology
- Exercise Physiology
Background:
- Coronary artery disease (CAD) management relies on risk stratification.
- Silent ischemia, identified during exercise testing, requires further evaluation for prognostic significance.
Purpose of the Study:
- To assess the clinical features and long-term prognosis of silent ischemia during exercise in symptomatic CAD patients.
- To compare outcomes between patients with no ischemia, silent ischemia, and symptomatic ischemia.
Main Methods:
- Studied 1,698 symptomatic CAD patients undergoing treadmill testing and cardiac catheterization.
- Classified patients into three groups: no ST deviation, painless ST deviation (silent ischemia), and angina with ST deviation.
- Analyzed 5-year survival rates and clinical characteristics across groups.
Main Results:
- Silent ischemia (painless ST deviation) showed a 5-year survival rate of 86%, similar to no ST deviation (88%).
- Symptomatic ischemia (angina with ST deviation) had a significantly lower 5-year survival rate (73%).
- Patients with silent ischemia had less aggressive anginal symptoms and less severe coronary artery disease than those with symptomatic ischemia.
Conclusions:
- Silent ischemia during exercise testing in symptomatic CAD patients is an intermediate risk marker.
- It signifies a less aggressive disease course and better prognosis compared to symptomatic ischemia.
- This finding aids in refining risk stratification for patients with known coronary artery disease.
Abstract:
To evaluate the clinical correlates and long-term prognostic significance of silent ischemia during exercise, 1,698 consecutive symptomatic patients with coronary artery disease who had both treadmill testing and cardiac catheterization were studied. These patients were classified into three groups: Group 1 = patients with no exercise ST deviation (n = 856), Group 2 = patients with painless exercise ST deviation (n = 242) and Group 3 = patients with both angina and ST segment deviation during exercise (n = 600). Patients with exercise angina had a history of a longer and more aggressive anginal course (with a greater frequency of angina, with nocturnal episodes and/or progressive symptom pattern) and more severe coronary artery disease (almost two-thirds had three vessel disease). The 5 year survival rate among the patients with painless ST deviation was similar to that of patients without ST deviation (86% and 88%, respectively) and was significantly better than that of patients with both symptoms and ST deviation (5 year survival rate 73% in patients with exercise-limiting angina). Similar trends were obtained in subgroups defined by the amount of coronary artery disease present. In the total study group of 1,698 patients, silent ischemia on the treadmill was not a benign finding (average annual mortality rate 2.8%) but, compared with symptomatic ischemia, did indicate a subgroup of patients with coronary artery disease who had a less aggressive anginal course, less coronary artery disease and a better prognosis. Thus, silent ischemia during exercise testing in patients with symptomatic coronary artery disease represents an intermediate risk response in the spectrum of exercise-induced ischemia.