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Painless myocardial ischemia in elderly patients compared with middle-aged patients and its relation to treadmill
1Department of Internal Medicine, National Defense Medical College, Saitama, Japan.
Insights
Elderly patients with coronary artery disease experience more painless myocardial ischemia episodes. Aging may impair coronary vascular reserve and promote anaerobic metabolism, despite similar coronary artery disease severity.
Area of Science:
- Cardiology
- Geriatric Medicine
- Ischemic Heart Disease
Background:
- Painless myocardial ischemia is a significant concern in elderly patients with coronary artery disease (CAD).
- Understanding age-related differences in ischemia presentation and mechanisms is crucial for effective management.
Purpose of the Study:
- To compare painless ST-segment depression in elderly versus middle-aged patients with CAD.
- To investigate the relationship between painless ischemia, exercise testing, and coronary hemodynamics across age groups.
Main Methods:
- 24-hour Holter monitoring to detect painless ST-segment depression (criteria: >=1 mm, >=80 ms, >=60 s).
- Treadmill exercise testing to assess exercise capacity and ischemic response.
- Coronary hemodynamic studies, including coronary sinus flow and lactate extraction, performed within 2 weeks.
Main Results:
- Elderly patients (>=65 years) showed a higher prevalence of painless ST-segment depression (77%) compared to middle-aged patients (<60 years) (45%) (p<0.05).
- No significant differences were observed in treadmill exercise scores or ST-segment depression between groups.
- Elderly patients exhibited reduced coronary sinus flow increment and a greater decrease in lactate extraction ratio during pacing stress, indicating impaired coronary vascular reserve and easier anaerobic metabolism.
Conclusions:
- Painless myocardial ischemia is more prevalent in elderly individuals with CAD.
- Aging is associated with impaired coronary vascular reserve and enhanced anaerobic myocardial metabolism during stress.
- These age-related changes occur despite similar coronary artery disease severity and ejection fraction between elderly and middle-aged patients.
Abstract:
We compared painless ST-segment depression (1 mm greater than or equal to 80 ms and lasting greater than or equal to 60 s) in elderly patients with coronary artery disease (greater than or equal to 65 years, mean 67 years; n = 22) and that of middle-aged patients (less than 60 years, mean 54 years; n = 20) by Holter monitoring for 24 hours to determine the relationship between episodes of painless myocardial ischemia, findings of treadmill testing, and coronary hemodynamics. Coronary arteriographic findings (Gensini score) and ejection fraction (EF) did not differ between the two groups. Painless ST-segment depression was found to be 77% in the older age group versus 45% in the middle-aged group (p less than 0.05). However, treadmill exercise score, ST-segment depression, and ST-segment integral achieved did not differ significantly between the two groups. Within 2 weeks after the above testing, coronary hemodynamic study was performed. The increment of coronary sinus flow in the older age group was 1.4 +/- 0.3 versus 1.8 +/- 0.3 in the middle-aged group (p less than 0.05), and the change of lactate extraction ratio from the basal condition in the older age group was -50 +/- 40% versus -2 +/- 15% in the middle-aged group (p less than 0.05). We conclude that episodes of painless myocardial ischemia in elderly patients with aging may be associated with the impairment of the coronary vascular reserve and easier anaerobic myocardial metabolism by pacing stress despite similar findings of coronary artery disease and EF in both groups.