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Prognostic value of dipyridamole thallium-201 imaging in elderly patients
L Shaw1, B R Chaitman, T C Hilton
1Department of Internal Medicine, Saint Louis University School of Medicine, Missouri 63110-0250.
Insights
Intravenous dipyridamole thallium-201 imaging effectively predicts cardiac events in elderly patients. A normal scan indicates a low risk of cardiac death or myocardial infarction, making it a valuable prognostic tool.
Area of Science:
- Cardiology
- Nuclear Medicine
- Geriatric Medicine
Background:
- Prognostic value of intravenous dipyridamole myocardial perfusion imaging in elderly patients (≥70 years) with coronary artery disease (CAD) is understudied.
- Elderly population represents a significant group with CAD, requiring reliable risk stratification tools.
Purpose of the Study:
- To evaluate the prognostic value of intravenous dipyridamole thallium-201 imaging in predicting cardiac death or nonfatal myocardial infarction in elderly patients.
- To identify independent predictors of cardiac events in this demographic.
Main Methods:
- Retrospective analysis of 348 patients (≥70 years) with known or suspected CAD.
- Intravenous dipyridamole thallium-201 imaging performed for myocardial perfusion assessment.
- Follow-up for cardiac death, nonfatal myocardial infarction, and revascularization procedures over 23 ± 15 months.
Main Results:
- Abnormal (fixed or reversible) dipyridamole thallium-201 defects were significantly associated with cardiac events (p < 0.05).
- Patients with a normal scan had a significantly lower event rate (5%, p < 0.001).
- Abnormal imaging was the strongest predictor of cardiac events (RR 7.2, p < 0.001), outperforming clinical factors like prior myocardial infarction and heart failure symptoms.
Conclusions:
- Intravenous dipyridamole thallium-201 imaging is a powerful independent predictor of cardiac events in elderly patients.
- A normal scan reliably identifies low-risk individuals, aiding in risk stratification and management decisions for elderly patients with CAD.
Abstract:
The prognostic value of intravenous dipyridamole myocardial perfusion imaging has not been studied in a large series of elderly patients. Patients greater than or equal to 70 years of age with known or suspected coronary artery disease were evaluated to determine the predictive value of intravenous dipyridamole thallium-201 imaging for subsequent cardiac death or nonfatal myocardial infarction. Of the 348 patients, 207 were symptomatic and 141 were asymptomatic; 52% of the asymptomatic group had documented coronary artery disease. During 23 +/- 15 months of follow-up, there were 52 cardiac deaths, 24 nonfatal myocardial infarctions and 42 revascularization procedures (percutaneous transluminal coronary angioplasty in 20; coronary artery bypass surgery in 22). Clinical univariate predictors of a cardiac event included previous myocardial infarction, congestive heart failure symptoms, hypercholesterolemia and diabetes (all p less than 0.05). The presence of a fixed, reversible or combined thallium-201 defect was significantly associated with the occurrence of cardiac death or myocardial infarction during follow-up (p less than 0.05). Cardiac death or nonfatal myocardial infarction occurred in only 7 (5%) of 150 patients with a normal dipyridamole thallium-201 study (p less than 0.001). Stepwise logistic regression analysis of clinical and radionuclide variables revealed that an abnormal (reversible or fixed) dipyridamole thallium-201 study was the single best predictor of cardiac events (relative risk 7.2, p less than 0.001). As has been demonstrated in younger patients, previous myocardial infarction (relative risk 1.8, p less than 0.001) and symptoms of congestive heart failure at presentation (relative risk 1.6, p = 0.02) were also significant independent clinical predictors of cardiac death or myocardial infarction.(ABSTRACT TRUNCATED AT 250 WORDS)