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A negative thallium (+/- dipyridamole) stress test excludes significant obstructive epicardial coronary artery
L M Prisant1, T W von Dohlen, J L Houghton
1Department of Medicine, School of Medicine, Medical College of Georgia, Augusta 30912-3150.
Insights
Thallium stress testing effectively identifies significant coronary artery disease (CAD) in hypertensive patients with chest pain or ischemia. Its high sensitivity and negative predictive value make it a valuable exclusion test for CAD.
Area of Science:
- Cardiology
- Nuclear Cardiology
- Diagnostic Imaging
Background:
- Hypertension is a significant risk factor for coronary artery disease (CAD).
- The diagnostic performance of thallium stress testing in hypertensive individuals with symptoms suggestive of CAD was previously undefined.
- Accurate detection of CAD is crucial in this high-risk population.
Purpose of the Study:
- To define the operating characteristics of thallium stress testing for detecting significant epicardial coronary artery disease (CAD) in hypertensive patients presenting with chest pain or electrocardiographic (ECG) ischemia.
- To evaluate the utility of thallium stress testing as an exclusion tool for CAD in this specific demographic.
Main Methods:
- Ninety-two hypertensive patients with chest pain or ECG ischemia underwent coronary arteriography and thallium-201 stress testing.
- Intravenous dipyridamole was administered if the rate-pressure product was below 20,000.
- Exclusion criteria included prior myocardial infarction, revascularization, valvular heart disease, and ethanol abuse.
Main Results:
- Eighteen patients (19.6%) had significant CAD (≥50% luminal narrowing) confirmed by catheterization.
- Thallium stress testing demonstrated high sensitivity (94.4%) and negative predictive value (97.9%) for significant CAD.
- Specificity was 63.5%, with a low false-negative rate of 2.1%.
Conclusions:
- Thallium stress testing, with or without dipyridamole, exhibits high sensitivity and negative predictive value in hypertensive patients with chest pain or ECG ischemia.
- These characteristics support its role as an effective exclusion test for significant epicardial CAD in this population.
- The findings aid in risk stratification and management decisions for hypertensive patients with suspected CAD.
Abstract:
The operating characteristics of thallium stress testing for detection of significant epicardial coronary artery disease (CAD) in hypertensive subjects with chest pain or electrocardiographic (ECG) ischemia have not been previously defined. This becomes important because of the high prevalence of both hypertensive heart disease and CAD. Ninety-two hypertensives with a history of typical or atypical chest pain or ECG myocardial ischemia underwent coronary arteriography, 2D-guided echocardiography, and thallium-201 stress testing, combined with intravenous dipyridamole if the rate-pressure product was less than 20,000. Patients with myocardial infarction, prior revascularization procedure, valvular heart disease, and chronic ethanol abuse were excluded. The mean age was 54.8 +/- 9.9 years with 55% blacks and 46% women. Eighteen patients (19.6%) had significant (greater than or equal to 50% luminal diameter narrowing) epicardial CAD at catheterization, of whom 17 had positive thallium scans. Overall, there were 17 true positives, 47 true negatives, 27 false positives, and one false negative resulting in 94.4 +/- 5.4% sensitivity (95% confidence limits [95% CL] 71 to 100%), 63.5 +/- 5.6% specificity (95% CL 51 to 74%), 38.6 +/- 7.3% positive predictive value (95% CL 25 to 54%), 97.9 +/- 2.1% negative predictive value (95% CL 88 to 100%), and 69.6 +/- 4.8% overall accuracy (95% CL 59 to 79%). For hypertensive patients with chest pain or ECG myocardial ischemia, the high sensitivity and negative predictive value and low false negative rate support the role of thallium stress testing +/- dipyridamole as an exclusion test for significant CAD.