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Determinants of abnormal blood pressure response to exercise in coronary artery disease
Insights
The extent of thallium perfusion defects, not the severity of coronary artery disease (CAD) or resting left ventricular dysfunction, predicts abnormal systolic blood pressure response during exercise in CAD patients.
Area of Science:
- Cardiology
- Nuclear Cardiology
- Exercise Physiology
Background:
- Abnormal systolic blood pressure (BP) response during exercise is common in patients with coronary artery disease (CAD).
- Understanding the determinants of this response is crucial for risk stratification and management in CAD patients.
Purpose of the Study:
- To identify the predictors of exercise-induced abnormal systolic blood pressure response in patients with documented CAD.
- To determine whether the extent of CAD, left ventricular dysfunction, or perfusion abnormalities best predicts hypotensive BP response.
Main Methods:
- 127 patients with documented CAD underwent exercise thallium-201 scintigraphy.
- Systolic BP response was categorized into three groups: increased >20 mm Hg, increased ≤20 mm Hg, or decreased ≥10 mm Hg.
- Clinical, angiographic, and scintigraphic data were analyzed using stepwise discriminant and multivariate analyses.
Main Results:
- Patients with a decreased or blunted systolic BP response (groups II and III) had significantly more thallium perfusion defects than those with a normal response (group I).
- Multivariate analysis identified the number of thallium perfusion defects as the sole significant predictor of a hypotensive BP response.
- Prior myocardial infarction, abnormal ejection fraction, and multivessel CAD were more prevalent in the abnormal BP response groups but were not independent predictors.
Conclusions:
- The functional significance of CAD, as indicated by the extent of thallium perfusion abnormalities, is the primary determinant of abnormal systolic BP response to exercise.
- Resting left ventricular dysfunction and the anatomical extent of CAD are less important predictors of exercise-induced BP abnormalities compared to perfusion defects.
Abstract:
This study assessed the determinants of exercise-induced abnormal systolic blood pressure (BP) response in 127 patients with documented coronary artery disease (CAD) who underwent exercise thallium-201 scintigraphy. Three types of systolic BP response to exercise were identified: an increase by more than 20 mm Hg (group I, n = 74); an increase by 20 mm Hg or less (group II, n = 36); and a decrease of at least 10 mm Hg (group III, n = 17). The 3 groups were not significantly different in age, gender or medications. The number of segments with perfusion defects was significantly higher in groups II and III than group I (group III, 2.9 +/- 1.5; group II, 2.9 +/- 2.1; and group I, 1.8 +/- 1.4, p = 0.009). Prior myocardial infarction, abnormal left ventricular ejection fraction, and multivessel CAD were more common in group III than in groups I and II. Stepwise discriminant analysis of 15 relevant clinical, angiographic and exercise scintigraphic descriptors showed that the number of thallium perfusion defects, abnormal LV ejection fraction at rest and multivessel CAD to be important predictors of hypotensive BP response. Multivariate analysis, however, showed that the number of thallium perfusion defects was the only important predictor of the hypotensive response. Thus, it is the functional significance of CAD assessed by the extent of thallium perfusion abnormalities rather than the extent of CAD or left ventricular dysfunction at rest that determines the systolic BP response to exercise.