Protective effect of high diastolic blood pressure during exercise against exercise-induced myocardial ischemia.

BACKGROUND: Hypertension is one of the risk factors for coronary artery disease. However, because most coronary blood flow to the left ventricle occurs during diastole, high diastolic blood pressure during exercise may have a protective effect against exercise-induced myocardial ischemia. The aim of the present study was to test this hypothesis. METHODS AND RESULTS: We identified 469 patients with sinus rhythm and known or suspected coronary artery disease who underwent exercise thallium-201 myocardial single-photon emission computed tomography and coronary arteriography. High diastolic blood pressure during exercise was defined as diastolic blood pressure at peak exercise > or = 90 mm Hg. There was no significant difference in medications, number of diseased vessels, or Gensini score between patients with high (n = 228) and normal (n = 241) diastolic blood pressure during exercise, whereas patients with high diastolic blood pressure during exercise exhibited a higher pressure-rate product during exercise than patients with normal diastolic blood pressure during exercise. The reversibility score on thallium-201 myocardial scan was significantly smaller in patients with high diastolic blood pressure during exercise than in patients with normal diastolic blood pressure during exercise (P = .021). CONCLUSIONS: High diastolic blood pressure during exercise has a potential protective effect against exercise-induced ischemia, although the mechanism of such effects remains to be determined.