Mechanism of angina pectoris in patients with systemic hypertension and normal epicardial coronary arteries by arteriogram

Abstract

Patients with arterial hypertension frequently have angina pectoris despite a normal coronary angiogram. This angina pectoris syndrome often goes along with an impaired coronary vasodilator reserve. The aim of the study was to find out whether an impaired coronary flow reserve is associated with electrographic signs of transient myocardial ischemia. Forty-three hypertensive patients not taking cardiovascular medication were studied with 24-hour Holter monitoring. Coronary blood flow and resistance were measured before and after intravenous administration of dipyridamole (0.5 mg/kg body weight). Coronary reserve was determined as the relation of coronary resistance before and after dipyridamole. For control purposes 9 normotensive subjects were studied with the same protocol. Hypertensive patients with ST-segment depressions (n = 31) had a significantly impaired coronary reserve (2.3 ± 0.5) compared with normotensive subjects (4.9 ± 1.0, p <0.01). Coronary reserve in hypertensive patients without ST-segment depressions was only slightly impaired (4.0 ± 1.8). Arterial pressure and left ventricular mass did not differ between hypertensive patients with and without ST-segment depressions. Left ventricular mass had no effect on coronary reserve. It is concluded that neither left ventricular hypertrophy nor arterial pressure were determinants for ST-segment depressions. Consequently primary functional and structural alterations on the level of the microcirculation appear to be responsible for the occurrence of transient ischemic episodes in the Hotter electrocardiogram.