Coronary vasodilator reserve in untreated and treated hypertensove patients with and without left ventricular hypertrophy

Abstract

Objectives. This study was initiated to compare the coronary reserve in treated hypertensive ptients with and without left ventricular hypertrophy with that in untreated patients.Background. Coronary reserve is impaired in hypertensive patients with left ventricular hypertrophy and normal coronary arteries. Moreover, basal coronary resistance is elevated in hypertensive patients without left ventricular hypertrophy.Methods. Coronary reserve was measured with a coronary Doppler catheter before and after a maximally vasodilating dose of intracoronary papaverine (peak/rest flow velocity ratio) in 16 control subjects and 37 hypertensive ptients with normal epicardial coronary arteries. Among 20 untreated hypertensive patients, myocardial mass was increased in 11 (group 2a) and normal in 9 (group 2b). Seventeen patients had been treated effectively for at least 1 year; nine (group 3a) had persistent left ventricular hypertrophy, and eight (group 3b) had no left ventricular hypertrophy before treatment. Left ventricular volumes and ejection fraction were normal in all groups.Results. Coronary reserve was moderately reduced in group 2b (3.1 ± 0.6 vs. 5.2 ± 0.8 in control subjects, p < 0.001) and markedly diminished in groups 2a and 3a (2.5 ± 0.5 and 2.7 ± 0.4, respectively; all p < 0.001 vs. control subjects). In group 3b, coronary reserve was comparable to that of control subjects (5.1 ± 1.4).Conclusions. The reduction in coronary reserve observed in untreated hypertensive patients with normal myocardial mass suggests that structural abnormalities of the coronary microvasculature may occur before left ventricular hypertrophy. Treated patients with normal mass before treatment had a coronary reserve comparable to that of normotenstve control subjects, whereas normalization of arterial pressure with persistent left ventricular hypertrophy was associated with a marked impairment of coronary reserve.