CORONARY BLOOD-FLOW AND MYOCARDIAL-ISCHEMIA IN HYPERTENSION

The aim of this investigation was to study the coronary pressure-flow relationship in 60 patients with chronic arterial hypertension of dive rse aetiologies and in 14 normotensive subjects (control group). The h ypertensive cohort included 6 patients with isolated systolic hyperten sion (ISH), 7 renovascular hypertensive patients with abnormally eleva ted angiotensin II plasma levels but without electrocardiographic and/ or echocardiographic evidence of left ventricular hypertrophy (LVH) an d 47 subjects with essential hypertension (EH), 21 of whom had LVH by electrocardiogram and/or echocardiogram. In the hypertensive cohort a Frank-Starling-like curve was found to describe the coronary pressure- flow relationship when the baseline values for coronary sinus blood fl ow (CBF, intravascular Doppler technique) were plotted against mean ao rtic pressure (intra-arterial blood pressure). In particular, the desc ending limb of such a curve represented a critical region where CBF wa s ''inappropriately'' low with respect to perfusion pressure. It was t hus concluded that this inability of the heart to adapt CBF to its nee ds might account for the higher propensity to develop myocardial ischa emia encountered in severe essential hypertensive subjects with concom itant LVH and renovascular hypertensive patients.