Coronary circulation in arterial hypertension

Area of Science:

• Cardiology
• Vascular Physiology
• Hypertension Research

Background:

• Arterial hypertension is a primary cause of congestive heart failure and a significant risk factor for coronary artery disease (CAD).
• Coronary reserve is often impaired in hypertensive individuals, even without diagnosed CAD.
• The underlying cause of this reduced coronary reserve (left ventricular hypertrophy vs. vascular alterations) requires investigation.

Purpose of the Study:

• To investigate whether reduced coronary reserve in hypertensive patients is linked to left ventricular hypertrophy (LVH) or primary vascular changes.
• To quantify coronary reserve and resistance in hypertensive patients with angina and normal coronary angiograms.
• To compare these parameters with those of normotensive individuals.

Main Methods:

• Coronary reserve was assessed in 31 hypertensive patients and 12 normotensive controls.
• Coronary resistance was measured before and after intravenous dipyridamole administration.
• Coronary blood flow was quantified using the argon gas chromatographic method; LV muscle mass was determined by ventriculography.

Main Results:

• Hypertensive patients exhibited 20% higher coronary resistance and 40% lower maximal coronary blood flow post-dipyridamole compared to controls.
• Minimal coronary resistance increased by 112% and coronary reserve was reduced by 37% in hypertensive subjects (p < 0.001).
• No significant correlation was found between impaired coronary reserve and left ventricular muscle mass (r = 0.024).

Conclusions:

• Hypertension significantly impairs coronary vasodilator reserve, independent of left ventricular hypertrophy.
• This impairment is characterized by increased coronary resistance and reduced maximal flow, contributing to myocardial ischemia.
• Findings suggest primary vascular alterations are responsible for reduced coronary reserve in hypertensive patients.