Coronary microangiopathy and cardiac hypertrophy

Area of Science:

• Cardiology
• Vascular Biology
• Hypertension Research

Background:

• Coronary vasodilator reserve is frequently impaired in hypertensive patients, even without coronary heart disease.
• The cause of reduced coronary reserve in hypertension—whether left ventricular hypertrophy or primary vascular changes—remains unclear.

Purpose of the Study:

• To investigate whether impaired coronary reserve in hypertensive patients is due to left ventricular hypertrophy or primary vascular alterations.
• To quantify coronary reserve and its relationship with left ventricular muscle mass and diastolic wall stress in hypertension.

Main Methods:

• Coronary reserve was assessed in 54 hypertensive patients with angina and normal coronary arteries, and 12 normotensive controls.
• Coronary blood flow was measured using the argon gas chromatographic method.
• Coronary resistance was determined before and after dipyridamole administration; left ventricular muscle mass was assessed via ventriculography.

Main Results:

• Hypertensive patients exhibited a 124% increase in minimal coronary resistance and a 38% reduction in coronary reserve compared to controls.
• No significant correlation was found between coronary reserve, minimal coronary resistance, and left ventricular muscle mass or diastolic wall stress.
• Myocardial oxygen consumption and resting coronary flow did not differ between hypertensive and normotensive groups.

Conclusions:

• Reduced coronary vasodilator reserve in hypertensive patients is not directly related to the degree of left ventricular hypertrophy.
• The findings suggest that primary microvascular lesions, independent of left ventricular hypertrophy, are responsible for impaired coronary reserve in hypertension.