Myocardial ischaemia in the hypertensive patient--the role of coronary microcirculation abnormalities.

Clinicians have long suspected that hypertrophied hearts have an inadequate coronary circulation. This clinical suspicion resulted from the observation that a large proportion of patients with left ventricular hypertrophy who have normal coronary arteriograms complain of angina and have ischaemia-like ST segment depression during effort. Hypertension is a known risk factor for the development of coronary artery disease and therefore the presence of angina in a patient with systemic hypertension is usually attributed to obstructive atherosclerotic coronary artery disease. However, angina may occur in hypertensive patients in the absence of coronary stenosis. A limitation of coronary flow reserve is responsible for signs and symptoms of myocardial ischaemia in many of these patients. This article will focus on the role of the coronary microcirculation in the genesis of ischaemia in patients with systemic hypertension who have no obstructive coronary artery disease. It will also briefly discuss other mechanisms potentially responsible for the angina syndrome in patients who have left ventricular hypertrophy but angiographically normal coronary arteries.