[Coronary reserve: a dynamic evaluation of coronary circulation].

Measuring the coronary reserve is a way of evaluating pathologies of the large coronary vessels as well as of coronary microcirculation. In man, measurement of the coronary sinus blood flow by the thermodilution method can be used to determine the increase in flow induced by selective injection of a contrast medium into the left coronary artery or by intravenous injection of dipyridamole. Such measurements have been performed in subjects with normal coronary blood flow and left ventricular function, in patients with cardiac or systemic diseases likely to alter coronary perfusion (e.g. atheromatous coronary disease, dilated cardiomyopathy, scleroderma, sarcoidosis) and in patients who had undergone heart transplantation. Flow and resistance reserves have been calculated from the maximal/basal coronary flows ratio and from the minimal/basal coronary resistance ratio. The results obtained provided information on the repercussions of coronary stenosis on myocardial perfusion and on alterations of coronary microcirculation in pathologies respecting the main coronary arteries. In addition, changes in coronary reserve induced by some pharmacological agents may be used to evaluate the effects of certain cardiovascular therapies.