RESUMEN
Hypertension and insulin resistance are associated with reduced coronary vasodilatory capacity, possibly caused by structural changes in the coronary resistance vessels. The goal of this study was to compare the effect of an angiotensin receptor blocker (ARB) with that of a calcium channel blocker (CCB) on coronary flow reserve and insulin resistance among essential hypertensive patients without left ventricular hypertrophy. A total of 40 consecutive essential hypertensive patients were randomized to daily 40 mg telmisartan or 20 mg nifedipine coat-core treatment. Coronary flow velocity reserve (CFVR) measurement using transthoracic Doppler echocardiography and blood tests were performed before and after 12 weeks of treatment. At baseline, blood pressure, CFVR, and homeostasis model assessment of insulin resistance (HOMA-IR) were not significantly different between the two groups. At the end of the treatment period, the telmisartan and nifedipine groups exhibited similar declines in blood pressure. CFVR was improved in the telmisartan group (2.4+/-0.4 to 2.9+/-0.4; p<0.01), but there was no difference in the nifedipine group (2.5+/-0.3 to 2.5+/-0.3; n.s.). HOMA-IR was improved in the telmisartan group (3.1+/-1.1 to 1.6+/-0.7; p<0.01), but there was no difference in the nifedipine group (2.8+/-1.1 to 2.4+/-0.7; n.s.). In conclusion, this study demonstrates that antihypertensive therapy with telmisartan, but not nifedipine, has a beneficial effect on coronary microcirculation and insulin resistance among essential hypertensive patients.