PRESENCE OF CARDIOVASCULAR STRUCTURAL-CHANGES IN ESSENTIAL HYPERTENSIVE PATIENTS WITH CORONARY MICROVASCULAR DISEASE AND EFFECTS OF LONG-TERM TREATMENT

In asymptomatic essential hypertensive patients with angiographically normal coronary arteries and without left ventricular hypertrophy, dip yridamole-induced ischemic-like ST segment depression may be a marker of coronary microvascular disease. In this study we evaluated, first, whether this cardiac abnormality is linked to structural or functional vascular abnormalities, and second, the effect of antihypertensive tr eatment by 12-month administration of the angiotensin converting enzym e (ACE) inhibitor captopril (50 mg twice a day orally). In essential h ypertensives with dipypridamole echocardiography stress test (DET) (DE T+, n = 8) and without (DET-, n = 8) ST segment depression greater tha n 0.1 mV during intravenous dipyridamole infusion (0.84 mg/kg over 10 min), we studied the forearm blood now (FBF, venous plethysmography, m L/100) modifications induced by intrabrachial acetylcholine (Ach) (0.1 5, 0.45, 1.5, 4.5, 15 mu g/100 mL/min X 5 min each), an endothelium-de pendent vasodilator, and by sodium nitroprusside (SNP) (1, 2, 4 mu g/1 00 mL/min X 5 min each), a smooth muscle cell relaxant compound. Minim al forearm vascular resistances (MFVR), an index of arteriolar structu ral changes, were also calculated. Both Ach and SNP caused greater vas odilation in DET- as compared to DET+ while MFVRs were lower in DET- c ompared to DET+. After treatment, both DET+ and DET-patients showed a significant and similar reduction in blood pressure and left ventricul ar mass index, while vasodilation to acetylcholine and sodium nitropru sside was increased only in the DET+ group. In addition, forearm minim al vascular resistances were significantly reduced only in DET+ patien ts, who showed disappearance of dipyridamole-induced ischemic-like ST segment depression. In conclusion, these data confirm that essential h ypertensive patients with microvascular coronary disease are character ized by the presence of structural changes in the forearm vascular bed . Our results also indicate that both cardiac and forearm vascular abn ormalities can be reversed by antihypertensive treatment with an ACE i nhibitor.