Lucarini A R, Picano E, Salvetti A
Clinica Medica I, University of Pisa, Italy.
Clin Exp Hypertens A. 1992;14(1-2):55-66. doi: 10.3109/10641969209036171.
Arterial hypertension can badly affect coronary circulation through several mechanisms that are not mutually exclusive, namely, coronary artery disease, left ventricular hypertrophy, and microvascular disease. Theoretical and experimental data suggest that coronary microvascular disease may exist in hypertensives, in whom it can cause both a reduction of coronary flow reserve and a shift to the right of the coronary flow autoregulation curve. To address this issue, we used dipyridamole- echocardiography test, which causes ischemic-like ST segment depression with no detectable changes in left ventricular function in different subsets of patients with microvascular disease (Syndrome X; Hypertrophic cardiomyopathy; acute heart rejection). We found that dipyridamole infusion can cause a similar pattern of response (i.e., echocardiographically silent ST segment depression) in mild-moderate essential hypertensives with normal epicardial coronary arteries, without left ventricular hypertrophy, with increased forearm minimal vascular resistances and with a reduced coronary reserve. This pattern of response identifies hypertensives with higher risk of ventricular arrhythmias, is amplified by acute reduction of diastolic blood pressure and can be reversed, together with the reduction of forearm vascular resistances by chronic antihypertensive treatment. Taken together these findings suggest that microvascular coronary disease can exist in hypertensives with two adverse consequences, consistent with the experimental background: the reduction of coronary flow reserve as well as a shift to the right of the coronary flow autoregulation curve.
动脉高血压可通过几种并非相互排斥的机制严重影响冠状动脉循环，即冠状动脉疾病、左心室肥厚和微血管疾病。理论和实验数据表明，高血压患者可能存在冠状动脉微血管疾病，它可导致冠状动脉血流储备降低以及冠状动脉血流自动调节曲线右移。为解决这一问题，我们使用了双嘧达莫超声心动图试验，该试验可使不同微血管疾病亚组（X综合征；肥厚型心肌病；急性心脏排斥反应）患者出现类似缺血性的ST段压低，而左心室功能无明显变化。我们发现，双嘧达莫静脉输注可使轻度至中度原发性高血压患者（无左心室肥厚、心外膜冠状动脉正常、前臂最小血管阻力增加且冠状动脉储备降低）出现类似的反应模式（即超声心动图显示无明显变化的ST段压低）。这种反应模式可识别出室性心律失常风险较高的高血压患者，急性舒张压降低可使其加剧，而慢性降压治疗可使其与前臂血管阻力降低一起逆转。综上所述，这些发现表明高血压患者可能存在冠状动脉微血管疾病，这会产生两个不良后果，与实验背景一致：冠状动脉血流储备降低以及冠状动脉血流自动调节曲线右移。
