Buus N H, Bøttcher M, Bøttker H E, Sørensen K E, Nielsen T T, Mulvany M J
Department of Pharmacology, Aarhus University, PET Centre, Aarhus University Hospital, Denmark.
Am J Cardiol. 1999 Jan 15;83(2):149-54. doi: 10.1016/s0002-9149(98)00815-7.
The combination of angina pectoris, angiographically normal epicardial coronary arteries, and a positive exercise test is referred to as syndrome X. Previous studies have demonstrated an impaired coronary flow reserve and a peripheral vascular dysfunction, suggesting that vascular abnormalities in syndrome X may not be confined to the heart. The aim of this study was to investigate whether any vascular disorder of syndrome X is due to intrinsic structural or functional disturbances in resistance arteries. We compared 16 patients with syndrome X (56.6+/-1.2 years, 3 men) with 15 matched control subjects. Myocardial blood flow was measured with 13N-ammonia positron emission tomography. Forearm blood flow was measured in the brachial artery with high-resolution ultrasound. Gluteal subcutaneous resistance arteries were dissected and mounted on a myograph for measurement of active tension development, lumen diameter, and media thickness. Baseline myocardial blood flow was similar in patients and controls, but dipyridamole-induced hyperemia was decreased in patients (1.67+/-0.13 vs 2.31+/-0.12 ml/ min/g, p <0.01). Patients and controls had similar baseline forearm blood flow, but hyperemic flow after transient occlusion of the brachial artery was impaired in patients (198+/-20 vs 273+/-32 ml/min, p <0.05). Isolated resistance arteries showed no differences in constriction to noradrenaline, or relaxation to acetylcholine, dipyridamole, or nitroglycerin. Furthermore, the ratio between media thickness and lumen diameter were similar in syndrome X patients and controls. Our data show that when compared with a well-matched control group, syndrome X patients have a decreased coronary and peripheral vasodilator capacity. However, this is not reflected by functional abnormalities or structural changes as evaluated in subcutaneous resistance arteries. We conclude that syndrome X is not a generalized intrinsic abnormality of the resistance circulation.
心绞痛、冠状动脉造影显示心外膜冠状动脉正常以及运动试验阳性同时出现被称为X综合征。既往研究已证实冠状动脉血流储备受损和外周血管功能障碍，提示X综合征中的血管异常可能并不局限于心脏。本研究的目的是调查X综合征的任何血管紊乱是否归因于阻力动脉内在的结构或功能障碍。我们将16例X综合征患者（年龄56.6±1.2岁，男性3例）与15例匹配的对照者进行了比较。用13N-氨正电子发射断层扫描测量心肌血流量。用高分辨率超声在肱动脉测量前臂血流量。解剖臀皮下阻力动脉并安装在肌动描记器上以测量主动张力发展、管腔直径和中膜厚度。患者和对照者的基础心肌血流量相似，但患者双嘧达莫诱导的充血减少（1.67±0.13 vs 2.31±0.12 ml/min/g，p<0.01）。患者和对照者的基础前臂血流量相似，但患者肱动脉短暂闭塞后的充血流量受损（198±20 vs 273±32 ml/min，p<0.05）。分离的阻力动脉对去甲肾上腺素的收缩或对乙酰胆碱、双嘧达莫或硝酸甘油的舒张无差异。此外，X综合征患者和对照者的中膜厚度与管腔直径之比相似。我们的数据显示与匹配良好的对照组相比，X综合征患者的冠状动脉和外周血管扩张能力降低。然而，皮下阻力动脉评估的功能异常或结构变化并未反映这一点。我们得出结论，X综合征不是阻力循环的全身性内在异常。
