Comparison of Metabolic and Vasoconstrictor Stimuli on Coronary Vascular Resistance in Man
Comparison of Metabolic and Vasoconstrictor Stimuli on Coronary Vascular Resistance in Man
复制标题
代谢刺激和血管收缩刺激对人体冠状血管阻力的比较
作者：
G. Mudge;S. Goldberg;S. Gunther;T. Mann;W. Grossman
冠状动脉血流量 (CBF) 被认为与代谢需求 (MVO) 成正比。然而，最近的研究报道了冠状动脉疾病（CAD）患者对α-肾上腺素能刺激的不适当的血管收缩反应。为了评估血管舒张储备和肾上腺素能血管收缩的相互作用，我们比较了 13 名对照患者和 14 名 CAD 患者在快速心房起搏代谢应激期间和皮肤冷（冷加压试验，CPT）的 α 肾上腺素能刺激期间冠状血管阻力 (CVR) 的变化。对照组和 CAD 患者的起搏心率相似，两组对 CPT 的高血压反应相似；因此，起搏和 CPT 均增加了 MVO2 的主要决定因素。与 MVO 增加相关，对照组和 CAD 患者的 CVR 随快速起搏而下降（分别为 -24% 和 -27%），但在 CPT 期间 CAD 患者的 CVR 增加（+24%）。 13 名 CAD 患者中，有 7 名的 CBF 实际上有所减少，而所有对照患者的 CBF 均因 CPT 的反应而增加。两名 CAD 患者在 CPT 期间 CBF 显着降低，排除左心室舒张压升高对壁内冠状血管的压迫作为 CVR 增加的致病机制。这些数据进一步证明 CAD 患者的冠状血管舒张机制可能有限。叠加的α-肾上腺素能介导的冠状血管收缩可能显着导致 CAD 患者的心肌缺血。
Coronary blood flow (CBF) is considered proportional to metabolic demand (MVO,). However, recent studies have reported inappropriate vasoconstrictor response to a-adrenergic stimulation in patients with coronary artery disease (CAD). To assess the interaction of vasodilatory reserve and adrenergic vasoconstriction, we compared changes in coronary vascular resistance (CVR) during the metabolic stress of rapid atrial pacing and during the a-adrenergic stimulus of cutaneous cold (cold pressor test, CPT) in 13 control patients and 14 patients with CAD. Similar heart rates were achieved with pacing in both control and CAD patients, and both groups had a similar hypertensive response to CPT; thus, both pacing and CPT increased major determinants of MVO2. In association with this increased MVO, CVR decreased with rapid pacing in control and CAD patients (-24% and -27%, respectively), but increased in CAD patients (+24%) during CPT. Seven of 13 CAD patients actually had a reduction in CBF, whereas CBF increased in all control patients in response to CPT. Compression of intramural coronary vessels by elevated left ventricular diastolic pressure was excluded as a pathogenic mechanism for increase in CVR in two CAD patients who showed marked reduction in CBF during CPT.These data are further evidence that patients with CAD may have limited coronary vasodilatory mechanisms. Superimposed a-adrenergically mediated coronary vasoconstriction may contribute significantly to myocardial ischemia in patients with CAD.