Hess O M, Büchi M, Kirkeeide R, Niederer P, Anliker M, Gould K L, Krayenbühl H P
Department of Internal Medicine, University Hospital, Zürich, Switzerland.
Eur Heart J. 1990 Apr;11 Suppl B:58-64. doi: 10.1093/eurheartj/11.suppl_b.58.
Coronary vasomotion plays an important role in the regulation of coronary perfusion at rest and during exercise. Normal coronary arteries show coronary vasodilation of the proximal (+20%) and distal (+40%) vessel segments during supine bicycle exercise. However, patients with coronary artery disease show exercise-induced vasoconstriction of the stenotic vessel segments. The exact mechanism of exercise-induced stenosis narrowing is not clear but might be related to a passive collapse of the disease-free vessel wall (Venturi mechanism), elevated plasma levels of circulating catecholamines, an insufficient production of the endothelium-derived vasorelaxing factor or increased platelet aggregation due to turbulent blood flow with release of thromboxane A2 and serotonin. Various vasoactive drugs, such as nitroglycerin and calcium antagonists, prevent exercise-induced stenosis vasoconstriction. An additive effect on coronary vasodilation of the stenotic vessel segment was observed after combination of nitroglycerin with diltiazem. Thus, exercise-induced stenosis narrowing plays an important role in the pathophysiology of myocardial ischaemia during dynamic exercise. The antianginal effect of vasoactive substances can be explained--besides the effect on pre- and afterload--by a direct action on coronary stenosis vasomotion.
冠状动脉舒缩运动在静息及运动时冠状动脉灌注调节中起重要作用。正常冠状动脉在仰卧位自行车运动时，近端血管节段（+20%）和远端血管节段（+40%）会出现冠状动脉扩张。然而，冠心病患者在运动时狭窄血管节段会出现血管收缩。运动诱发狭窄变窄的确切机制尚不清楚，但可能与无病变血管壁的被动塌陷（文丘里效应）、循环儿茶酚胺血浆水平升高、内皮源性血管舒张因子产生不足或因血流紊乱导致血小板聚集增加并释放血栓素A2和5-羟色胺有关。各种血管活性药物，如硝酸甘油和钙拮抗剂，可预防运动诱发的狭窄血管收缩。硝酸甘油与地尔硫䓬联合应用后，观察到对狭窄血管节段的冠状动脉扩张有相加作用。因此，运动诱发的狭窄变窄在动态运动时心肌缺血的病理生理学中起重要作用。血管活性物质的抗心绞痛作用，除了对前负荷和后负荷的作用外，还可通过对冠状动脉狭窄舒缩运动的直接作用来解释。
