虚血性心疾患の診断における dipyridamole 負荷試験の有用性に関する臨床的並びに基礎的研究

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This study was undertaken to examine the diagnostic significance of dipyridamole ([D]) test in patients with ischemic heart disease and the pathophysiological mechanism responsible for [D]-induced myocardial ischemia. In 31 patients with angina pectoris, [D] 0.5-0.65 mg/kg was injected intravenously under the monitor of heart rate (HR). blood pressure (BP) and 12-lead ECG. The sensitivity and specificity of [D] test to provoke anginal attacks were examined and compared with those of treadmill exercise test. [D] produced trivial reduction in BP and increase in HR by 20-25%. In patients 'with positive [D] test, the threshold of pressure-rate product to provoke attacks by [D] test reached only 70% value of treadmill test. [D] test was more specific than treadmill test for detection of fixed coronary stenosis, although it was less sensitive. The ischemic response to [D] test was not likely to be related to the number of stenotic vessels, prior myocardial infarction or development of collateral circulation. On the other hand, the response to [D] test was closely related to the severity of coronary stenosis, i.e., the severer the degree of coronary stenosis was, the higher the ratio of positive to negative results was. These observations suggest that [D]-induced anginal attack may result from the transmural blood flow redistribution distal to the severe coronary stenosis. Experimental study was designed to examine whether vasodilatory stimuli can alter coronary hemodynamics and lead to mypcardial ischemia in the presence of high-grade coronary stenosis. In anesthetized open chest dogs, coronary blood flow(CBF) of the left circumflex artery (LCx), its distal perfusion pressure (DCPP), HR and aortic pressure were monitored and regional myocardial ischemia was estimated from ST segment deviation in the epicardial and intramyocardial electrograms. During severe LCx constriction intracoronary administrations of adenosine (0.01mg/kg/min) and dipyridamole (0.05mg/kg), potent coronary dilating agents, failed to augment CBF and induced further reduction in DCPP without any changes in systemic hemodynamics. In parallel with these hemodynamic changes, significant ST elevation was observed in the inner layer of compromised myocardium. These results reveal that subepicardial vasodilation following arteriolar dilating agents can induce flow redistribution across the ventricular wall and subendocardial ischemia in the presence of severe coronary steosis.
神戸大学の論文

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川嶋成乃亮
神戸大学医学部内科学第一講座

虚血性心疾患の診断における dipyridamole 負荷試験の有用性に関する臨床的並びに基礎的研究

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