| Budget Amount *help |
¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 1987: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1986: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1985: ¥900,000 (Direct Cost: ¥900,000)
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| Research Abstract |
I. Experimental study:
The subendocardium is known to be the most vulnerable ergion of the heart to ischemic or hypoxic injury. The purpose of this study was to examine and compare the changes of 1) myocardial tissue oxygen tension(PO2, mmHg) and 2) regional blood flow (BF, ml/100g/min) by direct online measurement from the living myocardium during induced hypotension with nitroglycerine (NTG),isoflurane (ISO) or adenosine triphosphate (ATP). In normal heart, during drug induced graded hypotension, epicardial layer perfusion and metabolic activity were relatively well maintained. Endocardial layer PO2 was most affected and disturbed which was accompanied by various degrees of BF changes: NTG causing the most, and ATP the least changes. Thus, we conclude that although NTG is considered a good myocardial vasodilator, this is not necessarily so during hypotension.
With ATP, both myocardial BF and PO2 values were maintained well above 80% of control in all stages of hypotension.
II. Clinical study:
ATP, prostaglandin E1 and nitroglycerine are known to be potent and extremely short acting vasodilators, producing transient but profound hypotension. For this reason, these. agents have been particularly suited for short time surgical procedures which require rapid control of blood pressure. When hypotension is needed for long periods, the large doses of vasodilators may be required.
In this study, we found that dipyridamode reduced the ATP dose requirement to 1/10 to 1/15 to attain the same BP reduction. ATP/Dipyridamole showedvery favorable effects on both cardiovascular (includes coronary artery) and metabolic parameters during and after prolonged infusion (>4 hrs) in man. No deleterious or adverse changes were detected in neither blood nor ruine. Thus, the ATP/Dipyridamole combination can be more safely used chinically than prostaglandin E1 or nitroglycerine.
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