Effects of Dipyridamole on Anastomotic Blood Flow in Experimental Myocardial Infarction

Rees, John; Redding, V. J.

doi:10.1093/cvr/1.2.179

Cited by 19 publications

(8 citation statements)

References 2 publications

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“…The clearance of radioactivity from the ischaemic muscle was measured with a collimator having a narrow angle of acceptance. Full details of this method of assessing infarct blood flow are outlined by Rees & Redding (1967) and by Marshall et al (1973). The experimental model used in this study thus allows simultaneous assessments to be made of blood flow in essentially normal regions of the left ventricular wall (left circumflex flow), of infarct blood flow ('33xenon clearance and arterial backflow) and of oxygen extraction and consumption in both normal areas of the ventricular wall (coronary sinus sampling) and in the ischaemic area (coronary venous sampling).…”

Section: Methodsmentioning

confidence: 99%

The effects of dipyridamole on blood flow and oxygen handling in the acutely ischaemic and normal canine myocardium

Marshall

Parratt

1973

British J Pharmacology

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Summary1. The effects of the intravenous administration of dipyridamole (0 25 mg/kg) were examined in a canine preparation that enabled simultaneous measurements to be made of blood flow in ischaemic and in essentially normal areas of the myocardium and also of oxygen handling (availability, consumption and extraction) in both these regions. 2. When administered to dogs anaesthetized with trichlorethylene 2-3 h after acute ligation of the descending branch of the left coronary artery, dipyridamole markedly increased blood flow in essentially normal regions (left circumflex flow) but failed to increase flow in the area supplied by the ligated vessel (measured by "xenon clearance and by retrograde flow). In five of the six animals definite decreases in flow ('stealing') were observed in the ischaemic region. These flow changes were related to the decreased trans-ventricular perfusion pressure (diastolic peripheral coronary pressure minus left ventricular end-diastolic pressure) and were accompanied by electrocardiographic evidence of increasingly severe myocardial ischaemia. The results support the suggestion that only increasing the perfusion gradient will usefully improve blood flow (and hence oxygen availability) to the acutely ischaemic myocardium. 3. Despite these effects on ischaemic muscle blood flow, the oxygen tension of the blood draining the infarcting muscle was markedly elevated. The conclusion is drawn that dipyridamole decreases the efficiency of the myocardial circulation by opening up vessels that do not take part in tissue exchange.

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Section: Methodsmentioning

confidence: 99%

The effects of dipyridamole on blood flow and oxygen handling in the acutely ischaemic and normal canine myocardium

Marshall

Parratt

1973

British J Pharmacology

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“…However, in the latter situation, increased flow may merely be going to myocardial regions fed by normal vessels rather than areas supplied by obstructed vessels. While some investigators have found that vasodilators increase flow to compromised myocardium (2)(3)(4)(5)(6)(7)(8), others have found a decrease or no change (9)(10)(11)(12)(13)(14). Fam and McGregor (11) have pointed out that these discrepancies may be related in part to differences in action among the various coronary dilators.…”

Section: Introductionmentioning

confidence: 99%

“…injection of 1 mg/kg dipyridamole. After 10 min 51Cr (7)(8)(9)(10) ,tm) spheres were injected and epicardial electrocardiograms repeated. Mean aortic pressure was adjusted to control levels with i.v.…”

Section: Introductionmentioning

confidence: 99%

Effect of nitroglycerin and dipyridamole on regional left ventricular blood flow during coronary artery occlusion.

Becker

1976

J. Clin. Invest.

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A B S T R A C T Coronary vasodilators have been vari-ously reported to increase, decrease, or have no effect upon blood flow to ischemic myocardium. Consequently, the effects of two different types of dilators, nitroglycerin (TNG) and dipyridamole, were studied with radioactive microspheres in open-chested dogs after coronary artery ligation. Given as a bolus i.v. injection, 0.4 mg TNG resulted in an increase in blood flow to nonischemic areas of myocardium and a preservation of flow to ischemic regions, despite a fall in blood pressure. 5 min later blood pressure and nonischemic flow were back to base line, and a small selective increase in flow to ischemic myocardium was found (0.15-0.18 ml/min per g, P < 0.05). During an 0.2 mg/min infusion of TNG, and also after 1 mg/kg i.v. dipyridamole, ischemic flow was maintained in the face of a 20-30%o reduction in blood pressure. In this setting, nonischemic flow was unchanged during TNG and doubled after dipyridamole. With the addition of methoxamine in both dilator groups, blood pressure retumed to base line while flow to ischemic areas increased above base-line values (TNG, 0.16-0.20 ml/min per g, P < 0.01; dipyridamole, 0.18-0.31 ml/min per g, P < 0.05). Epicardial ST segment elevations increased during TNG infusion and were unchanged after dipyridamole, but with addition of methoxamine, ST segments became less elevated in both drug groups, concomitant with the observed increase in collateral blood flow. These data indicate thaA both types of coronary vasodilators, when used in conjunction with methoxamine to support blood pressure, reduce collateral resistance, increase collateral flow, and reduce epicardial ST-segment elevations.

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“…Previous experimental investigations (1,2) have demonstrated in canine hearts the alterations in coronary hemodynamics which follow acute and chronic coronary arterial constriction. These studies indicate the collateral circulation is capable of restoring flow to normal distal to coronary arterial obstructions.…”

Section: Introductionmentioning

confidence: 99%

Myocardial Blood Flow in Man: Effects of Coronary Collateral Circulation and Coronary Artery Bypass Surgery

Smith¹,

Gorlin²,

Herman³

et al. 1972

J. Clin. Invest.

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A B S T R A C T The effects of coronary artery bypass graft (CAB) and coronary collaterals (CC) even with CAB occluded. Vessels with greater than 80% stenosis or total occlusion by angiography had significant pressure gradients with marked reduction of postobstructive MBF. No significant difference in postobstructive MBF was found when vessels with CC (21±4 ml/min per 100 g) were compared to those without CC (17+4 ml/min per 100 g) (P > 0.4).These studies demonstrate that (a) mean MBF increased 268% after CAB, (b) heterogeneous MBF persisted after CAB, (c) CC were not associated with significant increases in MUBF, and (d) vessels with less than 80% stenosis had less than 20 mm Hg gradient with minimal effect on resting MBF.

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Effects of Dipyridamole on Anastomotic Blood Flow in Experimental Myocardial Infarction

Cited by 19 publications

References 2 publications

The effects of dipyridamole on blood flow and oxygen handling in the acutely ischaemic and normal canine myocardium

The effects of dipyridamole on blood flow and oxygen handling in the acutely ischaemic and normal canine myocardium

Effect of nitroglycerin and dipyridamole on regional left ventricular blood flow during coronary artery occlusion.

Myocardial Blood Flow in Man: Effects of Coronary Collateral Circulation and Coronary Artery Bypass Surgery

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