Hyperemic response of the coronary circulation to brief diastolic occlusion in the conscious dog.

Schwartz, Gregory G.; McHale, Philip A.; Greenfield, Joseph C.

doi:10.1161/01.res.50.1.28

Cited by 28 publications

(10 citation statements)

References 21 publications

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“…Tension-time index was calculated from the left ventricular pressure tracing, and stroke volume was obtained from numerical integration of the phasic aortic flow waveform. The coronary perfusion pressure has been shown to correspond closely to the aortic pressure for the purpose of these calculations (21). The five beats immediately preceding each intervention were analyzed and averaged to provide the control hemodynamic parameters for the intervention.…”

Section: Discussionmentioning

confidence: 99%

Demonstration of coronary artery myogenic vasoconstriction in the awake dog

et al. 1987

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The aim of this study was to determine whether or not coronary vasoconstriction occurs in response to a transient increase in coronary perfusion pressure. Eleven awake dogs with formalin-induced heart block, chronically instrumented with aortic and left ventricular catheters and left circumflex coronary and aortic electromagnetic flowprobes, were studied at a paced heart rate of 60 beats/min. A transient increase in aortic diastolic pressure of 17.3 +/- 1.5% for 330 +/- 20 ms and of 33.6 +/- 2.2% for 520 +/- 20 ms, via the inflation of an intra-aortic balloon, resulted in an increase in diastolic coronary vascular resistance index in the first response beat of 6 +/- 1% and 11 +/- 1%, respectively. An identical increase in diastolic coronary flow produced by the omission of a single paced beat resulted in no significant change in diastolic coronary vascular resistance index in the first response beat. Thus, the increase in diastolic coronary vascular resistance index following diastolic pressure augmentation is related to the increase in aortic diastolic pressure and not to the increase in diastolic coronary flow. These data are consistent with that of a brief myogenic response.

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Section: Discussionmentioning

confidence: 99%

Demonstration of coronary artery myogenic vasoconstriction in the awake dog

et al. 1987

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“…The following hemodynamic parameters were calculated for each cardiac cycle: mean aortic systolic and diastolic pressure, mean systolic and diastolic coronary blood flow and diastolic coronary vascular resistance index (mean aortic diastolic pressure divided by mean diastolic coronary flow). The coronary perfusion pressure has been shown to correspond closely to the aortic pressure for the purpose of these calculations (18). Data from at least 5 beats prior to each intervention were analyzed to provide baseline hemodynamie parameters.…”

Section: Discussionmentioning

confidence: 99%

“…Previous studies in our laboratory have shown that a 400-msec diastolic coronary artery occlusion results in a reactive hyperemic response lasting for several beats (18). Similarly, the increased cardiac demand following a single ventricular electrical extra-activation leads to a brief increase in coronary blood flow which cannot be explained by the transient increase in coronary perfusion pressure that accompanies the potentiation of ventricular contractility (19).…”

Section: Introductionmentioning

confidence: 94%

“…The pneumatic occluder was connected through an automatic solenoid-activated valve, to either a source of compressed helium during inflation or to a vacuum during deflation. The signal to inflate the occluder could be activated either manually (for 10-see occlusions) or triggered by the R-wave of the ECG (for 400-msec diastolic occlusions) (18).…”

Section: Experimental Protocolmentioning

confidence: 99%

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Functional and reactive hyperemia are unaltered by homocysteine in conscious dogs

et al. 1985

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The purpose of this study was to test the hypothesis that L-homocysteine thiolactone (L-HCTL), through its reaction with adenosine to form S-adenosylhomocysteine, may modulate myocardial functional and reactive hyperemic responses. Reactive hyperemic responses to 10-sec occlusions or 400-msec diastolic occlusions of the circumflex coronary artery and functional hyperemic responses to ventricular extra-activations were studied in a chronic heart-blocked dog preparation during a control period and following L-HCTL (40 mg/kg). In two additional dogs multiple venous blood samples and left ventricular myocardial biopsies were obtained following L-HCTL to measure changes in plasma homocysteine and tissue S-adenosylhomocysteine. Despite a 75-fold increase in peak plasma homocysteine and a 26-fold increase in tissue S-adenosylhomocysteine, L-HCTL did not alter myocardial functional and reactive hyperemic responses. The rapid increase in myocardial S-adenosylhomocysteine confirmed cellular entry of homocysteine and its reaction with endogenous adenosine. The failure of L-HCTL to alter functional and reactive hyperemic responses suggests that either such treatment does not affect myocardial release of adenosine or that adenosine is not an important regulator of coronary flow.

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“…All substances were administered by injection by the same person throughout the study, and the injection rate was 2 ml/sec. In group A, the following injections were given: 6 ml arterial blood (drawn from the coronary artery catheter), 6 ml coronary venous blood (obtained via the coronary sinus catheter), 3 and 6 ml isotonic saline, 3 and 6 ml hypertonic glucose (30% solution, which corresponds to 1400 mOsm/kg), and 6 ml sodium metrizoate (Isopaque Coronar 370, Nyegaard & Co A/S), which is an ionic contrast medium with calcium added and with an osmolality of 2100 mOsm/kg.…”

mentioning

confidence: 99%

Factors that modify the flow response to intracoronary injections.

Emanuelsson¹,

Holmberg²,

Selin³

et al. 1985

Circulation

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Coronary sinus flow (CSF) was measured in seven patients with normal coronary arteries (group A) during intracoronary injections of 6 ml arterial blood, 6 ml blood from the coronary sinus, 3 and 6 ml isotonic saline, 3 and 6 ml hypertonic glucose, and 6 ml of a contrast agent (sodium metrizoate). In 10 patients with coronary artery disease (group B), CSF was measured after administration of 6 ml isotonic saline, 6 ml sodium metrizoate, and 6 ml of another contrast medium (iohexol). In group A, arterial blood did not affect CSF, while coronary sinus blood induced a 33% increase. After 6 ml isotonic saline, there was a 35% increase in flow and after hypertonic glucose an increase of 70%. Metrizoate induced a rise in flow of 109%. In group B, the increase in CSF after intracoronary injection of saline, metrizoate, and iohexol was 30%, 83%, and 67%, respectively. Blood from the coronary sinus, in contrast to arterial blood, induced a marked rise in peak flow, suggesting a role for reactive hyperemia secondary to myocardial hypoxia in this response. A similar mechanism might have been operative after injection of isotonic saline, as well as after the hyperosmolar contrast agents. However, additional mechanisms mediated by the high osmotic pressure of these substances, such as induction of the Bezold-Jarisch reflex, which will induce coronary vasodilation, may have played a role. Finally, when hyperosmolar agents are used, the possibility of some direct vasodilating properties of the agents cannot be excluded. Circulation 72, No. 2, 287-291, 1985 Material and methodsPatients. Seventeen patients who had been admitted to the hospital for coronary angiographic examination due to anginalike chest pain were investigated. Seven patients (group A) had angiographically normal coronary arteries. Two were women and five men, and their median age was 57 years (range 39 to 62). Group B consisted of 10 patients, all of whom proved to have significant coronary artery disease with narrowing of at least one vessel of more than 70%. There were two female and eight male patients in this group and their median age 57 years (range 48 to 62). No

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Hyperemic response of the coronary circulation to brief diastolic occlusion in the conscious dog.

Cited by 28 publications

References 21 publications

Demonstration of coronary artery myogenic vasoconstriction in the awake dog

Demonstration of coronary artery myogenic vasoconstriction in the awake dog

Functional and reactive hyperemia are unaltered by homocysteine in conscious dogs

Factors that modify the flow response to intracoronary injections.

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