What is the clinical evidence from this study?

Study design: Other. Population: Myocardial ischemia and reperfusion. Intervention: Coronary artery occlusion and reperfusion vs. Control conditions (pre-ischemia). Primary outcome: Coronary artery diameter and coronary blood flow responses to acetylcholine and glyceryl trinitrate (p=<0.05).

What question did this study set out to answer?

To determine whether large coronary artery reactivity and coronary blood flow responsiveness in vivo are altered following transient coronary artery occlusion and reperfusion.

May 1, 1990Coronary Artery Disease

Impaired vasodilatation of epicardial coronary arteries and resistance vessels following myocardial ischemia and reperfusion in anesthetized dogs

Q: What are the key findings of this study?

Coronary artery occlusion and reperfusion significantly attenuated endothelium-dependent and -independent dilatation of large coronary arteries and resistance vessels in vivo (P<0.05).

Q: What question did this study set out to answer?

To determine whether large coronary artery reactivity and coronary blood flow responsiveness in vivo are altered following transient coronary artery occlusion and reperfusion.

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Key result

Coronary artery occlusion and reperfusion significantly attenuated endothelium-dependent and -independent dilatation of large coronary arteries and resistance vessels in vivo (P<0.05).

Why the study?

Does myocardial ischemia and reperfusion impair vasodilatation of epicardial coronary arteries and resistance vessels in anesthetized dogs?

Population

Anesthetized, open-chest dogs

Comparison

60 minutes of left circumflex coronary artery… vs Control conditions prior to coronary artery…

Design

Preclinical

Follow-up

30 minutes of reperfusion

Authors

CSChristopher G. SobeyBaker Heart and Diabetes Institute GDGregory J. DustingCentre for Eye Research Australia HGHoward GrossmanThe University of Melbourne

Discussion

Member takes

Implication

Ischemia-reperfusion impairs coronary vasodilation beyond endothelial mechanisms in vivo; hypothesis-generating for post-MI vasomotor dysfunction in patients.

Key Points

To determine whether large coronary artery reactivity and coronary blood flow responsiveness in vivo are altered following transient coronary artery occlusion and reperfusion.
Measured left circumflex coronary artery diameter, coronary blood flow, systemic arterial pressure, and heart rate in anesthetized, open-chest dogs exposed to 60 minutes of occlusion and 30 minutes of reperfusion.
Assessed in vivo vascular responses to intracoronary acetylcholine and glyceryl trinitrate alongside ultrastructural electron microscopy and in vitro isolated arterial ring relaxation assays.
Ischemia and reperfusion significantly attenuated in vivo increases in coronary diameter and blood flow elicited by acetylcholine (diameter increase dropped from 0.06 ± 0.02 mm to 0.01 ± 0.02 mm) and glyceryl trinitrate (flow increase dropped from 50 ± 11 mL/min to 19 ± 5 mL/min; P < 0.05).
Electron microscopy demonstrated endothelial detachment, leukocyte adherence on large coronary arteries, and leukocyte plugging within ischemic myocardial capillaries.
In isolated arterial rings, acetylcholine-induced maximal relaxation decreased from 59% ± 19% to 15% ± 14% (P < 0.05), whereas glyceryl trinitrate-induced relaxation remained unchanged.

Structured PICO

Does myocardial ischemia and reperfusion impair vasodilatation of epicardial coronary arteries and resistance vessels in anesthetized dogs?

Population

Anesthetized, open-chest dogs subjected to 60 minutes of coronary artery occlusion and 30 minutes of reperfusion to assess coronary vasoreactivity.

Intervention

60 minutes of left circumflex coronary artery occlusion followed by 30 minutes of reperfusion, tested with intracoronary injections of acetylcholine and glyceryl trinitrate

Comparator

Control conditions prior to coronary artery occlusion

Outcome

Changes in left circumflex coronary artery diameter and coronary blood flow in response to vasodilatorssurrogate

Main Result

p-value: p=<0.05

Myocardial ischemia and reperfusion attenuate both endothelium-dependent and -independent dilatation of large coronary arteries and resistance vessels in vivo, indicating that mechanisms beyond endothelial dysfunction contribute to reduced vasodilator responses.

Cite This Study

Sobey et al. (1990) studied Myocardial ischemia and reperfusion. Coronary artery occlusion and reperfusion vs. Control conditions (pre-ischemia) was evaluated on Coronary artery diameter and coronary blood flow responses to acetylcholine and glyceryl trinitrate (p=<0.05). Coronary artery occlusion and reperfusion significantly attenuated endothelium-dependent and -independent dilatation of large coronary arteries and resistance vessels in vivo (P<0.05).

synapsesocial.com/papers/6a1f7b081aa80b0346072072 https://doi.org/10.1097/00019501-199005000-00011

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Implication

Ischemia-reperfusion impairs coronary vasodilation beyond endothelial mechanisms in vivo; hypothesis-generating for post-MI vasomotor dysfunction in patients.

Impaired vasodilatation of epicardial coronary arteries and resistance vessels following myocardial ischemia and reperfusion in anesthetized dogs

Discussion

Member takes

Implication

Key Points

Structured PICO

Main Result

Cite This Study

Impaired vasodilatation of epicardial coronary arteries and resistance vessels following myocardial ischemia and reperfusion in anesthetized dogs

Discussion

Member takes

Implication

Key Points

Structured PICO

Main Result

Cite This Study

Also Consider

Also Consider