What question did this study set out to answer?

April 1, 1989AJP Heart and Circulatory Physiology

Persistent right coronary flow reserve at low perfusion pressure

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Why the study?

Does intracoronary adenosine increase right coronary blood flow at low perfusion pressures in anesthetized dogs?

Population

18 anesthetized dogs

Comparison

Intracoronary adenosine at reduced right… vs Baseline at normal and reduced perfusion pressures

Design

Preclinical

Authors

HMHironori MurakamiSPring-8 SKS. J. KimUniversity of North Texas HDH. Fred DowneyUniversity of North Texas

Discussion

Member takes

Implication

Persistent right coronary flow reserve at low pressures in dogs leaves open relevance to human RV ischemia; prospective studies needed before clinical consideration.

Key Points

To determine whether right coronary flow reserve persists at perfusion pressures below the standard autoregulatory range.
Cannulated and perfused the right coronary artery at 80, 40, and 20 mmHg in 18 anesthetized dogs with and without intracoronary adenosine infusion.
Measured regional right ventricular blood flow using radioactive microspheres across the right ventricular free wall.
Assessed right ventricular myocardial oxygen consumption and lactate extraction ratio at normal and reduced perfusion pressures (n=8).
Right coronary blood flow decreased from 65.3 ± 6.1 to 33.7 ± 2.3 ml·min⁻¹·100 g⁻¹ when perfusion pressure dropped from 80 to 40 mmHg, but adenosine significantly boosted flow by 97.9 ± 10.6 ml·min⁻¹·100 g⁻¹ (P < 0.001).
Perfusion pressure reduction to 20 mmHg lowered blood flow to 9.5 ± 1.7 ml·min⁻¹·100 g⁻¹ without a significant overall increase during adenosine administration.
Right ventricular myocardial oxygen consumption fell at 40 mmHg without signs of ischemia (lactate extraction remained normal), and oxygen consumption returned to baseline when flow reserve was mobilized with adenosine.

Structured PICO

Does intracoronary adenosine increase right coronary blood flow at low perfusion pressures in anesthetized dogs?

Population

18 anesthetized dogs

Intervention

Intracoronary adenosine at reduced right coronary perfusion pressures (40 mmHg and 20 mmHg)

Comparator

Baseline (before adenosine infusion) at normal (80 mmHg) and reduced perfusion pressures

Outcome

Right coronary blood flow (RCBF) and right ventricular myocardial O2 consumption (MVo2)surrogate

Right coronary flow reserve persists at perfusion pressures below the apparent autoregulatory range (40 mmHg) in a canine model, and can be mobilized by adenosine.

Cite This Study

Murakami et al. (1989) studied this question.

synapsesocial.com/papers/6a7944f114b028facf0daa58 https://doi.org/10.1152/ajpheart.1989.256.4.h1176

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April 1, 1989AJP Heart and Circulatory Physiology

Persistent right coronary flow reserve at low perfusion pressure

View Full Paper

Ask AI

Bookmark

Why the study?

Does intracoronary adenosine increase right coronary blood flow at low perfusion pressures in anesthetized dogs?

Population

18 anesthetized dogs

Comparison

Intracoronary adenosine at reduced right… vs Baseline at normal and reduced perfusion pressures

Design

Preclinical

Authors

HMHironori MurakamiSPring-8 SKS. J. KimUniversity of North Texas HDH. Fred DowneyUniversity of North Texas

Discussion

Member takes

Implication

Persistent right coronary flow reserve at low pressures in dogs leaves open relevance to human RV ischemia; prospective studies needed before clinical consideration.

Key Points

To determine whether right coronary flow reserve persists at perfusion pressures below the standard autoregulatory range.
Cannulated and perfused the right coronary artery at 80, 40, and 20 mmHg in 18 anesthetized dogs with and without intracoronary adenosine infusion.
Measured regional right ventricular blood flow using radioactive microspheres across the right ventricular free wall.
Assessed right ventricular myocardial oxygen consumption and lactate extraction ratio at normal and reduced perfusion pressures (n=8).
Right coronary blood flow decreased from 65.3 ± 6.1 to 33.7 ± 2.3 ml·min⁻¹·100 g⁻¹ when perfusion pressure dropped from 80 to 40 mmHg, but adenosine significantly boosted flow by 97.9 ± 10.6 ml·min⁻¹·100 g⁻¹ (P < 0.001).
Perfusion pressure reduction to 20 mmHg lowered blood flow to 9.5 ± 1.7 ml·min⁻¹·100 g⁻¹ without a significant overall increase during adenosine administration.
Right ventricular myocardial oxygen consumption fell at 40 mmHg without signs of ischemia (lactate extraction remained normal), and oxygen consumption returned to baseline when flow reserve was mobilized with adenosine.

Structured PICO

Does intracoronary adenosine increase right coronary blood flow at low perfusion pressures in anesthetized dogs?

Population

18 anesthetized dogs

Intervention

Intracoronary adenosine at reduced right coronary perfusion pressures (40 mmHg and 20 mmHg)

Comparator

Baseline (before adenosine infusion) at normal (80 mmHg) and reduced perfusion pressures

Outcome

Right coronary blood flow (RCBF) and right ventricular myocardial O2 consumption (MVo2)surrogate

Right coronary flow reserve persists at perfusion pressures below the apparent autoregulatory range (40 mmHg) in a canine model, and can be mobilized by adenosine.

Cite This Study

Murakami et al. (1989) studied this question.

synapsesocial.com/papers/6a7944f114b028facf0daa58 https://doi.org/10.1152/ajpheart.1989.256.4.h1176

Also Consider

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