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Updated: Oct 18, 2026
Evaluation of Coronary Flow Reserve After Myocardial Ischemia Reperfusion in Rats
Published on: June 28, 2019
Coronary flow velocity immediately after reperfusion reflects myocardial microcirculation in canine models of acute
1Second Department of Internal Medicine, School of Medicine, The University of Tokushima, Japan. wakatuki@clin.med.tokushima-u.ac.jp
Insights
Assessing coronary microcirculation after acute myocardial infarction (AMI) is crucial. Coronary blood flow velocity patterns, particularly the diastolic-to-systolic velocity ratio, may indicate microcirculatory injury post-reperfusion.
Area of Science:
- Cardiovascular Research
- Myocardial Infarction Studies
- Microcirculation Imaging
Background:
- Coronary microcirculation injury can occur despite successful reperfusion in acute myocardial infarction (AMI).
- Angiography alone is insufficient for immediate post-reperfusion microcirculatory assessment.
Purpose of the Study:
- To investigate the correlation between coronary blood flow velocity patterns and myocardial microcirculatory injury immediately after reperfusion in AMI.
- To evaluate the utility of Doppler guide wire and myocardial contrast echocardiography in assessing microcirculatory status.
Main Methods:
- Utilized a canine model of AMI, recording left circumflex coronary flow velocity using Doppler guide wire 10 minutes post-reperfusion.
- Performed myocardial contrast echocardiography before and after reperfusion to assess microcirculatory injury.
- Calculated the normalized gray-level ratio from contrast-enhanced echocardiography and correlated it with coronary flow velocity variables, including the diastolic-to-systolic velocity ratio (DSVR).
Main Results:
- A positive correlation (r = 0.75, p < 0.01) was observed between DSVR (< 4.0) and the normalized gray-level ratio, indicating microcirculatory integrity.
- Dogs with DSVR ≥ 4.0 showed distinct flow patterns (decreased systolic velocity, early systolic retrograde flow) and lower normalized gray-level ratios, suggesting microcirculatory injury.
- These findings suggest that specific coronary flow velocity patterns are indicative of microcirculatory damage.
Conclusions:
- Coronary flow velocity patterns immediately after reperfusion can reflect the extent of myocardial microcirculatory injury in AMI.
- Doppler guide wire assessment of coronary flow velocity, particularly DSVR, may serve as a valuable tool for evaluating microcirculatory function post-reperfusion.
Abstract:
Recent reports indicate that the coronary microcirculation is sometimes injured, despite successful reperfusion in acute myocardial infarction (AMI). However, it is difficult to evaluate the coronary microcirculation immediately after reperfusion by using only angiography. The purpose of this study was to examine the relationship between the pattern of coronary blood flow velocity and myocardial microcirculatory injury immediately after reperfusion in AMI. The authors recorded the left circumflex coronary flow velocity by using the Doppler guide wire method 10 minutes after reperfusion in a canine model of AMI. In addition, myocardial contrast echocardiography was performed with the injection of contrast medium into the left circumflex coronary artery before clamping of the coronary artery and 15 minutes after release of the clamp. From these images, the ratio of the normalized gray-level postreperfusion to preclamping in the contrast-enhanced area was determined. It was compared with coronary flow velocity variables. In the 10 dogs with a diastolic-to-systolic velocity ratio (DSVR) < 4.0, this velocity ratio 10 minutes after reperfusion correlated positively (r = 0.75, p < 0.01) with the normalized gray-level ratio. However, the remaining three dogs with a DSVR > or = 4.0 markedly deviated from this pattern. Coronary flow velocities in the three dogs were characterized by a greater decrease in systolic flow velocity and occurrence of early systolic retrograde flow. Myocardial contrast echocardiographic images in these three dogs demonstrated a lower normalized gray-level ratio. In conclusion, the coronary flow velocity pattern immediately after reperfusion may reflect myocardial microcirculatory injury.
