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Updated: Aug 29, 2026
Evaluation of Coronary Flow Reserve After Myocardial Ischemia Reperfusion in Rats
Published on: June 28, 2019
Effects of glycoprotein IIb/IIIa inhibition on microvascular flow after coronary reperfusion. A quantitative
Hideki Kunichika1, Ori Ben-Yehuda, Stephane Lafitte
1Division of Cardiology, University of California at San Diego, San Diego, California 92103-8411, USA.
Objectives:
We assessed the effect of glycoprotein IIb/IIIa inhibition (GPI) on microvascular flow after coronary occlusion/reperfusion using quantitative myocardial contrast echocardiography (QMCE).
Background:
Platelets may play a major role in the dissociation of epicardial artery recanalization and tissue-level reperfusion, referred to as the "no-reflow phenomenon." Therefore, GPI might improve myocardial reperfusion, distinct from its effects on epicardial patency.T METHOD: hree-hour occlusion of the left anterior descending coronary artery (LAD) was followed by 3-h reperfusion in 16 open-chest dogs: 8 controls and 8 given a continuous infusion of the GPI tirofiban, starting 45 min before LAD reopening. Perfusion of the LAD bed was quantified by the rate of intensity rise (b) by QMCE; myocardial blood flow (MBF) was assessed by fluorescent microspheres.
Results:
No differences in b or MBF were observed within the risk area between the control and GPI groups at baseline or occlusion. However, b and MBF were higher in GPI dogs than in controls during reperfusion, despite similar epicardial flow (p < 0.05 at 30, 60, and 90 min; p = NS at 180 min). Infarct area size was significantly reduced in GPI dogs compared with non-treated dogs (26.9 +/- 10.5% vs. 49.0 +/- 11.1% of at-risk area, respectively).
Conclusions:
As demonstrated by QMCE, GPI improves microvascular flow and reduces the infarct area after coronary occlusion/reperfusion, independent of epicardial flow. These data demonstrate the usefulness of QMCE in assessing microvascular flow, provide novel evidence for the role of platelets in the early phase of reperfusion injury, and show that GPI is of value in preserving microvascular perfusion after coronary reperfusion.
Insights
Glycoprotein IIb/IIIa inhibition (GPI) improves microvascular flow and reduces infarct size after coronary reperfusion. This study highlights GPI
Area of Science:
- Cardiovascular Research
- Platelet Biology
- Myocardial Reperfusion Injury
Background:
- Platelets contribute to the no-reflow phenomenon, impairing tissue reperfusion after epicardial artery recanalization.
- Glycoprotein IIb/IIIa inhibitors (GPI) may enhance myocardial reperfusion independent of epicardial patency.
Purpose of the Study:
- To assess the effect of GPI on microvascular flow post-coronary occlusion/reperfusion using quantitative myocardial contrast echocardiography (QMCE).
- To evaluate GPI's role in mitigating reperfusion injury and preserving myocardial perfusion.
Main Methods:
- 16 open-chest dogs underwent 3-hour left anterior descending coronary artery occlusion followed by 3-hour reperfusion.
- 8 dogs received continuous tirofiban (GPI) starting 45 minutes before reperfusion; 8 served as controls.
- Microvascular flow was quantified by QMCE (rate of intensity rise, b) and myocardial blood flow (MBF) by microspheres.
Main Results:
- GPI treatment resulted in significantly higher microvascular flow (b) and MBF during reperfusion compared to controls, despite similar epicardial flow.
- Infarct area size was significantly reduced in the GPI group (26.9%) versus the control group (49.0%).
Conclusions:
- GPI improves microvascular flow and reduces infarct size following coronary occlusion/reperfusion, independent of epicardial flow.
- QMCE is effective in assessing microvascular flow, demonstrating GPI's value in preserving perfusion and mitigating early reperfusion injury mediated by platelets.
