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Time course and relation to local viability of microvascular function and volume after reperfused acute myocardial
Philippe Garot1, Olivier Pascal, Marc Simon
1Fédération de Cardiologie, Hôpital Henri Mondor, INSERM U400, Créteil, France. philippe.garot@hmn.ap-hop-paris.fr
Insights
Early assessment of microvascular function after acute myocardial infarction is crucial. Reversible microvascular dysfunction predicts tissue viability and improved myocardial perfusion following angioplasty.
Area of Science:
- Cardiology
- Cardiovascular Research
- Medical Imaging
Background:
- Acute myocardial infarction (AMI) often leads to persistent myocardial dysfunction.
- Microvascular function and perfusion alterations are key determinants of recovery post-AMI.
- Assessing local inotropic reserve (IR) is important for understanding myocardial recovery.
Purpose of the Study:
- To evaluate the time course of microvascular function and myocardial perfusion after primary coronary angioplasty in AMI patients.
- To determine the relationship between microvascular function, myocardial perfusion, and local inotropic reserve (IR).
- To investigate the association between early microvascular dysfunction and local tissue viability.
Main Methods:
- Intracoronary Doppler and myocardial contrast echocardiography were used to assess coronary flow reserve (CFR) and myocardial perfusion.
- Dobutamine echocardiography was employed to evaluate local IR.
- Measurements were taken immediately after angioplasty, and on days 1 and 8 post-procedure.
Main Results:
- Coronary flow reserve (CFR) was initially impaired in all patients, with a significant improvement by day 1 in those with IR.
- Microvascular obstruction remained unchanged at day 1 but decreased by day 8 in patients with IR.
- Improved myocardial perfusion post-angioplasty correlated with recruitable microvascular function.
Conclusions:
- Subsequent improvement in myocardial perfusion after acute myocardial infarction is linked to pre-existing recruitable microvascular function.
- The presence of reversible microvascular dysfunction early after AMI indicates local tissue viability.
- Early microvascular assessment aids in predicting myocardial recovery and guiding treatment strategies.
Abstract:
We assessed the time course of the alterations of microvascular function and myocardial perfusion, as well their relation to local inotropic reserve (IR), in 21 patients who underwent successful primary coronary angioplasty for acute myocardial infarction and in whom local myocardial dysfunction persisted at hospital discharge. Coronary flow reserve (CFR) and myocardial perfusion were assessed immediately after angioplasty, and on day 1 and day 8 by intracoronary Doppler and myocardial contrast echocardiography, respectively. Dobutamine echocardiography was performed on day 7 for assessment of local IR. After angioplasty, CFR was severely altered in patients with (n = 14) and without (n = 7) IR (1.44 +/- 0.26 and 1.36 +/- 0.21, respectively; p = NS). Among patients with IR, CFR increased significantly at day 1 (2.26 +/- 0.62, p <0.005 vs acute stage) compared with those without IR (p = NS vs acute). In contrast, the extent of microvascular obstruction as defined by contrast echocardiography remained unchanged in all patients at day 1 compared with acute measurements. Microvascular obstruction decreased at day 8 in the sole subset of patients with local IR (p <0.05 vs acute stage). In patients treated by immediate coronary angioplasty for acute myocardial infarction, subsequent improvement of myocardial perfusion is associated with preexistent recruitable microvascular function in the infarct-related artery. The presence of reversible microvascular dysfunction at the early stage after acute myocardial infarction is associated with local tissue viability in humans.