IMR is useful for assessing the microvascular dysfunction after primary percutaneous coronary intervention (PCI). It remains unknown whether index of microcirculatory resistance (IMR) reflects the functional outcome in patients with anterior myocardial infarction (AMI) with or without microvascular obstruction (MO).This study was performed to evaluate the clinical value of the IMR for assessing myocardial injury and predicting microvascular functional recovery in patients with AMI undergoing primary PCI. We enrolled 34 patients with first anterior AMI. After successful primary PCI, the mean distal coronary artery pressure (Pa), coronary wedge pressure (Pcw), mean aortic pressure (Pa), mean transit time (Tmn), and IMR (Pd * hyperemic Tmn) were measured. The presence and extent of MO were measured using cardiac magnetic resonance image (MRI). All patients underwent follow-up echocardiography after 6 months. We divided the patients into two groups according to the existence of MO (present; n = 16, absent; n = 18) on MRI. The extent of MO correlated with IMR (r = 0.754; P < 0.001), Pcw (r = 0.404; P = 0.031), and Pcw/Pd of infarct-related arteries (r = 0.502; P = 0.016). The IMR was significantly correlated with the DeltaRegional wall motion score index (r = -0.61, P < 0.01) and DeltaLeft ventricular ejection fraction (r = -0.52, P < 0.01), implying a higher IMR is associated with worse functional improvement. Therefore, Intracoronary wedge pressures and IMR, as parameters for specific and quantitative assessment of coronary microvascular dysfunction, are reliable on-site predictors of short-term myocardial viability and Left ventricle functional recovery in patients undergoing primary PCI for AMI.
Adult ; Aged ; Aged, 80 and over ; Anterior Wall Myocardial Infarction/*physiopathology ; Arterial Pressure/physiology ; Coronary Occlusion/pathology ; Echocardiography ; Female ; Humans ; Magnetic Resonance Imaging ; Male ; Microcirculation/*physiology ; Middle Aged ; Percutaneous Coronary Intervention ; *Predictive Value of Tests ; Prospective Studies ; Recovery of Function ; Risk Factors

Cardioprotective effect of fimasartan, a new angiotensin receptor blocker (ARB), was evaluated in a porcine model of acute myocardial infarction (MI). Fifty swine were randomized to group 1 (sham, n=10), group 2 (no angiotensin-converting enzyme inhibitor [ACEI] or ARB, n=10), group 3 (perindopril 2 mg daily, n=10), group 4 (valsartan 40 mg daily, n=10), or group 5 (fimasartan 30 mg daily, n=10). Acute MI was induced by occlusion of the left anterior descending artery for 50 min. Echocardiography, single photon emission computed tomography (SPECT), and F-18 fluorodeoxyglucose cardiac positron emission tomography (PET) were performed at baseline, 1 week, and 4 weeks. Iodine-123 meta-iodobenzylguanidine (MIBG) scan was done at 6 weeks for visualization of cardiac sympathetic activity. Left ventricular function and volumes at 4 weeks were similar between the 5 groups. No difference was observed in groups 2 to 5 in SPECT perfusion defect, matched and mismatched segments between SPECT and PET at 1 week and 4 weeks. MIBG scan showed similar uptake between the 5 groups. Pathologic analysis showed similar infarct size in groups 2 to 5. Infarct size reduction was not observed with use of fimasartan as well as other ACEI and ARB in a porcine model of acute MI.
3-Iodobenzylguanidine ; Angiotensin II Type 1 Receptor Blockers/therapeutic use ; Angiotensin Receptor Antagonists/*therapeutic use ; Angiotensin-Converting Enzyme Inhibitors/therapeutic use ; Animals ; Anterior Wall Myocardial Infarction/*drug therapy/physiopathology ; Biphenyl Compounds/*therapeutic use ; Cardiotonic Agents/*therapeutic use ; Disease Models, Animal ; Echocardiography ; Fluorodeoxyglucose F18 ; Perindopril/therapeutic use ; Positron-Emission Tomography ; Pyrimidines/*therapeutic use ; Random Allocation ; Swine ; Tetrazoles/*therapeutic use ; Tomography, Emission-Computed, Single-Photon ; Valsartan/therapeutic use ; Ventricular Function, Left/*physiology