Plain Computed Tomography for Assessment of Early Coronary Microcirculatory Damage After Revascularization Therapy in Acute Myocardial Infarction

Abstract

yocardial salvage after reperfusion may be limited by deleterious changes in the microcirculation of the previously ischemic tissue, 1 which can result in a progressive decrease of capillary blood flow to potentially viable myocytes (no-reflow phenomenon) in acute myocardial infarction (MI). 2 Previous studies using an intracoronary Doppler guidewire demonstrated that the coronary flow velocity pattern measured immediately after successful revascularization is predictive of the recovery of regional and global left ventricular function in patients with acute MI. 3,4 Furthermore, myocardial contrast echocardiography can independently detect microcirculatory damage and myocardial viability early after acute MI. [5][6][7] Recently, computed tomography (CT) has been used to evaluate the myocardial perfusion in stable angina or acute coronary syndrome. 8,9 A previous experimental study in a canine model demonstrated that both progression of the contrast defect area in myocardial contrast echocardiography with a gradual thickening of the wall and an enhancement of myocardial area detected by CT just after reperfusion are charCirculation Journal Vol. 70, November 2006 acteristic of hemorrhagic infarction. 10,11 The aim of the present study was to clarify the relationship between the microcirculatory impairment and prolonged enhancement of reperfused myocardium after successful revascularization in acute MI. Methods Patient Population and Study DesignThirteen consecutive patients (11 men, 2 women), aged from 45 to 79 years (mean age: 67±12 years), who suffered their first acute anterior MI were enrolled in the study. The diagnosis of acute MI was made on the basis of chest pain lasting for over 30 min, ST elevation of at least 2 mm in 2 adjacent leads on the electrocardiogram, and an increase of serum creatine kinase (CK) to more than twice the normal upper limit. Each patient had complete occlusion or severe stenotic lesion of the proximal or middle segment of the left anterior descending artery (LAD) on emergency coronary angiography, and underwent successful percutaneous coronary intervention (PCI) within 6 h after the onset of symptoms. The coronary blood flow velocity pattern and coronary flow velocity reserve in the LAD were measured immediately after PCI using a Doppler guidewire in 13 patients. All patients underwent chest CT immediately after successful revascularization. The left ventricular ejection fraction (LVEF) and left ventricular end-diastolic volume (LVEDV) Background Coronary microcirculatory damage is an important factor for the prognosis for acute myocardial infarction (MI) after revascularization. The myocardial enhancement area with contrast media infused during coronary revascularization therapy, detected by computed tomography (CT) just after revascularization, has been reported to correspond to the area of hemorrhagic infarction. The relationship between myocardial contrast enhancement and coronary microcirculatory damage was investigated in the present study. Methods and ResultsThirteen pati...

A PKC-β inhibitor protects against cardiac microvascular ischemia reperfusion injury in diabetic rats

“…Diabetic hearts are more sensitive to ischemic injury than the hearts of nondiabetics [3,4]. Myocardial salvage after reperfusion may be limited by deleterious changes in the microcirculation of the previously ischemic tissue [5]. Endothelial barrier dysfunction is considered to be one of the initiating mechanisms underlying the pathogenesis of diabetic microvascular complication [6].…”

CT Approaches for the Assessment of Myocardial Viability

“…This idea has first been applied in 2006 using ungated chest CT with 5 mm sections obtained at the level of the mid-ventricle. At that time, the authors did not focus on the prognostic value of delayed myocardial contrast enhancement but did establish a correlation between delayed myocardial contrast enhancement and myocardial blood flow in the ischemically injured region as measured in the target vessel with a Doppler-tipped flow wire (Kato et al 2006).…”