Right ventricular visualization at SPECT perfusion imaging before and after revascularization in patients with postinfarction cardiosclerosis

Abstract

Aim. To evaluate the intersystemic (between the myocardium of the left coronary artery system and the right coronary artery system redistribution mechanisms of perfusion in the myocardium after revascularization in patients with coronary artery disease with focal cardiosclerosis using gated single photon emission computed tomography. Сardiosclerosis foci were initially identified by magnetic resonance imaging. Material and Methods. The study included 17 patients with coronary artery disease with multivessel coronary disease and large-focal cardiosclerosis according to the results of magnetic resonance imaging with contrast; the diagnosis of left ventricular aneurysm was established in 14 patients, the focal subendocardial cardiosclerosis was diagnosed in 3 patients. For various reasons, all patients underwent myocardial revascularization without the left ventricle reconstruction (coronary artery bypass grafting in 10 patients, percutaneous coronary intervention in 7 patients). Magnetic resonance imaging was used as the gold standard for focal cardiosclerosis before revascularization. All patients before and after revascularization underwent gated single photon emission computed tomography with MIBI scan. During the initial analysis of peaks on the profile slices of coronal and transversal midsections passing along the lateral walls of the left and right ventricles, we did not notice a clear visualization of in 8 patients (group 1), while an increased MIBI scan accumulation in the right ventricle myocardium was clearly visualized in 9 patients (group 2). Based on the peaks height of profile curves, we compared changes in the maxima of radiopharmaceutical accumulation before and after revascularization in the lateral walls of the left ventricle and right ventricle. All studies were performed using the original Cardiac Functional Imaging medical program in order to obtain quantitative information about the myocardial function of both the left ventricle, and also the right ventricle. This program made it possible to highlight the right ventricle area even in the case of its weak visualization through the initial formation of parametric images, where the right ventricle area was visualized. Results. When comparing the revascularization results of the two groups, we noted that the left ventricle ejection fraction increased significantly only in patients without initial visualization of the right ventricular myocardium. Left ventricle ejection fraction did not change after revascularization in patients with initially increased accumulation of the radiopharmaceutical in the right ventricle. Globally, only an improvement in the diastolic function of the left and right ventricles was noted in the latter group of patients. In addition, an increase in the right ventricular uptake level was noted for patients with focal cardiosclerosis and the initially increased uptake in the right ventricle after the maximum possible complete myocardial revascularization, which may indicate a redistribution of perfusion in favor of a more intact right ventricular myocardium. Conclusions. 1. In patients without signs of increased visualization of the right ventricle (group 1) after revascularization, we revealed a statistically significant increase in the left ventricle ejection fraction (p-value=0.024), a decrease in the end-systolic volume (p-value=0.024), an increase in the motion in segments corresponding to the peri-infarct scar zone (p-value=0.016), and a change in systolic thickening in the segment of the basal parts of the anterolateral wall (p-value=0.046). 2. Initially increased visualization of the right ventricle in patients with extensive focal cardiosclerosis in the myocardium of the left ventricle suggests the absence of the left ventricle ejection fraction increase after myocardial revascularization. 3. An increase in the visualization of the right ventricle after complete myocardial revascularization indicates an intersystemic redistribution of perfusion in favor of the preserved myocardium of this part of the heart.

Keywords

• visualization of the right ventricular myocardium
• intersystemic mechanisms of perfusion redistribution