Layer-specific myocardial strain analysis: investigation of regional deformation in a rabbit model of diabetes mellitus during different stages.

AIM: The purpose of the present study was to determine the characteristics of myocardial damage at different stages of diabetes mellitus (DM) using layer-specific myocardial strain. MATERIAL AND METHODS: Thirty six New Zealand white rabbits were randomly divided into either the control group (n =18) or the DM group (induced with alloxan) (n=18). For the myocardial deformation studies echocardiography and layer-specific strain were performed at baseline and after 3, 6, and 9 months in all of the rabbits. Three-layer longitudinal strain (LS) was calculated in the apical 4-chamber view, and three-layer circumferential strain (CS) in the short-axis view at the level of mitral valve. Layer-specific longitudinal and circumferential strains were assessed from endocardium, mid-myocardium and epicardium. For histomorphological study of the heart structure, the rabbits were sacrificed at 3, 6 and 9 months. Routine hematoxylin and eosin staining was performed. RESULTS: The highest absolute values of left ventricular longitudinal strain (LS) and circumferential strain (CS) were registered in the endocardium and the lowest in the epicardium in both groups. At 3 months, there was no significant difference in three-layer LS and CS (p>0.05), but at 6 months the LS of endocardium (LSendo) and CS of endocardium (CSendo) were lower in the DM group compared with the control group; at 9 months, the rest of the parameters were also decreased (p<0.05). Moreover, in ROC analysis at 6 months LSendo yielded better sensitivity and specificity in the detection of diabetic cardiomyopathy (AUC of LSendo was 0.897 and AUC of CSendo was 0.617). With the progression of untreated diabetes, the histopathological abnormalities intensified gradually beginning at 6 months. CONCLUSION: The progressive impairments in LV myocardial deformation and structure occurs early in diabetic rabbits, the myocardial damage may be nontransmural, and endocardial function is more susceptible to be affected by DM. Layer-specific myocardial strain echocardiography may identify subtle myocardial dysfunction in the early stages of DM.

Diagnostic Value of Transthoracic Echocardiography in Patients With Anomalous Origin of the Left Coronary Artery From the Pulmonary Artery.

Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) is a rare congenital coronary abnormality associated with early infant mortality and sudden death in adults. Transthoracic echocardiography (TTE) plays an important role in early detection and diagnosis of ALCAPA as a noninvasive modality. However, its diagnostic value is not well studied. The purpose of this study is to determine the performance of TTE in the diagnostic assessment of ALCAPA as compared with coronary CT and invasive coronary angiography. A total of 22 patients (13 women and 9 men, mean age, 12.9 ±â€Š19.5 years) with ALCAPA who underwent echocardiographic examination for clinical diagnosis were retrospectively reviewed and analyzed. Transthoracic echocardiographic features of ALCAPA were analyzed and its diagnostic value was compared with invasive coronary angiography and coronary CT angiography (CTA) with surgical findings serving as the gold standard. Surgery was performed in all of the patients to establish the dual coronary artery system. Five underwent the Takeuchi procedure and 17 had re-implantation of the anomalous left coronary artery. Of 20 patients, echocardiographic diagnoses were in good agreement with findings at surgery, resulting in the diagnostic accuracy of 90.9%. Two cases were misdiagnosed-one as the right coronary artery to pulmonary artery fistula and the other as rheumatic heart disease. The echocardiographic features of these patients with ALCAPA included: abnormal left coronary ostium arising from the pulmonary trunk with retrograde coronary artery flow in 20 patients; enlargement of the right coronary artery in 17 patients; abundant intercoronary septal collaterals in 17 patients; and moderate and significant mitral regurgitation in 14 patients. The diagnostic accuracy of invasive coronary angiography (in 17 patients) and coronary CTA (in 9 patients) was 100%. This study shows that TTE is an accurate, noninvasive imaging modality for displaying the origin of coronary arteries and demonstrating the coronary courses as well as other associated abnormalities in patients with ALCAPA.