Diagnostic Value of 2D Strain Imaging In Patients with Suspected Coronary Artery Disease

Background: Strain imaging (SI) has been shown to quantify regional myocardial function in both acute ischemic myocardium and infarcted myocardium. The aim of this study is to determine the diagnostic value of SI for the detection of coronary lesions in pts with chest pain, but without apparent wall motion abnormalities. Methods: SI for advanced wall motion analysis was performed in 59 pts with suspicious stable angina (SA) and in 57 pts with suspicious unstable angina (UA), prior to coronary angiography (CAG). Longitudinal strain was measured in 3 apical views. For the identification of ischemia a magnitude parameter, being defined as a reduction of the peak systolic strain, was used. A homogenous pattern of strain was defined as relatively uniform distribution of the peak systolic strain. Heterogeneity of strain was considered abnormal; these segments were called strain (+) and the rest were called strain (-). Results: Out of the 59 SA patients, 28 had >70% stenosis (ischemic-SA) and 31 had normal coronary anatomy or 50% stenosis (normal-SA). Of the 28 patients in the ischemic-SA group, 9 patients (32%) showed a homogeneous pattern of peak systolic strain throughout the wall (strain negative) and 19 patients (67%) showed heterogeneity of strain (strain positive). 31 patients with normal coronary anatomy or <50% stenosis (normal-SA), 6 patients (19%) showed heterogeneity of strain (strain positive) and 25 patients (80%) showed a homogeneous pattern of peak systolic strain throughout the wall (strain negative). The positive predictive value of strain was 76% in the SA group. In the group of 57 UA patients, 32 had >70% stenosis (ischemic-UA), and 25 had normal coronary anatomy or 50% stenosis (normal-UA). From the 32 patients in the ischemic-UA group, 7 patients (22%) were determined to be strain negative, and 25 patients (78%) were determined to be strain positive. Out of 25 patients with normal coronary anatomy or 50% stenosis (normal-UA), 25 patients (80%) showed a homogeneous pattern of peak systolic strain throughout the wall (strain negative) and 6 patients (19%) showed heterogeneity of strain (strain positive). The positive predictive value of strain was 80.6% in the UA group. Sensitivity and specificity of 2D strain was evaluated using diagnostic test. The results were: 68% and 80.6% respectively in the stable angina group and 78% and 76% respectively in the unstable angina group.Conclusion: Ultrasound-based SI demonstrates a strong correlation with CAG and it has potential as a non-invasive diagnostic tool for detecting CAD in pts with chest pain and without wall motion abnormalities