Abstract 1550: Non-Doppler Two-Dimensional Strain Imaging for Early Detection of Heart Transplant Recipients with Coronary Stenoses
Background: Non-Doppler based two-dimensional (2D) strain imaging can reveal wall motion alterations not visible by conventional echocardiography (ECHO) and like tissue Doppler imaging (TDI) it can detect myocardial deformation (regional shortening and thickening) in the absence of visible ventricular wall displacement. Because TDI is dependent on the direction of Doppler angle of incidence in relation to myocardial motion, in our attempt to assess of the diagnostic value of strain and strain rate changes for early detection of transplant coronary arteriopathy (TCA), we focused our attention on the angle independent 2D strain imaging.
Methods: In 68 heart recipients with normal LV wall motion and ejection fraction in conventional ECHO, 2D strain LV wall motion analysis were additionally performed before each follow-up cardiac catheterization. Circumferential, radial and longitudinal strain and strain rate were calculated from parasternal short axes and apical (3- and 4-chamber) views, respectively. 2D strain parameters were tested for relationships with angiographic findings.
Results: In comparison with patients without TCA, those with angiographic TCA showed lower global systolic strain rate (radial, circumferential and longitudinal) values and longer systolic times measured from onset of contraction to the peak of systolic strain (p<0.01). For radial peak systolic global strain rate values below 1.1/s we found a 93.3% likelihood of angiographic TCA in general, regardless of the presence or absence of focal stenoses on main coronaries. Regional strain and strain rate analyses showed differences in contraction asynchrony and dyssynergy indexes between patients with and without focal stenoses (p<0.01). For longitudinal midsystolic dyssynchrony index values >0.5 we found an 88.2% likelihood of relevant focal coronary stenoses (>50% narrowing).
Conclusions: In heart allografts with apparently normal LV kinetics in conventional ECHO, simple global strain rate measurements allow early TCA prediction, but without the ability to differentiate between diffuse TCA and predominantly focal coronary stenoses. Such differentiation is possible with more complex regional strain analyses using contraction asynchrony and dyssynergy indexes.