Abstract
Background: Chronic pressure overload secondary to severe aortic stenosis causes impairment of left ventricular myocardial deformation and associated with adverse outcome. The present study aimed to assess the response of myocardial mechanics after transcatheter aortic valve implantation (TAVI).
Methods: Assessment of myocardial mechanics by quantification of LV longitudinal, circumferential strain and rotational deformation (apical, basal rotation and twist) by 2-D Speckle-tracking echocardiography at baseline and at midterm follow-up post-TAVI. The patients were divided into 2 groups based on baseline left ventricular ejection fraction. 46 patients had preserved LV EF >= 50% preserved ejection fraction (PEF) and 34 patients had reduced left ventricular ejection (REF) < 50%.
Results: 80 patients with severe AS and high surgical risk were evaluated. At a mean follow-up of 8 +/- 3 months after TAVI, left ventricular longitudinal strain (LS) significantly improved in reduced ejection fraction (REF) group from -9.88 +/- 3.93% to 11.89 +/- 3.15% (P = 0.001). In preserved ejection fraction (PEF) group, longitudinal strain improved from -13.8 +/- 3.1% to -15.2 +/- 3.3% (P < 0.001). Longitudinal strain rate (LSR) improved significantly in REFgroup, -0.48 +/- 0.20sec(-1)to -0.62 +/- 0.16sec(-1) (P < 0.001) and in PEF group,-0.73 +/- 0.19sec(-1)to-0.77 +/- 0.16sec(-1) (P < 0.005). In PEF group, LV twist angle was supra-physiological at baseline and decreased after TAVI towards normal values (P = 0.006). In REF group LV twist angle was reduced at baseline with significant increase towards normal value after transcatheter aortic valve implantation (TAVI),P = 0.005. That was attributed to severe LV dysfunction associated with reduction of left ventricular twist at baseline which improved in response to TAVI alongside with improvement of left ventricular systolic function. In reduced ejection fraction (REF) group circumferential strain and strain rate improved significantly after TAVI.
Conclusions: Myocardial mechanics of the left ventricle including strain, strain rate and twist are deformed in severe aortic stenosis. TAVI restores myocardial mechanics towards physiological values in patients with preserved and reduced ejection fraction.