P1382 Evidence for longitudinal aorta strain relationship with noninvasive left ventricular myocardial work: another component for the ventricular-aorta coupling?

Abstract

Abstract The force required to produce longitudinal strain of the aorta represents an often overlooked mechanical load imposed on the left ventricle (LV). 2D speckle tracking strain analysis (2D-SpTa) may be applied on aorta wall in order to evaluate regional longitudinal strain (AoSTR). A noninvasive method for measuring LV myocardial work (MW) has been recently proposed, based on 2D-SpTa combined with estimated pressure curve. Aim of the study was to assess the relationship of both LV conventional functional indices and the new MW ones with the aorta function estimated by AoSRT in normals and to interrogate the potential effect of aging. Methods Fifty four normals, 24 males (M) and 30 females(F), age: 52 ± 13 (25-75 years), were selectively studied, provided that they had an efficient image quality to apply both AFI analysis for MW estimation and ascending aorta interrogation for AoLSTR (EchoPac GE) . LAoLSTR was measured in the posterior aorta wall (apical long axis view). Aortic wall borders were traced longitudinally adjusting width using 4 points of interest. The first point was put at the sinotubular junction and approximately 3-4 cm of the ascending aorta were analyzed. 2D-SpTa divided the regions of interest into proximal, middle and distal segments and the respective peak LAoSTR were considered. The following indexes of MW were estimated: GWI (global work index = total work from mitral valve closure to mitral valve opening), GCW (global constructive work = total work contributing to pump function, namely due to shortening during isovolumic contraction and ejection and lengthening during isovolumic relaxation), GWW (global wasted work = elongation during isovolumic contraction/ejection and shortening during isovolumic relaxation), GWE (global work efficiency = fraction of GCW/[GCW + GWW]). AFI derived LV strain (LVGS), biplane LV ejection fraction and stroke volume (SV) were also calculated. Results LAoSTR in any wall position was not affected by age. LAoLSTR of the proximal segment was related to both EF and LVGS (r = 0.31, p = 0.03 and r=-0.28 p = 0.05, respectively). Middle and distal LAoSTR were not related to either EF or LVGS. SV was not related to any of LAoSTR. LAoSTR of the proximal segment was related to both GWI and GCW ( r = 0.34 p = 0.016 and r = 0,31 p = 0.03 respectively). LAoSTR of the middle and distal segments were not related with any LV MW parameters. Conclusion Longitudinal aorta strain evaluation by 2D-SpTa is feasible and it is related with functional performance of the LV estimated by either conventional or MW indices based on 2D-SpTa. Moreover , the longitudinal performance of the proximal segment of the aorta above the sinotubular junction is linked to the constructive component of the LV myocardial work thus providing an alternative evidence for the LV ventricular–aorta coupling which was independent from aging.