Association of Right Ventricular Longitudinal Strain with Mortality in Patients Undergoing Transcatheter Aortic Valve Replacement

Abstract

Conventional right ventricular (RV) echocardiographic measurements of systolic function (SF) have demonstrated conflicting results when their association with long-term outcomes after transcatheter aortic valve replacement (TAVR) is evaluated. RV free-wall (FW) longitudinal strain (LS) is a novel, single parameter to measure RV SF and may provide a better evaluation than fractional area change, tricuspid annular plane systolic excursion, and myocardial velocity (S'). The value of RV FW LS in patients undergoing TAVR and its association with 1-year mortality are unknown. The aim of this study was to test the hypothesis that RV FW LS would be associated with 1-year all-cause mortality in patients undergoing TAVR. Consecutive patients who underwent TAVR between 2007 and 2014 in whom RV FW LS was measurable were included; a subgroup that had 1-year follow-up echocardiographic evaluation of RV FW LS was analyzed. FW LS was derived from speckle-tracking analyses. The standard reference was determined as normal or impaired RV SF, the latter defined as the presence of ≥50% of tricuspid annular plane systolic excursion < 1.7cm, S' < 9.5cm/sec, and fractional area change < 35%. Cox proportional-hazards regression analysis was used to assess the association of RV FW LS with 1-year all-cause mortality. Of 612 patients, 334 were included for RV FW LS analysis on pre-TAVR echocardiography (feasibility 55%); exclusion criteria included atrial fibrillation (n=92 [15%]), pacemaker (n=73 [12%]), and poor image quality (n=113 [18%]). Baseline impaired RV SF was present in 19% of cases. RV FW LS did not change significantly at 1-year follow-up, in both the groups with baseline impaired and normal function. Cox regression analysis showed that RV FW LS was associated with all-cause mortality at 1year (hazard ratio, 1.06; 95% CI, 1.01-1.11). For each unit increase in RV FW LS, there was a 6% higher risk for 1-year mortality. In a high-risk TAVR population, RV FW LS should be considered a single echocardiographic parameter for the assessment of RV SF. When measurable, RV FW LS is associated with all-cause mortality at 1year after TAVR.