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

Background: 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.

Methods: 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 < 1.7 cm, S' < 9.5 cm/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.

Results: 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 1 year (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.

Conclusions: 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 1 year after TAVR.