(P133) PROGNOSTIC VALUE OF EXERCISE RIGHT VENTRICULAR FREE WALL STRAIN IN PATIENTS WITH SICKLE CELL DISEASE

Background: Exercise stress echocardiography (SE) is increasingly recognized as a useful tool for assessment of pulmonary hypertension (PH) in patients with sickle cell disease (SCD). However, while the prognostic significance of resting systolic pulmonary artery pressure (SPAP) is well established and global longitudinal right ventricular free wall strain (RV FWS) has been identified as an independent prognostic marker in patients with PH, little is known about the prognostic value of RV FWS in this population, whether the SPAP is elevated at rest or not. We therefore examined the prognostic significance of RV FWS response to exercise in patients with SCD and normal resting SPAP.

METHODS AND RESULTS: Consecutive patients with SCD referred to our center for bicycle ergometer SE with measurable tricuspid regurgitation velocity (TRV) were enrolled from July 2019 to January 2021. Conventional echocardiography parameters, including TRV and estimated SPAP, as well as left ventricular global longitudinal strain (LV GLS) and RV FWS, were assessed at rest and peak exercise. Exercise performance was also recorded. Repeat SE was then performed at a median follow-up of 2 years. The cohort consisted of 96 patients (mean age 30±11 years, 68% females), all of whom had normal resting TRV (TRVrest) < 2.8 m/s, RV FWS and LV GLS at baseline. There were 74 (77%) patients who had peak exercise TRV (TRVpeak) > 2.8 m/s. They had higher resting E/e’, left atrial volume index and resting SPAP, as well as higher peak exercise E/e’, SPAP and RV basal diameter compared to patients with TRVpeak ≤ 2.8m/s (p < 0.05 for all). Resting and peak stress LV GLS as well as exercise performance did not differ between both groups, but peak stress RV FWS was worse among those with TRVpeak > 2.8 m/s (-23±4% vs. -27±4%, p=0.001). At a median follow-up of 2 years, patients with baseline TRVpeak > 2.8 m/s experienced a non-significant worsening in exercise performance. When stratified by baseline peak RV FWS > -20% (i.e., < 20% in absolute value), patients had significantly decreased exercise performance (exercise time 8.1±2.4 mins at baseline vs. 6.0±2.5 mins at follow-up, p=0.01).

Conclusion: Among patients with SCD who underwent bicycle ergometer SE, peak stress RV FWS was inversely correlated with TRVpeak. A baseline peak RV FWS value > -20% predicted poorer exercise performance at follow-up.