Abstract 15809: Right Ventricular Systolic Strain by Speckle-Tracking Echocardiography Predicts Mortality Among 575 Subjects Evaluated for Pulmonary Hypertension

Abstract

Background: While it is recognized that the degree of right ventricular (RV) dysfunction is a major determinant of outcome in patients with pulmonary hypertension (PH), the best non-invasive measure is unclear. Recent small studies have suggested speckle-tracking echocardiography (STE) based RV strain is a feasible measure of contractility with prognostic significance. We hypothesized that RV strain by STE predicts mortality over a broad range of pulmonary pressures.

Methods: Prospective peak longitudinal RV systolic strain measurement (GE Healthcare) of the RV free wall was performed on 575 patients referred for transthoracic echocardiography for known or suspected PH. Patients with group 2 PH (pulmonary venous hypertension) were excluded. Survival status was assessed over 18 months.

Results: The mean age was 56±18 years, and 364 (63%) were female. The median estimated RV systolic pressure was 43 mmHg (range 19-127). There were 406 (71%) with a diagnosis of PH (58% group 1, 42% group 3) and 169 (29%) without PH. Among PH patients, 46% were functional class III-IV. The mean RV strain was −21.2±6.7% for all patients (−19.6±6.6% for those with and −25.0±5.2% for those without PH, p<0.001). The degree of RV strain reduction correlated with worse functional class, shorter 6 minute walk distances, higher NT-pro BNP levels and a greater proportion of right heart failure. Eighteen-month survival was 92%, 88%, 85% and 71% according to quartiles RV strain (p<0.001) (Figure), with a 2.32 fold higher risk of death (95% CI 1.68-3.22) per 6.7% decline in RV strain. RV strain predicted survival when adjusted for pulmonary pressure, pulmonary vascular resistance or right atrial pressure.

Conclusion: Among patients referred for evaluation of known or suspected PH, routine assessment of RV free wall systolic strain is feasible. The severity of strain-based RV dysfunction is associated with clinical findings and is predictive of outcome independent of loading conditions.