Geert Kleinnibbelink

RV Strain in Pulmonary Hypertension 6 141 INTRODUCTION Pulmonary hypertension (PH) is a progressive disease with a 5-year survival rate of approximately 50%, depending on aetiology and disease severity. 1 Although the aetiology of PHrelates toan increasedpulmonaryartery resistance, theprimary causeof death relates to right ventricular (RV) failure since the RV has to overcome the increased pulmonary resistance in order to maintain cardiac output. 2 Consequently, echocardiographic measurements of RV structure and function are routinely performed during follow-up of patients with PH. 3, 4 Due to complex RV geometry and load dependency of the RV functional parameters, traditional echocardiographic indices such as RV fractional area change (RVFAC) and tricuspid annular plane systolic excursion (TAPSE), have limited prognostic power in patients with PH. 3 The introduction of speckle tracking echocardiography has allowed for the measurement of ventricular longitudinal strain, a measure of ventricular deformation to assess specific local and global function. 5 In heart failure, valvular heart disease, cardiomyopathy and ischaemic heart disease, left ventricular longitudinal strain independently predicts future events. 6 Patients with PH demonstrate a reduced RV longitudinal strain (RVLS) compared to healthy controls, whilst several studies have examined the prognostic value of RVLS in patients with PH. 7-30 These studies report a broad range of outcomes, ranging from no significant predictive capacity to a high predictive capacity. These differences in outcome may relate to differences in methodology between studies, such as variation in aetiology (PH vs pulmonary arterial hypertension (PAH)), included population for HR calculation (inclusion of healthy controls or non PH patient vs just PH patients), patient management at time of inclusion (treatment naive vs. single or combined therapy), follow-up duration (0.6-5.0 years), outcome parameters (morbidity vs all-causemortality), group size (n=17 up to n=406) andmethods inwhich the HRs were determined (percentile change (continuous parameter) vs a predefined cut-off point (dichotomous parameter)). 7-11, 14-17, 21, 23, 24, 28, 29 The heterogeneity in study designs and outcomes provide a challenge when attempting to establish the potential prognostic value of RVLS in patients with PH. Combining these studies in a systematic review and meta-analysis will provide clarity on the prognostic value of RVLS in patients with PH.