Geert Kleinnibbelink

Chapter 1 22 The introduction of speckle tracking has allowed for the measurement of ventricular longitudinal strain, ameasure of ventricular deformation to assess specific local and global function. 39 Several studies have examined the prognostic value of RV longitudinal strain in patients with PH, however, these studies report a broad range of outcomes, ranging from no significant predictive capacity to a high predictive capacity. 40-46 These differences may relate to the heterogeneity between the studies such as study design, included study population, treatment used etcetera. Therefore, one of the aims of this thesis is to perform a meta-analysis to determine the independent prognostic value of RV longitudinal strain in patients with PH. Echocardiography Echocardiography represents the central technique in this thesis to better understand RV changes and remodelling to (patho)physiological stimuli. It is based on ultrasound technology and can be used to evaluate cardiac structure and function. Structures such as cavities can be quantified in linear measurements, areas or volumes whereas wall thickness can be quantified with linear measurements ( Figure 5 ). RV wall thickness can be linearly measured in the subcostal view at end-diastole ( Figure 5A ). Linear dimensions of the RV cavity are obtained in the RV-focused view ( Figure 5B ) whilst RV outflow tract linear dimensions can be measured in the parasternal short-axis ( Figures 5C ) and the parasternal long-axis view (not shown). Contemporary methods to assess RV function by echocardiography are the tricuspid annular plane systolic excursion (TAPSE), right ventricular fractional area change (RVFAC) and tissue doppler imaging (TDI) ( Figure 5 ). 47 TAPSE represents the displacement of the annulus as a measure of RV longitudinal function and is obtained in the apical four- chamber view ( Figure 5D ). RVFAC provides a global estimation of the global RV function and is calculated by 100*(end-diastolic area – end-systolic area)/end-diastolic area with end-diastolic and -systolic areas obtained in the RV focused apical four-chamber view ( Figure 5E ). TDI measures velocity of the myocardium and represents a useful estimation of global RV function ( Figure 5F ). However, these measures of RV function have inherent limitations related to angle and load dependency secondary to the complex geometry, heterogenous morphology and function of the RV. 47, 48 Novel echocardiography such as