Page 87 - Assessing right ventricular function and the pulmonary circulation in pulmonary hypertension Onno Anthonius Spruijt

unexpected that the more of the geometry of the RV is taken into account within a 2D measurement, the better it correlates to a 3D function parameter.
In addition, we assessed RV systolic function by the fractional transverse and longitudinal wall motion from the four-chamber view. The fractional transverse wall motion correlated better with CMRI-derived-RVEF compared to TAPSE and fractional longitudinal wall motion. This finding is in line with Kind et al. [15] comparing 2D-CMRI-derived parameters with CMRI-derived-RVEF. It has been shown that during deterioration of RV function in PH patients, the decrease in longitudinal wall motion is reaching a floor effect, while this does not apply to the decrease in transverse wall motion [6]. This could explain why fractional transverse wall motion better correlated to RVEF compared to fractional longitudinal wall motion.
Ability of echo to predict a deterioration in CMRI-derived-RVEF
Since monitoring RV function during follow-up of PH patients is of utmost importance, we assessed which echo-derived parameter of RV systolic function best followed the change in CMRI-derived- RVEF over time. The strongest correlation was found between the change in RVFAC and RVEF (r2=0.349). Based on repeatability studies, a decrease in CMRI-derived-RVEF>3% is accepted as a real decrease in RV function [3, 16]. Since, as far as we know, no repeatability studies have been performed for TAPSE and RVFAC, echo-based cut-off values for a deterioration in RV function were based on the interobserver variability. All four echo parameters showed a poor sensitivity for detecting a deterioration in RV function. This suggests that echo-derived RVFAC, TAPSE, FTWM and FLWM may not be suitable parameters for the serial assessment of RV function in the follow-up of patients with precapillary PH.
We investigated four simple and rapidly assessable parameters of RV systolic function. Echo-derived parameters of RV systolic function, in particular RVFAC, could reasonably distinguish between a decreased or preserved CMRI-derived-RVEF. However, all four investigated echo-derived parameters of RV systolic function were insufficiently sensitive for detecting a deterioration in RV systolic function during follow-up. Therefore, CMRI remains the gold standard for the serial assessment of RV systolic function.
The number of patients that we used for measuring the ability of echo-derived parameters to follow the change in CMRI-derived RVEF is relatively low. This can have affected the positive and negative predictive values of the different echo-derived parameters.
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