Tricuspid annular plane systolic excursion in pulmonary hypertension-Moving beyond the sector plane

Tricuspid annular plane systolic excursion (TAPSE) is usually measured with M-mode using sector line, however, this may not align with the anatomical shortening of the right ventricular (RV). In this study, we compared the different methods to measure TAPSE using three different reference lines (sector line, anatomical line, and apico-annular line). We included 148 patients diagnosed with pulmonary arterial hypertension (PAH) who underwent TTE and right heart catheterization within 2 weeks of each other. TAPSE was measured by M-mode (sector, anatomical), 2D (sector, anatomical), or as tricuspid apico-annular displacement (TAAD). Agreement between measures was assessed using coefficient of variation (COV), Spearman's correlation, and Bland-Altman analysis. Receiver-operating characteristics and Kaplan-Meier analysis were used to explore associations with the combined outcome of death or lung transplantation at 5 years. There was a good concordance between anatomical and sector M-mode with a COV of 15.5 ± 1.6% and a bias of -0.6 ± 3.2 mm. In contrast, anatomical M-mode TAPSE and TAAD differed significantly with the mean difference of 3.3 ± 3.8 mm (COV 30.5 ± 6.1%; p < 0.0001). Among the different 2D methods, anatomical 2D agreed well with anatomical M-mode TAPSE (COV of 11.8 ± 2.0%; r = 0.89; p < 0.0001). Among the five methods, TADD had the strongest association with the combined endpoint of death or transplantation at 5 years (C-statistic 0.64, 95% confidence interval [CI] 0.57-0.71). We concluded that different measures of TAPSE are not interchangeable.