Use of three-dimensional echocardiography to define the echocardiographic criteria for tricuspid valve prolapse

Abstract Background and aims Tricuspid valve prolapse (TVP) is reported to occur in up to 50% of patients with mitral valve prolapse (MVP). However, the current methods for diagnosing TVP through echocardiography are often empirical or based on criteria developed for MVP, as there is no established evidence-based echocardiographic criterion specifically for TVP. To address this, we used three-dimensional transthoracic echocardiography to: 1) propose diagnostic criteria for TVP; 2) evaluate the prevalence of TVP in patients with MVP; and 3) assess the clinical implications of TVP regarding tricuspid regurgitation (TR). Methods We analyzed fifty age- and sex-matched healthy volunteers (mean age 68 ± 13 years, 54% women) to determine normal tricuspid leaflet displacement and propose criteria for TVP. The threshold for identifying TVP was set at the mean displacement value plus 1.96 standard deviations of each tricuspid leaflet. We then phenotyped 287 consecutive patients with MVP (mean age 72 ± 13 years, 53% women) for the presence and clinical significance of TVP. Results In the healthy volunteers, the maximal systolic displacement was measured at 0.2 ± 0.9 mm for the septal leaflet, 0.2 ± 0.7 mm for the anterior leaflet, and 0.7 ± 0.8 mm for the posterior leaflet. Based on these findings, our proposed criteria for TVP included a right atrial displacement of ≥2 mm for all three tricuspid leaflets. Consequently, 196 (68%) of the MVP patients met these proposed criteria for TVP. A three-leaflet TVP was found in 64 patients (32%), and a two-leaflet TVP in 54 patients (27%). The most frequently involved leaftlet was the posterior (164 patients), followed by the anterior (115 patients), and the septal (96 patients). Compared to MVP patients without TVP, those with TVP were more likely to experience moderate-to-severe mitral regurgitation (38% vs. 18.9%; p 0.001) and moderate-to-severe TR (36% vs. 6.2%; p 0.001). Furthermore, compared to patients with isolated MVP, those with MVP and TVP exhibited a larger right atrium (median 27 mL/m²; interquartile range 22-40 mL/m² vs. 14 mL/m²; 11-20 mL/m²), better right atrial reservoir longitudinal strain (29 ± 13% vs. 21 ± 11%, p 0.001), a higher right ventricular ejection fraction (60 ± 7% vs. 58 ± 8%, p = 0.012), and greater right ventricular free-wall longitudinal strain (26 ± 4% vs. 23 ± 5%, p 0.001). Conclusions TR in patients with MVP should not be routinely classified as functional, given that TVP is a common finding associated with MVP and is more frequently linked to advanced TR than patients with primary mitral regurgitation without TVP. A thorough assessment of tricuspid valve anatomy should be a vital part of the preoperative evaluation for mitral valve repair.