Prevalence and Clinical Implications of Tricuspid Valve Prolapse Based on Magnetic Resonance Diagnostic Criteria.

BACKGROUND: Tricuspid valve prolapse (TVP) is an uncertain diagnosis with unknown clinical significance because of a scarcity of published data. OBJECTIVES: In this study, cardiac magnetic resonance was used to: 1) propose diagnostic criteria for TVP; 2) evaluate the prevalence of TVP in patients with primary mitral regurgitation (MR); and 3) identify the clinical implications of TVP with regard to tricuspid regurgitation (TR). METHODS: Forty-one healthy volunteers were analyzed to identify normal tricuspid leaflet displacement and propose criteria for TVP. A total of 465 consecutive patients with primary MR (263 with mitral valve prolapse [MVP] and 202 with nondegenerative mitral valve disease [non-MVP]) were phenotyped for the presence and clinical significance of TVP. RESULTS: The proposed TVP criteria included right atrial displacement of ≥2 mm for the anterior and posterior tricuspid leaflets and ≥3 mm for the septal leaflet. Thirty-one (24%) subjects with single-leaflet MVP and 63 (47%) with bileaflet MVP met the proposed criteria for TVP. TVP was not evident in the non-MVP cohort. Patients with TVP were more likely to have severe MR (38.3% vs 18.9%; P < 0.001) and advanced TR (23.4% of patients with TVP demonstrated moderate or severe TR vs 6.2% of patients without TVP; P < 0.001), independent of right ventricular systolic function. CONCLUSIONS: TR in subjects with MVP should not be routinely considered functional, as TVP is a prevalent finding associated with MVP and more often associated with advanced TR compared with patients with primary MR without TVP. A comprehensive assessment of tricuspid anatomy should be an important component of the preoperative evaluation for mitral valve surgery.

Extracellular Volume in Primary Mitral Regurgitation.

OBJECTIVES: This study used cardiovascular magnetic resonance (CMR) to evaluate whether elevated extracellular volume (ECV) was associated with mitral valve prolapse (MVP) or if elevated ECV was a consequence of remodeling independent of primary mitral regurgitation (MR) etiology. BACKGROUND: Replacement fibrosis in primary MR is more prevalent in MVP; however, data on ECV as a surrogate for diffuse interstitial fibrosis in primary MR are limited. METHODS: Patients with chronic primary MR underwent comprehensive CMR phenotyping and were stratified into an MVP cohort (>2 mm leaflet displacement on a 3-chamber cine CMR) and a non-MVP cohort. Factors associated with ECV and replacement fibrosis were assessed. The association of ECV and symptoms related to MR and clinical events (mitral surgery and cardiovascular death) was ascertained. RESULTS: A total of 424 patients with primary MR (229 with MVP and 195 non-MVP) were enrolled. Replacement fibrosis was more prevalent in the MVP cohort (34.1% vs. 6.7%; p < 0.001), with bi-leaflet MVP having the strongest association with replacement fibrosis (odds ratio: 10.5; p < 0.001). ECV increased with MR severity in a similar fashion for both MVP and non-MVP cohorts and was associated with MR severity but not MVP on multivariable analysis. Elevated ECV was independently associated with symptoms related to MR and clinical events. CONCLUSIONS: Although replacement fibrosis was more prevalent in MVP, diffuse interstitial fibrosis as inferred by ECV was associated with MR severity, regardless of primary MR etiology. ECV was independently associated with symptoms related to MR and clinical events. (DeBakey Cardiovascular Magnetic Resonance Study [DEBAKEY-CMR]; NCT04281823).