title: Clinical context and mechanism of functional tricuspid regurgitation in patients with and without pulmonary hypertension.
abstract: BACKGROUND
  Functional tricuspid regurgitation (FTR) with structurally normal valve is of poorly defined mechanisms. Prevalence and clinical context of idiopathic FTR (Id-FTR) (without overt TR cause) are unknown.
  
  
  RESULTS
  To investigate prevalence, clinical context, and mechanisms specific to FTR types, Id-FTR versus pulmonary hypertension-related (PHTN-FTR, systolic pulmonary pressure ≥50 mm Hg), we analyzed 1161 patients with prospectively quantified TR. Id-FTR (prevalence 12%) was associated with aging and atrial fibrillation. For mechanistic purposes, we measured valvular and right ventricular (RV) remodeling in 141 Id-FTR matched to 140 PHTN-FTR and to 99 controls with trivial TR for age, sex, atrial fibrillation, and ejection fraction. PHTN-FTR and Id-FTR were also matched for TR effective-regurgitant-orifice (ERO). Id-FTR valvular alterations (versus controls) were largest annular area (3.53±0.6 versus 2.74±0.4 cm(2), P<0.0001) and lowest valvular/annular coverage ratio (1.06±0.1 versus 1.45±0.2, P<0.0001) but normal valve tenting height. PHTN-FTR had mild annular enlargement but excessive valve tenting height (0.8±0.3 versus 0.35±0.1 cm, P<0.0001). Valvular changes were linked to specific RV changes, largest basal dilatation, and normal length (RV conical deformation) in Id-FTR versus longest RV with elliptical/spherical deformation in PHTN-FTR. With increasing FTR severity (ERO ≥40 mm(2)), changes specific to each FTR type were accentuated, and RV function (index of myocardial performance) was consistently reduced.
  
  
  CONCLUSIONS
  Id-FTR is frequent, linked to aging and atrial fibrillation, can be severe, and is of unique mechanism. In Id-FTR, excess annular and RV-basal enlargement exhausts valvular/annular coverage reserve, and RV conical deformation does not cause notable valvular tenting. Conversely, PHTN-FTR is determined by valvular tethering with tenting linked to RV elongation and elliptical/spherical deformation. These specific FTR-mechanisms may be important in considering surgical correction in FTR.
authors.affiliation: Division of Cardiovascular Diseases and Internal Medicine, Health-Science Research, and Cardiovascular Surgery, Mayo College of Medicine, Rochester, MN 55905, USA.
authors.forename: Yan
authors.initials: Y
authors.lastname: Topilsky
authors.forename: Amber
authors.initials: A
authors.lastname: Khanna
authors.forename: Thierry
authors.initials: T
authors.lastname: Le Tourneau
authors.forename: Soon
authors.initials: S
authors.lastname: Park
authors.forename: Hector
authors.initials: H
authors.lastname: Michelena
authors.forename: Rakesh
authors.initials: R
authors.lastname: Suri
authors.forename: Douglas W
authors.initials: DW
authors.lastname: Mahoney
authors.forename: Maurice
authors.initials: M
authors.lastname: Enriquez-Sarano
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D015897:Comorbidity; D018618:Echocardiography, Doppler, Color / Q000379:methods; D005260:Female; D006801:Humans; D006976:Hypertension, Pulmonary / Q000453:epidemiology*; D008297:Male; D015995:Prevalence; D011446:Prospective Studies; D014261:Tricuspid Valve / Q000000981:diagnostic imaging; D014262:Tricuspid Valve Insufficiency / Q000000981:diagnostic imaging* / Q000453:epidemiology*