Tricuspid Valve #3: TR Etiology

Tricuspid regurgitation is not a single disease entity; it is a final common hemodynamic phenotype produced by distinct anatomic and geometric mechanisms. A clinically useful framework is to separate primary (organic) TR from secondary/functional TR, because the dominant mechanism predicts what a durable intervention must target—structure (leaflet/chordae) versus geometry (annulus + RA/RV remodeling) [1,2].

1) Primary TR (Organic TR): “The valve is diseased”

Definition: TR caused by intrinsic pathology of the tricuspid valve apparatus (leaflets, chordae, papillary muscles, or supporting tissue) [1].

Common etiologies (mechanism-first)

• Congenital malformations
• Ebstein anomaly (leaflet displacement/dysplasia → malcoaptation)
• Leaflet cleft/dysplasia; abnormal chordal architecture (often mixed restriction + prolapse physiology) [1]
• Infective endocarditis
• Leaflet destruction/perforation (fenestration-like defects), chordal rupture, flail segment → often acute severe TR [2]
• Rheumatic / carcinoid disease
• Rheumatic: thickening/retraction with restriction
• Carcinoid: plaque-like fixation and retraction (often severe restriction) [1]
• Trauma / iatrogenic injury
• Leaflet/chordal disruption (including catheter/device-related trauma) [2]
• Myxomatous degeneration
• Redundant leaflet tissue ± prolapse/flail physiology [1]

Practical surgical principle: Primary TR is a lesion-driven problem—first define what is broken (tear, perforation, ruptured chord, dysplasia), then select repair techniques that directly neutralize that lesion; replacement is reserved for non-reconstructable tissue or advanced destructive pathology [1].

2) Secondary TR (Functional TR): “The valve is normal; the geometry is not”

Secondary TR accounts for the majority of clinically encountered TR and is fundamentally a right-heart remodeling disease with failure of coaptation due to annular dilation and/or leaflet tethering [1,2].

A. Atrial Functional TR (AFTR): RA-driven geometry (Carpentier I physiology)

Core mechanism: Right atrial enlargement/dysfunction → annular dilation with relatively preserved leaflet mobility and limited tethering early in the disease course [1,3].

Typical clinical drivers

• Long-standing atrial fibrillation/flutter
• Chronic RA pressure/volume loading (including left-sided valve disease history)
• “Atrial myopathy” phenotype: RA/annular remodeling out of proportion to RV systolic failure [1,3]

Imaging signature (high-yield):

• Disproportionate RA and annular enlargement; less tethering (smaller tenting height/area) compared with ventricular phenotypes [1,3].

Implication for durability: When tethering is limited, annuloplasty (or annuloplasty-equivalent transcatheter strategies) is often the core mechanical solution.

B. Ventricular Functional TR (VFTR): RV-driven geometry (Carpentier IIIb physiology)

Core mechanism: RV remodeling (pressure and/or volume overload) causes papillary displacement and leaflet tethering with restricted systolic leaflet motion, often accompanied by annular dilation [2].

Typical clinical drivers

• Pulmonary hypertension (precapillary or postcapillary physiology)
• LV dysfunction with secondary pulmonary vascular/venous hypertension
• RV infarction/cardiomyopathy; chronic RV volume overload states [2]

Implication for durability: Annuloplasty alone may under-correct TR when tethering is advanced; consider tethering-directed strategies (e.g., leaflet augmentation or subvalvular concepts) and recognize that late-stage RV remodeling is a key determinant of recurrent TR and adverse outcomes [2].

3) Special Etiologies (Mechanistically Mixed, Clinically High-Impact)

A. Device/Lead-Related TR (CIED-associated TR)

This is best treated as a distinct phenotype because the mechanism can be primary-like (direct leaflet impingement/entanglement/adherence) or secondary-like (pacing-related RV dyssynchrony/dysfunction → remodeling) [1]. Management hinges on identifying which mechanism dominates, because the therapeutic priority may shift toward lead management, valve intervention, or both.

B. TR after Left-Sided Valve Disease/Surgery

Late or progressive TR after mitral/aortic intervention often reflects persistent or progressive right-heart remodeling, frequently mediated by pulmonary hypertension and/or atrial remodeling [2]. Importantly, data support addressing annular dilation at the time of left-sided valve surgery, with an annular diameter threshold commonly cited around ≥3.5 cm as a practical trigger for concomitant tricuspid repair rather than “wait-and-see” [4].

Imaging: What Must Be Measured (Not Just “Seen”)

A mechanism-based TR report should explicitly answer: Why is it leaking? How severe is it? What is the right-heart response? Two-dimensional echocardiography remains foundational for defining etiology and grading severity, while 3D echocardiography refines annular and leaflet geometry and clarifies remodeling patterns that distinguish AFTR from VFTR [1]. Contemporary echocardiographic guidance emphasizes a multiparametric severity assessment (including quantitative measures when feasible) and structured reassessment before/after interventions [5].

Prognostic note: Quantitative TR measures (e.g., effective regurgitant orifice area and regurgitant volume) are strongly associated with outcomes in functional TR populations, supporting earlier recognition and timely referral rather than late “end-stage” intervention [6].

Intervention Strategy: A Mechanism-to-Target Map

1. Primary TR → repair the structure
• Address leaflet/chordal lesions directly; replace when tissue is not reconstructable [1,2].
2. Secondary TR → repair the geometry
• AFTR: annulus is the dominant target (often better repair mechanics early) [1,3].
• VFTR: annulus plus tethering/RV remodeling must be acknowledged; advanced tethering predicts recurrence risk [2].
3. Surgical choice (repair vs replacement)
• When feasible, repair is associated with better survival compared with replacement in pooled analyses, without a clear penalty in reoperation risk across multiple datasets [7].
4. High-risk patients / evolving options
• Transcatheter therapies are increasingly integrated for selected high-risk patients, and contemporary position statements emphasize careful phenotype selection and right-heart geometry assessment when choosing repair versus replacement strategies [8].

Practical “Surgeon-Facing” Summary (One Mental Model)

1. Primary TR: fix the structure (leaflet/chordae/PM pathology) [1].
2. Secondary TR: fix the geometry
• RA-driven → annulus (AFTR; Carpentier I) [1,3]
• RV-driven → tethering + annulus (VFTR; Carpentier IIIb) [2]
3. Special TR: always ask “lead/device? prior left-sided surgery? pulmonary hypertension?” because these shift mechanism, recurrence risk, and the optimal procedural target [2,4].
4. Phenotype matters: TR clusters defined by comorbidity and remodeling patterns have distinct risk profiles—use phenotype language to communicate prognosis and align timing of intervention across the team [9].

References

[1] Prihadi EA, Delgado V, Leon MB, Enriquez-Sarano M, Topilsky Y, Bax JJ. Morphologic Types of Tricuspid Regurgitation: Characteristics and Prognostic Implications. JACC Cardiovasc Imaging. 2019;12(3):491-499.

[2] Gerçek M, Rudolph V. Secondary Tricuspid Regurgitation: Pathophysiology, Incidence and Prognosis. Front Cardiovasc Med. 2021;8:701243.

[3] Schlotter F, Dietz MF, Stolz L, et al. Atrial Functional Tricuspid Regurgitation: Novel Definition and Impact on Prognosis. Circ Cardiovasc Interv. 2022;15(9):e011958.

[4] Shiran A, Sagie A. Tricuspid regurgitation in mitral valve disease incidence, prognostic implications, mechanism, and management. J Am Coll Cardiol. 2009;53(5):401-408.

[5] Badano LP, Tomaselli M, Muraru D, et al. Advances in the Assessment of Patients With Tricuspid Regurgitation: A State-of-the-Art Review on the Echocardiographic Evaluation Before and After Tricuspid Valve Interventions. J Am Soc Echocardiogr. 2024;37(11):1083-1102.

[6] Bartko PE, Arfsten H, Frey MK, et al. Natural History of Functional Tricuspid Regurgitation: Implications of Quantitative Doppler Assessment. JACC Cardiovasc Imaging. 2019;12(3):389-397.

[7] Choi JW, Jang MJ, Kim KH, Hwang HY. Repair versus replacement for the surgical correction of tricuspid regurgitation: a meta-analysis. Eur J Cardiothorac Surg. 2018;53(4):748-755.

[8] Antunes MJ, Rodríguez-Palomares J, Prendergast B, et al. Management of tricuspid valve regurgitation: Position statement of the European Society of Cardiology Working Groups of Cardiovascular Surgery and Valvular Heart Disease. Eur J Cardiothorac Surg. 2017;52(6):1022-1030.

[9] Anand V, Scott CG, Hyun MC, et al. The 5 Phenotypes of Tricuspid Regurgitation: Insight From Cluster Analysis of Clinical and Echocardiographic Variables. JACC Cardiovasc Interv. 2023;16:156-165.