Residency · Residency · Cardiothoracic Surgery

Tricuspid Valve Disease: The Forgotten Valve

Overview

Tricuspid valve disease, particularly tricuspid regurgitation (TR), has historically been undertreated — hence its moniker "the forgotten valve." Growing evidence that significant TR is associated with excess mortality, combined with emerging transcatheter options, has brought renewed attention to this valve. This chapter covers the anatomy, pathophysiology, surgical indications, and repair techniques for tricuspid valve disease.

Anatomy

Tricuspid Valve Structure

The tricuspid valve has three leaflets: the anterior (the largest), the septal (the smallest, most restricted by chordal attachments), and the posterior (inferior). The annulus is saddle-shaped and the largest of the four cardiac valve annuli, measuring approximately 11 to 12 cm in circumference in normal adults. Annular dilatation occurs predominantly along the anterior and posterior segments (the free wall portions), while the septal annulus is relatively fixed due to its fibrous attachment to the septum.

Critical Relationships

The AV node and bundle of His reside within the triangle of Koch, bounded by the tendon of Todaro, the coronary sinus ostium, and the septal leaflet annulus. The right coronary artery courses in the AV groove adjacent to the anterior and posterior annulus, creating a risk of injury during annuloplasty. The coronary sinus ostium, located just posterior to the septal leaflet, must be identified to avoid obstruction during repair.

Etiology of Tricuspid Regurgitation

Functional (Secondary) TR — Most Common

The most common cause of TR is functional, resulting from right ventricular and annular dilatation secondary to left-sided heart disease. Left-sided valve disease (especially mitral) causes pulmonary hypertension, RV pressure overload, RV dilatation, and tricuspid annular dilatation. Atrial fibrillation can dilate the right atrium alone, stretching the tricuspid annulus and causing TR even without RV dysfunction. In all these cases, the leaflets are structurally normal but fail to coapt due to annular enlargement.

Etiology of Tricuspid Regurgitation Summary

Organic (Primary) TR

Primary TR stems from intrinsic valve pathology. Rheumatic disease causes leaflet thickening and retraction (usually concomitant with mitral disease). Endocarditis, particularly in IV drug users, produces right-sided infection. Carcinoid syndrome causes leaflet thickening and retraction from serotonin-mediated fibrosis. Ebstein anomaly involves apical displacement of the septal and posterior leaflets. Traumatic TR from blunt chest trauma can rupture papillary muscles or chordae. Iatrogenic TR from pacemaker or ICD leads (through lead impingement, leaflet perforation, or chordal entanglement) is increasingly recognized. Radiation therapy can cause leaflet fibrosis and retraction.

Natural History and Impact

Consequences of Untreated Significant TR

Untreated significant TR leads to right heart failure with peripheral edema, ascites, and hepatic congestion. Chronic venous congestion can progress to cardiac cirrhosis. Renal dysfunction results from reduced cardiac output and venous congestion. Exercise capacity and quality of life are impaired. Importantly, severe TR is an independent predictor of death.

The Problem of Late TR After Left-Sided Valve Surgery

TR may progress years after successful mitral valve surgery due to persistent pulmonary hypertension, progressive RV remodeling, and atrial fibrillation. Isolated reoperation for TR carries high mortality (5-10%) because patients present at an advanced stage. This recognition has driven a shift toward more aggressive concomitant tricuspid intervention during left-sided surgery.

Indications for Surgery

ACC/AHA 2020 Guidelines

Concomitant Tricuspid Surgery During Left-Sided Valve Surgery

Severe TR during left-sided valve surgery is a Class I indication. Mild, moderate, or greater TR with tricuspid annular dilatation (at or above 40 mm or at or above 21 mm/m2) is a Class IIa indication. Progressive TR with signs of RV dilatation or dysfunction during left-sided surgery is also Class IIa.

Isolated Tricuspid Surgery

Severe TR with symptoms of right heart failure despite medical therapy is a Class I indication. Severe TR with progressive RV dilatation or dysfunction, even if asymptomatic, is Class IIa. Severe TR post-left-sided surgery with symptoms or progressive RV dysfunction is Class IIb.

Key Principle

The threshold for concomitant tricuspid repair is low — it is far better to address the tricuspid valve at the time of left-sided surgery than to subject the patient to reoperation later for progressive TR.

Surgical Techniques

Tricuspid Annuloplasty

Ring Annuloplasty (Preferred)

A rigid or semi-rigid incomplete ring is placed along the anterior and posterior annulus, intentionally avoiding the septal segment to protect the conduction system. The ring is sized to the septal leaflet (which is least affected by dilatation). This restores annular geometry, prevents further dilatation, and achieves greater than 90% freedom from significant TR at 5 years.

DeVega Annuloplasty

This suture-based technique plicates the anterior and posterior annulus in a semicircular fashion without prosthetic material. It is less durable than ring annuloplasty, with higher recurrence rates, but may still be used when prosthetic material is to be avoided (such as in active endocarditis) or when cost is a concern.

Tricuspid Annuloplasty Techniques Comparison

Kay Annuloplasty (Bicuspidization)

This older technique plicates the posterior leaflet annulus, converting the tricuspid valve to a bicuspid valve. It is rarely used currently because it is inferior to ring annuloplasty.

Tricuspid Valve Replacement

Replacement is reserved for severely diseased valves not amenable to repair (rheumatic, carcinoid, Ebstein, lead-related destruction). Bioprosthetic valves are strongly preferred because mechanical valves in the tricuspid position have unacceptably high thrombosis rates due to the low-pressure flow environment. Even with bioprosthetic valves, warfarin is often recommended for 3 to 6 months. The septal leaflet and subvalvular apparatus should be preserved when possible. Sutures along the septal annulus must be placed superficially to avoid AV block.

Lead Management in Device-Related TR

Pacemaker or ICD leads causing TR may need to be removed or relocated. Repairing the valve around the lead is technically challenging. If the lead cannot be managed percutaneously, lead extraction with epicardial lead placement may be necessary.

<image>Surgeon's view of the tricuspid valve from the right atrium with anatomic landmarks. The three leaflets (anterior, septal, and posterior) are labeled. The triangle of Koch is delineated by the tendon of Todaro, the coronary sinus ostium, and the septal leaflet attachment, with the AV node location marked within the triangle. The annuloplasty ring placement is shown along the anterior and posterior annulus with the septal segment intentionally excluded. The right coronary artery course in the AV groove adjacent to the anterior annulus is illustrated. An inset shows the correct suture placement depth along the septal annulus to avoid conduction injury.</image>

Emerging Transcatheter Options

Transcatheter Tricuspid Valve Repair

Edge-to-edge repair devices for the tricuspid valve (TriClip, PASCAL) are gaining traction. The TRILUMINATE Pivotal trial showed that TriClip achieves significant TR reduction and improved quality of life compared to medical therapy. Patient selection focuses on high surgical risk patients with symptomatic severe TR.

Transcatheter Tricuspid Valve Replacement

Multiple devices are in development (EVOQUE, GATE, NaviGate), though challenges remain including the large annulus, proximity to the conduction system and RCA, and variable anatomy.

Annuloplasty Devices

Transcatheter annuloplasty devices such as the Cardioband are deployed along the tricuspid annulus. Early results demonstrate feasibility, with long-term data awaited.

<image>Echocardiographic assessment of tricuspid regurgitation severity. Four panels of apical four-chamber views show: (A) normal tricuspid valve with proper coaptation, (B) moderate functional TR with annular dilatation and central regurgitant jet on color Doppler, (C) severe TR with wide vena contracta and large coaptation gap, and (D) post-repair result showing restored coaptation after ring annuloplasty. Each panel includes measurements of annular diameter and vena contracta width. Doppler criteria for TR severity grading are shown in a summary table below.</image>

Clinical Pearls

The tricuspid valve is no longer "forgotten" — significant TR is an independent predictor of mortality and must be addressed proactively. At the time of left-sided valve surgery, the threshold for concomitant tricuspid repair should be low: annular dilatation at or above 40 mm alone (even without severe TR) is a Class IIa indication for annuloplasty. Ring annuloplasty is more durable than suture-based techniques (DeVega) and is the preferred repair method. The septal portion of the annulus is intentionally excluded from ring placement to protect the AV node and bundle of His in the triangle of Koch. Isolated reoperation for TR after prior cardiac surgery carries high mortality (5-10%) — this is the strongest argument for aggressive concomitant treatment at the initial operation. Mechanical prostheses in the tricuspid position have unacceptably high thrombosis rates, and bioprosthetic valves are strongly preferred when replacement is needed. Atrial fibrillation-related TR from RA dilatation alone is an increasingly recognized entity, particularly in the aging population. Lead-related TR from pacemaker or ICD leads is underdiagnosed and can be difficult to manage surgically.

References

• Otto CM, Nishimura RA, Bonow RO, et al. 2020 ACC/AHA Guideline for Valvular Heart Disease. Circulation. 2021;143(5):e72-e227.
• Dreyfus GD, Corbi PJ, Chan KM, Bahrami T. Secondary tricuspid regurgitation or dilatation: which should be the criteria for surgical repair? Ann Thorac Surg. 2005;79(1):127-132.
• Navia JL, Nowicki ER, Blackstone EH, et al. Surgical management of secondary tricuspid valve regurgitation: annulus, commissure, or leaflet procedure? J Thorac Cardiovasc Surg. 2010;139(6):1473-1482.
• Lurz P, Stephan von Bardeleben R, Weber M, et al. TRILUMINATE Pivotal: Transcatheter tricuspid valve repair for symptomatic tricuspid regurgitation. N Engl J Med. 2024;390(4):295-306.
• Taramasso M, Benfari G, van der Merwe J, et al. Transcatheter versus medical treatment of patients with symptomatic severe tricuspid regurgitation. J Am Coll Cardiol. 2019;74(24):2998-3008.

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