Tricuspid regurgitation (TR) represents the most common valvular heart disease in the general population, with an increasing incidence due to population aging and the consequent rise in associated cardiac comorbidities. In all circumstances leading to its onset, TR serves as an independent risk factor for increased mortality, with a direct correlation between the severity of regurgitation and mortality rates. In light of these findings, research and the number of publications on TR and its potential repair alternatives have increased exponentially over the last decade.

Surgical repair or replacement of the tricuspid valve, when treated as an isolated valvular disease, was practically the only therapeutic alternative until the first reports of percutaneous repair emerged in 2015. Traditionally, TR was considered a benign condition primarily managed with medical therapy, with a lower level of recommendation for isolated surgical repair in both American and European guidelines. However, this paradigm has shifted due to the previously mentioned epidemiological changes, leading to a broader selection of patients for both treatment approaches. The recent surge in percutaneous treatment has been facilitated by these developments, alongside advancements and refinements in transcatheter techniques, which frequently aim to replicate surgical repair. Conversely, surgical treatment remains constrained by the age and comorbidities of these patients, which explains why hospital mortality following surgery has not shown significant reductions over the past two decades, stabilizing at approximately 8% for the overall surgical cohort.

The decision to intervene percutaneously on severe TR remains a complex debate, often requiring input from multiple specialists. Within the natural history of the disease, certain conditions—such as right ventricular dilation and dysfunction or severe pulmonary hypertension—are considered points of no return when evaluating reparative treatment options. Additionally, in some cases, appropriate medical management can control the disease and delay the need for intervention. The threshold between these situations varies among patients, necessitating close follow-up and monitoring through imaging techniques, laboratory tests, and invasive studies such as right heart catheterization. A study published this year analyzing data from the EuroTR registry of patients treated with percutaneous interventions highlights that those who benefit the most from this approach are typically in an intermediate stage of disease progression, as determined by echocardiographic and analytical parameters (primarily renal function and natriuretic peptides).

Percutaneous treatment of tricuspid regurgitation

Percutaneous tricuspid valve repair has demonstrated clinical benefits but has not yet shown prognostic improvement in patients with severe tricuspid regurgitation, mainly in terms of reducing hospitalizations and improving quality of life. Randomized clinical trials such as TRI-LUMINATE (2023) and TRISCEND II (2025) have consistently confirmed these findings, despite the lack of significant improvement in overall survival rates (long-term results are still pending). These studies have been a crucial step toward better patient selection. They have also demonstrated the low morbidity and high safety profile of these procedures, with an almost negligible procedure-related mortality rate (practically 0%), making them a viable option for most patients who meet the clinical and anatomical criteria for each device.

Among the currently available devices, four well-defined groups can be identified, each mimicking different previously established surgical techniques for treating tricuspid regurgitation based on its etiology and anatomy. Each category presents specific advantages and limitations, and they can be used in a combined approach:

• Edge-to-edge repair devices: These simulate leaflet approximation techniques similar to the Alfieri method in mitral regurgitation. The most widely used devices in our setting, which have CE marking and have been studied in randomized clinical trials, are the Edwards PASCAL® and Abbott TriClip® systems. Their optimal use is in central coaptation defects that are small and without significant ventricular restriction of leaflet movement, as well as in primary tricuspid regurgitation due to leaflet prolapse.
• Annuloplasty devices: These are represented mainly by the Edwards Cardioband® system and are useful in atrial secondary tricuspid regurgitation caused by annular dilation.
• Orthotopic tricuspid valve prostheses: Several models are currently under development, including Edwards EVOQUE®, LuX®, and Medtronic Intrepid®. These are the treatment of choice for cases that are not suitable for edge-to-edge repair, particularly in cases of organic tricuspid valve disease, leaflet motion restriction, or perforation.
• Heterotopic prostheses: Devices such as TricValve®, which are implanted at the junction of both venae cavae with the right atrium, represent a last-resort option that is currently considered a palliative treatment for symptomatic patients who are not candidates for other techniques.

Tricuspid Valve Academic Research Consortium

In October 2023, a state-of-the-art document was published in the Journal of the American College of Cardiology focusing on severe tricuspid regurgitation, aiming to consolidate all the available information from recent years regarding classification, prognosis, and treatment to provide patients with the best possible therapeutic options.

The document is divided into two sections:

1. Definitions: It establishes precise criteria for the different etiologies of tricuspid regurgitation. Two main groups are defined:
   1. Primary tricuspid regurgitation: Less common (5%-10% of cases), with a degenerative, congenital, or acquired origin (e.g., tumors, trauma, radiation, rheumatic disease, carcinoid syndrome).
   2. Secondary tricuspid regurgitation: Accounts for approximately 80% of cases, primarily caused by right atrial dilation and annular enlargement. This group also includes cases related to right ventricular dilation and those associated with pacemaker leads or implantable defibrillators (10%-15%), either due to direct mechanical interference or secondary effects altering valvular function.
2. Objectives for future studies and clinical trials: This section outlines the key aspects necessary for designing high-quality research protocols to optimize patient selection, refine risk stratification models, and unify study endpoints.

From an anatomical standpoint, the document classifies tricuspid valve morphology into four major types. The Type I configuration, consisting of three leaflets (anterior, posterior, and septal), is the most common. The second most frequent variant, Type IIIB, is characterized by a bifid posterior leaflet, which accounts for a significant percentage of cases. The presence of additional commissures and leaflet fenestrations can pose technical challenges for certain percutaneous repair techniques, such as edge-to-edge repair.

The development of percutaneous techniques and the increasing number of clinical trials have led to improved surgical risk assessment tools. One of the most relevant advancements is the TRI-SCORE, a risk stratification model for isolated tricuspid regurgitation treatment, which has demonstrated greater predictive accuracy than traditional risk scores such as EuroSCORE I-II and the Society of Thoracic Surgeons (STS) score. This model is currently considered the best available stratification strategy for patients undergoing invasive treatment.

In terms of mortality outcomes, while the global surgical mortality for TR remains at 8%, TRI-SCORE classification into high, moderate, and low-risk categories has allowed for improved risk-adjusted survival outcomes. Notably, patients classified as low-risk undergoing surgery have demonstrated superior survival rates compared to those receiving percutaneous interventions. Among moderate-risk patients, surgery has also yielded better long-term outcomes when procedural success is achieved, defined as a post-treatment reduction of TR severity to ≤2+.

Quantification of severity and its clinical impact: a key aspect

One of the most significant modifications in the quantification of tricuspid regurgitation (TR) severity in recent years is the transition from a three-tier to a five-tier classification. This change is based on the observation that not all patients with severe TR present the same prognosis. In 2017, Dr. Rebecca Hahn (Columbia University) and Dr. José Luis Zamorano (Hospital Ramón y Cajal) introduced the massive and torrential TR categories, driven by an improved characterization of hemodynamic parameters and quality of life. This refinement has demonstrated that any degree of TR reduction within this expanded classification correlates with improved clinical outcomes, as previously observed in percutaneous intervention trials such as SCOUT.

The echocardiographic evaluation of the tricuspid valve includes multiple parameters that aid in determining severity. Among these, the biplane vena contracta width is likely the most reproducible and robust parameter, while the most specific is systolic flow reversal detected via pulsed Doppler in the hepatic veins. It is recommended to analyze severity using multiple methods, including the calculation of the effective regurgitant orifice area (EROA) using the PISA method and volumetric approaches such as regurgitant fraction. Additionally, cardiac magnetic resonance imaging (MRI) could be a useful noninvasive tool, providing an accurate assessment of right ventricular volume and function, as well as TR severity, without requiring radiation or contrast agents.

The natural history of TR follows a vicious cycle, where volume overload leads to progressive right heart chamber dilation and annular enlargement, further worsening leaflet coaptation. As a result, quantifying right ventricular morphology and function—especially the role of the right ventricle—has gained significant importance and is now included in TR classification as a key parameter for assessing disease severity.

Medical, surgical, or percutaneous treatment, but with a successful outcome

The previously mentioned document defines the key objectives that must be met to consider percutaneous tricuspid valve repair (TTVR) successful. Beyond complications related to the procedure, such as bleeding or vascular access issues, the selected repair technique must ensure at least a reduction in TR severity to ≤2+ (moderate) and the absence of residual stenosis. It is important to recognize that TR cases with a component of ventricular dilation and leaflet tenting with an area ≥1.92 cm² and/or a vena contracta width >11 mm tend to present higher rates of residual regurgitation following valve repair.

Among the parameters used to assess residual TR severity, one of the most useful is the three-dimensional vena contracta area measured via transesophageal echocardiography, particularly for annuloplasty and edge-to-edge repair devices. For orthotopic valve prostheses, additional methods such as PISA-derived EROA are recommended, as their evaluation closely resembles that of surgical bioprostheses.

The second part of the document is of great relevance for advancing scientific rigor in TR research, as it introduces standardized classifications for key outcome parameters, including mortality, hospitalizations, procedure-related complications (e.g., bleeding, device embolization, thrombosis), and device-related complications (e.g., malposition, dysfunction, endocarditis). These definitions play a crucial role in unifying scientific language in TR research, streamlining study design, and improving the overall scientific quality of publications on tricuspid regurgitation.

COMMENTARY:

Tricuspid regurgitation is a highly prevalent condition associated with significant morbidity and mortality, particularly in an elderly, high-surgical-risk population. Although medical therapy has historically been the mainstay of management, percutaneous treatment alternatives are undergoing rapid and exponential growth. To date, edge-to-edge repair devices have the strongest supporting evidence and are the most widely used, with randomized clinical trials demonstrating improvements in quality-of-life metrics and reductions in heart failure-related hospitalizations. The recently published Tricuspid Valve Academic Research Consortium document represents a major step toward standardizing diagnostic criteria, follow-up strategies, study endpoints, and treatment objectives, facilitating improved patient selection and the individualized application of these therapies.

REFERENCES:

Hahn RT, Lawlor MK, Davidson CJ, Badhwar V, Sannino A, Spitzer E, et al. Tricuspid Valve Academic Research Consortium Definitions for Tricuspid Regurgitation and Trial Endpoints. J Am Coll Cardiol. 2023 Oct 24;82(17):1711-1735. doi: 10.1016/j.jacc.2023.08.008.

Hahn RT, Weckbach LT, Noack T, Hamid N, Kitamura M, Bae R, et al. Proposal for a Standard Echocardiographic Tricuspid Valve Nomenclature. JACC Cardiovasc Imaging. 2021 Jul;14(7):1299-1305. doi: 10.1016/j.jcmg.2021.01.012.

Hahn RT, Zamorano JL. The need for a new tricuspid regurgitation grading scheme. Eur Heart J Cardiovasc Imaging. 2017 Dec 1;18(12):1342-1343. doi: 10.1093/ehjci/jex139.

Chang CC, Veen KM, Hahn RT, Bogers AJJC, Latib A, Oei FBS, et al. Uncertainties and challenges in surgical and transcatheter tricuspid valve therapy: a state-of-the-art expert review. Eur Heart J. 2020 May 21;41(20):1932-1940. doi: 10.1093/eurheartj/ehz614.

Taramasso M, Benfari G, van der Bijl P, Alessandrini H, Attinger-Toller A, Biasco L, et al. Transcatheter Versus Medical Treatment of Patients With Symptomatic Severe Tricuspid Regurgitation. J Am Coll Cardiol. 2019 Dec 17;74(24):2998-3008. doi: 10.1016/j.jacc.2019.09.028.

Topilsky Y, Maltais S, Medina Inojosa J, Oguz D, Michelena H, Maalouf J, et al. Burden of Tricuspid Regurgitation in Patients Diagnosed in the Community Setting. JACC Cardiovasc Imaging. 2019 Mar;12(3):433-442. doi: 10.1016/j.jcmg.2018.06.014.