Moderate‑to‑severe tricuspid regurgitation (TR) has a high prevalence in the general population,¹ and it progressively increases in older individuals, in whom it is close to 4%.² Primary TR is rare, and it is usually secondary to left‑sided heart disease, pulmonary hypertension, and / or right ventricular dysfunction (RVD).³

In heart failure (HF), the impact of secondary TR has been for long neglected or considered a bystander without prognostic consequences, and therefore no particular efforts have been undertaken to correct it.⁴ However, recent large studies and meta‑analyses have demonstrated that TR directly contributes to increased morbidity and mortality in chronic HF,^5-7 capturing the attention of the HF community. This is not only due to learning that TR can actively influence the progression of HF syndrome, but also to a growing amount of evidence supporting novel treatment strategies for TR.^2-5 A percutaneous approach to the correction of TR provides an alternative pathway for patients with isolated TR, as in the past they were rarely referred for surgery due to high postoperative mortality.^6,7

Growing interest in the coexistence of TR and HF has also encouraged new research in this field aimed at better understanding of the complex interaction between these 2 conditions. There are many different structural mechanisms behind the progression of valve regurgitation, and they depend on the primary etiology and phenotype of HF. Identification of the atrial TR phenotype has further expanded the complexity of the problem, but has also represented an important step in the understanding of the pathophysiology of TR in HF.⁸

In the setting of hospitalization for acute decompensated HF (ADHF), the prognostic role of TR has remained undefined for a long time. In the recent years, the association of TR with poorer survival has been confirmed in the acute setting, and it was independent of the HF phenotype and the type of TR. Similarly to the chronic setting, patients with severe TR have several characteristics of a more advanced disease as well as more complex comorbidities, but an adjusted analysis supported the independent prognostic role of TR.

TR has also demonstrated its dynamic nature during hospitalization. It seems to be secondary to the response to therapeutic interventions, and changes in TR severity have important implications for the prognosis of patients after discharge.⁹ Moreover, in ADHF with reduced ejection fraction (EF), TR may be a barrier to the implementation of guideline‑directed medical therapy after discharge, providing an additional explanation of the increased TR‑related mortality risk.

Risk stratification of patients with TR remains a major challenge, especially considering patient eligibility for surgery. High mortality rates discouraged clinicians and surgeons from approaching isolated TR, but no efforts have been made to define the phenotype of patients at risk to improve their selection. In 2022, Dreyfus et al¹⁰ proposed a novel tool, the TRI‑SCORE scale, for in‑hospital mortality prediction in patients undergoing isolated surgery of the tricuspid valve. The score includes 8 simple variables: age of at least 70 years, New York Heart Association class III–IV, right‑sided HF signs, daily dose of furosemide at least 125 mg, glomerular filtration rate below 30 ml/min/1.73 m², elevated level of bilirubin, left ventricular EF below 60%, and moderate‑to‑severe RVD, which are the manifestations of the clinical status in terms of right HF severity rather than of the anatomical valve characteristics. The score outperformed more general risk scores and was validated in other settings, including transcatheter valve repair, providing a reliable tool for risk estimation and timely referral of patients for TR correction.^11-13 As the components of the TRI‑SCORE reflect more the severity of right HF than the complexity of valve disease, its performance could be easily extended to different contexts, not strictly depending on the correction of the valve defect. In a recent report by the TRIGISTRY investigators,¹⁴ the TRI‑SCORE scale indeed stratified the mortality risk of patients regardless of treatment allocation, including those managed conservatively. However, the TRIGISTRY registry enrolled patients with severe isolated TR, and was not specifically designed for patients with HF and secondary TR. Moreover, patients with moderate TR were not included, whereas in HF moderate TR has also demonstrated to negatively influence the outcome.¹⁵ In this issue of Polish Archives of Internal Medicine, Sonsöz et al¹⁶ significantly contributed to filling this gap by analyzing the performance of the TRI‑SCORE in a HF population with moderate‑to‑severe TR hospitalized for ADHF. Moreover, they extended the landscape of risk estimation beyond the in‑hospital mortality risk evaluating the performance of the TRI‑SCORE over a median (interquartile range) follow‑up of 8 (2–21) months. As can be expected with a score including markers of right HF severity, the TRI‑SCORE discriminated the risk in HF patients and allowed for stratification of risk classes with distinct survival trajectories. Moreover, the patients with high TRI‑SCORE values required more intensive treatments, such as inotropic support, paracentesis, and dialysis. This is important, as it might help identify individuals with low probability of gaining benefit from aggressive treatment or, alternatively, avoid a delay of treatment intensification. However, some points still need answers. The risk stratification in patients with right HF is a major topic in the current era of long‑term mechanical circulatory support, and identifying tools that can contribute to defining this risk is crucial. The application of the TRI‑SCORE to the general ADHF or chronic HF population with or without TR might provide further instruments for proper risk estimation. Moreover, Sonsöz et al¹⁶ did not assess the impact of TR correction on the long‑term risk, whereas the HF community urgently needs information on the prognostic benefit of procedural treatments of TR in patients with HF to understand who is the optimal candidate for TR correction and which is the best approach.

In conclusion, the efforts made by Sonsöz et al¹⁶ are highly valuable, as important conclusions can be derived from their data. This is another milestone on the path of linking HF to TR and the incentive to move from observation to action, since treatment of secondary TR represents the future of HF management.