Severe aortic stenosis (AS) is a frequent and potentially severe disease if left untreated. Despite the widespread adoption of surgical aortic valve replacement (SAVR) and more recently transcatheter aortic valve implantation (TAVI), mortality rates in the mid- to long-term follow-up remain relatively high, especially for higher-risk patients. ^, Yet, transfemoral TAVI became the dominant approach for patients with age > 70 years, enabling a significant reduction in the all-cause and cardiac mortality rates with respect to SAVR, even though the prognosis of a certain subgroup of patients is still jeopardized. Therefore, prior studies in the TAVI field have focused on helping in risk stratifying such patients. For instance, Genereux et al. ^, have shown that the extent of cardiac damage among patients with AS undergoing TAVI could play an important role. Accordingly, a stepwise impact in the mortality at follow-up was demonstrated when patients with AS also had left chamber involvement, with or without mitral regurgitation, followed by pulmonary hypertension, with or without tricuspid regurgitation (TR), and finally with right ventricle dysfunction. Of note, the last two stages (with moderate or severe TR and right ventricle dysfunction) represent the highest mortality rate, up to 20% at 1 year. Apart from TR grade, there is controversy on whether the changes in TR grade in the follow-up might also affect the clinical outcomes.

In this journal issue, Erbano et al. evaluated the association between TR and mortality in a systematic review and meta-analysis of patients with AS undergoing TAVI and further assessed the changes in TR severity post-TAVI and its relationship with short and mid-term mortality. The primary endpoint was defined as the incidence of all-cause mortality according to TR grade at baseline. Secondary endpoints included cardiac mortality and heart failure hospitalization. The authors included 24 studies and more than 45.000 patients, whose mean age was 81.7±8.5 years; 52% were female, with a mean Society of Thoracic Surgeons (STS) score of 8.2±6.0. Approximately 22% of patients had moderate or severe TR at baseline. After a mean follow-up of 1.2 years, pooled analysis of 14 studies revealed that higher grades of TR were associated with a worse prognosis. Severe TR was associated with an 83% increased mortality compared to no/mild TR in the short-term and 56% in the mid-term. In the pooled analysis, the persistence of moderate/severe TR grades, after a mean follow-up of 21 months post-TAVI, was also associated with a 2-fold increase in all-cause mortality.

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Abstract

Severe tricuspid regurgitation (TR) is associated with high morbidity and mortality. Given that surgical treatment of TR alone has been associated with high mortality, transcatheter interventions in the tricuspid valve (TV) have been used for its treatment, with relatively lower risk. There is a delay in intervention for TR, and this is probably related to a limited understanding of the anatomy of the TV and the right ventricle, in addition to an underestimation of the severity of TR. In this scenario, it is necessary to have comprehensive anatomical knowledge of the TV, the pathophysiology involved in the mechanism of regurgitation, and more accurate grading. The TV has anatomical, histological, and spatial peculiarities that make its assessment more complex when compared to the mitral valve, requiring knowledge and training in the various echocardiographic techniques that will often be used in combination for accurate assessment.

This review will describe the anatomy of the TV, the role of echocardiography in the diagnosis, grading, and pathophysiology involved in TR; the main transcatheter treatment options currently available for TR; and the assessment of outcomes after transcatheter intervention by means of multiple echocardiographic modalities.