Transcatheter tricuspid interventions: time to re-think guidelines?

defined by the backflow of blood from the right ventricle into the right atrium, what in normal conditions should be avoided by systolic leaflets coaptation. In almost 90% of TR cases, the valve is anatomically preserved, and the regurgitation is secondary to right ventricular or right atrial dilation (functional TR) due to left-sided heart disease, atrial fibrillation, or pulmonary hypertension, culminating in tricuspid annular dilation or leaflet tethering. The presence of some TR degree is considered the most common valvular heart disease, affecting from 65 to 85% of the population [1], what means a 1.6 and 3.0 million individuals prevalence, and a 200.000 and 300.000 yearly incidence in the United States and Europe, respectively [2]. If considered only significant TR (moderate/severe), the prevalence is one in 25 individuals with 75 years old and over, similar to that observed in significant aortic stenosis [3], and probably underestimated, owing to its long clinically silent time (no specific murmur or symptoms). Still regarding age, it is remarkable that this variable is not only a predictor of TR, but it is also associated with worse outcomes and increased TR recurrence after surgical treatment [4]. Despite its high prevalence and the implied two-fold increase in mortality [5], more than 90% of the patients with significant TR will never receive surgical management [2,6], the only treatment considered class I recommendation in the current guidelines. Two main reasons are responsible for this undertreatment. The first is an obsolete belief that functional TR should improve or disappear after the primary left-sided problem treatment, which was refuted by well-conducted studies proving that TR remains or progresses after left-sided interventions [7]. The second is an unacceptable high morbimortality rate associated with conventional TR surgery, what, unfortunately, remains at least partially true, since TR carries the highest surgical mortality among all cardiac valve surgeries (8.8% – 9.7%) [4]. However, such a bad reputation is in part biased by the advanced stage that patients are referred to surgery, with severe right ventricle dysfunction and end-organ damage, totally opposed to left-sided valves, where surgery is performed before the onset of left ventricle dysfunction or symptoms. Efforts to change the paradigm of poor outcomes related to TR management, and to reduce the gap between the Editorial