Based on a lecture given at the Mitral Valve Meeting 2017 in Zurich Tricuspid regurgitation: assessment and new frontiers Shingo Kuwata, Michel Zuber, Alberto Pozzoli, Fabian Nietlispach, Felix C. Tanner, Francesco Maisano, Maurizio Taramasso University Heart Centre Zurich, University Hospital of Zurich, University of Zurich, Switzerland Introduction Tricuspid regurgitation (TR) can result from organic (primary) and functional (secondary) pathology. Of these, functional TR is the most prevalent and is stead- ily increasing in frequency [1]. Functional TR is mainly due to a combination of tricuspid annular dilatation and leafet tethering caused by further right ventricu- lar dilatation. It develops progressively in patients with lef-sided heart disease or pulmonary artery hyperten- sion of any cause, or by remodelling with atrial fbrilla- tion. Although functional TR responds initially to medical therapy, this may delay tricuspid valve (TV) surgery beyond the ideal period [2–4]. Since signifcant TR afer lef-sided valvular surgery is associated with poor prognosis, today a lower thresh- old for TR repair at the time of lef-sided valve open heart surgery or intervention is recommended by in- ternational guidelines [5, 6]. At present, the ideal timing of surgery for TV disease remains controversial because of the limited data available. However, international guidelines suggest the threshold for intervention to be a tricuspid annu- lus dilated to ≥40 mm or >21 mm/m 2 , regardless of whether the TR is moderate or severe [5, 6]. CARDIOVASCULAR MEDICINE – KARDIOVASKULÄRE MEDIZIN – MÉDECINE CARDIOVASCULAIRE 2017;20(9):203–208 MINIREVIEW 203 Percutaneous procedures may be an attractive alterna- tive to surgery for patients with symptomatic func- tional TR and high surgical risk. TR assessment with multi-imaging modalities Detailed knowledge of the complex anatomy of the tri- cuspid valve (TV) is fundamental to understanding the several new challenges of percutaneous TR therapy. The TV is composed of three leafets: anterior, poste- rior and septal. Echocardiography is the essential imaging technique in the assessment of patients with TR (fg. 1). Two-di- mensional (2D) transthoracic echocardiography (TTE) is the standard imaging techniques for to assessing the anatomy, the mechanism and severity of TR, and the haemodynamics. The European Society of Echocardio- graphy and the American Society of Echocardiography have provided specifc recommendations for grading the severity of TR on the basis of a combination of qualitative, semiquantitative and quantitative echo- cardiographic measures [6–9]. Three-dimensional (3D) transthoracic echocardiography may provide incre- mental diagnostic information, in particular regard- ing leafet anatomy. Transoesophageal echocardiography (TEE) as well as intracardiac echocardiography (ICE) play an essential role in addition to TTE, and are particularly helpful during TV intervention. Computed tomography (CT) has become a crucial tool for defning patients’ anatomy and assessing the eligi- bility of transcatheter TV therapies. Electrocardio- gram-gated angio-CT is an essential step in the assess- ment of TV anatomy, and the tricuspid annular shape and dimensions, as well as semi-quantitative assess- ment of the tissue characteristics of tricuspid annulus and leafets. Additionally, CT can assess the surround- ing structures of TV including the coronary arteries, inferior vena cava and superior vena cava. Summary Tricuspid regurgitation is the most frequent disease of the tricuspid valve. Of these, functional tricuspid regurgitation is the most frequent, and severe in- suffciency is associated with an increasing risk of cardiovascular events and bad prognosis. The pathophysiology and assessment of tricuspid regurgita- tion is essential for transcatheter treatments, new treatment options. The aim of this short review is to summarise the assessment of tricuspid regur- gitation and to show new transcatheter therapeutic options. Current experi- ence with these new therapies is preliminary and further studies are needed to develop the evidence of transcatheter tricuspid valve therapy. P e e r r e v i e w e d a r t i c l e Published under the copyright license “Attribution – Non-Commercial – NoDerivatives 4.0”. No commercial reuse without permission. See: http://emh.ch/en/services/permissions.html