A Novel Transcatheter Device for the Edge-to-Edge Treatment of Tricuspid Regurgitation: A Preliminary Evaluation

Abstract

Tricuspid regurgitation (TR) is the most common pathology of the tricuspid valve (TV), with significant mortality in severe cases. A well-established strategy to treat TR is represented by the clover surgical technique, which consists of stitching together the free edges of TV leaflets, producing a clover-shaped valvular orifice. Transcatheter treatments for TR constitute a valuable alternative for high-risk patients. In this work we investigated haemodynamic performances and safety of a novel device (StarTric device (STD)) aiming to perform the clover technique via percutaneous access. To assess haemodynamic performances, STD and clover were applied on porcine pathological TVs and tested. Fluid dynamic indexes of both strategies were compared to the pathological model. To evaluate device safety, forces exchanged between device and leaflets were compared to the extraction force (EF) required to STD to completely pass through the leaflet. Clover technique and STD induced a comparable TV backflow reduction (48% and 47%, respectively), with associated increase of TV flow in all tested conditions. Diastolic transvalvular pressure similarly increased indicating a reduction, though not significant, of the valvular orifice. Forces ranged from 1N to 1.71N, compared to an EF of 22.16 ± 8.6N. Force varied significantly amongst different working conditions (normotensive, mild, and severe hypertensive) for each leaflet, whilst no significative variation was found on different leaflets in the same working condition. In the adopted experimental scenario, STD demonstrated comparable efficacy to the surgical strategy in restoring TV haemodynamic. The forces acting on the leaflets following STD implantation were far lower when compared to EFs.

Keywords: Clover technique; Percutaneous treatments; Tricuspid regurgitation.

Fig. 1

Schematic representation of device implant. RA right atrium; RV right ventricle, TV tricuspid valve

Fig. 2

a Scheme of the pulsatile flow mock loop. TV tricuspid valve, PV pulmonary valve; b picture of a heart sample connected to afterload and preload

Fig. 3

Surgical steps of the clover technique

Fig. 4

In-house-developed load cell

Fig. 5

Tricuspid leaflet prepared for the test. a Leaflet on custom-made 3D-printed frame. b Closed frame with anchor channel

Fig. 6

Schematic representation of the STD and load cell mounting

Fig. 7

Endoscopic views of the TV in the tested cases in systolic and diastolic phase. S, A, P: septal, anterior, and posterior leaflet

Fig. 8

Comparison of indexes evaluated in the haemodynamic assessment

Fig. 9

Representation of raw data acquired in time. Anterior, posterior, and septal: force value recorded by the load cell on the anterior, posterior, and septal leaflet; ΔP tricuspid transvalvular pressure, TV flow tricuspid flow rate

Fig. 10

F_max recorded on each of the TV leaflet in the imposed working conditions (Normotensive, Mild Hypertensive, and Severe Hypertensive condition). Values are represented as mean value; error bars show standard deviation