MitraClip NTR vs XTR system for transcatheter tricuspid valve repair of tricuspid regurgitation

Abstract

Abstract Background Transcatheter tricuspid valve repair (TTVr) is a novel modality for treatment of severe tricuspid regurgitation (TR) in patients at high surgical risk. So far, the most frequently used system is the MitraClip® providing two different clip types (NTR vs XTR). Purpose To compare XTR vs NTR clip systems for TTVr regarding safety, feasibility, and effectiveness. Methods 35 consecutive high-risk patients (78.4±7.9 years, EUROScore II 10.7±10.8%, STS Score 7.9±4.1) with symptomatic TR were treated using the MitraClip® system between 2017–2020. with an NTR (N=18, 51.4%) or XTR (N=17, 48.6%) system. The primary outcome was successful TTVr with TR reduction of ≥1 grade with no mortality, single leaflet device attachment (SLDA), or conversion to surgery until hospital discharge. At 30-day follow-up, TR severity grade and NYHA functional class were assessed. Results We found more severe initial TR grades in the XTR group compared to the NTR group expressed with wider TR V. contracta (14.8±4.3 vs 11.1±3.8 mm, p=0.011), larger EROA (0.99±0.4 vs 0.72±0.3 cm2, p=0.032), wider coaptation depth (9.6±2.8 vs 7.3±0.4 mm, p=0.036) and V. cava inferior (30.7±3.6 vs. 25.8±6.4 mm in NTR, p=0.013). 5 patients (29.4%) in the XTR and 3 patients (16.7%) in the NTR group presented initially with torrential TR. No significant differences were observed for clinical characteristics, comorbidities, co-medication, laboratory parameters or initial NYHA functional class (3.0±0.5 in NTR vs 3.2±0.4 in XTR, p=0.45). TTVr was safe with no intraprocedural deaths, emergency surgery or major vascular complications. Duration of the procedure and fluoroscopy did not differ. Both, NTR and XTR system led to procedural success in 72.2% (N=13) and 76.5% (N=13), respectively. At discharge, a significant reduction of initial TR grade was observed in both groups (2.4±0.9 in NTR and 2.3±0.9 in XTR, p<0.001) with a tendency of greater mean reduction in the XTR group (1.9±1.0 vs. 1.3±0.9, p=0.09). All 5 patients with torrential TR in the XTR group (100%) and just 1 patient (33.3%) in the NTR group achieved the primary outcome. At 30-day follow-up, overall SLDA rate was 22% vs 17.6% for NTR and XTR, respectively. However, these cases were attributed to very high risk patients with poor anatomy. Mortality rate was 11.1% in NTR vs 5.9% in XTR group (p=0.59). Achieved reduction of TR was maintained in both groups (2.6±0.9 in NTR and 2.8±0.9 in XTR, p<0.001). Also, improvement of NYHA functional class was seen (2.5±0.5, p=0.001 in NTR and 2.9±0.6, p=0.055 in XTR). Conclusion MitraClip® NTR and XTR systems for TTVr of severe TR in high-risk patients are safe and effective leading to a significant reduction of TR and clinical improvement. The XTR system seems to allow successful treatment of more severe TR stages compared to NTR. Funding Acknowledgement Type of funding sources: None.