First-in-Human Transcatheter Tricuspid Valve Repair: 30-Day Follow-Up Experience With the Mistral Device

Objectives: This study sought to report short-term results of safety, performance, and efficacy of the Mistral device first-in-human study in patients suffering from severe functional tricuspid insufficiency.

Background: Patients who suffer from severe tricuspid regurgitation (TR) and who are at high surgical risk have no standard care therapy. Therefore, minimally invasive and safer methods are sought. The Mistral device is an investigational spiral-shaped device intended for percutaneous transcatheter repair. The Mistral device approximates the tricuspid leaflets by grasping together the chordae tendineae of the tricuspid valve.

Methods: Seven patients (4 women; mean age 73.14 ± 7.4 years) with severe (n = 5) and massive (n = 2) symptomatic TR and high surgical risk underwent Mistral tricuspid repair under transesophageal echocardiography guidance.

Results: Mistral was successfully implanted in all cases with a single device deployed in 6 patients, with 2 devices deployed in 1 patient. No procedural or 30-day adverse events occurred. TR was reduced by at least 1 grade in all patients. Effective regurgitant orifice area was reduced from median 0.52 cm² (interquartile range [IQR]: 0.40 to 0.60 cm²) at baseline to 0.15 cm² (IQR: 0.14 to 0.21 cm²) at 30 days post-procedure (p < 0.01), vena contracta width was reduced from 0.95 cm (IQR: 0.81 to 1.16 cm) to 0.62 cm (IQR: 0.52 to 0.67 cm) (p < 0.05), and regurgitant volume decreased from 49.4 ml/beat (IQR: 45.2 to 57.7 ml/beat) to 19.7 ml/beat (IQR: 12.4 to 23.9 ml/beat) (p < 0.01). Right ventricular fractional area change improved from 27.0% (IQR: 21.3% to 33.5%) at baseline to 38.5% (IQR: 29.0% to 47.1%) at 30-day follow-up (p < 0.05). Significant improvements in New York Heart Association functional class, Kansas City Cardiomyopathy Questionnaire score, and 6-min walk test were observed at 30 days.

Conclusions: Tricuspid valve repair with the Mistral device appears safe and leads to 30-day reduction of tricuspid insufficiency and improvement of right ventricular function and exercise capacity.