Dimas VV, Babaliaros V, Kim D, Lim DS, Morgan G, Jones TK, Armstrong AK, Berman D, Aboulhosn J, Mahadevan VS, Gillespie MJ, Balzer D, Zellers T, Yu X, Shirali G, Parthiban A, Leipsic J, Blanke P, Zahn E, Shahanavaz S. JACC Cardiovasc Interv. 2024 Oct 14;17(19):2287-2297. doi: 10.1016/j.jcin.2024.07.036.PMID: 39415386
Commentary by:
Dr. Jonathon Hagel (C.S. Mott Children’s Hospital, University of Michigan)
Take-home Points:
- The Alterra Adaptive Prestent in conjunction with the 29mm Sapien 3 THV has shown excellent valve function with 92.5% of patients demonstrating mild or less pulmonary regurgitation at 2 years
- The present and valve were successfully implanted in 98.3% of patients during a single procedure with no deaths, coronary compression or device embolization reported through 2 years
- The Alterra/Sapien 3 system led to improved RV volumes and function, a sustained reduction in PR and high rates of NYHA Class I functional status at follow-up
Pulmonary regurgitation (PR) is a common problem in patients with dilated right ventricular outflow tracts (RVOT) after previous surgical or transcatheter intervention for congenital heart disease. Particularly after repair of tetralogy of Fallot, transcatheter pulmonary valve replacement (TPVR) has historically been challenging because native RVOTs are highly variable in size and shape without a well-defined landing zone making it difficult to anchor a balloon expandable valve. The Alterra Adaptive Prestent was specifically designed to reshape the RVOT to create a stable landing zone for a 29 mm Sapien 3 transcatheter heart valve (THV), extending TPVR eligibility to a broader patient population.
The Alterra pivotal trial was a prospective, single-arm, multicenter trial conducted at 11 U.S. centers between August 2017 and September 2019. Sixty patients with moderate or greater PR underwent implantation of the Alterra prestent followed by Sapien 3 THV. The primary endpoint was THV dysfunction at 6 months, defined as need for RVOT/PV reintervention, moderate or greater total PR and moderate or greater RVOT/PV stenosis (gradient ≥35 mmHg on echocardiography). Secondary endpoints included improvement in PR at 30 days and safety measures (mortality, major complications, and device integrity). Patients were followed for 2 years with imaging (echocardiography, CT, MRI) and clinical evaluation.
Of 97 patients screened, 61 were enrolled and 60 underwent the procedure with 59/60 undergoing Alterra prestent and Sapien 3 implantation in a single-stage procedure. One patient required a staged procedure to allow prestent endothelialization due to proximal migration of the prestent within the RVOT. Two patients required valve-in-valve placement during the index procedure for severe PR. No explantations or deaths occurred within 24 hours of implantation. At 2 years, 92.5% of patients had mild or less PR, there were no deaths, coronary compression or endocarditis reported. There was one case of reintervention due to RVOT obstruction successfully managed with a stent and Sapien 3 THV. Twenty-two patients experienced arrhythmia with 21 occurring within 24 hours of the procedure, 12 of which were non-sustained ventricular tachycardia that was medically managed and only 3 patients remained on antiarrhythmic medications beyond 6 months. All patients remained NYHA class I or II throughout follow-up with 93% remaining functional class I.
The Alterra Adaptive Prestent, paired with the 29mm Sapien 3 THV, successfully addresses the anatomical variability of the native RVOT, offering a safe and effective transcatheter solution for patients with severe pulmonary regurgitation. Long-term surveillance will be critical to evaluate durability, arrhythmias, and monitor for potential coronary compression with repeat interventions, but the 2-year results are highly encouraging, confirming the system’s role in expanding transcatheter therapy options for patients with dysfunctional RVOTs.
