Covered CP stent for treatment of right ventricular conduit injury during melody transcatheter pulmonary valve replacement: Results from the PARCS study

BACKGROUND: High-pressure balloon and stent angioplasty are frequently necessary to prepare the dysfunctional right ventricular outflow tract conduit before transcatheter pulmonary valve replacement (TPVR). Conduit injury can result, which may be catastrophic to the patient or prevent successful TPVR. METHODS AND RESULTS: The PARCS trial (Pulmonary Artery Repair With Covered Stent) was a pivotal, prospective multicenter trial to evaluate the safety and efficacy of the NuMED Covered CP Stent (CCPS) for treatment of conduit injury occurring during TPVR. The study also evaluated immediate and short-term TPVR function in patients receiving covered stents. A total of 616 patients were consented; 120 (19.5%) had a wall injury identified and were treated with CCPS. Severe conduit injuries were uncommon (5%), but predictors for severe injury were not identified. Stenotic homografts had the highest incidence of injury (29%), compared with other conduit substrates. Among patients receiving CCPS implant, 96% required no further therapy for conduit injury, and 94% underwent TPVR at that procedure. Only 2 patients (1.6%) required urgent surgery for conduit injury, despite CCPS implant. There were few CCPS-related complications. TPVR function was similar between CCPS and non-CCPS groups at follow-up. CONCLUSIONS: Conduit injury during TPVR is common, although severe injury is rare. The CCPS was a safe and effective treatment for right ventricular outflow tract conduit injury during preparation for TPVR, allowing nearly all patients to complete the procedure without identifiable impact on valve performance. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01824160.