Percutaneous therapy shows favorable outcomes in congenital patients with severe pulmonary regurgitation
WASHINGTON – A percutaneous transcatheter therapy for congenital heart disease (CHD) patients with severe pulmonary regurgitation (PR) has been slow to materialize, in comparison to transcatheter pulmonary valve (TPV) therapy for a dysfunctional surgical RV-PA conduit which was first implanted twenty years ago as the Melody TPV. Findings from the Medtronic Harmony TPV Pivotal Trial were presented today during the SCAI 2020 Scientific Sessions Virtual Conference and showed favorable outcomes utilizing the device in patients with severe PR.
Pulmonary regurgitation occurs when a patient has a leaky pulmonary valve, which allows flow back into the right ventricle heart chamber before it gets to the lungs for oxygen. This usually occurs after failure over time of a surgical correction of obstruction of the right ventricular outflow tract (RVOT).
The Harmony TPV is a self-expandable covered frame with a porcine pericardial valve inside that accommodates the larger right ventricular outflow tract (RVOT) of patients with congenital defects who develop severe PR after surgical repair. The TPV is available in 22- and 25-mm sizes with differences in frame size and length. An Early Feasibility Study (EFS) with TPV 22 showed high procedural success, safety, and favorable device performance through three years.
The Pivotal Trial is ongoing at 12 sites in the United States, Canada, and Japan. Patients with severe PR on echocardiography or PR fraction ≥30% by magnetic resonance imaging and an indication for surgical placement of a RV-pulmonary artery conduit or prosthetic PV were eligible. Forty patients were implanted and ten patients subsequently received a modified version of the TPV 25. The primary safety endpoint is freedom from procedure- or device-related mortality at 30 days. The primary effectiveness endpoint is acceptable hemodynamic function at six months, defined as mean RVOT gradient ≤40 mmHg on echocardiography, PR fraction <20% on magnetic resonance imaging; and no prior TPV reintervention. For the modified TPV 25, 30-day hemodynamic performance and safety is reported.
The investigators reported that the median age of patients in the study was 28 years old with 92% having a diagnosis of. Tetralogy of Fallot. The primary indication for intervention was severe PR in 94%, while 6% had moderate PR. The femoral vein was used in 94% of the patients to deliver the Harmony TPV. Freedom from procedure- or device- related mortality at 30 days was 100%. The measured efficacy for the Pivotal Trial (a composite of acceptable hemodynamics and no catheter interventions) was 89% and increased to 91% when including the EFS patients (versus a performance target of 75%, meeting the primary efficacy endpoint). Freedom from TPV dysfunction was 89% at 6 months. At six months, the mean RVOT gradient remained low at 14.6mmHg, while residual significant PR was only 6% with only 3% having moderate paravalvular leak (PVL). The Harmony TPV Pivotal Trial met its intended safety and efficacy goals.
“Until recently, the only option for a patient that had severe PR after previous open heart surgery was to return to the operating room for another open heart surgical procedure, either a bioprosthetic Pulmonary Valve replacement or an RV-PA conduit,” said John P. Cheatham, MD, Interventional Cardiologist in The Heart Center at Nationwide Children’s Hospital , and Professor Emeritus at The Ohio State University in Columbus, OH. Dr. Cheatham also serves as the lead Principal Investigator of the Harmony Trials. “The Harmony TPV therapy finally offered a non-surgical option to treat severe PR and restore pulmonary valve competence.”
Abstract #10994 “Primary Outcomes of the Harmony Transcatheter Pulmonary Valve Pivotal Trial.” SCAI 2020 Scientific Sessions Virtual Conference, May 14-16, 2020.