Carcinoid Heart Valve Disease: Transcatheter Pulmonary Valve-In-Valve Implantation in Failing Biological Xenografts

Carcinoid heart valve disease (CHVD) occurs as the cardiac manifestation of carcinoid syndrome (also known as Hedinger's syndrome), which develops secondary to neuroendocrine tumor activity. CHVD almost exclusively affects right-sided heart valves, since circulating serotonin is metabolized by pulmonary endothelial cells, thus sparing left-sided valves. Replacement of the tricuspid and pulmonary valve is a well-established and feasible therapeutic option for these patients. Whether biological valve substitutes are subject to a continuous degenerative process is not entirely clear at present due to the rarity of the disease and inconclusive findings in the current literature.Herein are presented the details of two patients suffering from advanced CHVD who had undergone previous combined tricuspid valve replacement (TVR) and pulmonary valve replacement (PVR) using biological xenografts, and had subsequently been readmitted with failure of the pulmonary valve substitute.Due to the increased risk for repeat surgical valve replacement, the patients were treated by percutaneous stent implantation into the pulmonary artery, followed by the implantation of a balloon- expandable transcatheter heart valve (THV). The procedures were feasible and safe through the intact TVR.This strategy resulted in a favorable acute outcome in both patients, with adequate valve function and no PVL as documented by TTE, although the transvalvular gradients were elevated in both cases. The patients had an uneventful postoperative course and were discharged home in timely fashion. Whether the residual elevated transvalvular gradients following the valve-in-valve procedures, or an early degeneration of the implanted bioprostheses, will have a negative impact on the patients' further course will become clear in the future.