Near-normal opening and closing characteristics can be achieved by a technique that preserves the shape and independent mobility of the sinuses of Valsalva.

Background-Tissue engineering (TE) of heart valves reseeded with autologous cells has been successfully performed in vitro. Here, we report our first clinical implantation of pulmonary heart valves (PV) engineered with autologous endothelial progenitor cells (EPCs) and the results of 3.5 years of follow-up. Methods and Results-Human PV allografts were decellularized (Trypsin/EDTA) and resulting scaffolds reseeded with peripheral mononuclear cells isolated from human blood. Positive stain for von Willebrand factor, CD31, and Flk-1 was observed in monolayers of cells cultivated and differentiated on the luminal surface of the scaffolds in a dynamic bioreactor system for up to 21 days, indicating endothelial nature. PV reseeded with autologous cells were implanted into 2 pediatric patients (age 13 and 11) with congenital PV failure. Postoperatively, a mild pulmonary regurgitation was documented in both children. Based on regular echocardiographic investigations, hemodynamic parameters and cardiac morphology changed in 3.5 years as follows: increase of the PV annulus diameter (18 to 22.5 mm and 22 to 26 mm, respectively), decrease of valve regurgitation (trivial/mild and trivial, respectively), decrease (16 to 9 mm Hg) or a increase (8 to 9.5 mm Hg) of mean transvalvular gradient, remained 26 mm or decreased (32 to 28 mm) right-ventricular end-diastolic diameter. The body surface area increased (1.07 to 1.42 m 2 and 1.07 to 1.46 m 2 , respectively). No signs of valve degeneration were observed in both patients. Conclusions-TE of human heart valves using autologous EPC is a feasible and safe method for pulmonary valve replacement. TE valves have the potential to remodel and grow accordingly to the somatic growth of the child.

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The autograft principle results in postoperative long-term survival comparable with that of the age- and gender-matched general population and reoperation rates within the 1%/patient-year boundaries and should be considered in young, active patients who want to avoid the shortcomings of conventional prostheses.

A single dose of methylene blue seems to be a potent approach to norepinephrine-refractory vasoplegia after cardiopulmonary bypass for most patients, with no obvious side effects. Guanylate cyclase inhibitors could be a novel class of agents for the treatment of norepinephrine-refractory vasoplegia after cardiopulmonary bypass. A controlled clinical trial is now needed to evaluate the role of methylene blue in this situation.