Original article
Adult cardiac
Ten Years of Clinical Results With a Tissue-Engineered Pulmonary Valve

https://doi.org/10.1016/j.athoracsur.2011.06.009Get rights and content

Background

This study was performed to collect prospective safety and effectiveness data from a tissue-engineered heart valve implanted for reconstruction of the right ventricular outflow tract during the Ross operation.

Methods

From May 2000 until June 2002, 11 consecutive patients, mean age 39.6 ± 10.3 years, received a tissue-engineered heart valve (additive and logistic European System for Cardiac Operative Risk Evaluation, respectively, 3.3 ± 1.3 and 2.8% ± 1.4%). Two to four weeks prior to the Ross operation a piece of forearm vein or saphenous vein was harvested to isolate, characterize, and expand endothelial cells. A cryopreserved pulmonary allograft was decellularized, coated, and seeded with autologous vascular endothelial cells, using a specially developed bioreactor. Cell seeding density was 1.1 × 105 ± 0.5 × 105 cells/cm2 with a viability of 93.2% ± 2.1%.

Results

All patients survived surgery. Postoperatively no fever of unknown origin was evident. Currently all patients are in New York Heart Association class I. Evaluation of the tissue-engineered heart valve by transthoracic echocardiography showed a mean pressure gradient of 5.4 ± 2.0 mm Hg at 10 years. Multislice computed tomography showed no calcification up to 10 years.

Conclusions

Tissue-engineered heart valves showed excellent hemodynamic performance and may prevent degeneration during long-term follow-up.

Section snippets

Material and Methods

The scaffold used for seeding was a commercially available cryopreserved pulmonary allograft (Cryolife Inc, Kennesaw, GA). The valves were decellularized and sterilized according to a proprietary process in the AutoTissue laboratories (AutoTissue GmbH, Berlin, Germany) to yield a scaffold exclusively composed of collagen and elastin [9]. The scaffolds were seeded with AVEC respecting the standards of good manufacturing practice. Sterility was proven during each single production step as well as

Valve Assembly: Endothelial Cell Harvesting and Culture

From the first 7 patients a piece of cephalic vein was harvested, and from the remaining 4 a piece of the greater saphenous vein was prepared. Preparation of the saphenous vein allowed the decrease of cell culture time to a total of 2 weeks. In one patient, the autologous serum was not sufficient to grow endothelial cells in vitro. For this patient pooled donor serum was used.

After the second passage a mean number of 5.4 × 106 ± 2.9 × 106 endothelial cells were available, which was considered

Comment

Although mechanical and biological valve prostheses are widely used, both have limitations in younger patients. Hammermeister and colleagues [15] showed, in 394 patients undergoing isolate aortic valve replacement, that the number of reoperations was significantly higher with bioprosthetic valves than with mechanical valves at 15 years follow-up (29 ± 5% vs 10 ± 3%, p = 0.004).

In a recent study, Ruel and colleagues [16] showed in patients under 60 years, after aortic valve replacement (n =

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    Copyright © 2011 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.