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Original Articles: Pediatric Cardiac

Invited commentary

University Hospital Aachen, Priv. Eberburgweg 15, Aachen, D-52076 Germany

(Email: bmessmer{at}ukaachen.de).

Valve choice for reconstruction of the right ventricular outflow tract (RVOT) is still a matter of debate among cardiac surgeons dealing with complex congenital lesions. Due to the fact that many of the patients are infants, children, or youngsters, the use of homografts or heterografts has become standard, even though age-dependent degeneration and the need for reoperation has been, and still is, an inherent risk of these grafts. Reports on the use of mechanical valves in the RVOT are scarce and mostly negative; therefore, their reputation may be worse than they are.

Hörer and colleagues [1] report a series of 19 patients with mechanical valve implantation in the pulmonary artery position. Outcome is compared with an identical number of patients who were matched for gender, age, and time of follow-up for pulmonary homograft implantation. Unfortunately, important information regarding the homograft procurement, preparation, and storing, as well as selection criteria (ie, AB0 compatibility) are lacking. Therefore, the results of this homograft group, characterized by increasing gradients and valve insufficiency due to tissue degeneration, are somewhat difficult to interpret. However, the main issue of this report is that with time, a bi-leaflet prosthetic valve conduit is equal to a pulmonary homograft. On first glance this may be provocative. Yet, the mean age of the patients was 25 years, and strict anticoagulation, even with a target international normalized ratio of 3.5 to 4.0 is relatively easy. Furthermore, self management of oral anticoagulation with the CoaguCheck System, as used in this series, provides excellent prophylaxis against bleeding and thromboembolic complications [2]. In 2006, Waterbolk and colleagues [3] reported a series of 27 patients with a similarly low thromboembolic complication rate, but again the median age of the patients was 33 years.

In adults, the need for RVOT reconstruction implantation of a mechanical valve is justified and even preferable to a homograft or heterograft on the condition that absolute contraindications (ie, hemorrhagic diseases) or relative contraindications (ie, women desiring future children) are taken into account. A mechanical valve largely prevents further reoperation. The argument from our colleagues in cardiology that nowadays percutaneous transcatheter implantation of tissue valves into pulmonary position is an easy procedure is not yet sound enough as long as these valves have not proven to last longer than customary homografts and heterografts, respectively. Valve-in-valve procedures may be possible, once or twice, but not forever.

The group of the German Heart Center in Munich has to be complimented for this comparative study that does not, however, resolve the problem in infants and children in which bioprosthetic reconstruction remains the first choice, even if we know that due to an increased calcium metabolism the degeneration runs much faster than in adults. Tissue-engineered autografts may resolve this problem in the future.

	References

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1. Hörer J, Vogt M, Stierle U, et al. A comparative study of mechanical and homograft prostheses in the pulmonary position Ann Thorac Surg 2009;88:1534-1540.[Abstract/Free Full Text]
2. Christensen TD, Andersen NT, Attermann J, Hjortdal VE, Maegaard M, Hasenkam JM. Mechanical heart valve patients can manage anticoagulation therapy themselves Eur J Cardiothorac Surg 2003;23:292-298.[Abstract/Free Full Text]
3. Waterbolk TW, Hoendermis ES, den Hamer IJ, Ebels T. Pulmonary valve replacement with a mechanical prosthesis. Promising results of 28 procedures in patients with congenital heart disease. Eur J Cardiothorac Surg 2006;30:28-32.[Free Full Text]

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Personal Folders Download to citation manager Author home page(s): Bruno Messmer Permission Requests Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Messmer, B. Search for Related Content PubMed PubMed Citation Articles by Messmer, B. Related Collections Congenital - acyanotic Related Article