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Ann Thorac Surg 2003;76:658
© 2003 The Society of Thoracic Surgeons

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Correspondence

Pannus formation after mitral valve replacement with the omniscience prosthesis: letter 1

^a Division of Cardiovascular Surgery, Jichi Medical School, 3311-1 Yakushiji, Minami-kawachi, Tochigi, Japan

e-mail: tcvmisa{at}jichi.ac.jp

To the Editor:

I read with great interest the paper by Edwards and associates [1]. They showed that the incidence of nonstructural dysfunction after mitral valve replacement was 1.66 per 100 patient-years. Although they did not reveal the onset times of the complications, we have treated two cases of nonstructural dysfunction of implanted prostheses 17 years after operation.

Between 1981 and 1983, 23 patients underwent mitral valve replacement with the Omniscience prosthetic heart valve in our institute [2]. Among them, 2 men (63 and 67 years old), developed nonstructural prosthetic valve dysfunction caused by pannus formation around the prostheses. The patients had undergone mitral valve replacement for rheumatic heart valve disease in 1983, and by 2000 dyspnea during exercise associated with peripheral edema had developed gradually. Anticoagulation therapy was adequate throughout their postoperative courses. Echocardiographic examination confirmed prosthetic valve stenoses with turbulent blood flow through the prostheses, indicating restriction of prosthetic leaflet motion. Both men consented to reoperation. Operative findings included pannus formation around the prostheses on the left ventricular side, which prevented the leaflets from fully opening. Pannus formation was not observed on the prosthetic surfaces on the left atrial side. The implanted valves were replaced with bicarbon bileaflet valves (Sorin Biomedica Cardio, Saluggia, Italy). Both postoperative courses were uneventful.

The Omniscience valve consists of a tilting disc, a rotatable titanium housing, and a flexible Dacron suture ring without surface coating, which can adapt to the native annulus and can lead to a good tissue growth process between the ring and annulus. However, tissue growth can exceed the ring toward the orifices and cause prosthetic valve dysfunction long after operation, as with our patients. Pannus formation is troublesome after valve replacement, and its causes remain unknown. Suture rings of some mechanical valves are coated with pyrolytic carbon on the blood-contacting surfaces. In the early postoperative phase, coated suture rings can contribute to minimizing thrombus formation around the prosthetic valve ring, and can reduce inflammatory processes thereafter. However, pannus formation might not always result from thrombus formation or inflammation, particularly in the long term. We used Bicarbon valves with suture rings coated with pyrolyte carbon, expecting reduction on tissue overgrowth [3]. Long-term follow-up studies are needed to confirm whether the suture ring coating is clinically effective.

References

1. Edwards M.S., Russell G.B., Edwards A.F., Hammon J.W., Jr, Cordell A.R., Kon N.D. Results of valve replacement with Omniscience mechanical prostheses. Ann Thorac Surg 2002;74:665-670.[Abstract/Free Full Text]
2. Misawa Y., Hasegawa T., Kato M., Ide H. Clinical experience with Omniscience and Omnicarbon prosthetic heart valves. Nippon Kyobu Geka Gakkai Zasshi 1991;39:885-890.[Medline]
3. Misawa Y, Saito T, Konishi H, et al. Single center experience with the Bicarbon prosthetic valve. Artificial Organs 2002;26:856–61

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): Yoshio Misawa Permission Requests Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Misawa, Y. Search for Related Content PubMed PubMed Citation Articles by Misawa, Y. Related Collections Valve disease