J Thorac Cardiovasc Surg 1999;118:772-773
© 1999 Mosby, Inc.
Possible mechanism of calcification of the BioCor stentless mitral valve treated with the No-React formula
Simcha Milo, MD
Department of Cardiac Surgery
Rambam Medical Center
Haifa 35254, Israel
Reply to the Editor:
Dr Gabbay was deeply involved in choosing the type of stentless valves used in these 2 children and in observing them after the operation. We informed him of the results of all echocardiographic studies done on the children. Early postoperative studies in the 2 children showed that both leaflets of the stentless mitral valves had a full spectrum of movement and that both coaptation and closure were good. In fact, an inexperienced observer could barely recognize an implanted prosthesis in the mitral position. Furthermore, one of the authors (Dr Bar-El) was invited to present these promising early results at the 1996 meeting of The Society of Thoracic Surgeons at Gabbay’s presentation on the No-React detoxification process (Shelhigh Inc, Millburn, NJ).
1 One month later, as the children’s hearts began to recover and return to near normal size, we noted a progressive prolapse of both leaflets. As the prolapse steadily increased, we began to consider replacing the valves, not because of the length of the chordae tendineae, but because of the prolapse itself. However, calcification, not the prolapse, determined the time of surgical intervention. Our follow-up echocardiographic data do not support Gabbay’s contention that torn chordae resulted from undue tension. We believe that the early biodegradation of the valve resulted in calcification, which led to rupture of the chordae.
We do believe that a stentless mitral prosthesis that incorporates the entire subvalvular apparatus may cause problems when implanted in hearts that may eventually change size. Our results with the No-React–treated BioCor stented and stentless valves (BioCor, Belohorizonte, Brazil) in adults correlate with those of Von Oppell and associates 2 but are not different from results obtained with valves in which the glutaraldehyde was not rinsed out. Massetti and associates 3 reported that No-React pulmonic porcine valve conduits they implanted in children were free from calcification at 18 months, and we are hopeful that the valves will remain so for several years. In our study, the valves were free from calcification at 18 months too. However, on June 11, 1999, we had to explant the last stentless BioCor No-React–treated aortic valve on an emergency basis because of rupture of 2 of its cusps (Fig 1). The left and right coronary cusps had entirely disintegrated at the free edges, but we saw no evidence of calcification. The condition of the valve caused acute and severe aortic incompetence. We may learn about the need to detoxify the tissues and the potential effect on its mechanical properties from this last patient.
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Fig. 1. Cusps of explanted BioCor stentless aortic valve treated with the No-React formula, which was implanted 5 years ago. Note disintegration of 2 of the cusps.
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References
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Abolhoda A, Yu S, Oyarzun JR, et al. No-React detoxification process: a superior anticalcification method for bioprostheses. Ann Thorac Surg 1996;62:1724-30.[Abstract/Free Full Text]
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Von Oppell U, Stemmet F, Brink J, LeVetan B, Heijke S. BioCor No-React stentless aortic valve: short term results. Presented at the Stentless Bioprostheses Third International Symposium. 1999; May 12-16 (abstract).
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Massetti P, Ussia GP, Gazzolo D, Marianeschi MS, Abella FR, Cipriani A, et al. Aortic pulmonary autograft implant: medium term follow-up with a note on a new right ventricular pulmonary artery conduit. J Card Surg 1998;13:173-6.[Medline]
