J Thorac Cardiovasc Surg 1994;107:1542-1543
© 1994 Mosby, Inc.
Premature leaflet dysfunction in a tricuspid bioprosthesis
Shalom Silberman , MD,
Bernard S. Goldman , MD
Sunnybrook Health Science Center
Toronto, Ontario, Canada
To the Editor:
Porcine bioprosthetic valves are frequently used in patients requiring valve replacement for whom anticoagulant therapy is not advisable. These valves are known to undergo gradual deterioration, ultimately leading to failure. The 10-year rate of freedom from structural valve failure on the left side of the heart for porcine valves is 70% to 80%.
1-3 Younger patient age has been shown to be an independent predictor of structural valve deterioration. 1 Valves implanted on the right of the heart are generally expected to be more durable than those implanted on the left side. 2 Kawachi and colleagues 4 recently reported on a total of 27 Hancock porcine bioprostheses implanted in the right side of the heart (pulmonary, 4, tricuspid, 6, mitral and tricuspid, 13; and aortic, mitral, and tricuspid, 4) with failure of only 1 valve—in the tricuspid position in a 9-year-old boy. However, time to failure in this patient was not mentioned. In 3 patients with tricuspid valve replacement younger than 15 years, their Hancock valves (except for that in the 9-year-old patient mentioned) have continued to function well at 11.3 and 14.8 years after operation.
We have been concerned about the fate of bioprostheses in the tricuspid position in younger patients. We recently reoperated on a young man with early failure of a Hancock II porcine valve (Medtronic Heart Valves, Irvine, Calif.) implanted in the tricuspid position. This 20-year-old patient had undergone tricuspid valve replacement 1 year earlier for traumatic disruption of the tricuspid valve as a result of a snowmobile accident. A 33 mm Hancock II bioprosthesis was inserted with preservation of the tricuspid apparatus. The patient did well for 6 months, when he began to report fatigue and exertional dyspnea. Doppler echocardiographic studies suggested that the tricuspid insufficiency was the result of primary leaflet dysfunction.
The patient underwent another operation 1 year after his initial operation. There was no evidence for perivalvular dehiscence or sequelae of endocarditis. However, two of the three valve leaflets appeared shrunken and retracted, with a gross central triangle of insufficiency (Fig. 1). The valve was excised and replaced with a 29 mm St. Jude Medical mechanical prosthesis (St. Jude Medical, Inc., St. Paul, Minn.). The patient's postoperative course was uneventful.
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Fig. 1. A, Outflow view of Hancock II porcine valve shows one pliable leaflet and two thickened, retracted, immobile leaflets. B, Inflow view of the same valve.
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We are uncertain of the reasons for primary leaflet dysfunction in this young patient. The dysfunction did not appear to be related to the insertion technique or to the positions of the stents. The residual tricuspid leaflet and chordae did not appear redundant and were well retracted from the bioprosthetic cusps. Whether this dysfunction represents a manufacturing fault, is related to resolution of right ventricular dysfunction from the original blunt chest trauma, or was caused by the patient's young age, with enhanced and rapid deterioration of valve tissue, is entirely speculative.
The article of Kawachi and associates 4 suggests that porcine bioprostheses in the tricuspid position are relatively durable. This report of premature leaflet dysfunction should act as a caution regarding the natural history of tissue valves in young patients. The possible consequences of a second tricuspid valve replacement should be balanced against those inherent in initial insertion of a mechanical prosthesis.
References
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Burdon TA, Miller DC, Oyer PE, et al. Durability of porcine valves at fifteen years in a representative North American patient population. J THORAC CARDIOVASC SURG 1992;103:238-52. [Abstract]
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Cohn LH, Collins JJ, DiSesa VJ, et al. Fifteen year experience with 1678 Hancock porcine bioprosthetic heart valve replacements. Ann Surg 1989;210:435-43. [Medline]
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Foster AH, Greenberg GJ, Underhill DJ, McIntosh CL, Clarke RE. Intrinsic failure of Hancock mitral bioprostheses: 10–15 year experience. Ann Thorac Surg 1987;44:568-77. [Abstract]
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Kawachi Y, Tanaka J, Tominaga R, Kinoshita K, Tokunaga K. More than ten years' follow-up of the Hancock porcine bioprosthesis in Japan. J THORAC CARDIOVASC SURG 1992;104:5-13.[Abstract]
