Ann Thorac Surg 2007;84:1425
© 2007 The Society of Thoracic Surgeons
Correspondence
Reply
Sak Lee, MD,
Byung-Chul Chang, MD
Division of Cardiovascular Surgery, Yonsei Cardiovascular Center, Yonsei University College of Medicine, Seoul, 120-752 South Korea
(Email: bcchang{at}yumc.yonsei.ac.kr).
To the Editor:
We thank Dr Rafiq and colleagues [1] for their letter.
Valve thrombosis and pannus formation are important valve-related complications after tricuspid valve replacement (TVR) with mechanical prosthetic valves. There may be a higher incidence of prosthetic valve thrombosis with the low-pressure and low velocity chamber at the tricuspid valve position. Several authors have already confirmed the higher incidence of tricuspid valve thrombosis, especially in previously designed tilting disc mechanical valves [2–5]. However, recently developed bileaflet pyrolytic carbon prostheses are relatively low thrombogenic, therefore, low intensity anti-coagulation is proposed. In our recent study, 10 episodes of valve thromboses among 103 patients with TVR occurred within 46 months, and 9 of the patients were successfully managed with thrombolytic therapy. In these patients, anticoagulation levels were inadequate when comparing others (international normalized ratio [INR] < 2.0) [6].
The protocol in our institution is to start intravenous heparin from the first or second postoperative day, unless there are clinical contraindications, and sodium warfarin is started on the second postoperative day. In Yonsei University, the prothrombin time is maintained at an INR of 2.0 
3.5 for a mechanical valve in tricuspid position, and the results seemed relatively good (free from thromboembolic event at 15 years [87.8%]) in 103 cases [6].
Regarding bioprosthesis at the tricuspid position, INR has been maintained as the same level of the mitral valve position. There was no incidence of thromboembolic event in our series. We would like to recommend an INR between 1.5 and 2.5 for the bioprosthetic valve in the tricuspid position. In addition it seems that pannus formation is another problem other than anticoagulation, which is related to the surgical techniques, design, and character of the sewing cuff of the prosthesis rather than the intensity of anticoagulation. So far there is no evidence that early bioprosthetic degeneration is related to anticoagulation intensity. Figure 1
demonstrates that the degree of prosthetic valve calcification in both the mitral and tricuspid position was the same in a patient who underwent re-replacement of the mitral and tricuspid valves 10 years after the first operation.
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Fig 1. Prosthetic valve calcification in both the mitral (left) and tricuspid (right) positions removed from a patient who had mitral and tricuspid valve replacement 10 years ago.
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We suppose that patient compliance is the most important factor, and the tight control of individualized anticoagulation level and regular education of the patients are mandatory to prevent thromboembolic complications. In addition, anticoagulation measures should be strictly regulated even with low thrombogenic bileaflet pyrolytic carbon prostheses.
Because there are few reports regarding optimal anticoagulation intensity for TVR, further prospective trials with large number of patients for the development of an ideal prosthesis to prevent thrombosis and pannus formation are necessary.
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References
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- Rafiq I, Freeman LJ, Woods S. Importance of long-term anticoagulation in both prosthetic and biological tricuspid valve replacements (letter) Ann Thorac Surg 2007;84:1424.[Free Full Text]
- Sanfelippo PM, Giuliani ER, Danielson GK, Wallace RB, Pluth JR, McGoon DC. Tricuspid valve prosthetic replacement: early and late results with the Starr-Edwards prosthesis J Thorac Cardiovasc Surg 1976;71:441-445.[Abstract]
- Jugdutt BI, Fraser RS, Lee SJ, Rossall RE, Callaghan JC. Long-term survival after tricuspid valve replacement: results with seven different prostheses J Thorac Cardiovasc Surg 1977;74:20-27.[Abstract]
- Wallens F, Goldstein J. Tricuspid valve replacement Cardiovasc Clin 1987;17:111-115.[Medline]
- Thorburn CW, Morgan JJ, Shanahan MX, Chang VP. Long-term results of tricuspid valve replacement and the problem of prosthetic valve thrombosis Am J Cardiol 1983;51:1128-1132.[Medline]
- Chang BC, Lim SH, Yi G, et al. Long-term clinical results of tricuspid valve replacement Ann Thorac Surg 2006;81:1317-1323discussion 1323–4.[Abstract/Free Full Text]
Related Article
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Importance of Long-Term Anticoagulation in Both Prosthetic and Biological Tricuspid Valve Replacements
- Isma Rafiq, Leisa J. Freeman, and Sheila Wood
Ann. Thorac. Surg. 2007 84: 1424.
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