Ann Thorac Surg 2008;85:1308-1309. doi:10.1016/j.athoracsur.2007.12.070
© 2008 The Society of Thoracic Surgeons
Original Articles: Adult Cardiac
Invited Commentary
Jean G. Dumesnil, MD, FRCPC,
Philippe Pibarot, DVM, PhD
Quebec Heart Institute, Laval Hospital, 2725 Chemin Sainte-Foy, Sainte-Foy, PQ G1V 4G5 Canada
(Email: medjgd{at}hermes.ulaval.ca; philippe.pibarot{at}med.ulaval.ca).
Japanese people have a markedly smaller body surface area (BSA) than their Occidental counterparts. Hence, this study [1] is a unique opportunity to view the problem of patient-prosthesis mismatch (PPM) from a different perspective. Indeed, an analogous study was performed by the Mayo Clinic [2] in 388 Occidental patients having received a 19-mm or 21-mm St. Jude Medical prosthesis (St. Jude Medical, Inc, St. Paul, MN). The average BSA was 1.76 cm2, the prevalence of PPM was 60% (17% severe, 43% moderate), and severe PPM was found to be an independent predictor of higher long-term mortality and congestive failure. The authors concluded that preventive strategies, such as aortic root enlargement or implantation of a prosthesis with a larger effective orifice area (EOA) should be considered in patients at risk of developing severe PPM at the time of aortic valve replacement. In contrast, the average BSA in the present study was 1.44 m2 and 1.47 m2, respectively in the patients with a 19-mm or 21-mm prosthesis, and overall the prevalence of PPM in these patients was 34% (6% severe, 28% moderate). Moreover, as a group, they had excellent prognosis with no differences in outcomes being observed as compared with patients with a 23-mm prosthesis. These interesting observations underline the following concepts: (1) Contrary to what might still be implied in some studies, it is not the size of the prosthesis per se that matters but rather its hemodynamic performance in relation to the patient’s body size; (2) Conversely, the results, however, should not be interpreted as justification for indiscriminate use of smaller prostheses in this type of population. Indeed, severe PPM was still present in some patients. Unfortunately, numbers were too small to specifically analyze their outcome, but by inference they were likely at higher risk, and a preventive strategy to avoid PPM [3] would still appear to have been indicated. An interesting corollary to this study is also that in patients with a small BSA, the preoperative calculation of the projected indexed EOA [3] can be used in a reverse fashion to validate the use of a small prosthesis and hence avoid more aggressive procedures, such as aortic root enlargement. Indeed, whereas some might still advocate systematic avoidance of smaller prostheses, this study illustrates that such procedures should be perfectly safe and adequate in patients with a smaller BSA and in whom preoperative calculation of projected indexed EOA shows a low risk of developing PPM.
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References
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- Yoshikawa K, Fukunaga S, Arinaga K, et al. Long-term results of aortic valve replacement with a small St. Jude Medical valve in Japanese patients Ann Thorac Surg 2008;85:1303-1309.[Abstract/Free Full Text]
- Mohty D, Malouf JF, Girard SE, et al. Impact of prosthesis-patient mismatch on long-term survival in patients with small St. Jude medical mechanical prostheses in the aortic position Circulation 2006;113:420-426.[Abstract/Free Full Text]
- Pibarot P, Dumesnil JG. Prosthesis-patient mismatch: definition, clinical impact, and prevention Heart 2006;92:1022-1029.[Abstract/Free Full Text]
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Long-Term Results of Aortic Valve Replacement With a Small St. Jude Medical Valve in Japanese Patients
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Ann. Thorac. Surg. 2008 85: 1303-1308.
[Abstract]
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