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Ann Thorac Surg 1995;60:1461
© 1995 The Society of Thoracic Surgeons

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Correspondence

Evaluation of the Hemodynamic Performance of Stentless Porcine Aortic Valves

Department of Cardiac Surgery, University of Bristol and Bristol Royal Infirmary, Bristol B52 8hw, United Kingdom

To the Editor:

We read with interest the recent article by Kon and associates [1] comparing two implantation techniques of stentless porcine aortic valves; total root replacement and partial scallop aortic inclusion technique. Kon and associates report excellent resting transvalvular gradients in all patients, measured by Doppler echocardiography, with significantly lower gradients in the total root replacement group than in the partial scallop aortic inclusion group.

Although such data are of great interest, valve performance in the resting supine patient may not necessarily reflect the patient's hemodynamic state during daily activities or exercise. Indeed, small prostheses are known to produce high gradients at high cardiac output that are not seen at rest [2], and this has highlighted the importance of the evaluation of aortic prostheses under various flow conditions [3, 4]. Traditionally, this has been achieved through exercise testing, which, however, requires a considerable degree of patient cooperation and is not entirely suitable for wider clinical use. Furthermore, reliable Doppler echocardiographic images are difficult to obtain in the tachypneic exercising patient.

We have recently reported the use of dobutamine-stress echocardiography in the evaluation and comparison of the hemodynamic performance of small aortic prostheses [5, 6]. This method has proved to be a valid alternative to treadmill-exercise testing with a higher diagnostic yield. With this method, patients remain in the supine position throughout the study period, and body position can be optimized to obtain high-quality echocardiographic images and precise Doppler measurements. Our results were consistent with the few studies available in the literature reporting exercise echocardiographic assessment of prosthetic valves [4, 7, 8].

Accepting resting transvalvular gradients as a measure of the hemodynamic performance of a valve prosthesis is an over-simplistic approach. If meaningful information is to be obtained, stress evaluation of a valve prosthesis should be an integral part of its functional assessment. Dobutamine-stress echocardiography is a simple, safe, and readily available method that could be used. Such data concerning stentless porcine valves are awaited with great interest.

References

1. Kon ND, Westaby S, Amarasena N, Pillai R, Cordell AR. Comparison of implantation techniques using Freestyle stentless porcine aortic valve. Ann Thorac Surg 1995;59: 857–62.[Abstract/Free Full Text]
2. Teoh KH, Fulop JC, Weisel RD, et al. Aortic valve replacement with a small prosthesis. Circulation 1987;76(Suppl 3):123–31.
3. Tatineni S, Barner HB, Pearson AC, Halbe D, Woodruff R, Labovitz AJ. Rest and exercise evaluation of St. Jude Medical and Medtronic Hall prostheses. Circulation 1989;80(Suppl 1):16–23.
4. De Paulis R, Sommariva L, Russo F, et al. Doppler echocardiography evaluation of the CarboMedics valve in patients with small aortic annulus and valve prosthesis—body surface area mismatch. J Thorac Cardiovasc Surg 1994;108:57–62.[Abstract/Free Full Text]
5. Izzat MB, Wilde P, Bryan AJ, Angelini GD. Dobutamine-stress Doppler echocardiography in the evaluation of patient-prosthesis mismatch for small size aortic bileaflet prostheses [Abstract]. Br Heart J 1995;73(Suppl 2):38.
6. Izzat MB, Birdi I, Wilde P, Bryan AJ, Angelini GD. Evaluation of the hemodynamic performance of small CarboMedics aortic prostheses using dobutamine-stress Doppler echocardiography. Ann Thorac Surg 1995;60:1048–52.[Abstract/Free Full Text]
7. Ihlen H, Molstad P, Simonsen S, et al. Hemodynamic evaluation of the CarboMedics prosthetic heart valve in the aortic position: comparison of noninvasive and invasive techniques. Am Heart J 1992;123:151–9.[Medline]
8. Chambers J, Cross J, Deverall P, Sowton E. Echocardiographic description of the CarboMedics bileaflet prosthetic heart valve. J Am Coll Cardiol 1993;21:398–405.[Abstract]

This Article 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): Mohammad Bashar Izzat Massimo Caputo Gianni D. Angelini Permission Requests Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Izzat, M. B. Articles by Angelini, G. D. Search for Related Content PubMed PubMed Citation Articles by Izzat, M. B. Articles by Angelini, G. D.