J Thorac Cardiovasc Surg 1994;108:178-179
© 1994 Mosby, Inc.
Valve thrombosis and strut fracture with the Björk-Shiley valve
Thomas A. Orszulak, MD
Thoracic and Cardiovascular Surgery
Rochester, MN 55905
Reply to the Editor:
Dr. Lindblom's comments are appreciated, and we compliment his efforts and accomplishments with the Björk-Shiley prosthesis. Although the results of the original paper from our institution may be viewed from a different perspective and appear to satisfy different results, the fact remains that the altered design of the Björk-Shiley valve did not reduce or eliminate the risk of valve thrombosis. More spherical than convexo-concave discs were affected by thrombosis; however, the mean time to valve thrombosis was 3.7 years. The follow-up of the convexo-concave cohort was not sufficiently long to state that the risk was absent. The presence of two of ten aortic thromboses confirms the possibility. The development of thrombosis in any location would be cause for concern. Our data demonstrated that thrombosis did occur and appears time related. The absence of a mitral occurrence in our review with the convexo-concave prosthesis is not a valid testimony to correction of this complication of thrombosis, as time will verify or negate its occurrence.
We do not recommend elective replacement of the convexo-concave prosthesis alone. If the need for repeat cardiac surgery for other cardiac disease arises, elective replacement should be considered, and if the combined procedure does not increase the operative risk significantly, we would support the explantation of the convexo-concave prosthesis.
There is no U.S. experience with the Monostrut valve, but I would surmise from Dr. Lindblom's comments that strut fracture and thrombosis have been avoided in his experience. We are attentive to any improvements that will minimize or eliminate risks to our patients. It is difficult to predict when or whether this prosthesis will reach the U.S. market.
