Ann Thorac Surg 2005;79:782-783
© 2005 The Society of Thoracic Surgeons
INVITED COMMENTARY
Alfred Nicolosi, MD
Department of Cardiothoracic Surgery, Medical College of Wisconsin, Froedtert Memorial Lutheran Hospital, 9200 W Wisconsin Ave, Milwaukee, WI 53226-0099
(E-mail: nicolosi{at}mcw.edu).
This article by Emery and colleagues represents a unique experience by a premier surgical group. As noted by the authors, inherent thrombogenicity of the prosthesis and the resultant need for anticoagulation remain the major causes of valve-related events in these patients. At 15 years, the cumulative incidences of thromboembolic and hemorrhagic events reach 15% and 21%, respectively with aortic replacements and they reach 20% and 20%, respectively with mitral valve replacements. These values are important, as nearly 50% of patients are still alive at 15 years. More importantly, there were 61 fatal thromboembolic events after aortic valve replacement (or 14% of all thromboembolic events after aortic valve replacement). Similarly, 15% of thromboembolic events after mitral valve replacement were fatal (45 of 293) as were 11% of hemorrhagic events after aortic valve replacement (63 of 589), and 7% of hemorrhagic events after mitral valve replacement (21 of 285). These consequences of mechanical valves are clearly not insignificant and underscore the comments by the authors that optimization of anticoagulation therapy with home monitoring or alternative thrombin inhibitors, or both, will be important in maximizing the efficacy and safety of mechanical valves in the future.
The authors also note that despite the outstanding durability of the prosthesis, patients having valve replacement do not survive in parallel with the normal population. (Life tables from the middle part of the study period do indeed indicate that the average life expectancy of a 60-year-old in the United States is approximately 20 years.) The authors suggest that this dichotomy results from patient-related, rather than valve-related factors, and that the recorded valve-related mortality is actually overstated because the most common cause of valve-related mortality is sudden death. However, the role of the prosthesis itself in late mortality remains unconfirmed, as deaths were not correlated with either valve gradients or the extent of left ventricular mass regression in individual patients. The mere presence of a rigid prosthesis where pliable tissue is normally found may contribute to late mortality in some patients, as has been suggested by proponents of stentless valves.
Although these and other issues will continue to fuel debate over the optimal valve replacement, the report by Emery and colleagues clearly documents the durability and efficacy of the St. Jude Medical valve, and their results can serve as a benchmark for others.
Related Article
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The St. Jude Medical Cardiac Valve Prosthesis: A 25-Year Experience With Single Valve Replacement
- Robert W. Emery, Christopher C. Krogh, Kit V. Arom, Ann M. Emery, Kathy Benyo-Albrecht, Lyle D. Joyce, and Demetre M. Nicoloff
Ann. Thorac. Surg. 2005 79: 776-782.
[Abstract]
[Full Text]
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