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Recently readers have contacted Cartagena Surgery to contribute to our many ongoing discussions on issues in cardiology, and cardiac surgery.

One of the points that readers have brought up has been the massive attention that TAVI/ TAVR has gotten from the media (and admittedly, we here at Cartagena Surgery are guilty of this), to the detriment of other issues in medicine and surgery.

In an attempt to address this very valid comment, we have started a series of posts looking at other issues in cardiac surgery – specifically in the area of valvular disease(s) and valvular replacement – and why it is important to re-focus our attention to these conditions such as infective endocarditis, mitral and tricuspid valve disorders, as well as bicuspid aortic valve disease.

Valve Disease and Dr. Didier  Lapeyre

In a current environment where TAVI/ TAVR dominate the landscape of discussion regarding valvular disease, other serious and persuasive problems in valvular disease treatments remain largely unaddressed.  The domination of conversations and considerations regarding the use of ‘less invasive’ mechanisms to correct aortic stenosis in the extreme elderly is something that could only be considered in the wealthiest of nations.

Burden of disease

Elsewhere in the world, and in the minds of more globally aware citizens, more important consideration is given to the burden of valvular disease across all populations including young adults and children.  In fact, in my limited travels, it is this scenario that encountered with much more frequency than the “frail octogenarian” that TAVI is designed for.

(For information on the burden of valvular disease in emerging countries – read The Need For A Global Perspective On Heart Valve Disease Epidemiology. )

Then why, as so many other cardiac surgeons and other authors have asked – are we expending some many resources on this minority population[1] to the exclusion and detriment of other developments in cardiac surgery?

Does TAVI detract attention from more common problems in cardiac surgery?

Some may argue, that TAVI/ TAVR is adjacent to, not exclusive to, the development of other improvements and advancements in the field but in my opinion that is a naïve view of the world.  Money and resources are not endless, and corporations and institutions expending large sums investing in transcatheter therapies are certainly not devoting similar resources to such mundane causes such as improving existing therapies.

Dr. Didier Lapeyre

But sometimes it takes a leader, and a legend to do these things, and that’s where Dr. Didier Lapeyre comes in.  As one of the original innovators of mechanical valve technology, he is not content to rest on his laurels or in the pages of medical textbooks.  As he and his colleagues note, current mechanical valve technologies continue to leave much to be desired.  As Zilla et. al. noted back in 2007, “Prosthetic heart valves: catering for the few?” this technology has been essentially stagnant for the last several years despite an enormous need, worldwide for a safe, durable mechanical valve.

Current therapies for valvular disease consist of two options; each with significant drawbacks.  The bioprosthetic or tissue valve requires no additional therapies after implantation but durability leaves much to be desired, making it inappropriate for most young candidates.

The trials and limitations of true mechanical valves are well-known.  As a foreign, metallic material, these valves are prone to cause platelet breakage, and hypercoagulability.  This leads to the dreaded thromboembolic complications of valve thrombosis and cerebral vascular accident.

If the heightened risk of post-TAVI stroke gives us pause in our frail elderly population, consider the elevated risks inherent with mechanical valves and their target population; children and young adults.

At present, the current solution of lifetime anticoagulation for patients with mechanical valves is a stopgap solution at best.  Problematic, potentially dangerous, and unpredictable are excellent descriptions of anti-coagulation with warfarin.  Unavailable and unrealistic are often as accurate; particularly when describing potential use in third-world populations.

After a recent post, talking about controversies and discussions in cardiac surgery in regards to TAVI, Dr. Lapeyre contacted Cartagena Surgery to add his thoughts on the issue.

This has opened a dialogue – and offers a new and interesting opportunity for my readers to hear about Dr. Lapeyre, his work, and (hopefully), the future of mechanical valves in addition to talking about related valvular conditions and treatments.


[1]  As we have argued several times, at Cartagena Surgery, many of the people who have been deemed ‘frail elderly ‘by their cardiologists can be successfully treated with conventional surgery.

References

Current Anti-coagulation recommendations:

Whitlock RP, Sun JC, Fremes SE, Rubens FD, Teoh KH; American College of Chest Physicians.  2012. Antithrombotic and thrombolytic therapy for valvular disease: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest. 2012 Feb;141(2 Suppl):e576S-600S.

Akhtar RP, Abid AR, Zafar H, Khan JS. (2009).  Anticoagulation in patients following prosthetic heart valve replacement.  Ann Thorac Cardiovasc Surg. 2009 Feb;15(1):10-7. Study from Pakistan, where rheumatic heart disease remains common.  Also looks at genetic and racial differences in response to anti-coagulation. Readers will also notice that this study demonstrates the wide disparities in global medicine as discussed above.  How many western patients received a ball and cage valve in 2003?

Cannegieter SC, Rosendaal FR, Briët E. (1994).  Thromboembolic and bleeding complications in patients with mechanical heart valve prostheses.   Circulation. 1994 Feb;89(2):635-41.  Review.  [Linked in text above.]  While this article is considerably dated (based on data prior to 1993) it gives an excellent overview of the many problems/ complications in mechanical valve replacement. However, the statistics cited in their work may differ considerably from more recent results. (Presumably, the rate of ‘real world’ complications are much higher than what I see cited here.)

Matsuyama K, Matsumoto M, Sugita T, Nishizawa J, Yoshida K, Tokuda Y, Matsuo T. (2002).  Anticoagulant therapy in Japanese patients with mechanical mitral valves.  Circ J. 2002 Jul;66(7):668-70. A smaller scale Japanese study.

Not available as free text: Links to abstracts, when available

Taniguchi S, Hashizume K, Ariyoshi T, Hisata Y, Tanigawa K, Miura T, Odate T, Matsukuma S, Nakaji S, Eishi K. (2012).  Twelve years of experience with the ATS mechanical heart valve prostheses.  Gen Thorac Cardiovasc Surg. 2012 Jul 6.

Van Nooten GJ, Caes F, François K, Van Bellleghem Y, Bové T, Vandenplas G, Taeymans Y.  (2012).  Twenty years’ single-center experience with mechanical heart valves: a critical review of anticoagulation policy.  J Heart Valve Dis. 2012 Jan;21(1):88-98

Brown JW, Fiore AC, Ruzmetov M, Eltayeb O, Rodefeld MD, Turrentine MW. (2012).  Evolution of mitral valve replacement in children: a 40-year experience.  Ann Thorac Surg. 2012 Feb;93(2):626-33; discussion 633. Epub 2011 Dec 7. This article talks about why we still need to improve and innovate new valve technology – high mortality in this population.

Suri V, Keepanasseril A, Aggarwal N, Chopra S, Bagga R, Sikka P, Vijayvergiya R. (2011).  Mechanical valve prosthesis and anticoagulation regimens in pregnancy: a tertiary centre experience.  Eur J Obstet Gynecol Reprod Biol. 2011 Dec;159(2):320-3. Epub 2011 Oct 1.  Another important issue that affects our decisions to use mechanical or tissue valves.

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