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Stavros Apostolakis, MD, PhD; Renee M. Sullivan, MD; Brian Olshansky, MD; Gregory Y. H. Lip, MD
Author and Funding Information

From the University of Birmingham Centre for Cardiovascular Sciences (Drs Apostolakis and Lip), City Hospital; University of Missouri Health Care (Dr Sullivan); and the Division of Cardiovascular Medicine, University of Iowa Hospitals and Clinics (Dr Olshansky).

Correspondence to: Gregory Y. H. Lip, MD, University of Birmingham Centre for Cardiovascular Sciences, City Hospital, Dudley Rd, Birmingham, B18 7QH, England; e-mail: g.y.h.lip@bham.ac.uk


Financial/nonfinancial disclosures: The authors have reported to CHEST the following conflicts of interest: Dr Lip has served as a consultant for Bayer; Astellas Pharma; Merck & Co; Sanofi; Bristol-Myers Squibb/Pfizer Inc; Daiichi Sankyo, Inc; BIOTRONIK; Portola Pharmaceuticals, Inc; and Boehringer-Ingelheim GmbH and has been on the speakers’ bureau of Bayer, Bristol-Myers Squibb/Pfizer Inc, Boehringer-Ingelheim GmbH, and Sanofi-Aventis. Drs Apostolakis, Sullivan, and Olshansky have reported that no potential conflicts of interest exist with any companies/organizations whose products or services may be discussed in this article.

Reproduction of this article is prohibited without written permission from the American College of Chest Physicians. See online for more details.


Chest. 2014;145(2):419-420. doi:10.1378/chest.13-2775
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To the Editor:

We thank Dr Zhang and colleagues for their thoughtful feedback on our article1 and agree that further work may be needed to validate our score in larger real-life databases. However, they have missed the point.

In our study, we aimed to develop a simple user friendly tool to assist decision-making when oral anticoagulation is considered in patients with atrial fibrillation.1 SAME-TT2R2 (sex female, age < 60 years, medical history [more than two comorbidities], treatment [interacting drugs, eg, amiodarone for rhythm control], tobacco use [doubled], race [doubled]) is presently the best (and only) simple user friendly clinical tool in the literature available to determine who will (or will not) achieve reasonable (and clinically important) time in therapeutic range (TTR) with warfarin anticoagulation. The goal was not to consider all potential confounders that could affect TTR, but to identify those common clinical factors that were most influential, measurable, and accessible.2 Genotyping is not easily accessible, and there is no convincing evidence that genotyping has clinical value; more likely, genotyping has a limited role in the management of warfarin anticoagulation.3,4 Based on the SAME-TT2R2 score, a reasonably quick decision can be made early on regarding the use of warfarin, or perhaps a novel anticoagulant, during busy clinic or ward rounds.

We respectfully disagree with the argument that patients with valvular heart disease would not fit into the strategy we outlined using SAME-TT2R2, but recognize that the majority of patients (95%) in the Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) trial had no valvular disease. We believe the all-comers real-world design of AFFIRM is a major advantage.5 Future studies may find that the presence of valvular heart disease plays a role in anticoagulation strategies or in anticoagulation outcomes but we have no specific reason to suggest that now.

We concur that there are various methods to determine TTR but our approach was guided by the advantages and limitations of our databases. The Rosendaal method is the most validated approach to measure TTR, and it can only be used when consecutive international normalized ratio measurements are available. When only random samples exist, the percentage of international normalized ratio measurements within therapeutic range is the method of choice. What we are considering in our study1 was the long-term management of warfarin anticoagulation and not short-term fluctuations that may occur in the first month. We suspect this approach reflects as accurately as possible real-life practice.

Finally, we would like to point out that SAME-TT2R2 score does not predict TTR but detects a group’s TTR outliers. Put simply, how likely is someone not to achieve the group’s average TTR? This feature makes TTR useful for both very efficient and inefficient centers. We encourage investigators to validate SAME-TT2R2 aiming to their centers outliers and not specific TTR cutoff points.

In summary, the considerations and concerns mentioned by Dr Zhang and colleagues only highlight the nature of TTR measurements in clinical practice and focus even more on the clinical and important application of the SAME-TT2R2 score, which is presently the only available, simple to use, and systematic approach to assist decision-making regarding oral anticoagulation. Until alternative efficient approaches are found, the available options are systematic decision-making using the SAME-TT2R2 score or reliance on so-called clinical judgment or guesswork.

References

Apostolakis S, Sullivan RM, Olshansky B, Lip GYH. Factors affecting quality of anticoagulation control among patients with atrial fibrillation on warfarin: the SAMe-TT2R2score. Chest. 2013;144(5):1555-1563. [CrossRef] [PubMed]
 
De Caterina R, Husted S, Wallentin L, et al; Position Paper of the ESC Working Group on Thrombosis–Task Force on Anticoagulants in Heart Disease. Vitamin K antagonists in heart disease: current status and perspectives (section III). Thromb Haemost. 2013;110(6):1087-1107. [CrossRef] [PubMed]
 
Kimmel SE, French B, Kasner SE, et al; the COAG Investigators. A pharmacogenetic versus a clinical algorithm for warfarin dosing [published online ahead of print November 19, 2013]. N Engl J Med. doi:10.1056/NEJMoa1310669.
 
Kurnik D, Qasim H, Sominsky S, et al. Effect of the VKORC1 D36Y variant on warfarin dose requirement and pharmacogenetic dose prediction. Thromb Haemost. 2012;108(4):781-788. [CrossRef] [PubMed]
 
Wyse DG, Waldo AL, DiMarco JP, et al; Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) Investigators. A comparison of rate control and rhythm control in patients with atrial fibrillation. N Engl J Med. 2002;347(23):1825-1833. [CrossRef] [PubMed]
 

Figures

Tables

References

Apostolakis S, Sullivan RM, Olshansky B, Lip GYH. Factors affecting quality of anticoagulation control among patients with atrial fibrillation on warfarin: the SAMe-TT2R2score. Chest. 2013;144(5):1555-1563. [CrossRef] [PubMed]
 
De Caterina R, Husted S, Wallentin L, et al; Position Paper of the ESC Working Group on Thrombosis–Task Force on Anticoagulants in Heart Disease. Vitamin K antagonists in heart disease: current status and perspectives (section III). Thromb Haemost. 2013;110(6):1087-1107. [CrossRef] [PubMed]
 
Kimmel SE, French B, Kasner SE, et al; the COAG Investigators. A pharmacogenetic versus a clinical algorithm for warfarin dosing [published online ahead of print November 19, 2013]. N Engl J Med. doi:10.1056/NEJMoa1310669.
 
Kurnik D, Qasim H, Sominsky S, et al. Effect of the VKORC1 D36Y variant on warfarin dose requirement and pharmacogenetic dose prediction. Thromb Haemost. 2012;108(4):781-788. [CrossRef] [PubMed]
 
Wyse DG, Waldo AL, DiMarco JP, et al; Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) Investigators. A comparison of rate control and rhythm control in patients with atrial fibrillation. N Engl J Med. 2002;347(23):1825-1833. [CrossRef] [PubMed]
 
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