Clinical Update Thirty-Five: Lowered Anticoagulation

Lowered Anticoagulation Trial Preliminary Results

The On-X® Prosthetic Heart Valve continues to demonstrate tolerance of low INR that has been seen in worldwide studies.

 

A unique study of On-X heart valves

The Prospective Randomized On-X Valve Anticoagulation Trial (PROACT) was initiated in 2006 and is currently ongoing in 36 centers throughout the United States and Canada (Figure 1).1-3 The study groups are presented in Figure 1. This unique study was approved by the FDA for an IDE trial because of the exceptional clinical outcomes seen in trials of the On-X valve since 1996.4-8

PROACT Test Groups

Current results

A preliminary report of PROACT trial data for the high risk aortic patient test and control groups was made by John Puskas of Emory University in Atlanta at the American College of Cardiology on April 5, 2011.9 As hypothesized, patients in the test group with INR’s between 1.5 and 2.0 are currently equal in composite thromboembolic and hemorrhage rates compared to the control group of patients. All patients were participating in home monitoring of INR—a treatment proven to reduce bleeding complications related to anticoagulation therapy.10

The future of a unique mechanical valve

According to Dr. Puskas, “Our goal is to maintain patients with this type of mechanical valve [On-X] on a safer and more convenient regimen that’s closer to the benefits of biological valves. . . The data so far are encouraging and the other study limbs are likely to show similar findings. If final data confirm these early results, the FDA may grant a label for lower doses of anticoagulation drugs. . . .One day we may be able to offer a durable mechanical heart valve with no blood thinner to selected patients.”11

Consistent results

These results emphasize the ability of the On-X valve to tolerate an inconsistent INR level without an increase in thromboembolic events that are exhibited by other currently available mechanical valves.12,13 Table 1 shows composite thromboembolic and hemorrhage rates from the FDA PMA approval studies for current products implanted in the USA.14-23

Table 1. Comparison of composite bleeding and thromboembolism rates for aortic valves from FDA IDE approval studies14-23

Table 1.  Comparison of composite bleeding and thromboembolism rates for aortic valves from FDA IDE approval studies

Until the completion and analysis of the PROACT Trial study data is complete, On-X Life Technologies, Inc. continues to recommend that all patients should be retained on existing ACC/AHA guidelines for mechanical valve anticoagulation.3

 

References

  1. FDA Approved Non-Warfarin and Reduced Warfarin Anticoagulation Trial of the On-X Prosthetic Heart Valve Initiated at Emory Crawford Long Hospital – Tuesday, August 22, 2006. News release Medical Carbon Research Institute, LLC, Austin, Texas USA; © 2006 http://www.onxvalves.com/about_news_item.asp?NewsID=31
  2. PROACT Investigation Plan. Medical Carbon Research Institute, LLC, Austin, Texas USA; © 2006
  3. ACC/ AHA 2006 Guidelines for the Management of Patients With Valvular Heart Disease: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the1998 Guidelines for the Management of Patients With Valvular Heart Disease): Developed in Collaboration With the Society of Cardiovascular Anesthesiologists Endorsed by the Society for Cardiovascular Angiography and Interventions and the Society of Thoracic Surgeons Circulation 2006;114;84-231. DOI: 10.1161/CIRCULATIONAHA.106.176857
  4. Palatianos G, Laczkovics A, Simon P, et al. Multicentered European study on the safety and effectiveness of the On-X® Prosthetic Heart Valve: Intermediate follow-up. Ann Thorac Surg 2007;83:40-46
  5. Williams MA, van Riet S. The On-X heart valve – Mid term results in a poorly anticoagulated population. J Heart Valve Dis 2006;15:80-86
  6. Colli A, Paré C, Rufilanches JJ, et al. The On-X Prosthetic Heart Valve: results of European trial. Presented at the Society of Heart Valve Disease Third Biennial Meeting, Vancouver BC, Canada, June 2005; P119
  7. Takanashi S, et al. Effectiveness of the On-X prosthetic heart valve in the aortic position: Safety of lower INR anticoagulation therapy. J Thorac Surg 2008;56 [Abstract of presentation at the Japanese Association of Thoracic Surgery in Fukuoka City, Japan, October 12-15, 2008]
  8. Tsai HW, Hsieh SR, Wei HJ, et al. Seven-year experience with On-X® Prosthetic Heart Valves in an Asian population with high risk cardiac status and reduced anticoagulation. Society for Heart Valve Disease 4th Biennial Meeting, New York, June 15-18, 2007. Poster 146 [Poster]
  9. Puskas JD, Quinn R, Fermin L, McGrath M, Gerdisch M, Hughes C, Martin T, Kong B, Nichols D. Reduced anticoagulation for a mechanical heart valve. Presented at the American College of Cardiology 2011, New Orleans, Louisiana, USA, April 4, 2011 in Late-Breaking Clinical Trials
  10. Körtke H, Körfer R. International normalized ratio self-management after mechanical heart valve replacement: Is an early start advantageous? Ann Thorac Surg 2001;72:44–48
  11. On-X Heart Valve shows good safety with reduced blood thinners–Encouraging early data reported from large FDA IDE clinical trial. News release from the American College of Cardiology 2011 News Room; April 5, 2011
  12. Horstkotte D, Schulte H, Bircks W, et al. Unexpected findings concerning thromboembolic complications and anticoagulation after complete 10 year follow up of patients with St. Jude Medical prostheses. J Heart Valve Dis 1993;2:291-301
  13. Baudet EM, Puel V, McBride JT, et al. Long-term results of valve replacement with the St. Jude Medical prosthesis. J Thorac Cardiovasc Surg 1995;109:858-70
  14. On-X® Prosthetic Heart Valve. Summary of Safety and Effectiveness Data submitted to the United States Food and Drug Administration. PMA P000037. Approval date May 30, 2001 and October 11, 2002
  15. SJM Regent® Valve. Clinical Study Summary (package insert)
  16. CarboMedics® Prosthetic Heart Valve. Summary of Safety and Effectiveness Data submitted to the United States Food and Drug Administration. PMA P900060. Approval date April 13, 1993
  17. ATS Open Pivot® Bileaflet Heart Valve. Summary of Safety and Effectiveness Data submitted to the United States Food and Drug Administration. PMA P990046. Approval date October 13, 2000
  18. Edwards Life Sciences Carpentier-Edwards Perimount Magna Pericardial Bioprosthesis. Instructions for Use. Copyright 2003
  19. Mitroflow Aortic Pericardial Heart Valve. Summary of Safety and Effectiveness Data submitted to the United States Food and Drug Administration. PMA P060038. Approval date October 23, 2007
  20. SJM Biocor® Valve and SJM Biocor® Supra Valve. Summary of Safety and Effectiveness Data submitted to the United States Food and Drug Administration. PMA P040021. Approval date August 5, 2005
  21. Medtronic Freestyle® Aortic Root Prosthesis. Summary of Safety and Effectiveness Data submitted to the United States Food and Drug Administration. PMA P970031 Approval date November 26, 1997
  22. Mosaic Heart Valve. Summary of Safety and Effectiveness Data submitted to the United States Food and Drug Administration. PMA P990064. Approval date July 14, 2000
  23. ATS 3f® Aortic Bioprosthesis, Model 1000. Instructions for Use

On-X aortic and mitral valves are FDA approved.
CAUTION: Federal law restricts this device to sale by or on the order of a physician. Refer to the Instructions for Use that accompany each valve for indications, contraindications, warnings, precautions and possible complications. CAUTION: Investigational use of this device in the Prospective Randomized On-X Valve Anticoagulation Trial (PROACT) is limited by federal law to investigational sites. For further information, visit www.onxlti.com .

 

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