Clinical Update Thirty-Four: On-X Heart Valve Outperform

On-X Heart Valves outperform tissue valves in a matched study

On-X® Prosthetic Heart Valve patients in a prospective study matched to patients implanted with tissue valves showed a definite advantage in mortality.1


The On-X® Prosthetic Heart Valve provides lower mortality

Study results reported at the recent Society of Thoracic Surgeons (STS) meeting in San Diego, California, USA provide new evidence that On-X mechanical valve patients receive a survival advantage compared with propensity matched patients that were implanted with tissue valves. These results confirm those of other published studies.2-5 The REFORM trial, Reduced Anticoagulation for On-X Heart Valves: An Observational Non-Randomized Safety Study, studied On-X valve patients on low end warfarin treatment (aortic valve patients with a target INR of 2.0, mitral valve patients with a target INR of 2.5).6 These REFORM patients were matched with tissue valve recipients (Carpentier Edwards pericardial valve or Medtronic porcine valve) who did not regularly receive warfarin (Table 1).1 On-X valve patients had a similar composite rate of bleeding and thromboembolism (TE) with a lower rate of TE. There was no late bleeding in either group (Table 2). Additionally, the linearized rate of mortality favored the On-X valve patients at four years.

Table 1. Preoperative characteristics of On-X patients and tissue valve patients1

Preoperative Data
Number of patients matched 175
Mean age 56.4 ± 9.7 years
Age range 24-72 years
Median follow-up 3.8 years
Total follow-up 506.0 years

Table 2. Comparison of results of the On-X valve to tissue valves—linearized rates (% per patient-year)1
TE = thromboembolism

  TE Hemorrhage Mortality
On-X valve 0.43 0 1.71
Tissue valve 1.10 0 3.67

Comparisons of On-X valve results to tissue valve results in clinical trials performed for FDA market approval suggest the same advantage.7-13 The On-X aortic valve average thromboembolic and hemorrhage rates were lower than the average aortic tissue valve results along with those for reoperation and valve-related mortality (Table 3).

Does home monitoring of INR cause the difference in anticoagulant related events?

Home INR studies such ESCAT (Early Self-Controlled Anticoagulation Trial)14 in Europe prove that home monitoring can decrease complication rates for patients with mechanical valves as much as 35%. However, when results of the On-X valve patients without home monitoring are compared to results from the ESCAT trial, the On-X patients had a clear advantage (Table 4).7,14 Clearly, home-monitoring does not offer the full explanation of why the On-X valve performs clinically better than other mechanical valves and tissue valves. Additionally, other mechanical valves have shown a clear trend for an increase in thromboembolic events when INR goes below an optimal range of about 2.2.15

Table 3. Comparison of FDA trial data for the aortic On-X valve and aortic tissue valve averages (% per patient-year).
TE = thromboembolism

  TE Hemorrhage Reoperation Valve Related Mortality Total Events
On-X valve 1.7 0.7 0.7 0.2 3.3
Tissue valve (average rate) 2.1 0.9 0.9 1.4 5.3

Table 4. ESCAT vs. On-X valve results—comparison of Grade III complications7,14

Grade III Complications On-X® conventional ESCAT conventional ESCAT self-managed
Avg Follow-up yrs 2.8 3.2 3.2
Follow-up pt-yrs 885 943 976
Hemorrhagic N (% per pt-yr) 5(0.6) 25(2.6) 17(1.7)
Thromboembolic N (% per pt-yr) 8(0.9) 20(2.1) 12(1.2)
Total N (% per pt-yr) 13(1.5) 45(4.7) 29(2.9)

On-X Conform-X Heart Valve

Advanced design features of the On-X heart valve that reduce turbulence and blood damage16,17 clearly provide the benefit of lowered complication rates when compared to other valves including tissue valves. Lowered complication rates contribute to better survival with the On-X heart valve.


  1. Badhwar V. Ofenloch J, Rovin J, et al. Equivalency of closely monitored mechanical valves to bioprostheses overshadowed by early mortality benefit in younger patients. The Society of Thoracic Surgeons 47th Annual Meeting Program Book, Poster Abstract 12, page 359
  2. Brown ML, Schaff HV, Lahr BD, et al. Aortic valve replacement in patients aged 50 to 70 years: Improved outcome with mechanical versus biologic prostheses. J Thorac Cardiovasc Surg 2008;135:878-84
  3. Vicchio M, Della Corte A, De Santo LS, et al. Tissue versus mechanical prostheses: Quality of life in octogenarians. Ann Thorac Surg 2008;85:1290-95
  4. de Vincentiis C, Kunkl AB, Trimarchi S, et al. Aortic valve replacement in octogenarians: Is biologic valve the unique solution? Ann Thorac Surg 2008;85:1296-1301
  5. Stassano P, Di Tommaso L, Monaco M, et al. Aortic valve replacement: A prospective randomized evaluation of mechanical versus biological valves in patients ages 55 to 70 years. JACC 2009;54:1862-68
  6. Badhwar V, Campbell M, Ofenloch, J, et al. Reduced anticoagulation for On-X Heart Valves: A prospective multicenter experience using home monitoring. Presented at Controversies and Advances in the Treatment of Cardiovascular Disease, The Ninth in the Series, Beverly Hills, CA, Thursday, October 1, 2009
  7. 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
  8. Edwards Life Sciences Carpentier-Edwards Perimount Magna Pericardial Bioprosthesis. Instructions for Use. Copyright 2003
  9. 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
  10. 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
  11. 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
  12. 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
  13. ATS 3f® Aortic Bioprosthesis, Model 1000. Instructions for Use
  14. Kortke H, Korfer R. International normalized ratio self-management after mechanical heart valve replacement: Is an early start advantageous? Ann Thorac Surg 2001;72:44-48
  15. 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 Disease 1993;2:291-301
  16. Birnbaum D, Laczkovics A, Heidt M, et al. Examination of hemolytic potential with the On-X® Prosthetic Heart Valve. J Heart Valve Disease 2000;9:142-45
  17. Yezbick AB, Ho JK, Crowley R, et al. Echardiographic signature of the On-X valve. Echocardiography 2008;25:1016-18

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. For further information, visit


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