Randy & Robyn
Well-known member
For those of you interested, here is a written summary of the Aspirin Study Update from a presentation that was given recently.
Update: On-X® Aortic Valve Aspirin Study -
February 15, 2005
Prepared by Medical Carbon Research Institute, L.L.C.
Introduction/Observation
Uwe Mehlhorn, M.D., PhD, University Clinic Cologne Germany provided a clinical update at a meeting held during the recent Society of Thoracic Surgeons Meeting held in Tampa, Florida, January 24, 2005.
Dr. Mehlhorn?s observation: ?Early experience suggests that selected patients with an On-X valve in the aortic position can be safely maintained on 100mg per day of aspirin, which is similar to the anticoagulation protocol for tissue valves. Based upon this experience, continued study and longer follow-up of patients are justified.?
Dr Mehlhorn further observed ?All Thrombosis, TE and Hemorrhagic events are presently within the range of previous mechanical valve studies using Coumadin.?
Study Objective
The objective of the study is to determine if the material and design of the On-X mechanical heart valve has evolved sufficiently to allow for an aspirin-only anticoagulation regimen making it possible for selected, isolated aortic valve replacement patients to use 100 mg/d of aspirin rather than warfarin-based anticoagulation, which is currently the standard of care for all mechanical valves. This study was designed to test the On-X aortic mechanical valve under an anticoagulation protocol normally used with biological valves.
Anticoagulation Regime
The intent of the study is to treat mechanical valve patients in a manner identical to the treatment received by tissue valve patients. Therefore the drug regime is generally consistent with the recommendations of the American College of Chest Physicians (ACCP) and the American College of Cardiology (ACC) for tissue valves.
First 3 months postoperatively: Patients were given Coumadin/warfarin
INR target 2.5
After 3 months: Switch drugs to aspirin only at 100 mg/day.
INR is measured every two (2) weeks up to the three-month follow-up at an anticoagulation clinic or like facility. Prior to weaning each patient from Coumadin/warfarin a platelet aggregation test was performed to confirm aspirin responsiveness. If platelet function was normal despite the presence of aspirin, the patient was not to be included in the test group. Patients were also screened for absence of thrombophilic disorders.
Current Patient Enrollment
Total Patients Enrolled in the Study 72
Patients in Control Group 33
Patients on Aspirin Only 22
Patients Waiting to Convert to Aspirin Only 9
Total Patient Experience 21 pt/yrs (First 2 patients placed on Aspirin only 16 months ago)
Note: 8 patients in total have been withdrawn from the aspirin only group for a variety of reasons, including atrial fibrillation, one death, lack of compliance, patient choice and one reversible ischemic neurologic deficit. In the control group, one patient experienced a transient ischemic attack.
Patient Inclusion:
1. Isolated aortic valve replacement
2. Sinus rhythm
3. Concomitant bypass, septal defect repair, tricuspid or mitral repair allowed
4. Adult patients
Patient Exclusion:
1. Multiple valve replacement
2. Chronic atrial fibrillation, ejection fraction <30%
3. Enlarged left atrium >50mm diameter
4. Spontaneous echo contrasts in the left atrium
5. Previous Thromboembolic event
6. Vascular pathology or neurological events
7. Hypercoagulability
8. Ventricular aneurysm
9. Lack of therapeutic response to aspirin
10. Active endocarditis
11. Other terminal illness
12. Patients who are in an emergency state
13. Inability to return for required follow-ups
14. No prisoners, no persons unable to give adequate informed consent
15. Permanent cardiac pacemaker
Update: On-X® Aortic Valve Aspirin Study -
February 15, 2005
Prepared by Medical Carbon Research Institute, L.L.C.
Introduction/Observation
Uwe Mehlhorn, M.D., PhD, University Clinic Cologne Germany provided a clinical update at a meeting held during the recent Society of Thoracic Surgeons Meeting held in Tampa, Florida, January 24, 2005.
Dr. Mehlhorn?s observation: ?Early experience suggests that selected patients with an On-X valve in the aortic position can be safely maintained on 100mg per day of aspirin, which is similar to the anticoagulation protocol for tissue valves. Based upon this experience, continued study and longer follow-up of patients are justified.?
Dr Mehlhorn further observed ?All Thrombosis, TE and Hemorrhagic events are presently within the range of previous mechanical valve studies using Coumadin.?
Study Objective
The objective of the study is to determine if the material and design of the On-X mechanical heart valve has evolved sufficiently to allow for an aspirin-only anticoagulation regimen making it possible for selected, isolated aortic valve replacement patients to use 100 mg/d of aspirin rather than warfarin-based anticoagulation, which is currently the standard of care for all mechanical valves. This study was designed to test the On-X aortic mechanical valve under an anticoagulation protocol normally used with biological valves.
Anticoagulation Regime
The intent of the study is to treat mechanical valve patients in a manner identical to the treatment received by tissue valve patients. Therefore the drug regime is generally consistent with the recommendations of the American College of Chest Physicians (ACCP) and the American College of Cardiology (ACC) for tissue valves.
First 3 months postoperatively: Patients were given Coumadin/warfarin
INR target 2.5
After 3 months: Switch drugs to aspirin only at 100 mg/day.
INR is measured every two (2) weeks up to the three-month follow-up at an anticoagulation clinic or like facility. Prior to weaning each patient from Coumadin/warfarin a platelet aggregation test was performed to confirm aspirin responsiveness. If platelet function was normal despite the presence of aspirin, the patient was not to be included in the test group. Patients were also screened for absence of thrombophilic disorders.
Current Patient Enrollment
Total Patients Enrolled in the Study 72
Patients in Control Group 33
Patients on Aspirin Only 22
Patients Waiting to Convert to Aspirin Only 9
Total Patient Experience 21 pt/yrs (First 2 patients placed on Aspirin only 16 months ago)
Note: 8 patients in total have been withdrawn from the aspirin only group for a variety of reasons, including atrial fibrillation, one death, lack of compliance, patient choice and one reversible ischemic neurologic deficit. In the control group, one patient experienced a transient ischemic attack.
Patient Inclusion:
1. Isolated aortic valve replacement
2. Sinus rhythm
3. Concomitant bypass, septal defect repair, tricuspid or mitral repair allowed
4. Adult patients
Patient Exclusion:
1. Multiple valve replacement
2. Chronic atrial fibrillation, ejection fraction <30%
3. Enlarged left atrium >50mm diameter
4. Spontaneous echo contrasts in the left atrium
5. Previous Thromboembolic event
6. Vascular pathology or neurological events
7. Hypercoagulability
8. Ventricular aneurysm
9. Lack of therapeutic response to aspirin
10. Active endocarditis
11. Other terminal illness
12. Patients who are in an emergency state
13. Inability to return for required follow-ups
14. No prisoners, no persons unable to give adequate informed consent
15. Permanent cardiac pacemaker
