Related Experiment Videos
Pattern of anticoagulation control after heart valve surgery at the Kenyatta National Hospital, Nairobi
1Department of Surgery, College of Health Sciences, University of Nairobi, P.O. Box 19676, Nairobi.
Insights
Anticoagulation control for heart valve surgery patients at Kenyatta National Hospital shows suboptimal International Normalized Ratio (INR) values, indicating a need for improved clinic attendance and warfarin dosage adjustments for better patient outcomes.
Area of Science:
- Cardiology
- Pharmacology
- Clinical Medicine
Background:
- Effective anticoagulation is crucial for patients with mechanical heart valves to prevent thromboembolic events.
- Warfarin is a commonly prescribed anticoagulant, requiring regular monitoring of the International Normalized Ratio (INR).
- Suboptimal anticoagulation control can lead to increased risks of bleeding or clotting.
Purpose of the Study:
- To assess the pattern of anticoagulation control in patients post-heart valve surgery.
- To evaluate the management of warfarin therapy and INR levels in this patient population at Kenyatta National Hospital (KNH).
Main Methods:
- A combined prospective and retrospective hospital-based study was conducted.
- Data were collected from post-heart valve surgery patients on warfarin attending the cardiothoracic surgery clinic at KNH.
- Key outcome measures included clinic attendance intervals, warfarin dosages, INR values, and variations from accepted normal ranges.
Main Results:
- 103 patients (77 mitral valve replacements, 18 aortic valve replacements, 7 double valve replacements, 1 mitral valve repair) were included.
- Average clinic attendance was every 59 days, with warfarin dose adjustments occurring 1.48 times per patient annually.
- Adequate anticoagulation (within the therapeutic INR range) was maintained for only 18% of the follow-up time, with 6.9% of patients achieving this for over 50% of their follow-up.
Conclusions:
- Anticoagulation control for heart valve surgery patients at KNH requires improvement.
- Enhancing clinic attendance frequency and optimizing warfarin dosage adjustments are necessary to achieve more appropriate INR values.
- Better anticoagulation management is essential to reduce the risk of complications in this patient group.
Objective:
To determine the pattern of anticoagulation control for post heart-valve surgery for patients on follow up at Kenyatta National Hospital (KNH).
Design:
A combined prospective and restrospective hospital-based study. Retrospective period from January 1991 to 31st August 1997, while the prospective period was from 1st September 1997 to 31st November 1999.
Setting:
Cardiothoracic surgery clinic, Kenyatta National Hospital, Nairobi.
Patients:
Post heart valve surgery patients on warfarin and attending the cardiothoracic surgery clinic at Kenyatta National Hospital.
Main Outcome Measures:
Clinic attendance intervals, average warfarin dosages, interval of dosage change, INR values and variations from accepted normal.
Results:
A total of 103 patients fulfilled the criteria for inclusion into the study consisting of 77 mitral valve replacements, 18 aortic valve replacements, seven double valve replacements and one mitral valve repair. The total follow up time for the study period is 316.9 patients years. On average, patients attended their anticoagulation clinic once every 59 days. The average dose of warfarin prescribed was 6.81 mg daily (+/-2.67 mg), with double valve replacement patients receiving a statistically significant lower dosage of 6.04 mg (+/-1.36 mg), (95% confidence limits). On average, a warfarin dose change was made 1.48 times a year per patient. For all the patients, the mean INR was 2.50 (+/-1.18). The respective values for mitral, aortic, double valve replacement and the mitral repairs were 2.53 (+/-1.21), 2.32 (+/-1.04), 2.5 (+/-1.05) and 2.02 (+/-0.53), respectively. Mitral valve repair patients maintained a significantly lower level of INR (95% confidence limits). Only during 18% of the follow up time was adequate anticoagulation maintained. During the study period only 6.9% of patients were able to maintain adequate anticoagulation for 50% or more of their follow up time.
Conclusion:
Anticoagulation control at the KNH still needs some improvements in clinic attendance and better dosage adjustments to achieve more appropriate INR values.