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Fixed-dose versus adjusted-dose warfarin in patients with prosthetic heart valves in a peri-urban impoverished population.
J Heart Valve Dis. 2002 Jul; 11(4):583-92; discussion 593.JH

Abstract

BACKGROUND AND AIMS OF THE STUDY

Patients with mechanical heart valves are critically dependent upon adequate anticoagulation. The present patients are young, geographically dispersed and socioeconomically deprived. Hospital attendance is erratic, and compliance with conventional anticoagulation difficult. The need exists for an alternative method of anticoagulation that requires neither regular visits nor adjustment of the warfarin dose.

METHODS

A five-year prospective randomized double-blind study was undertaken to compare the efficacy and safety of a predetermined, individualized fixed-dose versus adjusted-dose warfarin. Postopoeratively, 296 patients, after an initial dose-finding phase (International Normalized Ratio (INR) 2.0 - 3.5), were randomized to either fixed-dose or adjusted-dose warfarin.

RESULTS

For the intention-to-treat analysis, the groups were well-matched with regard to baseline characteristics. Among patients on fixed-dose warfarin, 63% of INRs were in the range 2.0 - 4.5 compared with 64% in patients on adjusted-dose warfarin. The mean follow up period was 2.4 years in both groups; total follow up was 725 patient-years. There were seven deaths in the fixed-dose warfarin group, and five in the adjusted-dose group (p = 0.52). Thirteen major thrombotic events, occurred in the fixed-dose warfarin group, and four in the adjusted-dose group (p = 0.02). Twelve major hemorrhagic events occurred in each group.

CONCLUSION

In this predominantly young, impoverished population, despite similar overall INR control, fixed-dose warfarin was associated with an increase in thromboembolic events, but no significant increase in mortality or hemorrhagic events. Fixed-dose warfarin may be an acceptable option where conventional anticoagulation is impracticable. In particular, the study highlighted the difficulties of adequate anticoagulation in a population where compliance is erratic and often non-existent.

Authors+Show Affiliations

Buchanan-Leel B
Cardiac Clinic, Department of Medicine, University of Cape Town and Groote Schuur Hospital, South Africa.
Levetan BN
No affiliation info available
Lombard CJ
No affiliation info available
Commerford PJ
No affiliation info available

MeSH

AdolescentAdultAgedAnticoagulantsBioprosthesisDeveloping CountriesDose-Response Relationship, DrugDouble-Blind MethodDrug Administration ScheduleFemaleFollow-Up StudiesHeart Valve DiseasesHeart Valve ProsthesisHumansMaleMiddle AgedPatient CompliancePostoperative CarePovertyProbabilityProspective StudiesReference ValuesRheumatic Heart DiseaseRisk FactorsSouth AfricaSurvival AnalysisThromboembolismTreatment OutcomeWarfarin

Pub Type(s)

Clinical Trial
Comparative Study
Journal Article
Randomized Controlled Trial
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

12150309

Citation

Buchanan-Leel, Biddy, et al. "Fixed-dose Versus Adjusted-dose Warfarin in Patients With Prosthetic Heart Valves in a Peri-urban Impoverished Population." The Journal of Heart Valve Disease, vol. 11, no. 4, 2002, pp. 583-92; discussion 593.
Buchanan-Leel B, Levetan BN, Lombard CJ, et al. Fixed-dose versus adjusted-dose warfarin in patients with prosthetic heart valves in a peri-urban impoverished population. J Heart Valve Dis. 2002;11(4):583-92; discussion 593.
Buchanan-Leel, B., Levetan, B. N., Lombard, C. J., & Commerford, P. J. (2002). Fixed-dose versus adjusted-dose warfarin in patients with prosthetic heart valves in a peri-urban impoverished population. The Journal of Heart Valve Disease, 11(4), 583-92; discussion 593.
Buchanan-Leel B, et al. Fixed-dose Versus Adjusted-dose Warfarin in Patients With Prosthetic Heart Valves in a Peri-urban Impoverished Population. J Heart Valve Dis. 2002;11(4):583-92; discussion 593. PubMed PMID: 12150309.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Fixed-dose versus adjusted-dose warfarin in patients with prosthetic heart valves in a peri-urban impoverished population. AU - Buchanan-Leel,Biddy, AU - Levetan,Basil N, AU - Lombard,Carl J, AU - Commerford,Patrick J, PY - 2002/8/2/pubmed PY - 2003/1/18/medline PY - 2002/8/2/entrez SP - 583-92; discussion 593 JF - The Journal of heart valve disease JO - J Heart Valve Dis VL - 11 IS - 4 N2 - BACKGROUND AND AIMS OF THE STUDY: Patients with mechanical heart valves are critically dependent upon adequate anticoagulation. The present patients are young, geographically dispersed and socioeconomically deprived. Hospital attendance is erratic, and compliance with conventional anticoagulation difficult. The need exists for an alternative method of anticoagulation that requires neither regular visits nor adjustment of the warfarin dose. METHODS: A five-year prospective randomized double-blind study was undertaken to compare the efficacy and safety of a predetermined, individualized fixed-dose versus adjusted-dose warfarin. Postopoeratively, 296 patients, after an initial dose-finding phase (International Normalized Ratio (INR) 2.0 - 3.5), were randomized to either fixed-dose or adjusted-dose warfarin. RESULTS: For the intention-to-treat analysis, the groups were well-matched with regard to baseline characteristics. Among patients on fixed-dose warfarin, 63% of INRs were in the range 2.0 - 4.5 compared with 64% in patients on adjusted-dose warfarin. The mean follow up period was 2.4 years in both groups; total follow up was 725 patient-years. There were seven deaths in the fixed-dose warfarin group, and five in the adjusted-dose group (p = 0.52). Thirteen major thrombotic events, occurred in the fixed-dose warfarin group, and four in the adjusted-dose group (p = 0.02). Twelve major hemorrhagic events occurred in each group. CONCLUSION: In this predominantly young, impoverished population, despite similar overall INR control, fixed-dose warfarin was associated with an increase in thromboembolic events, but no significant increase in mortality or hemorrhagic events. Fixed-dose warfarin may be an acceptable option where conventional anticoagulation is impracticable. In particular, the study highlighted the difficulties of adequate anticoagulation in a population where compliance is erratic and often non-existent. SN - 0966-8519 UR - https://www.unboundmedicine.com/medline/citation/12150309/Fixed_dose_versus_adjusted_dose_warfarin_in_patients_with_prosthetic_heart_valves_in_a_peri_urban_impoverished_population_ DB - PRIME DP - Unbound Medicine ER -