Substandard Monitoring of Warfarin in North America

Hirsh, Jack

doi:10.1001/archinte.1992.00400140011002

Cited by 32 publications

(5 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Traditionally, the PT has been reported in seconds. The value (in seconds) is highly dependent on the sensitivity of the particular thromboplastin reagent, as well as the clot detection method and instrumentation employed (2)(3)(4)(5)(6)(7)(8)(9)(10). Consequently results (in seconds) are not directly comparable between centres (2)(3)(4)8).…”

Section: Introductionmentioning

confidence: 99%

Assessment of the Validity of the INR System for Patients with Liver Impairment

et al. 1994

View full text Add to dashboard Cite

SummaryThe INR system was developed to standardize PT reporting in patients on oral anticoagulants. We prospectively collected blood samples from 29 patients with liver impairment (INR 1.5-3.5). Control patients were on warfarin (n = 31). PT’s were measured on an ACL-300 with three thromboplastin reagents. INR’s were calculated using instrument specific ISI’s. Other tests performed were FDP’s, fibrinogen, aPTT, factors II, V, VII and X. The INR’s for each patient in the study population using the three thromboplastin reagents were significantly different (p = 0.0001). Those for the control population were not (p = 0.0658). Fibrinogen, factors V, II and X were different at the 5% level of significance between the populations. FDP’s were detected in 17 study subjects. The INR system is not valid for comparison of patients with liver impairment because different reagents do not give the same INR for the same sample. It is, however, no less valid than the use of PT with different thromboplastin reagents. Further study is recommended.

show abstract

Section: Introductionmentioning

confidence: 99%

Assessment of the Validity of the INR System for Patients with Liver Impairment

et al. 1994

View full text Add to dashboard Cite

show abstract

“…First, the prothrombin time reagent used for all controls in the WARIS Study is extremely sensitive at the therapeutic level. Relatively insensitive reagents may lead to overdosing and increase the risk of bleeding [13]. Secondly, compared with the Sixty Plus and ASPECT studies, fewer patients in the WARIS study exhibited INR values exceeding the upper therapeutic limit during follow‐up.…”

Section: Side‐effectsmentioning

confidence: 99%

Oral anticoagulants are effective long term after acute myocardial infarction

Smith

1999

Journal of Internal Medicine

View full text Add to dashboard Cite

Abstract. Smith P (Bñrum Hospital, Norway) Oral anticoagulants are effective long term after acute myocardial infarction (Minisymposium: Oral anticoagulants). J Intern Med 1999; 245: 383]387.Three long-term studies on oral anticoagulation, the Sixty Plus trial, the WARIS study, and the ASPECT trial all meet the methodological requirements for modern stand alone clinical trials: large number of patients, double-blinded, placebo-controlled design, and intention to treat analysis. All demonstrate significant reduction in recurrent myocardial infarction, and all show reduction in the risk of total stroke. The WARIS study, however, is the only study demonstrating efficacy in terms of statistically significant reduction of all-cause mortality. These findings are confirmed by a recent meta-analysis. The overall benefit of oral anticoagulation after myocardial infarction suggests avoidance of 4]26 events per 100 patients treated for 2]3 years. Given the results from the trials applying the most adequate control of anticoagulation, avoidance of 10]14 events per 100 patients treated seems to be a realistic benefit. Provided there is sound management of the anticoagulant therapy, especially employment of suitable control methods, the incidence of bleeding may be kept at a low level.

show abstract

“…The types of bleeding were: epistaxis (2). haematuria (2), vaginal (l), gastrointestinal (4), muscular and haemarthrosis (2), fatal haemorrhagic pancreatitis (l), intraabdominal and subarachnoid (l), fatal subarachnoid (1) and intracerebral (3). In other words, of the 1 7 haemorrhages, two were fatal, five were potentially life-threatening (intracranial or severe gastrointestinal), nine were major (hospitalization and/or transfusion), and one required only ambulatory treatment with oral vitamin K. In six cases, there was a contributing factor causing the bleeding : diverticulitis (2), trauma (2), cystoscopy and cancer (1 each).…”

Section: Haemorrhagic Events During Oral Anticoagulationmentioning

confidence: 99%

“…Even so, far from all of the fatal haemorrhages are being reported, because these occurrences are considered by many physicians to be the result of an excessive therapeutic effect rather than being a sideeffect. The monitoring of oral anticoagulation in North America was recently subjected to thorough evaluation [2] and criticism [3], as most laboratories did not report international normalized ratios (INRs) and there was a wide variability in thromboplastin sensitivity. Hence, it is almost impossible to evaluate many US publications in this field.…”

Section: Introductionmentioning

confidence: 99%

Quality of oral anticoagulant control and treatment in Sweden

Schulman

1994

Journal of Internal Medicine

View full text Add to dashboard Cite

The performance of the laboratories was acceptable. Clinically important differences between the hospitals were not observed. The incidences of thromboembolic and haemorrhagic complications were low, even in comparison with other randomized trials concerning venous thromboembolism. However, it might be possible to reduce the risk of haemorrhage further with increased centralization and improved education of patients as well as medical staff, and perhaps to reduce the risk of recurrent venous thromboembolism by aiming at a more intensive range of anticoagulation during the 1st month.

show abstract

Substandard Monitoring of Warfarin in North America

Cited by 32 publications

References 9 publications

Assessment of the Validity of the INR System for Patients with Liver Impairment

Assessment of the Validity of the INR System for Patients with Liver Impairment

Oral anticoagulants are effective long term after acute myocardial infarction

Quality of oral anticoagulant control and treatment in Sweden

Contact Info

Product

Resources

About