BACKGROUND: Timely reversal of excessive anticoagulation is important in preventing bleeding complications. The use of vitamin K in correcting over-anticoagulation is widely accepted to be superior to discontinuation of therapy but its effectiveness and safety in large scale cohort studies has not been assessed. METHODS: According to our protocol, 2 mg of oral vitamin K in addition to omitting the day's dose of warfarin, were administered to all patients presenting INR levels >or=5.0 and below 10.0; the INR values were checked 20 h after vitamin K administration. The rate of decay of INR, bleeding and thromboembolic complications at presentation and the following 30 days, as well as resistance to warfarin were assessed. RESULTS: Of the 1,611 events, 1,043 (878 patients) met the selection criteria. The median (interquartile range) INR was 6.64 (6.12-7.52) at presentation (day zero) and fell to a median (interquartile range) INR of 2.72 (2.18-3.52, P < 0.0001) after the vitamin K administration (day one) and 90.6% of the INRs were below 4.5. In 98 (9.4%) instances the INR values did not fall below the safe limit of 4.5 and in 173 (17%) instances the INR values were overcorrected to below 2.0. Median INR value on day zero in these two groups was higher (7.3 vs. 6.6, P < 0.0001) and lower (6.5 vs. 6.7, P = 0.049) than that of the remaining cases, respectively. Overcorrection occurred more frequently in women (P = 0.0002). Female gender was an independent factor associated with INR overcorrection (P = 0.001; OR = 1.7, 95% CI 1.3-2.3). The INRs on day one were inside, above and below the therapeutic range in 44%, 36% and 20% respectively. Warfarin resistance was observed in six cases (0.6%). Major bleeding was reported in one case (1.1 per 100 patient-years), minor bleeding in 14 cases (16.1 per 100 patient-years) and thromboembolic events in six high risk patients (6.9 per 100 patient-years) during the one month period following vitamin K administration.
Effectiveness and safety of a management protocol to correct over-anticoagulation with oral vitamin K: a retrospective study of 1,043 cases
ILICETO, SABINO;PENGO, VITTORIO
2009
Abstract
BACKGROUND: Timely reversal of excessive anticoagulation is important in preventing bleeding complications. The use of vitamin K in correcting over-anticoagulation is widely accepted to be superior to discontinuation of therapy but its effectiveness and safety in large scale cohort studies has not been assessed. METHODS: According to our protocol, 2 mg of oral vitamin K in addition to omitting the day's dose of warfarin, were administered to all patients presenting INR levels >or=5.0 and below 10.0; the INR values were checked 20 h after vitamin K administration. The rate of decay of INR, bleeding and thromboembolic complications at presentation and the following 30 days, as well as resistance to warfarin were assessed. RESULTS: Of the 1,611 events, 1,043 (878 patients) met the selection criteria. The median (interquartile range) INR was 6.64 (6.12-7.52) at presentation (day zero) and fell to a median (interquartile range) INR of 2.72 (2.18-3.52, P < 0.0001) after the vitamin K administration (day one) and 90.6% of the INRs were below 4.5. In 98 (9.4%) instances the INR values did not fall below the safe limit of 4.5 and in 173 (17%) instances the INR values were overcorrected to below 2.0. Median INR value on day zero in these two groups was higher (7.3 vs. 6.6, P < 0.0001) and lower (6.5 vs. 6.7, P = 0.049) than that of the remaining cases, respectively. Overcorrection occurred more frequently in women (P = 0.0002). Female gender was an independent factor associated with INR overcorrection (P = 0.001; OR = 1.7, 95% CI 1.3-2.3). The INRs on day one were inside, above and below the therapeutic range in 44%, 36% and 20% respectively. Warfarin resistance was observed in six cases (0.6%). Major bleeding was reported in one case (1.1 per 100 patient-years), minor bleeding in 14 cases (16.1 per 100 patient-years) and thromboembolic events in six high risk patients (6.9 per 100 patient-years) during the one month period following vitamin K administration.Pubblicazioni consigliate
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