Peak Anti-factor Xa Activity Research Articles

Distribution of anti-factor Xa activity in patients with nonvalvular atrial fibrillation receiving 15 mg dose of edoxaban.

The distribution of anti-factor Xa activity (AXA) in patients with nonvalvular atrial fibrillation (NVAF) taking edoxaban 15 mg has not been fully elucidated. The trough and peak AXA were measured in 19 NVAF patients taking edoxaban 15 mg. We compared these results with those in patients taking edoxaban 30 mg. The peak AXA differed significantly between the 15 mg and the 30 mg groups (0.74 ± 0.40 IU/mL vs. 1.25 ± 0.48 IU/mL, respectively; p < 0.0001). Peak but trough AXA in the patients receiving edoxaban 15 mg were significantly lower than those in patients receiving edoxaban 30 mg.

Abstract 13192: Anti-Factor Xa Activity in Patients With Chronic Thromboembolic Pulmonary Disease With or Without Pulmonary Hypertension Treated With Factor Xa Inhibitors

Introduction and Hypothesis: Data on the efficacy and safety of factor Xa (FXa) inhibitors in chronic thromboembolic pulmonary disease (CTEPD) patients, especially in chronic thromboembolic pulmonary hypertension (CTEPH) patients, remain limited. Here, we aimed to evaluate the effect of FXa inhibitors by measuring anti-factor Xa activity (AXA) in both patients with CTEPD without pulmonary hypertension (PH) and CTEPH. Methods: Twenty-five CTEPD patients without PH and 52 CTEPH patients, treated with either of the FXa inhibitors were enrolled. AXA was measured by using HemosIL heparin calibrator. Blood samples were collected two times at the same day: immediately before the drug administration (trough) and 2-3 h after drug administration (peak). Results: In all 77 patients, median age was 66 (Interquartile range [IQR] 51–73) years, and 43% were male. In addition, 47% of the patients received rivaroxaban of 15 mg/day, 27% received apixaban of 10 mg/day, 14% received edoxaban of 60mg/day, and 12% received edoxaban of 30 mg/day. The median peak AXA of all 77 patients was 1.92 IU/mL and was comparable between CTEPD without PH and CTEPH patients. Significant difference of trough and peak AXA was shown among four different prescribed drugs (P &lt; .001 and P = .006, respectively). During the observational period of median 519 (IQR 364–1118) days, major and clinically relevant non-major bleeding occurred in six patients. ROC analysis to predict bleeding events revealed that the sensitivity and specificity of the cutoff point of a peak AXA of 2.1 IU/mL were 67% and 66%, respectively (AUC 0.66). The cumulative rate of major and clinically relevant non-major bleeding tended to be higher in patients with peak AXA ≥ 2.1 IU/mL than in patients with values below this point (p = .092, Figure). Conclusion: Measuring AXA could be a useful method to evaluate the effect of FXa inhibitors in CTEPD with or without PH patients.

Novel fondaparinux protocol for anticoagulation therapy in adults with renal failure and suspected heparin-induced thrombocytopenia: a retrospective review of institutional protocol

IntroductionThe literature recommends against the use of fondaparinux in patients with kidney failure and dialysis as it may, with repeated dosing, accumulate and put patients at risk of bleeding. The management of patients with thrombosis in the presence of heparin-induced thrombocytopenia HIT requires the introduction of an alternative anticoagulant like bivalirudin or argatroban. When these drugs are not available, fondaparinux, remains the only alternative. In similar scenarios, there are few studies addressing how to administer it. MethodsWe developed a protocol for fondaparinux in patients with renal failure where pharmacokinetic parameters are altered, and levels changed only after hemodialysis or in cases of residual renal activity. Patients received a full first dose except for high risk of bleeding. We targeted a peak anti-factor Xa activity level of 0.6–1.3 units/ml and changed the subsequent dose accordingly. Furthermore, we monitored the patients for signs of bleeding, a drop in hemoglobin level, or clinical signs of thrombosis. DiscussionWe described 10 patients with kidney failure and suspected HIT taking fondaparinux. All the patients achieved therapeutic anti-factor Xa activity levels. However, one developed new-onset venous thromboembolism (VTE) despite therapeutic anti-factor Xa levels. Another patient experienced a bleeding episode. We believe that these two patients developed complications due to their medical conditions rather than the use of fondaparinux.ConclusionFondaparinux can be safely used in kidney failure using our protocol. However, despite its safety profile and relative success, this case series was small. More robust studies need to be conducted prior to drawing conclusions.

Abstract 9574: Distribution of Anti-Factor Xa Activity Value, Prothrombin Time, and Activated Partial Thromboplastin Time in Patients Treated With Factor Xa Inhibitors

Introduction: The distribution of anti-factor Xa activity (AXA) values, prothrombin time (PT), and activated partial thromboplastin time (APTT) in patients administered each factor Xa (FXa) inhibitors (apixaban, edoxaban, and rivaroxaban) has not fully been assessed. Purpose: To clarify the distribution of AXA, PT, and APTT in patients taking FXa inhibitors. Methods: Trough and peak AXA values, PT, and APTT were measured in 85 patients taking apixaban, 105 patients taking edoxaban, and 27 patients taking rivaroxaban. The patients were further divided into three groups based on the dosage. Results: At trough time of apixaban, the AXA values in patients administered 20 mg were significantly higher than those administered 5 mg or 10 mg (P &lt; 0.001). PT in patients administered 20 mg were significantly higher than those administered 5 mg or 10 mg (P = 0.006). At peak time, the AXA values in patients administered 20 mg were significantly higher than those administered 5 mg or 10 mg (P &lt; 0.001). PT in patients administered 20 mg was significantly higher than those administered 5 mg or 10 mg (P &lt; 0.001). APTT in patients administered 20 mg was significantly higher than those administered 5 mg or 10 mg (P &lt; 0.001). At peak time of edoxaban, the AXA values in patients administered 60 mg were significantly higher than those administered 15 mg or 30 mg (P &lt; 0.001). PT in patients administered 60 mg were significantly higher than those administered 15 mg or 30 mg (P = 0.006). APTT in patients administered 60 mg was significantly higher than those administered 30 mg (P = 0.003). At trough time of rivaroxaban, the AXA values in patients administered 30 mg were significantly higher than those administered 10 mg or 15 mg (P = 0.001). At peak time, AXA values in patients administered 30 mg were significantly higher than those administered 15 mg (P = 0.028). Conclusion: This study determined the distribution of AXA, PT, and APTT in patients administered apixaban, edoxaban, and rivaroxaban.

Anti-factor Xa activity, prothrombin time, and activated partial thromboplastin time in patients treated with factor Xa inhibitors.

The regimens for factor Xa (FXa) inhibitors (apixaban, edoxaban, and rivaroxaban) vary with venous thromboembolism (VTE) or non-valvular atrial fibrillation (NVAF). The dosage and duration of FXa inhibitor therapy also differ. However, the distribution of anti-factor Xa activity (AXA) values, prothrombin time (PT), and activated partial thromboplastin time (APTT) in patients administered each FXa inhibitor has not fully been assessed. Trough and peak AXA values, PT, and APTT were measured in 85 patients taking apixaban, 105 patients taking edoxaban, and 27 patients taking rivaroxaban. The patients were further divided into three groups based on the dosage. Each FXa inhibitor showed various ranges of AXA values, and twice-daily use resulted in higher absolute AXA values than once-daily use. AXA values and PT for 20mg apixaban at both trough and peak times were significantly higher than those for 5mg or 10mg. AXA values for 60mg edoxaban at peak time were significantly higher than those for 15mg or 30mg. AXA values for 30mg of rivaroxaban at both trough and peak times were significantly higher than those for 10mg or 15mg. In a nonlinear regression model of the relationship between AXA and PT or APTT, PT was positively correlated with AXA values for each FXa inhibitor. This study obtained trough and peak levels of AXA, PT, and APTT in patients with VTE or NVAF who were administered apixaban, edoxaban, and rivaroxaban.

Impact of Renal Function on Anti-factor Xa Activity Concentrations with Edoxaban Use in Patients with Non-valvular Atrial Fibrillation

Chromogenic anti-factor Xa activity (AXA) assay is used to measure the pharmacodynamics of factor Xa inhibitors, including edoxaban. Although AXA concentrations in patients with non-valvular atrial fibrillation using edoxaban have been reported, the impact of renal function on AXA concentrations with edoxaban use in patients with non-valvular atrial fibrillation has not been fully assessed. Trough and peak AXA concentrations were measured in 93 patients with non-valvular atrial fibrillation taking edoxaban (73.6 ± 11.2 years, 48 were male). The patients were divided into three groups: patients with moderate renal dysfunction (creatinine clearance 15-49 mL/min), mild renal dysfunction (creatinine clearance 50-95 mL/min), and normal renal function (creatinine clearance >95 mL/min). Both trough and peak AXA concentrations were assessed among the groups according to the edoxaban dose (30 or 60 mg). At a 30-mg dose, patients with moderate renal dysfunction showed significantly higher trough AXA concentrations than patients with mild renal dysfunction or normal renal function. At a 60-mg dose, patients with mild renal dysfunction showed significantly higher trough AXA concentrations than patients with normal renal function. Peak AXA concentrations were not significantly different between the groups. Creatinine clearance was significantly and negatively correlated with trough AXA concentrations at a 60-mg dose, whereas the correlation of creatinine clearance with AXA concentrations was borderline significant at a 30-mg dose. No correlation was found between creatinine clearance and peak AXA concentrations at either dose. Creatinine clearance tends to be negatively correlated with trough AXA concentrations in patients with non-valvular atrial fibrillation taking edoxaban, while renal function is not correlated with peak AXA concentrations.

Coagulation markers in patients with venous thromboembolism treated with 10 mg apixaban twice daily.

Apixaban is used to treat venous thromboembolism (VTE) at 10 mg twice daily (BID) for 7 days, followed by 5 mg BID without dose adjustment, and non-valvular atrial fibrillation (NVAF) at 5 mg BID or 2.5 mg BID with dose adjustment criteria (DAC) including age, body weight, and renal function. The anti-factor Xa activity (AXA), prothrombin time (PT), and activated partial thromboplastin time (APTT) in patients with VTE receiving 10 mg BID of apixaban remains unclear. Twenty-six patients (70.8±15.4 years, 10 males) with VTE receiving 10 mg BID of apixaban were enrolled. The patients were divided into two groups based on whether they met the DAC of NVAF: DAC group (n=8) and non-DAC group (n=18). Trough and peak AXA values, PT, and APTT were measured at 10 mg BID dosage and then at 5 mg BID dosage. Coagulation markers in recipients of 10 mg BID therapy were significantly higher than those of 5 mg BID recipients. A significant and strong positive correlation was observed between AXA and PT at trough and peak times. The AXA values and PT in the DAC group were significantly higher than those in the non-DAC group. No significant inter-group differences were seen in APTT. This study provides the first report of AXA distribution in VTE patients receiving 10 mg BID of apixaban. Our findings indicate that coagulation markers may differ in patients with VTE-prescribed higher doses of apixaban and a DAC may be warranted in such patients.

Comparison of Anti-factor Xa Activity Among Three Different Factor Xa Inhibitors in Non-valvular Atrial Fibrillation Patients with Renal Impairment.

Factor-Xa inhibitors (FXaIs) are widely used for the treatment of non-valvular atrial fibrillation (NVAF). Although we have previously reported the distribution of the anti-factor Xa activity (AXA) values of three different FXaIs in NVAF patients, the differences in the distribution of AXA values among the different FXaIs in patients with renal impairment (RI) have not been fully elucidated. Trough and peak AXA values were measured in 94 patients taking rivaroxaban, 124 patients taking apixaban, and 66 patients taking edoxaban. Of them, we identified 26 patients with moderate RI [creatinine clearance (CrCl) 30-49mL/min] and 17 patients with severe RI (CrCl 15-29mL/min) in the rivaroxaban cohort, 37 patients with moderate RI and 17 patients with severe RI in the apixaban cohort, and 21 patients with moderate RI and 9 patients with severe RI in the edoxaban cohort. AXA values were measured using chromogenic AXA assays. Both trough and peak AXA values were compared between patients with moderate RI and those with severe RI in each cohort, and differences in the peak-to-trough ratio among the different drugs were assessed. In the rivaroxaban cohort, the peak AXA value was significantly higher in patients with severe RI than in those with moderate RI. In the apixaban cohort, neither the trough nor peak AXA values significantly differed between patients with moderate RI and those with severe RI. In the edoxaban cohort, the trough AXA value was significantly higher in patients with severe RI than in those with moderate RI, and peak AXA tended to be higher in patients with severe RI. The peak-to-trough ratio of AXA values was significantly lower in patients taking apixaban than in those taking rivaroxaban and edoxaban. Among Japanese NVAF patients with RI, the peak or trough AXA values were higher in patients with severe RI than in those with moderate RI when taking rivaroxaban and edoxaban, whereas both the peak and trough AXA values were similar between patients with severe RI and those with moderate RI when taking apixaban. The peak-to-trough ratio of AXA values was the lowest in patients taking apixaban.

No effect of norepinephrine dose on anti-Xa activity in critically ill patients .

Low-molecular-weight heparins are frequently used to prevent venous thromboembolism. Vasopressor therapy may be associated with inadequate anti-factor Xa activity, thereby increasing the risk of venous thromboembolism. We aimed to assess the association between anti-factor Xa activity and norepinephrine dose in intensive care unit (ICU) patients treated with subcutaneous dalteparin for venous thromboembolism prophylaxis. This was a prospective observational pilot study in adult ICU patients treated with dalteparin 5,000 IU subcutaneously once daily and norepinephrine >0.25µg/kg/min. Peak anti-factor Xa activity was monitored and dalteparin doses were adjusted following a predefined dose algorithm. From November 2016 to April 2018, 32 patients were included. No correlation was found between norepinephrine dose and anti-factor Xa activity (r = -0.01, 95% confidence interval = -0.47-0.27, p = 0.57). Furthermore, following dalteparin 5,000 IU once daily, 28% of the patients showed anti-factor Xa activity < 0.10 IU/mL. Higher body mass index (BMI) (p < 0.001) but not patients' norepinephrine dose, age, or serum creatinine were risk factors for anti-factor Xa activity < 0.10 IU/mL. Dose increments to 7,500 IU once daily resulted in anti-factor Xa activity ≥ 0.10 IU/mL in all 5 patients (p = 0.043). In this cohort of ICU patients, no association was found between norepinephrine dose and anti-factor Xa activity following subcutaneous dalteparin 5,000-IU administration once daily. Furthermore, nearly one-third of the patients showed anti-factor Xa activity below the target concentration for venous thromboembolism prophylaxis. Higher BMI was an independent risk factor for reduced anti-Xa activity.

Early Anti-Xa Assay-Guided Low Molecular Weight Heparin Chemoprophylaxis is Safe in Adult Patients with Acute Traumatic Brain Injury

This study evaluated the safety of early anti-factor Xa assay-guided enoxaparin dosing for chemoprophylaxis in patients with TBI. We hypothesized that assay-guided chemoprophylaxis would be comparable in the risk of intracranial hemorrhage (ICH) progression to fixed dosing. An observational analysis of adult patients with blunt traumatic brain injury (TBI) was performed at a Level I trauma center from August 2016 to September 2017. Patients in the assay-guided group were treated with an initial enoxaparin dose of 0.5 mg/kg, with peak anti-factor Xa activity measured four hours after the third dose. Prophylactic range was defined as 0.2 to 0.5 IU/mL with a dose adjustment of ± 10 mg based on the assay result. The assay-guided group was compared with historical fixed-dose controls and to a TBI cohort from the most recent Trauma Quality Improvement Project dataset. Of 179 patients included in the study, 85 were in the assay-guided group and 94 were in the fixed-dose group. Compared with the fixed-dose group, the assay-guided group had a lower Glasgow Coma Score and higher Injury Severity Score. The proportion of severe (Abbreviated Injury Score, head ≥3) TBI, ICH progression, and venous thromboembolism rates were similar between all groups. The assay-guided and fixed-dose groups had chemoprophylaxis initiated earlier than the Trauma Quality Improvement Project group. The assay-guided group had the highest percentage of low molecular weight heparin use. Early initiation of enoxaparin anti-factor Xa assay-guided venous thromboembolism chemoprophylaxis has a comparable risk of ICH progression to fixed dosing in patients with TBI. These findings should be validated prospectively in a multicenter study.

Distribution of Anti-Factor Xa Activity in Patients on Edoxaban Therapy for Non-Valvular Atrial Fibrillation.

The distribution of anti-factor Xa activity (AXA) values in non-valvular atrial fibrillation (NVAF) patients on edoxaban therapy has not been fully elucidated. The steady-state trough and peak AXA values were measured in 66 NVAF patients. The trough AXA value did not differ significantly between the 60-mg and the 30-mg OD groups (0.17±0.13 IU/ml vs. 0.12±0.11 IU/ml, respectively; P=0.17). Similarly, the peak AXA value did not differ significantly between the 2 groups (1.45±0.81 IU/ml vs. 1.25±0.48 IU/ml, respectively; P=0.26). Recommended dosing should be followed for sufficient efficacy of edoxaban. (Circ J 2016; 80: 745-747).

Measurement of Anti-Factor Xa Activity in Patients on Apixaban for Non-Valvular Atrial Fibrillation.

Chromogenic anti-factor Xa activity (AXA) assay is reported to be the most appropriate method to measure the pharmacodynamics of apixaban, but the distribution of AXA in non-valvular atrial fibrillation (NVAF) patients on apixaban therapy has not been fully elucidated. Steady-state trough and peak AXA were measured in 124 NVAF patients taking apixaban. In 25 patients, baseline, first peak, and trough AXA were also examined, and were 0.01±0.02 IU/ml, 0.83±0.43 IU/ml, and 0.34±0.17 IU/ml, respectively. First trough AXA was significantly lower than steady-state trough AXA, although it was significantly higher than baseline (P<0.0001). Similarly, first peak AXA was significantly lower than steady-state peak AXA (P<0.0001). In 124 patients, steady-state peak AXA was significantly higher in the 5-mg b.i.d. group than in the 2.5-mg b.i.d. group (2.05±0.73 IU/ml vs. 1.51±0.65 IU/ml, respectively; P<0.001), although there was no significant difference in trough AXA. Other than dose, age and serum creatinine were significantly related to both trough and peak AXA. The distribution of AXA in Japanese NVAF patients on apixaban therapy in daily clinical practice both in the acute and steady-state phase was measured. In patients taking apixaban, measurement of AXA clearly showed the pharmacodynamic profile of this drug.

A randomized direct comparison of the pharmacokinetics and pharmacodynamics of apixaban and rivaroxaban.

BackgroundCurrently, there are no direct comparisons of apixaban and rivaroxaban, two new oral direct factor Xa inhibitors approved for management of thromboembolic disorders.ObjectiveCompare the pharmacokinetics and anti-factor Xa activity (AXA) of apixaban and rivaroxaban.MethodsIn this randomized, open-label, two-period, two-treatment crossover study, healthy subjects (N=14) received apixaban 2.5 mg twice daily (BID) and rivaroxaban 10 mg once daily (QD) for 4 days with a ≥4.5-day washout. Plasma samples were obtained for pharmacokinetic and AXA assessments; parameters were calculated using noncompartmental methods.ResultsMedian time-to-maximum concentration was 2 hours for both compounds, and the mean half-life was 8.7 and 7.9 hours for apixaban and rivaroxaban, respectively. Daily exposure, the area under the curve (AUC(0–24)), appeared similar for rivaroxaban (1,094 ng · h/mL) and apixaban (935 ng · h/mL), whereas mean peak-to-trough plasma concentration ratio was 3.6-fold greater for rivaroxaban (16.9) than apixaban (4.7). Coefficient of variation for exposure parameters (AUC0–24, Cmax, Cmin) was 20%–24% for apixaban versus 29%–46% for rivaroxaban. Peak AXA, AXA AUC(0–24), and AXA fluctuation were ~2.5-, 1.3-, and 3.5-fold higher for rivaroxaban than apixaban, respectively. Trough concentrations and AXA were lower for rivaroxaban (10 ng/mL and 0.17 IU/mL vs 17 ng/mL and 0.24 IU/mL for apixaban, respectively). Rivaroxaban exhibited a steeper concentration–AXA response (slope: 0.0172 IU/ng vs 0.0134 IU/ng for apixaban, P<0.0001).ConclusionApixaban 2.5 mg BID demonstrated less intersubject variability in exposure, lower AXA AUC, and higher trough and smaller peak-to-trough fluctuations in plasma concentration and AXA, suggesting more constant anticoagulation compared with rivaroxaban 10 mg QD. However, the clinical impact of these differences on the relative efficacy and safety of apixaban and rivaroxaban remains to be determined.

PKP-006 Evaluation of the predictive ability of different formulas to estimate renal function when enoxaparin is used

BackgroundExposure to enoxaparin is significantly increased in patients with severe renal impairment (creatinine clearance ClCr <30 mL/min). Thus, a dose adjustment is recommended for both the therapeutic and prophylactic dose...

No accumulation of the peak anti-factor Xa activity of tinzaparin in elderly patients with moderate-to-severe renal impairment: the IRIS substudy.

In the elderly, concerns have been raised regarding the risk of accumulation of low molecular weight heparins, owing to their renal elimination. Although data exist for tinzaparin, they are observational. To assess whether: (i) there was an accumulation of anti-factor Xa activity; and (ii) there was any relationship between anti-FXa activity and age, weight, creatinine clearance or clinical outcomes in patients with moderate-to-severe renal impairment receiving tinzaparin (175 IU kg(-1) per 24 h) for acute venous thromboembolism. In 38 centers participating in the Innohep in Renal Insufficiency Study (IRIS), peak plasma anti-FXa activity was measured on day 2/day 3 and on day 5 or at visit S (VS) (end of tinzaparin treatment). There was considered to be absence of accumulation if the 90% confidence interval (CI) of the (anti-FXa day 5/VS)/(anti-FXa day 2/3) ratio did not exceed the predefined limit of 1.25. Eighty-seven patients, with a mean age of 83 ± 5 years (range: 75-99 years) and a mean creatinine clearance (CrCl) of 40.8 mL min(-1) , 24.1% of whom had severe renal impairment, were included. The mean duration of tinzaparin treatment was 8.4 days. No significant accumulation was detected: the mean accumulation ratio was 1.06 (90% CI 1.01-1.11). There was no correlation between the accumulation ratio and age, weight, or CrCl. The mean anti-FXa activity did not differ significantly between the eight patients who experienced clinically relevant bleeding and those who did not. No accumulation of anti-FXa activity was observed in elderly patients with renal impairment receiving therapeutic doses of tinzaparin, suggesting that there is no need for systematic anti-FXa monitoring in these patients. The high proportion of high molecular weight moieties in tinzaparin may account for its reduced dependence on renal elimination.

In situ thrombolysis for cerebral venous thrombosis complicating anti-leukemic therapy

A 23-year-old woman was treated for precursor B acute lymhoblastic leukemia with favorable risk cytogenetics, on the UKALL 003 protocol [1]. She achieved complete morphological and ytogenetic remission after induction therapy (regimen B), with n uncomplicated treatment course until Delayed Intensification hase 1. This comprised dexamethasone (days 1–7), vincristine nd doxorubicin (day 1), and intrathecal methotrexate and pegyated l-asparaginase (day 3); and she was also taking a combined ral contraceptive pill. On day 8 she presented with isolated rontal headache and nausea with a normal physical examination part from a Glasgow Coma Score (GCS) of 14/15 (E3, V5, M6). aboratory investigations showed a prolonged activated partial hromboplastin time (39.8 s; NR 25.8–33.8 s), hypofibrinogenemia 0.9 g/l; NR 1.65–3.75 g/l) and mild thrombocytopenia (platelet ount 129 × 109/l; NR 150–400 × 109/l), with normal prothrombin ime, hemoglobin and white cell count. CT head demonstrated acute thrombosis within the straight and ight transverse sinuses and torcula (Fig. 1A and B). Therapeutic nticoagulation with subcutaneous enoxaparin (1.5 mg/kg daily) as commenced and achieved a peak anti-factor Xa activity within he target range (0.76 IU/ml; target >0.7 IU/ml). However, from day of treatment there was marked neurological deterioration: iniially right-sided numbness of the face and upper limb, progressing ithin 24 h to a fall in GCS (13/15: E3, V4, M6), expressive dyshasia, inability to follow complex motor commands, extensive ight-sided hypoesthesia, reduced lower limb power and global

Regional Anesthesia for a Parturient with Venous Sinus Thrombosis and Placental Abruption Undergoing Fractional Heparin Therapy

THE increased incidence of thrombosis and hypercoagu-lability during pregnancy are well recognized and require anticoagulation for symptomatic sequelae. The following case illustrates our perioperative treatment of a patient with vaginal bleeding while undergoing treatment for a transverse sinus thrombosis.

Peak Antifactor Xa Activity Produced by Dalteparin Treatment in Patients with Renal Impairment Compared with Controls

To evaluate the relationship between impaired renal function and antifactor Xa activity in patients receiving dalteparin. Open-label prospective study. Inpatient and outpatient units of a large teaching hospital. Eleven patients with renal impairment and 11 control subjects with normal renal function. Subjects were administered dalteparin at a dosage of approximately 100 U/kg subcutaneously every 12 hours. Peak steady-state antifactor Xa levels were compared between the groups. Mean +/- SD levels were similar for patients with and without renal impairment: 0.47 +/- 0.25 and 0.55 +/- 0.20 U/ml, respectively. A test of equivalency showed statistical significance (p=0.0001). No meaningful difference in peak antifactor Xa activity was found between patients with renal impairment and control subjects. To the extent that peak antifactor Xa levels can be used as markers for adjusting doses of dalteparin, these data suggest that such adjustments are not necessary for patients with renal impairment who are not receiving dialysis.