Latest advances in the reversal strategies for direct oral anticoagulants.

BACKGROUND: Since the late 2000s, Europe has granted approval for various thrombotic risk-related uses of direct oral anticoagulants (DOACs). Unlike traditional anticoagulants, DOACs do not necessitate routine coagulation monitoring. Nevertheless, clinical practice often encounters bleeding events associated with these medications, making the need for effective reversal strategies evident. OBJECTIVES: The study aims to take stock of current reversal strategies for DOACs, with a particular emphasis on the latest compounds that have been developed or are currently under development. METHODS: For obtaining information regarding the ongoing reversal strategies and the compounds under development, we referred to ClinicalTrials website, PubMed, and Google Scholar. RESULTS: In 2024, two specific antidotes to DOACs have already received approval when reversal of anticoagulation is needed owing to life-threatening or uncontrolled bleeding: idarucizumab that reverses the effects of dabigatran, and andexanet alfa, designed to counteract activated factor X inhibitors such as apixaban and rivaroxaban. Furthermore, ciraparantag, a potential universal reversal agent, is currently in advanced stages of clinical development. Concerns remain regarding the safety of specific reversal agents, especially concerning the risk of thrombosis. Additionally, the cost of these antidotes remains high. Consequently, nonspecific strategies to counteract anticoagulant medications, including activated charcoal, hemodialysis, and concentrates of coagulation factors, still have utility. CONCLUSION: With the validation of specific and nonspecific antidotes, DOACs could supplant traditional oral anticoagulants. This progress represents a significant advancement in anticoagulation therapy. However, ongoing research is crucial to address remaining safety concerns of the specific reversion agents of DOACs in clinical practice.

Dose-response relationships of intravenous and perineural dexamethasone as adjuvants to peripheral nerve blocks: a systematic review and model-based network meta-analysis.

BACKGROUND: Superiority of perineural over intravenous dexamethasone at extending nerve block analgesia has been suggested but without considering the dose-response relationships for each route of administration. METHODS: Randomised control studies that evaluated intravenous or perineural dexamethasone as an adjuvant to unilateral peripheral nerve blocks in adults were searched up to October 2023 in MEDLINE, Central, Google Scholar, and reference lists of previous systematic reviews. The Cochrane Risk-of-Bias tool was used. A maximum effect (Emax) model-based network meta-analysis was undertaken to evaluate the dose-response relationships of dexamethasone. RESULTS: A total of 118 studies were selected (9284 patients; 35 with intravenous dexamethasone; 106 with perineural dexamethasone; dose range 1-16 mg). Studies with unclear or high risk of bias overestimated the effect of dexamethasone. Bias-corrected estimates indicated a maximum fold increase in analgesia duration of 1.7 (95% credible interval (CrI) 1.4-1.9) with dexamethasone, with no difference between perineural and intravenous routes. Trial simulations indicated that 4 mg of perineural dexamethasone increased the mean duration of analgesia for long-acting local anaesthetics from 11.1 h (95% CrI 9.4-13.1) to 16.5 h (95% CrI 14.0-19.3) and halved the rate of postoperative nausea and vomiting. A similar magnitude of effect was observed with 8 mg of intravenous dexamethasone. CONCLUSIONS: Used as an adjuvant for peripheral nerve block, intravenous dexamethasone can be as effective as perineural dexamethasone in prolonging analgesic duration, but is less potent, hence requiring higher doses. The evidence is limited because of the observational nature of the dose-response relationships and the quality of the included studies. SYSTEMATIC REVIEW PROTOCOL: PROSPERO CRD42020141689.

A framework to characterise the reproducibility of meta-analysis results with its application to direct oral anticoagulants in the acute treatment of venous thromboembolism.

The number of meta-analyses of aggregate data has dramatically increased due to the facility of obtaining data from publications and the development of free, easy-to-use, and specialised statistical software. Even when meta-analyses include the same studies, their results may vary owing to different methodological choices. Assessment of the replication of meta-analysis provides an example of the variation of effect 'naturally' observed between multiple research projects. Reproducibility of results has mostly been reported using graphical descriptive representations. A quantitative analysis of such results would enable (i) breakdown of the total observed variability with quantification of the variability generated by the replication process and (ii) identification of which variables account for this variability, such as methodological quality or the statistical analysis procedures used. These variables might explain systematic mean differences between results and dispersion of the results. To quantitatively characterise the reproducibility of meta-analysis results, a bivariate linear mixed-effects model was developed to simulate both mean results and their corresponding uncertainty. Results were assigned to several replication groups, those assessing the same studies, outcomes, treatment indication and comparisons classified in the same replication group. A nested random effect structure was used to break down the total variability within each replication group and between these groups to enable calculation of an intragroup correlation coefficient and quantification of reproducibility. Determinants of variability were investigated by modelling both mean and variance parameters using covariates. The proposed model was applied to the example of meta-analyses evaluating direct oral anticoagulants in the acute treatment of venous thromboembolism.

Replication of systematic reviews: is it to the benefit or detriment of methodological quality?

OBJECTIVES: To perform an overview of the overlap of systematic reviews (SRs) assessing direct oral anticoagulants and characterize these reviews in terms of bias and methodological quality (PROSPERO: CRD42022316273). STUDY DESIGN AND SETTING: A PubMed-indexed search was performed from inception to January 31, 2022 to identify SRs evaluating direct oral anticoagulants in patients treated for an acute venous thromboembolism. The risk of bias of these SRs was assessed according to the Risk Of Bias In Systematic reviews tool. Redundancy was defined as overlap in terms of the type of population considered, the interventions compared, and the studies included. RESULTS: A total of 144 SRs were evaluated, of which 26 (18.1%) were classified as original, 87 (60.4%) as conceptual replications, and 31 (21.5%) as excessive replications. The risk of bias was high in 19 (73.1%) of the original SRs, 65 (74.7%) of the conceptual replications, and 21 (67.7%) of the excessive replications. Compared to the original SRs, the overall methodological quality was not improved in either conceptual or excessive replications. CONCLUSION: A large number of SRs was classified as replications; a fifth constituted excessive replications. The replications showed no improvement in overall methodological quality compared to the original SRs.

Fetal Movement Counting in Prolonged Pregnancies: The COMPTAMAF Prospective Randomized Trial.

In prolonged pregnancies, the risks of neonatal morbidity and mortality are increased. The aim of this trial was to assess the benefits of maternal information about fetal movement (FM) counting on neonatal outcomes in prolonged pregnancy. It was a prospective, single center, randomized, open-label study conducted from October 2019 to March 2022. Intention-to-treat analyses were performed on 278 patients randomized into two 1:1 groups (control group and FM counting group). The primary outcome was a composite score of neonatal morbidity (presence of two of the following items: fetal heart rate abnormality at delivery, Apgar score of <7 at 5 min, umbilical cord arterial pH of <7.20, and acute respiratory distress with mutation in neonatal intensive care unit). There was no significant difference between the two groups in the rate of neonatal morbidity (14.0% in the FM counting group versus 22.9% in the standard information group; p = 0.063; OR 0.55, 95% CI 0.29−1.0). In this study, fetal movement counting for women in prolonged pregnancy failed to demonstrate a significant reduction in adverse neonatal outcomes.

Adjusted versus fixed doses of LMWHs in trauma patients: A systematic review and meta-analysis.

PURPOSE: Venous thromboembolism (VTE) causes significant morbidity and mortality in patients with traumatic injuries, despite thromboprophylaxis. To decrease both thrombotic and bleeding risks, some authors suggest adjusting the thromboprophylactic doses of low-molecular-weight heparins (LMWH), in particular according to body weight at treatment initiation or to changes in anti-factor Xa level during treatment. Our objective was to estimate in trauma patients the efficacy and safety of such adjustments, compared with the conventional strategy of fixed-dose LMWH thromboprophylaxis. SOURCE: A systematic review and a meta-analysis were conducted to identify and assess randomised control trials and observational studies with prospective enrolment that included trauma patients and compared adjustment of LMWH thromboprophylaxis versus no adjustment. The primary and secondary endpoints were VTE and bleeding, respectively. The Odds Ratio (OR) and 95% Confidence Interval (95% CI) were calculated using the Mantel-Haenszel method. PRINCIPAL FINDINGS: Nine studies were included in the meta-analysis. No significant reduction in the risk of VTE was observed with adjusted doses of LMWH compared with fixed doses when considering only randomised control trials (OR 1.02 [95% CI, 0.09 to 11.6]) or all trials (OR 0.70 [95% CI, 0.34 to 1.42]). Similarly, there was no significant difference in bleeding risk (OR 1.36, 95% CI 0.59 to 3.10). CONCLUSION: This meta-analysis shows that, to date, there is no evidence to justify adjusting LMWH doses, in agreement with the recommendations of the American College of Chest Physicians.

Robust K-PD model for activated clotting time prediction and UFH dose individualisation during cardiopulmonary bypass.

BACKGROUND AND OBJECTIVE: Activated clotting time (ACT) is a point-of-care test used to monitor the effect of unfractionated heparin (UFH) during cardiopulmonary bypass (CPB). This test sometimes returns aberrant values, which can lead to the administration of an inappropriate dosing regimen. The development of a population-robust K-PD model of UFH could allow the individualisation and automation of UFH therapy during CPB. METHODS: We conducted a prospective observational study to collect ACT measurements from patients undergoing surgery using CPB. The ACT data were split into a development and validation cohort. The development cohort was used to estimate a standard and robust population K-PD model characterised by a residual error following a normal distribution and student's t-distribution. The ACT prediction performance using Bayesian estimates of individual K-PD parameters was evaluated by comparing predicted versus observed ACTs. Using estimates of the robust K-PD model, a Bayesian individualisation strategy to automate UFH administration was proposed and evaluated using Monte Carlo simulations. RESULTS: A total of 295 patients were included in the study, and 1561 ACTs were collected. In patients without outlier values, Bayesian estimates (based on four ACT measurements) from both standard and robust K-PD models had similar performances, with a median prediction bias close to 0 s. In patients with outlier measurements, the use of the robust K-PD model greatly improved the prediction bias and root-mean-square error (RMSE), with a mean prediction bias of 3.25 s, IQR = [-19.9; 46.03] versus -86 s IQR = [-135.7; -63.8] for the standard model. Monte Carlo simulations showed that the robust Bayesian individualisation strategy allowed the ACT to be maintained above the target using only two to three ACT measurements. CONCLUSIONS: The use of a robust K-PD model reduced prediction bias and RMSE in patients with outlier ACT measurements. The Bayesian individualisation strategy using robust estimates of individual parameters may help automate UFH dosing regimens. Proper clinical validation is warranted before its use in daily clinical practice.

Pharmacokinetics of enoxaparin in COVID-19 critically ill patients.

BACKGROUND: In intensive-care unit (ICU) patients, pathophysiological changes may affect the pharmacokinetics of enoxaparin and result in underdosing. OBJECTIVES: To develop a pharmacokinetic model of enoxaparin to predict the time-exposure profiles of various thromboprophylactic regimens in COVID-19 ICU-patients. METHODS: This was a retrospective study in ICUs of two French hospitals. Anti-Xa activities from consecutive patients with laboratory-confirmed SARS-CoV-2 infection treated with enoxaparin for the prevention or the treatment of venous thrombosis were used to develop a population pharmacokinetic model using non-linear mixed effects techniques. Monte Carlo simulations were then performed to predict enoxaparin exposure at steady-state after three days of administration. RESULTS: A total of 391 anti-Xa samples were measured in 95 patients. A one-compartment model with first-order kinetics best fitted the data. The covariate analysis showed that enoxaparin clearance (typical value 1.1 L.h-1) was related to renal function estimated by the CKD-EPI formula and volume of distribution (typical value 17.9 L) to actual body weight. Simulation of anti-Xa activities with enoxaparin 40 mg qd indicated that 64% of the patients had peak levels within the range 0.2 to 0.5 IU.mL-1 and 75% had 12-hour levels above 0.1 IU.mL-1. Administration of a total daily dose of at least 60 mg per day improved the probability of target attainment. CONCLUSION: In ICU COVID-19 patients, exposure to enoxaparin is reduced due to an increase in the volume of distribution and clearance. Consequently, enoxaparin 40 mg qd is suboptimal to attain thromboprophylactic anti-Xa levels.

Exposure-Response Relationship of Tranexamic Acid in Cardiac Surgery.

BACKGROUND: It is unclear whether high-dose regimens of tranexamic acid in cardiac surgery (total dose, 80 to 100 mg/kg) confer a clinical advantage over low-dose regimens (total dose, approximately 20 mg/kg), particularly as tranexamic acid-associated seizure may be dose-related. The authors' aim was to characterize the exposure-response relationship of this drug. METHODS: Databases were searched for randomized controlled trials of intravenous tranexamic acid in adult patients undergoing cardiopulmonary bypass surgery. Observational studies were added for seizure assessment. Tranexamic acid concentrations were predicted in each arm of each study using a population pharmacokinetic model. The exposure-response relationship was evaluated by performing a model-based meta-analysis using nonlinear mixed-effect models. RESULTS: Sixty-four randomized controlled trials and 18 observational studies (49,817 patients) were included. Seventy-three different regimens of tranexamic acid were identified, with the total dose administered ranging from 5.5 mg/kg to 20 g. The maximum effect of tranexamic acid for postoperative blood loss reduction was 40% (95% credible interval, 34 to 47%), and the EC50 was 5.6 mg/l (95% credible interval, 0.7 to 11 mg/l). Exposure values with low-dose regimens approached the 80% effective concentration, whereas with high-dose regimens, they exceeded the 90% effective concentration. The predicted cumulative blood loss up to 48 h postsurgery differed by 58 ml between the two regimens, and the absolute difference in erythrocyte transfusion rate was 2%. Compared to no tranexamic acid, low-dose and high-dose regimens increased the risk of seizure by 1.2-fold and 2-fold, respectively. However, the absolute risk increase was only clinically meaningful in the context of prolonged open-chamber surgery. CONCLUSIONS: In cardiopulmonary bypass surgery, low-dose tranexamic acid seems to be an appropriate regimen for reducing bleeding outcomes. This meta-analysis has to be interpreted with caution because the results are observational and dependent on the lack of bias of the predicted tranexamic acid exposures and the quality of the included studies.

Predicting the dose of vancomycin in ICU patients receiving different types of RRT therapy: a model-based meta-analytic approach.

AIM: Previous pharmacokinetic (PK) studies have proposed various dosing regimens for vancomycin in intensive care unit (ICU) patients undergoing renal replacement therapy (RRT), but all are restricted to specific RRT modalities. To be useful in practice, a population PK model would need to predict vancomycin clearance during any RRT modality. Development of such a model is feasible using meta-analysis of published summarized estimates of vancomycin PK parameters. Our aims were: (i) to develop and validate a population PK model for vancomycin that takes into account any RRT modalities, and (ii) to predict vancomycin dosing for RRT patients in ICU. METHODS: Vancomycin pharmacokinetics were assumed to be two-compartmental, total body clearance being the sum of non-RRT clearance and RRT-induced clearance. Drug disposition and non-RRT clearance parameters were estimated by systematic review and meta-analysis of previously published parameter estimates. The relationship between RRT-induced clearance and RRT flowrate settings was assessed using a model-based meta-analysis. Prediction performances of the PK model were assessed using external data. RESULTS: The meta-analyses of disposition parameters, non-RRT clearance and RRT-induced clearance included 11, 6 and 38 studies (84 RRT clearance measurements) respectively. The model performed well in predicting external individual PK data. Individual vancomycin concentrations during RRT were accurately predicted using Bayesian estimation based solely on pre-RRT measurements. CONCLUSIONS: The PK model allowed accurate prediction of the vancomycin pharmacokinetics during RRT in ICU patients. Based on the model of RRT-induced clearance, an appropriate adjustment of the vancomycin dosing regimen could be proposed for any kind of flowrate settings.

Quality of Life After Cardiac Operations Based on the Minimal Clinically Important Difference Concept.

BACKGROUND: Health-related quality of life (HRQOL) is an increasingly important issue in assessing the consequences of any surgical or medical intervention. Our study aimed to evaluate change in HRQOL 6 months after elective cardiac operations and to identify specific predictors of poor HRQOL. METHODS: In this prospective, single-center study, HRQOL was evaluated before and 6 months after the operation using the Medical Outcome Study 36-Item Short Form Health Survey questionnaire and its two components: the Physical Component Summary and the Mental Component Summary. We distinguished patients with worsening of HRQOL according to the minimal clinically important difference. All consecutive adult patients undergoing cardiac operations were included. RESULTS: The preoperative and postoperative 36-Item Short Form Health Survey questionnaires were completed by 326 patients, and 24 patients died before completing follow-up questionnaires. On the basis of the definition used, clinically significant deterioration of HRQOL was observed in 93 patients (26.6%) for the Physical Component Summary and in 99 patients (28.2%) for the Mental Component Summary. Renal replacement for acute renal failure and mechanical ventilation for longer than 48 hours were independent risk factors for Physical Component Summary and Mental Component Summary worsening or death. CONCLUSIONS: Although our study showed overall improvement of quality of life after cardiac operations, more than one-quarter of the patients manifested deterioration of HRQOL at 6 months postoperatively. The findings from this study should help clinicians to inform patients about their likely postoperative functional status and quality of life.

Is tranexamic acid exposure related to blood loss in hip arthroplasty? A pharmacokinetic-pharmacodynamic study.

AIMS: Tranexamic acid (TXA) is an antifibrinolytic agent, decreasing blood loss in hip arthroplasty. The present study investigated the relationship between TXA exposure markers, including the time above the in vitro threshold reported for inhibition of fibrinolysis (10 mg l-1 ), and perioperative blood loss. METHODS: Data were obtained from a prospective, double-blind, parallel-arm, randomized superiority study in hip arthroplasty. Patients received a preoperative intravenous bolus of TXA 1 g followed by a continuous infusion of either TXA 1 g or placebo over 8 h. A population pharmacokinetic study was conducted to quantify TXA exposure. RESULTS: In total, 827 TXA plasma concentrations were measured in 166 patients. A two-compartment model fitted the data best, total body weight determining interpatient variability in the central volume of distribution. Creatinine clearance accounted for interpatient variability in clearance. At the end of surgery, all patients had TXA concentrations above the therapeutic target of 10 mg l-1 . The model-estimated time during which the TXA concentration was above 10 mg l-1 ranged from 3.3 h to 16.3 h. No relationship was found between blood loss and either the time during which the TXA concentration exceeded 10 mg l-1 or the other exposure markers tested (maximum plasma concentration, area under the concentration-time curve). CONCLUSION: In hip arthroplasty, TXA plasma concentrations were maintained above 10 mg l-1 during surgery and for a minimum of 3 h with a preoperative TXA dose of 1 g. Keeping TXA concentrations above this threshold up to 16 h conferred no advantage with regard to blood loss.

Intravenous Tranexamic Acid Bolus plus Infusion Is Not More Effective than a Single Bolus in Primary Hip Arthroplasty: A Randomized Controlled Trial.

BACKGROUND: Preoperative administration of the antifibrinolytic agent tranexamic acid reduces bleeding in patients undergoing hip arthroplasty. Increased fibrinolytic activity is maintained throughout the first day postoperation. The objective of the study was to determine whether additional perioperative administration of tranexamic acid would further reduce blood loss. METHODS: This prospective, double-blind, parallel-arm, randomized, superiority study was conducted in 168 patients undergoing unilateral primary hip arthroplasty. Patients received a preoperative intravenous bolus of 1 g of tranexamic acid followed by a continuous infusion of either tranexamic acid 1 g (bolus-plus-infusion group) or placebo (bolus group) for 8 h. The primary outcome was calculated perioperative blood loss up to day 5. Erythrocyte transfusion was implemented according to a restrictive transfusion trigger strategy. RESULTS: The mean perioperative blood loss was 919 ± 338 ml in the bolus-plus-infusion group (84 patients analyzed) and 888 ± 366 ml in the bolus group (83 patients analyzed); mean difference, 30 ml (95% CI, -77 to 137; P = 0.58). Within 6 weeks postsurgery, three patients in each group (3.6%) underwent erythrocyte transfusion and two patients in the bolus group experienced distal deep-vein thrombosis. A meta-analysis combining data from this study with those of five other trials showed no incremental efficacy of additional perioperative administration of tranexamic acid. CONCLUSIONS: A preoperative bolus of tranexamic acid, associated with a restrictive transfusion trigger strategy, resulted in low erythrocyte transfusion rates in patients undergoing hip arthroplasty. Supplementary perioperative administration of tranexamic acid did not achieve any further reduction in blood loss.

Prevention of venous thromboembolic events with low-molecular-weight heparin in the non-major orthopaedic setting: meta-analysis of randomized controlled trials.

PURPOSE: To assess the efficacy of low-molecular-weight heparin (LMWH) venous thromboprophylaxis in patients with transient reduced mobility in the non-major orthopaedic setting. METHODS: A meta-analysis was conducted using data from all available randomized trials comparing LMWH with placebo or no prophylactic treatment in patients with leg immobilization for fracture or soft-tissue injury of the lower limb or in patients undergoing knee arthroscopy. The primary endpoint was the incidence of major venous thromboembolic events (VTEs), including asymptomatic proximal deep-vein thrombosis, symptomatic VTEs, and VTE-related death. The Mantel-Haenszel method was used to generate the summary statistics for the overall effect of LMWH. RESULTS: Fourteen studies were included (4,726 patients). The weighted rate of major VTEs was estimated to be 2.9% (95% confidence interval [CI], 2.2% to 3.7%) without LMWH prophylaxis. Overall, a significant 68% reduction in the risk of major VTEs was observed with LMWH prophylaxis (relative risk [RR], 0.32; 95% CI, 0.20 to 0.51; P < .001). The treatment effect was not modified by the clinical setting, that is, distal lower limb injury (7 studies; 1,711 patients; RR, 0.42; 95% CI, 0.20 to 0.86) or knee arthroscopy (6 studies; 2,428 patients; RR, 0.27; 95% CI, 0.15 to 0.49). A nonsignificant 35% increase in the risk of major bleeding was observed in the LMWH prophylaxis group (RR, 1.35; 95% CI, 0.53 to 3.47). CONCLUSIONS: This meta-analysis indicates potential efficacy of LMWH in preventing thromboembolic events in patients with reduced mobility in the non-major orthopaedic setting compared with placebo or no treatment. However, the decision of whether to implement LMWH prophylaxis in each specific setting should also take into account the risk of VTEs in the absence of prophylaxis, the potential adverse effects of LMWH, and the cost. LEVEL OF EVIDENCE: Level II, meta-analysis of Level II studies or Level I studies with inconsistent results.

Quantification of total and unbound tranexamic acid in human plasma by ultrafiltration liquid chromatography/tandem mass spectrometry: application to pharmacokinetic analysis.

The present work describes the development and validation of rapid, sensitive and accurate liquid chromatography method, coupled with tandem mass spectrometry detection, for quantification of tranexamic acid in human plasma using isotopically labeled internal standard (IS). A one-step plasma protein precipitation was performed with acetonitrile. UPLC BEH amide column was used for chromatographic separation. Tranexamic acid and IS were detected in multiple reaction monitoring in electrospray positive ionization. The method was linear over the concentration range of 0.8-200mg/L. The intra- and inter-day precision values were below 11.5% and accuracy was better than 9.6%. Total analysis time was reduced to 6min including sample preparation. The present method was successfully applied to pharmacokinetic pilot study in patients undergoing orthopedic surgery. Ultrafiltration allowed confirming the weak binding to plasma proteins and confirming that total plasma TXA concentration is measured by this assay.

PK evaluation of fondaparinux sodium for the treatment of thrombosis.

INTRODUCTION: Fondaparinux sodium (pentasaccharide) was the first of a new class of antithrombotic agents developed for the prevention and treatment of venous thromboembolism (VTE), blocking thrombin generation by selectively inhibiting factor Xa. AREAS COVERED: This review focuses on the currently available information evaluating the pharmacokinetics, pharmacodynamics, clinical efficacy and safety of fondaparinux in the prevention and treatment of VTE and treatment of acute coronary syndromes (ACS). EXPERT OPINION: Fondaparinux is an alternative to low-molecular-weight heparins (LMWH) for thromboprophylaxis in various clinical settings (major orthopedic surgery of the lower limbs, major abdominal surgery, immobilized medical patients at high risk of VTE), as well as for the treatment of VTE (deep venous thrombosis, pulmonary embolism). It is currently challenged, in the context of both surgical thromboprophylaxis and acute VTE treatment, by the new oral anticoagulants. Fondaparinux remains the sole drug validated in patients with isolated superficial vein thrombosis of the lower limbs, and at prophylactic doses is a good alternative to LMWH at anticoagulant doses for patients with ACS, especially those ineligible for percutaneous coronary intervention.

Cervical epidural anesthesia is associated with increased cancer-free survival in laryngeal and hypopharyngeal cancer surgery: a retrospective propensity-matched analysis.

BACKGROUND AND OBJECTIVES: Regional anesthesia preserves perioperative immune competence and may reduce the risk of recurrence and metastasis after cancer surgery. Cervical epidural anesthesia provides adequate analgesia for head and neck cancer surgery, but its impact on cancer recurrence is unknown. METHODS: This study was a single-center retrospective cohort study of patients undergoing larynx or hypopharynx cancer surgery between January 1984 and December 2008. One hundred eleven patients had general anesthesia combined with intraoperative and postoperative cervical epidural; 160 had general anesthesia alone with postoperative morphine. From this cohort, matched pairs were selected using a propensity score to balance potential confounders of receiving epidural anesthesia. The primary end point was the length of cancer-free survival after surgery until September 2009. RESULTS: Propensity-based matching produced 65 pairs. Matching was effective in achieving balance between groups for each of the preoperative variables collected. Combined epidural and general anesthesia (68% 5-year cancer-free survival; 95% confidence interval [CI], 57%-82%) was associated with significantly increased cancer-free survival compared with general anesthesia alone (37% 5-year cancer-free survival; 95% CI, 25%-54%) with a corresponding adjusted hazard ratio of 0.49 (95% CI, 0.25-0.96; P = 0.04). Patients in the epidural group had an increased overall survival compared with the non-epidural group (P = 0.03). CONCLUSIONS: The association between cervical epidural anesthesia and increased cancer-free survival found in this retrospective study should be an important hypothesis to further investigate in head and neck cancer surgery.

A semi-mechanistic absorption model to evaluate drug-drug interaction with dabigatran: application with clarithromycin.

AIM: The aim of this study was to develop a PK/PD model to assess drug-drug interactions between dabigatran and P-gp modulators, using the example of clarithromycin, a strong inhibitor of P-gp. METHODS: Ten healthy male volunteers were randomized to receive in the first treatment period a single 300 mg dose of dabigatran etexilate (DE) and in the second treatment period 500 mg clarithromycin twice daily during 3 days and then 300 mg DE plus 500 mg clarithromycin on the fourth day, or the same treatments in the reverse sequence. Dabigatran plasma concentration and ecarin clotting time (ECT) were measured on 11 blood samples. Models were built using a non-linear mixed effect modelling approach. RESULTS: The best PK model was based on an inverse Gaussian absorption process with two compartments. The relationship between dabigatran concentration and ECT was implemented as a linear function. No continuous covariate was associated with a significant decrease in the objective function. The concomitant administration of clarithromycin induced a significant change only in DE bioavailability, which increased from 6.5% to 10.1% in the presence of clarithromycin. Clarithromycin increased peak concentration and AUC by 60.2% and 49.1% respectively. CONCLUSION: The model proposed effectively describes the complex PK of dabigatran and takes into account drug-drug interactions with P-gp activity modulators, such as clarithromycin.

Dabigatran: rational dose individualisation and monitoring guidance is needed.

Dabigatran is the first oral anticoagulant to be introduced in New Zealand without prescribing restrictions for over 50 years. Not surprisingly, the drug has created a great deal of interest amongst health care providers as well as the general public and media. There seems to be a general feeling that warfarin, with its requisite dose adjustments and INR monitoring, is an outdated drug and should be shelved in favour of this novel agent. The assumption is that the newer drug must be better and safer as well as easier to use. Much of the literature associated with dabigatran encourages this view, stressing that dabigatran is a 'game changer' with the advantage of fixed dosing for most patients and no anticoagulation monitoring. In this paper we question whether dabigatran can really live up to these expectations. We suggest that the safe and effective prescribing of dabigatran, like all anticoagulants used in therapeutic doses, will most likely require dose individualisation and selective monitoring. This requirement should not be viewed as a failure for dabigatran but rather as a success for rational therapeutics.