Effect of standardized perioperative dabigatran interruption on the residual anticoagulation effect at the time of surgery or procedure

Removing direct oral factor Xa inhibitor interferences from routine and specialised coagulation assays using a raw activated charcoal product

BACKGROUND

Direct oral anticoagulants (DOACs) are increasingly prescribed for the prevention and treatment of thrombosis. However, DOACs are associated with extensive interference in coagulation assays. Herein, we evaluate raw activated charcoal (AC) as an adsorbent material, to minimise DOAC-associated interferences in routine and specialised coagulation parameters on CS-series analysers (Sysmex, Kobe, Japan).

METHODS

Commercial human-derived non-anticoagulated plasma materials, with or without increasing concentrations of anticoagulant, were assayed for routine and specialised coagulation parameters before and after treatment with AC.

RESULTS

Treatment of non-anticoagulated plasma with raw AC had minimal impact on routine and specialised coagulation parameters available on the CS-series; however, clinically relevant prolongations of certain activated partial thromboplastin time (APTT)-based assays were observed after treatment. Furthermore, in apixaban- and rivaroxaban-containing plasma material, AC efficiently adsorbed therapeutic and supratherapeutic DOAC concentrations; and, treatment with raw AC resolved DOAC-associated interferences on all affected routine and specialised coagulation parameters.

CONCLUSIONS

Overall, raw AC efficiently adsorbed apixaban and rivaroxaban from human-derived plasma, without significantly affecting the majority of underlying routine and specialised coagulation parameters available on CS-series analysers.

Proactive Risk Assessment through Failure Mode and Effect Analysis (FMEA) for Perioperative Management Model of Oral Anticoagulant Therapy: A Pilot Project

INTRODUCTION

Correct perioperative management of anticoagulant therapy is essential to prevent thromboembolic events and reduce the risk of bleeding. The lack of universally accepted guidelines makes perioperative anticoagulant therapy management difficult. The present study aims to identify the perioperative risks of oral anticoagulant therapy and to reduce adverse events through Failure Mode and Effect Analysis (FMEA).

MATERIALS AND METHODS

A multidisciplinary working group was set up, and four main phases of the process were identified. Each of these phases was divided into micro-activities to identify the related possible failure modes and their potential consequences. The Risk Priority Number was calculated for each failure mode.

RESULTS AND DISCUSSION

Seventeen failure modes were identified in the entire perioperative period; those with a higher priority of intervention concern the incorrect timing between therapy suspension and surgery, and the incorrect assessment of the bleeding risk related to the invasive procedure.

CONCLUSION

The FMEA method can help identify anticoagulant therapy perioperative failures and implement the management and patient safety of surgical procedures.

A retrospective study of indications and consequences of monitoring direct oral anticoagulant plasma concentrations on patient care in a university hospital: The Retro-AOD study

INTRODUCTION

The use of direct oral anticoagulants (DOAC) is increasing. Specific concentrations are available and have been proven to be reliable and reproducible in optimising patient care. This retrospective, monocentric study aimed to describe the indications and consequences of monitoring DOAC plasma levels on patient care.

MATERIALS AND METHODS

We collected data of patients hospitalised at the Bordeaux University Hospital between January 2017 and December 2018. These included demographics, indications, type, dose of DOAC, standard coagulation tests, creatinine clearance and DOAC plasma concentration using specifically calibrated rivaroxaban and apixaban anti-Xa and dabigatran anti-IIa assays. The date of last DOAC intake, the time between intake and plasma level measurement were also collected and analysed.

RESULTS

A total of 2197 DOAC assays in 1488 patients were obtained in various clinical situations: urgent or elective procedures, context of acute renal failure, suspicion or occurrence of ischemic strokes, intra-cranial and other bleeding sites. Interpretation of these assays led physicians to maintain, postpone or cancel invasive and high haemorrhagic risk procedures in 757, 261 and 56 cases respectively. The remaining 1123 assays were associated with no significant modification of patient care. DOAC plasma concentration was ≤30 ng ml^-1 (sensitivity 85.4%, specificity 73.6%, positive predictive value 71.1%, negative predictive value 86.7%, AUC 0.81) after a last intake of at least 2 days.

CONCLUSIONS

Our study is, to date, the largest report of real-life measurement of specific DOAC plasma level at a single institution. Patient care was not modified in more than half of the assays.

Different Coagulation Indicators in Predicting Clinical Outcomes for Patients With Direct Oral Anticoagulants: A Systematic Review and Meta-analysis

PURPOSE

There are many anticoagulant test indexes available for direct oral anticoagulants (DOACs), but how to select the appropriate index and the index cutoff values are still controversial. This is the first study, to our knowledge, to assess the association of different coagulation indicators with clinical outcomes among DOACs using a meta-analysis of observational studies.

METHODS

A medical literature search was conducted using PubMed, Web of Science, EMBASE, ClinicalTrials.gov, and the Cochrane Library from inception to February 2020. Studies that reported relationships between coagulation indexes and clinical outcomes or the diagnostic value of coagulation assays were included in the analysis.

FINDINGS

A total of 17 articles (7 meta-analyses and 10 systematic reviews) from 8904 citations were included in the analysis. In the analysis of bleeding events with coagulation indexes for DOACs, for peak prothrombin time level (cutoff value of 19-25 s), the pooled results found a sensitivity of 0.61 (95% CI, 0.44-0.75) and a specificity of 0.71 (95% CI, 0.49-0.86). For rivaroxaban, the trough anti-factor Xa concentration (AXA-C) (cutoff value of 400-500 ng/mL) had a sensitivity of 0.53 (95% CI, 0.16-0.87) and a specificity of 0.87 (95% CI, 0.71-0.94), with a diagnostic odds ratio of 7 (95% CI, 2-32). For apixaban, trough AXA-C had a sensitivity of 0.85 (95% CI, 0.60-0.96) and a specificity of 0.83 (95% CI, 0.52-0.95). The AUC of the AXA-C peak was higher than that of the trough AXA-C for apixaban, with a higher sensitivity and specificity. Compared with trough concentration of anti-factor IIa for dabigatran, the peak concentration had a higher specificity (98%) at the cutoff value of 484 ng/mL. In the analysis of thromboembolic events with coagulation indexes for DOACs, peak and trough prothrombin time values were not typically correlated with subsequent symptomatic venous thromboembolism, without a sensitivity or specificity higher than 90%. Trough AXA-C had a sensitivity of 100% and but a low specificity (<50%) for rivaroxaban-apixaban. Trough AXA-C had a sensitivity of 100% and a specificity of 32% with a cutoff value of 108 ng/mL for dabigatran.

IMPLICATION

Peak prothrombin time (19-25 s) and AXA-C had a better predictive value on bleeding outcomes for rivaroxaban and apixaban, whereas peak concentration of anti-factor IIa activity can be an indicator for dabigatran. Coagulation indexes might not be a good indicator of thromboembolic events of DOACs. Because the limited studies focused on association of coagulation indicators and clinical outcomes, more studies are needed to verify this in the future.

Assessment of low plasma concentrations of apixaban in the periprocedural setting

INTRODUCTION

Estimation of residual apixaban plasma concentrations may be requested in the management of emergencies. This study aims at assessing the performance of specific anti-Xa assays calibrated with apixaban on real-life samples with low apixaban plasma concentrations (<30 ng/mL) and on-treatment ranges, with and without interference of low-molecular-weight heparin (LMWH).

METHODS

The performance of the STA^® -Liquid Anti-Xa assay (STA^® LAX) and the low and normal procedures of the Biophen^® Direct Factor Xa Inhibitors (DiXaI) assay was tested on 134 blood samples, collected from patients on apixaban, wherefrom 74 patients received LMWH after apixaban cessation. The results were compared with the liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) measurements.

RESULTS

The Biophen^® DiXaI, Biophen^® DiXaI LOW, and STA^® LAX showed very good correlation with LC-MS/MS measurements in patients without LMWH administration (Spearman r .95, .99, and .98, respectively). Their limits of quantitation were defined at 48, 24, and 12 ng/mL, respectively. The Bland-Altman test measured mean bias (SD) at 5.6 (13.1), -2.5 (5.0), and -0.8 (6.1) ng/ml, respectively. The Spearman r of the Biophen^® DiXaI decreased to 0.64 in presence of low apixaban concentrations. The Spearman r of the Biophen^® DiXaI LOW and STA^® LAX decreased to 0.39 and 0.26, respectively, in presence of LMWH.

CONCLUSIONS

The accuracy of the low methodologies (Biophen^® DiXaI LOW and STA^® LAX) is slightly improved for low apixaban plasma concentrations, compared with the normal procedure of Biophen^® DiXaI. The interference of LMWH on the low methodologies is measurable, however, less important than the previously reported interference of LMWH on rivaroxaban calibrated specific anti-Xa assays.

Direct oral anticoagulants and cardiac surgery: A descriptive study of preoperative management and postoperative outcomes

OBJECTIVE

Recommendations for perioperative management of direct oral anticoagulant (DOAC) treatment in cardiac surgery are lacking. To establish a standardized approach for these patients, we compared hemorrhagic complications and clinical outcomes in patients on DOAC medication, patients on vitamin K antagonists (VKA), and patients without preoperative anticoagulation.

METHODS

All 3 groups underwent major cardiac surgery and were retrospectively analyzed: patients on DOAC were advised to take their last DOAC dose 4 days before hospital admission, and DOAC plasma levels were measured the day before surgery. In patients with plasma levels of >30 ng/mL, surgery was postponed until plasma level was below this threshold level. Postoperative chest tube drainage, bleeding complications, use of blood products, and thromboembolic events were collected for all groups.

RESULTS

A total of 5439 patients no anticoagulation, 239 patients on VKA, and 487 patients on DOAC medication were included between April 2014 and July 2017. Adjusted postoperative chest tube drainage did not differ between the DOAC and VKA groups for the strategy applied in this study (380 mL/12 hours vs 360 mL/12 hours). Moreover, secondary endpoint measures, such as rethoracotomy (30 [6.16%] vs 15 [6.28%]), 30-day-mortality 12 [2.46%] vs 7 [2.93%]), blood-product use, and stroke, were not significantly different through implementation of our standardized study management (P > .05).

CONCLUSIONS

Our standardized management for perioperative discontinuation of DOAC therapy may provide a safe approach to minimize hemorrhagic complications in cardiac surgery in patients on DOACs.

The preoperative management of dabigatran and its specific antidote idarucizumab in patients with nonvalvular atrial fibrillation: Case reports

Dabigatran is a novel oral anticoagulant preferred due to its ease of use, favorable pharmacokinetics, decreased potential for drug-drug interactions, and the lack of monitoring requirements. With the growing use of dabigatran, it is important to highlight that dabigatran increases the risk of hemorrhage after some procedures. Therefore, when dabigatran is used before the elective or urgent procedures, it is necessary to compare the thromboembolic event risk with the relative risk of bleeding. Before the approval of a reversal agent, the lack of specific antidotes had been the major limitation against the widespread utilization of dabigatran. In October 2015, idarucizumab, a humanized monoclonal antigen-binding antibody fragment capable of reversing the anticoagulant activity of dabigatran, has been introduced into the market to be used in lifethreatening bleeding or urgent surgery. In this manuscript, the preoperative management of dabigatran and the initial experience of using idarucizumab in a patient with nonvalvular atrial fibrillation were described. We propose that the option of dabigatran reversal needs to be considered in patients with nonvalvular atrial fibrillation. However, additional research is needed to define optimal perioperative management of dabigatran and other novel oral anticoagulants, especially in high bleeding risk patients, and to determine whether pre-procedure coagulation testing should be performed.

Severe Enoral Bleeding with a Direct Oral Anticoagulant after Tooth Extraction and Heparin Bridging Treatment

Background

The number of patients receiving direct oral anticoagulants (DOACs) is increasing, however, this treatment is associated with the risk of bleeding. More than 10 percent of patients on DOACs have to interrupt their anticoagulation for an invasive procedure every year. For this reason, the correct management of DOACs in the perioperative setting is mandatory.

Case Presentation

An 81-year-old male patient, with known impaired renal function, presented to our emergency department with a severe enoral bleeding after tooth extraction. The DOAC therapy—indicated by known atrial fibrillation—was interrupted perioperatively and bridged with Low Molecular Weight Heparin (LMWH). The acute bleeding was stopped by local surgery. The factors contributing to the bleeding complication were bridging of DOAC treatment, together with prolonged drug action in chronic kidney disease.

Conclusion

In order to decide whether it is necessary to stop DOAC medication for tooth extraction, it is important to carefully weigh up the individual risks of bleeding and thrombosis. If DOAC therapy is interrupted, bridging should be reserved for thromboembolic high-risk situations. Particular caution is required in patients with impaired kidney function, due to the risk of accumulation and prolonged anticoagulant effect of both DOACs and LMWH.

The role of a specialist bridging service. A New Zealand prospective study of 600 patients

BACKGROUND

A proposition for the Wellington hospital thrombosis service to manage periprocedure anticoagulation bridging was made after a number of cancellations and key incidents were caused by lack of a consistent management approach. We provided individual bridging assessments, with implementation, communication, and education. The only funded anticoagulants in New Zealand at that time were dabigatran, warfarin, and enoxaparin.

METHODS

On initiation of the bridging service, we prospectively collected data on 600 consecutive patients referred to the periprocedure bridging service between May 2015 and February 2017. We recorded the 30-day major bleeding events, thrombotic events, and related mortality. We followed the patients up for 30 days postprocedure. As part of this process, we ensured optimal transition back to their initial anticoagulant.

CONCLUSION

We found low rates of major bleeding 1.9% and thrombosis 0.8% at day 30 comparable to randomized controlled trials. Of the 222 patients taking dabigatran experienced no major bleeding events. We believe using a specialist coagulation service is optimal to ensure surgery can proceed safely.

What Surgeons Should Know About Non-Vitamin K Oral Anticoagulants: A Review

Importance

Non-vitamin K oral anticoagulants (NOACs) are increasingly prescribed for patients to treat or prevent arterial or venous thromboembolism. The following 4 NOAC agents are approved by the US Food and Drug Administration for clinical use: dabigatran etexilate, apixaban, edoxaban tosylate, and rivaroxaban. A good understanding of these agents' pharmacologic properties is important for surgeons given their marked differences compared with warfarin sodium. This review highlights key practical issues surrounding the use of NOACs in the perioperative setting.

Observations

The PubMed and Cochrane Library databases were searched for English-language studies from May 1, 2009, until May 1, 2017, for randomized clinical trials, meta-analyses, systematic reviews, observational studies, and clinical guidelines. From a systematic review of the published literature that included 70 articles and 166 404 patients, this study identified 5 key practical issues surrounding the use of NOACs in the perioperative setting. These include patient populations for which NOAC use is indicated and contraindicated, the timing of NOAC treatment cessation before invasive interventions, management of NOAC-treated patients requiring urgent interventions, the need for "bridging," and the timing of NOAC treatment's reinitiation after invasive interventions. Important findings are as follows: NOAC agents are not recommended for patients with mechanical heart valves or advanced kidney disease (creatinine clearance, <15 mL/min); minimal to no anticoagulant effect remains when therapy with a NOAC is withheld for 48 to 72 hours before surgery in the context of normal kidney function; a reversal agent is clinically available for dabigatran, while reversal agents for apixaban, edoxaban, and rivaroxaban are under regulatory review; and laboratory testing of the anticoagulant effects of NOACs are not routinely available. There is a paucity of high-quality data on the optimal timing of NOAC cessation and resumption in the perioperative period, particularly for patients who undergo procedures with high bleeding risk.

Conclusions and Relevance

The anticoagulant effect of NOAC agents is predictable but not readily measurable in routine clinical practice. A number of uncertainties remain surrounding the use of these agents in the perioperative setting. Ongoing prospective studies and randomized clinical trials will provide greater clarity on these management issues in the near future.

Application value of thromboelastography in perioperative clinical blood transfusion and its effect on the outcome of patient

Application value of thromboelastography (TEG) in perioperative clinical blood transfusion and its effect on the outcome of patient were investigated. Seventy-four patients, admitted to The Surgical Department of the First Hospital of Zibo from March 2015 to March 2018, were selected for this study. Among them, 34 patients took only the traditional coagulation function testing method as the blood transfusion guide during the perioperative period and they were regarded as the control group. The other 40 patients used TEG as the blood transfusion guide during the perioperative period, and they were regarded as the TEG group. The coagulation function indicators in 2 h before the operation and in 24 h after the operation, the transfusion amount and blood loss during the operation, the condition of the blood transfusion during the perioperative period, the occurrence rate of the postoperative rebleeding, the length of hospital stay and mortality of the patients in the two groups were compared. The coagulation function indicators of the patients in the two groups in 2 h before the operation and in 24 h after the operation showed that there was no significant difference between the two groups (P>0.050). However, APTT and Pt of the patients in the two groups both increased when compared with those before the treatment (P<0.050) and Hb, Hct, Plt and Fib all decreased (P<0.050). The suspended erythrocytes, Plt, fibrinogen and plasma in the TEG group were both significantly lower than those in the control group (P<0.001). Compared with the traditional coagulation function test, TEG was more accurate for estimating the coagulation function of patient and was more suitable for estimating the condition of blood transfusion of patient in the perioperative period; also, it could shorten the recovery period of patient and it is worthwhile to promote it in the clinic.

Insight into the perioperative management of direct oral anticoagulants: concerns and considerations

INTRODUCTION

Direct oral anticoagulants (DOACs) have gained momentum in recent years in patients requiring anticoagulation for the prevention and management of venous thromboembolism and thromboembolic events caused by atrial fibrillation. The use of these agents involves potential bleeding complications, particularly during invasive procedures. With increasing use of DOACs, adequate knowledge regarding the perioperative management of patients on DOACs has become indispensable.

AREAS COVERED

This review covers the indications, mechanism of action, and pharmacokinetics of DOACs and their management in different perioperative settings based on various current guidelines and practices. The role of bridging therapy with heparin and the recently developed reversal agents are also discussed.

EXPERT OPINION

The perioperative management of DOACs is influenced by drug pharmacokinetics, potential comorbidities of the patient and perioperative thrombotic and bleeding risk. In low bleeding risk and minor procedures, continuing DOACs seems to be safe. Interrupting DOACs in high-risk procedures might be necessary and should be based on the elimination half-life of the drug and renal function of the patient. Further research is needed to better clarify the role of recently developed reversal agents in the perioperative setting and to identify specific laboratory tests to guide the perioperative management of DOACs.

Rapid determination of anticoagulating effects of dabigatran in whole blood with rotational thromboelastometry and a thrombin-based trigger

Essentials A rapid test to detect thrombin inhibition by dabigatran would be valuable in acute situations. A thrombin-based trigger was applied in whole blood using rotation thromboelastometry. Effects of dabigatran were assessed in vitro and in samples from patients on dabigatran. The test produced data rapidly and was sensitive to dabigatran concentrations from 20 to 500 ng mL-1 . SUMMARY: Background Rapid determination of the anticoagulant effect of dabigatran is essential in emergency situations. Objective To study a viscoelastic test (rotational thromboelastometry [ROTEM]) for rapid determination of dabigatran effects in whole blood samples. Method ROTEM measurements were performed with comparison of two triggers (thrombin-based versus the commercial tissue factor-based trigger Ex-tem) in samples from 10 healthy donors spiked with dabigatran (20-500 ng mL-1 ) and in samples from 35 patients receiving dabigatran treatment; 10 healthy subjects served as controls. Clotting time (CT) and the difference in CT without versus with addition of the dabigatran antidote idarucizumab (CTdiff ) were measured. Addition of idarucizumab reveals the contribution of dabigatran to ROTEM measurements and its potential reversibility. Results In vitro studies showed that thrombin CT and thrombin CTdiff were more sensitive than Ex-tem CT and Ex-tem CTdiff in detecting dabigatran in whole blood samples. In patient samples, when thrombin CT and thrombin CTdiff were used, it was possible to detect dabigatran with a cut-off of dabigatran at 20 ng mL-1 , whereas, when Ex-tem CT and Ex-tem CTdiff were used, the method was less sensitive. Data from patient samples were obtained within 15 min of blood sampling. Conclusions ROTEM CT with a thrombin-based trigger is more sensitive to dabigatran effects than Ex-tem CT, and detects anticoagulant effects of drug concentrations in the low-very low therapeutic range. Analysis with idarucizumab (CTdiff ) reveals dabigatran-specific effects. As data are rapidly obtained, this method could, with further development and validation of its performance, be suitable for detecting clinically significant dabigatran effects in emergency situations.

American Society of Hematology 2018 guidelines for management of venous thromboembolism: optimal management of anticoagulation therapy

BACKGROUND

Clinicians confront numerous practical issues in optimizing the use of anticoagulants to treat venous thromboembolism (VTE).

OBJECTIVE

These evidence-based guidelines of the American Society of Hematology (ASH) are intended to support patients, clinicians and other health care professionals in their decisions about the use of anticoagulants in the management of VTE. These guidelines assume the choice of anticoagulant has already been made.

METHODS

ASH formed a multidisciplinary guideline panel balanced to minimize potential bias from conflicts of interest. The McMaster University GRADE Centre supported the guideline development process, including updating or performing systematic evidence reviews. The panel prioritized clinical questions and outcomes according to their importance for clinicians and patients. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to assess evidence and make recommendations, which were subject to public comment.

RESULTS

The panel agreed on 25 recommendations and 2 good practice statements to optimize management of patients receiving anticoagulants.

CONCLUSIONS

Strong recommendations included using patient self-management of international normalized ratio (INR) with home point-of-care INR monitoring for vitamin K antagonist therapy and against using periprocedural low-molecular-weight heparin (LMWH) bridging therapy. Conditional recommendations included basing treatment dosing of LMWH on actual body weight, not using anti-factor Xa monitoring to guide LMWH dosing, using specialized anticoagulation management services, and resuming anticoagulation after episodes of life-threatening bleeding.

The vexed question of whether or not to measure levels of direct oral anticoagulants before surgery or invasive procedures

Direct oral anticoagulants (DOAC) possess high bioavailability, and their anticoagulant effect is more predictable than that of vitamin K antagonists, hence they do not require routine dose adjustment based on laboratory testing. However, there are circumstances when laboratory testing may be useful, including patients who need to undergo surgery or invasive procedures. Most guidelines state that patients on DOAC may safely undergo surgery/invasive procedures by stopping anticoagulation for a few days before intervention without testing if renal function is within normal limits. This review article discusses the pros and cons of measuring (or not measuring) DOAC levels before surgery/invasive procedures by a multidisciplinary team of experts with different background, including the thrombosis laboratory, clinical thrombosis, internal medicine, cardiology and nephrology. The conclusion is that measuring DOAC with dedicated tests before surgical or invasive procedures is important for patient safety. It provides the best and most direct evidence to rule in (or to rule out) clinically relevant concentrations of residual drugs. Regulatory agencies should urgently approve their use in clinical practice. Hospital administrators should make them available, and clinical laboratories should set up the relative methods and make them available to clinicians.

Safety of Anticoagulation Interruption in Patients Undergoing Surgery or Invasive Procedures: A Systematic Review and Meta-analyses of Randomized Controlled Trials and Non-randomized Studies

BACKGROUND

The safety of anticoagulation interruption in patients requiring surgical or invasive procedures remains unclear. We thus performed a systematic review and meta-analyses of randomized controlled trials (RCTs) and non-randomized studies (NRS).

METHODS

MEDLINE, Embase and Central databases were searched to March 2017 without date or language restrictions. We considered RCTs and NRS comparing anticoagulation interruption with any anticoagulation (continuation or heparin bridging) in adult surgical patients taking oral anticoagulation. Data were independently extracted. The quality of the evidence was assessed following recommendations from the Cochrane collaboration (GRADE approach). Risk ratios were calculated for 30-day events: thromboembolic (TE) events, major bleeding and mortality. Additional analyses explored the effects of different anticoagulation strategies.

RESULTS

Twelve reports were included: 4 RCTs (2190 participants) and 8 NRS (18993 participants). Trials included mostly participants with atrial fibrillation. Interrupting anticoagulation did not seem to increase TE events (RR 0.65, 95% CI [0.33, 1.30]-4 studies, 2190 participants) and resulted in less bleeding (RR 0.41, 95% CI [0.22, 0.78]-3 studies, 2126 participants) compared to anticoagulation continuation or heparin bridging. The GRADE assessment was moderate. Similar results were found in non-randomized studies, but the quality of the evidence was low. Possible strategy-specific effects were identified: forgoing heparin bridging seemed beneficial, but these effects were less clear with other strategies.

CONCLUSION

Interrupting anticoagulation in patients requiring invasive procedures did not seem to result in harm and protected against major bleeding. Uncertainty remains regarding the safety of this strategy in indications other than atrial fibrillation and in moderate- to high-risk surgery.

STUDY REGISTRATION

http://www.en.anaesthesie.usz.ch/research/Pages/Study-protocols.aspx.

Perioperative interruption of direct oral anticoagulants in patients with atrial fibrillation: A systematic review and meta-analysis

Background

Patients with atrial fibrillation (AF) frequently undergo invasive procedures that require temporary interruption of anticoagulation. There is little evidence to guide the perioperative interruption of direct oral anticoagulants (DOACs).

Methods

A systematic literature search including studies that evaluated the perioperative interruption of DOACs for non-emergent invasive procedures in patients with AF was performed. The primary outcomes of interest were the 30-day risk of thromboembolic events and major bleeding. Secondary outcomes of interest included the 30-day risk of minor bleeding and overall mortality. The systematic review protocol and search strategy were registered online (PROSPERO January 27th 2017:CRD42017056124).

Results

A total of 8 publications encompassing 14 446 patients and 17 107 periprocedural interruptions were included in our study. Our analysis revealed a pooled postoperative 30-day thromboembolic complication risk of 0.41% (95% CI 0.29- 0.54), and a pooled 30-day postoperative major bleeding risk of 1.81% (95% CI 0.84-3.13). Pooled 30-day postoperative risks of minor bleeding and overall mortality were 3.08% (95% CI 1.02-6.20) and 0.67% (95% CI 0.29-1.23), respectively. Meta-analysis of the included comparative studies did not reveal any significant differences in these postoperative outcomes following the perioperative interruption of DOACs or vitamin K antagonists.

Conclusions

The perioperative interruption of DOACs in patients with AF was associated with 0.4% thromboembolic and 1.8% major bleeding events at 30 days post surgery. These findings seem reassuring, but require validation in large prospective management studies where pre-operative DOAC levels are measured and compared with clinical outcomes in this patient population.

Laboratory testing in patients treated with direct oral anticoagulants: a practical guide for clinicians

Click to hear Dr Baglin's perspective on the role of the laboratory in treatment with new oral anticoagulants SUMMARY: One of the key benefits of the direct oral anticoagulants (DOACs) is that they do not require routine laboratory monitoring. Nevertheless, assessment of DOAC exposure and anticoagulant effects may become useful in various clinical scenarios. The five approved DOACs (apixaban, betrixaban, dabigatran etexilate, edoxaban and rivaroxaban) have different characteristics impacting assay selection and the interpretation of results. This article provides an updated overview on (i) which test to use (and their advantages and limitations), (ii) when to assay DOAC levels, (iii) how to interpret the results relating to bleeding risk, emergency situations and perioperative management, and (iv) what is the impact of DOACs on routine and specialized coagulation assays. Assays for anti-Xa or anti-IIa activity are the preferred methods when quantitative information is useful, although the situations in which to test for DOAC levels are still debated. Different reagent sensitivities and variabilities in laboratory calibrations impact assay results. International calibration standards for all specific tests for each DOAC are needed to reduce the inter-laboratory variability and allow inter-study comparisons. The impact of the DOACs on hemostasis testing may cause false-positive or false-negative results; however, these can be minimized by using specific assays and collecting blood samples at trough concentrations. Finally, prospective clinical trials are needed to validate the safety and efficacy of proposed laboratory thresholds in relation to clinical decisions. We offer recommendations on the tests to use for measuring DOACs and practical guidance on laboratory testing to help patient management and avoid diagnostic errors.

Update on Direct Oral AntiCoagulants (DOACs)

Recent findings require an update of previous recommendations for the perioperative use of Direct Oral AntiCoagulants (DOACs). A break in preoperative treatment of 24-96 hours is recommended based on the pharmacokinetic profiles of DOACs and depends on individual patient characteristics, their renal and possibly liver function, and their surgery-related risk of bleeding. In cases of renal or hepatic insufficiency, whether to extend the preoperative interruption of IIa- and Xa-inhibitors is a clinical decision that must be reached on an individual patient basis. In cases of epidural or spinal anaesthesia, more conservative pausing-intervals are recommended due to the risk of persistent neurologic deficits (e.g., paraplegia) following the development of spinal subdural and epidural haematomas. Elective surgery should be postponed according to these recommendations. Preoperative "bridging" with LMWH (more precisely referred to as "switching") should be omitted due to a significantly increased risk of bleeding. In addition, the incidence of perioperative thromboembolic risks, such as DVT, PE, and stroke, are no different whether interruption or "switching" is undertaken. Postoperatively, the DOACs can be reinstituted within the first 24 hours. In cases of major surgery or if there is a higher risk of bleeding, resumption of DOACS should only begin after 24-72 hours. In patients with an elevated thromboembolic risk, transient postoperative LMWH administration can be recommended during this period.Interaction of DOACs with other drugs usually occurs during the absorption, transport and elimination of these drugs. Therefore, substance- specific restrictions and recommendations should be observed during these times. In everyday clinical practice, webbased, independent information portals on drug-interactions are very helpful in providing safe and rapid information about potential interactions when DOACs are used in combination with other drugs, especially during perioperative management.Non-adherence to medications is a worldwide problem that has dangerous and costly consequences. Present data suggest that persistence is the primary factor that supports adherence. Despite the adherence data presented in the DOACS approval studies (e.g., persistence in the treatment of acute venous thromboembolism has been reported to be between 94-99%), the first registries and meta-analyses provide sobering results regarding the incidence of persistence and the success rate of interventions designed to improve adherence with DOACs in cases of long-term usage.

Position Paper on laboratory testing for patients on direct oral anticoagulants. A Consensus Document from the SISET, FCSA, SIBioC and SIPMeL

Although direct oral anticoagulants (DOAC) do not require dose-adjustment on the basis of laboratory test results, the measurement of their anticoagulant effect is useful in special situations. This position paper issued by the Italian Scientific Societies that are mainly involved in the management of patients on DOAC is aimed at providing guidance to care-givers on which tests should be used and the situations in which testing is useful. The guidance is based on the data from the literature so far available and/or on consensus among experts.

Perioperative management of patients on direct oral anticoagulants

Direct oral anticoagulants (DOACs) have been licensed worldwide for several years for various indications. Each year, 10–15% of patients on oral anticoagulants will undergo an invasive procedure and expert groups have issued several guidelines on perioperative management in such situations. The perioperative guidelines have undergone numerous updates as clinical experience of emergency management has increased and perioperative studies including measurement of residual anticoagulant levels have been published. The high inter-patient variability of DOAC plasma levels has challenged the traditional recommendation that perioperative DOAC interruption should be based only on the elimination half-life of DOACs, especially before invasive procedures carrying a high risk of bleeding. Furthermore, recent publications have highlighted the potential danger of heparin bridging use when DOACs are stopped before an invasive procedure.

As antidotes are progressively becoming available to manage severe bleeding or urgent procedures in patients on DOACs, accurate laboratory tests have become the standard to guide their administration and their actions need to be well understood by clinicians.

This review aims to provide a systematic approach to managing patients on DOACs, based on recent updates of various perioperative guidance, and highlighting the advantages and limits of recommendations based on pharmacokinetic properties and laboratory tests.

Use of oral anticoagulation for patients who undergo invasive procedures

The performance of invasive procedures in patients undergoing oral anticoagulation represents a risk. Without conclusive data on this issue, the recommendations on managing oral anticoagulation are generally weak, and its management is controversial and heterogeneous. We conducted a review of the evidence on the elective periprocedural management of oral anticoagulation following the publication of the 9th edition of the guidelines of the American College of Chest Physicians. Except for cases of procedures with minimal haemorrhagic risk, the use of oral anticoagulants is suspended with sufficient time so that it can be performed without a significant anticoagulant effect, which will depend on the half-life of the drug. For direct oral anticoagulants, the half-life is determined by the renal function. Recent studies have shown that the use of bridge therapy with heparin in patients who temporarily suspended the use of oral anticoagulation provided no benefits and increased the bleeding. However, there is no conclusive evidence against its use in patients with a high thromboembolic risk.

To measure or not to measure direct oral anticoagulants before surgery or invasive procedures

Patients on direct oral anticoagulants (DOAC) may need interruption of treatment before surgery or invasive procedures. Owing to their favorable pharmacokinetics, DOAC could be interrupted for a fixed number of days before surgery or invasive procedures without laboratory testing. However, there are a number of issues that raise concerns about the safety of this strategy. In contrast, laboratory testing prior to surgery or invasive procedures would provide a direct assessment of the residual drug concentration and minimize the risk of bleeding. This forum is aimed at discussing the pros and cons of the two strategies and fostering discussion on this important issue. Overall, the laboratory strategy appears superior in terms of patient safety and should be considered in patients undergoing surgical or invasive procedures.

New Direct Oral Anticoagulants (DOAC) and Their Use Today

The ideal anticoagulant is oral, has a wide therapeutic range, predictable pharmacokinetics and pharmacodynamics, a rapid onset of action, an available antidote, minimal side effects and minimal interactions with other drugs or food. With the development of the novel direct oral anticoagulants (DOAC), we now have an alternative to the traditional vitamin K antagonists (VKA) for the prevention and treatment of thrombosis. DOACs have limited monitoring requirements and very predictable pharmacokinetic profiles. They were shown to be non-inferior or superior to VKA in the prophylaxis or treatment of thromboembolic events. Particularly in terms of safety they were associated with less major bleeding, including intracranial bleeding, thus providing a superior benefit for the prevention of stroke in patients with atrial fibrillation. Despite these advantages, there are remaining limitations with DOACs: their dependence on renal and hepatic function for clearance and the lack of an approved reversal agent, whereas such antidotes are successively being made available. DOACs do not need regular monitoring to assess the treatment effect but, on the other hand, they interact with other drugs and interfere with functional coagulation assays. From a practical point of view, the properties of oral administration, simple dosing without monitoring, a short half-life allowing for the possibility of uncomplicated switching or bridging, and proven safety overwhelm the disadvantages, making them an attractive option for short- or long-term anticoagulation.