Should I consider a direct oral anticoagulant (DOAC) for my patient with pancreatic cancer and pulmonary embolism?

Classically, anticoagulant (AC) of choice in active malignancy with venous thromboembolism (VTE) has been low-molecular weight heparin (LMWH) (eg, enoxaparin) because of trials showing its superiority over warfarin. But now the pendulum is swinging toward DOACs as an alternative mode of treatment.

A 2018 trial found that oral edoxaban (an Xa inhibitor) was noninferior to subcutaneous dalteparin (a LMWH) with the composite outcome of recurrent VTE or major bleeding.1 Overall, recurrent VTE was significantly lower in edoxaban (7.9% vs 11.3%) but had higher major bleeding (6.9% vs 4.05). Of note, edoxaban was initiated after 5 days of treatment with LMWH.

More recently, the 2020 Caravaggio trial, showed non-inferiority of apixaban (at a dose of 10 mg twice daily for the first 7 days, followed by 5 mg twice daily) to dalteparin with recurrent VTE of 5.6% in the apixaban group vs 7.9% in the dalteparin.2 There was no significant difference in rates of major bleeding (3.8% vs 4%). A prior small study, the ADAM-VTE trial, compared apixaban to dalteparin in patients with malignancy and VTE.3 Apixaban had significantly lower VTE recurrence rates (0.7% to 6.3%) and non-significant lower major bleeding (0% vs 1.4%, p=0.138) consistent with the newer and larger trial. Of note, this trial excluded patients with brain tumor and had few patients with upper GI or hematologic malignancy.  

In addition, a pilot study, the SELECT-D trial, compared rivaroxaban to dalteparin.4 Rivaroxaban had significantly lower VTE recurrence (4% vs 11%), without a significant increase in major bleeding (6% vs 4%), but had an increased number of clinically relevant non-major bleeds (13% vs 4%), particularly in cancers of the upper GI tract.

Although decision regarding use of DOACs in patients with malignancy should be made on case-by-case basis, they are increasingly considered for treatment of VTE in this patient population with the strongest evidence supporting apixaban or the initial use of LMWH for 5 days followed by edoxaban.  

Contributed by Sean Mendez MD, Mass General Hospital, Boston, MA.

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References:  

  1. Raskob GE, van Es N, Verhamme P, Carrier M, Di Nisio M, Garcia D, Grosso MA, Kakkar AK, Kovacs MJ, Mercuri MF, Meyer G, Segers A, Shi M, Wang TF, Yeo E, Zhang G, Zwicker JI, Weitz JI, Büller HR. Edoxaban for the Treatment of Cancer-Associated Venous Thromboembolism. N Engl J Med. 2018 Feb 15;378(7):615-624. doi: 10.1056/NEJMoa1711948. Epub 2017 Dec 12. PubMed PMID: 29231094.
  2. McBane Ii R, Loprinzi CL, Ashrani A, Perez-Botero J, Leon Ferre RA, Henkin S, Lenz CJ, Le-Rademacher JG, Wysokinski WE. Apixaban and dalteparin in active malignancy associated venous thromboembolism. The ADAM VTE Trial. Thromb Haemost. 2017 Oct 5;117(10):1952-1961. doi: 10.1160/TH17-03-0193. Epub 2017 Aug 24. PubMed PMID: 28837207.
  3. Agnelli G, Becattini C, Meyer G, Muñoz A, Huisman MV, Connors JM, Cohen A, Bauersachs R, Brenner B, Torbicki A, Sueiro MR, Lambert C, Gussoni G, Campanini M, Fontanella A, Vescovo G, Verso M. Apixaban for the Treatment of Venous Thromboembolism Associated with Cancer. N Engl J Med. 2020 Mar 29;. doi: 10.1056/NEJMoa1915103. [Epub ahead of print] PubMed PMID: 32223112.
  4. Young AM, Marshall A, Thirlwall J, Chapman O, Lokare A, Hill C, Hale D, Dunn JA, Lyman GH, Hutchinson C, MacCallum P, Kakkar A, Hobbs FDR, Petrou S, Dale J, Poole CJ, Maraveyas A, Levine M. Comparison of an Oral Factor Xa Inhibitor With Low Molecular Weight Heparin in Patients With Cancer With Venous Thromboembolism: Results of a Randomized Trial (SELECT-D). J Clin Oncol. 2018 Jul 10;36(20):2017-2023. doi: 10.1200/JCO.2018.78.8034. Epub 2018 May 10. PubMed PMID: 29746227.

Disclosures: The listed questions and answers are solely the responsibility of the author and do not necessarily represent the official views of Massachusetts General Hospital, Harvard Catalyst, Harvard University, its affiliate academic healthcare centers, or its contributors. Although every effort has been made to provide accurate information, the author is far from being perfect. The reader is urged to verify the content of the material with other sources as deemed appropriate and exercise clinical judgment in the interpretation and application of the information provided herein. No responsibility for an adverse outcome or guarantees for a favorable clinical result is assumed by the author. Thank you!

Should I consider a direct oral anticoagulant (DOAC) for my patient with pancreatic cancer and pulmonary embolism?

Should I use aPTT or anti-Xa levels to monitor my patient on IV heparin infusion?

Despite more than half a century of use unfractionated heparin (UFH), the optimal method to monitor its anticoagulation effect remains unclear, with arguments for and against continued use of activated partial thromboplastin time, aPTT) vs switching to antifactor Xa heparin assay (anti-Xa HA). 1-4

The advantage of aPTT include decades of use and familiarity by providers, and its relative accessibility, ease of automation and cost.1 Its disadvantages include variation among the sensitivities of different aPTT reagents as well as susceptibility to factors that do not reflect intrinsic heparin activity (eg, liver dysfunction, hypercoagulable states). 1,2 Thus patients may receive unnecessarily high or low heparin doses because of physiologic and non-physiologic influences on aPTT.

In contrast, since anti-XA HA measures the inhibition of a single enzyme (factor Xa)1, it is a more direct measurement of heparin activity, with less variability and minimal interference by certain biological factors (eg, lupus anticoagulants). Anti-Xa monitoring may also improve the time to therapeutic anticoagulation and lead to fewer dose adjustments compared to aPTT monitoring.2

The disadvantages of anti-Xa HA include inaccuracy in the setting of hypertriglyceridemia (>360 mg/dL), hyperbilirubinemia (total bilirubin >6.6 mg/dL), recent use of low molecular weight heparin, fondaparinux and direct oral factor Xa inhibitors. Its relative expense and generally less laboratory availability among healthcare facilities may also limit its use in monitoring patients on therapeutic UFH. 1-3

Somewhat unsettling is the frequent discordance between aPTT and anti-Xa values having been reported in 46% to 60% of instances that may result in either thromboembolic or bleeding complications. 1,4 One study reported that aPTT may be therapeutic only 35% of the time that anti-Xa is also therapeutic! 2

What’s clearly missing are definitive studies that can shed light on the clinical impact of these intriguing findings on patient outcomes. So stay tuned!

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References

  1. Guervil DJ, Rosenberg AF, Winterstein AG, et al. Activated partial thromboplastin time versus antifactory Xa heparin assay in monitoring unfractionated heparin by continuous intravenous infusion. Ann Pharmacother 2011;45:861-68. https://www.ncbi.nlm.nih.gov/pubmed/21712506
  2. Whitman-Purves E, Coons, JC, Miller T, et al. Performance of Anti-factor Xa versus activated partial thromboplastin time for heparin monitoring using multiple nomograms. Clinical and Applied Thromosis/Hemostasis 2018;24:310-16. https://www.ncbi.nlm.nih.gov/pubmed/29212374
  3. Fruge KS, Lee YR. Comparison of unfractionated heparin protocols using antifactory XA monitoring or activated partial thrombin time monitoring. Am J Health-System Pharmacy. 2015; 72: S90-S97, https://doi.org/10.2146/sp150016
  4. Samuel S, Allison TA, Sharaf S, et al. Antifactor XA levels vs activated partial thromboplastin time for monitoring unfractionated heparin. A pilot study. J Clin Pharm Ther 2016;41:499-502.
  5. doi:10.1111/jcpt.12415. https://www.ncbi.nlm.nih.gov/pubmed/27381025
Should I use aPTT or anti-Xa levels to monitor my patient on IV heparin infusion?

When can I resume anticoagulation in my patient with atrial fibrillation and hemorrhagic stroke?

Optimal timing of resumption of therapeutic anticoagulation (AC) in patients with hemorrhagic stroke or intracranial hemorrhage (ICH) is unclear because of lack of randomized controlled trials, but existing evidence suggests that 4-8 weeks may be reasonable in our patient (1). 
The American Heart Association/American Stroke Association 2015 guidelines recommend avoiding AC for at least 4 weeks in patients without mechanical heart valves (class IIB-very weak), while 1 study reported that prediction models of ICH in atrial fibrillation at high risk of thromboembolic event suggest that resumption of AC at 7-8 weeks may be the “sweet spot” when weighing safety against efficacy of AC in this patient population (1-3).
Two meta-analyses (1 involving patients with non-lobar ICH, another ICH in patients with nonvalvular atrial fibrillation) found that resumption of AC ranging from 10 to 44 days following ICH may be associated with decrease rates of thromboembolic events without significant change in the rate of repeat ICH (4,5).
There are many limitations to the published literature including their retrospective nature, unreported location and size of ICH in many studies, and use of warfarin (not DOACs) as an AC agent (1).
Clearly we need randomized controlled trials to answer this important question. In the meantime, a heavy dose of clinical judgement on a case-by-case basis seems appropriate.

Bonus Pearl: Did you know that lobar ICH has high incidence of cerebral amyloid angiopathy and has been associated with higher bleeding rates than has deep ICH (i.e., involving the thalami, basal ganglia, cerebellum, or brainstem) usually due to hypertensive vessel disease (1)? 

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References
1. Gibson D et al. When is it safe to resume anticoagulation in my patient with hemorrhagic stroke. The Hospitalist, February 5, 2019. https://www.the-hospitalist.org/hospitalist/article/193924/neurology/when-it-safe-resume-anticoagulation-my-patient-hemorrhagic/page/0/1
2. Hemphill JC et al. Guidelines for the management of spontaneous intracerebral hemorrhage. Stroke. 2015 Jul;46:2032-60. https://www.ahajournals.org/doi/pdf/10.1161/STR.0000000000000069
3. Pennlert J et al. Optimal timing of anticoagulant treatment after intracerebral hemorrhage in patients with atrial fibrillation. Stroke. 2017 Feb;48:314-20 https://www.ahajournals.org/doi/pdf/10.1161/STROKEAHA.116.014643
4. Murthy SB et al. Restarting anticoagulation therapy after intracranial hemorrhage: A systematic review and meta-analysis. Stroke. 2017 Jun;48:1594-600. https://www.ahajournals.org/doi/full/10.1161/strokeaha.116.016327
5. Biffi A et al. Oral anticoagulation and functional outcome after intracerebral hemorrhage. Ann Neurol. 2017 Nov;82:755-65 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5730065/

When can I resume anticoagulation in my patient with atrial fibrillation and hemorrhagic stroke?

Should my patient with non-valvular atrial fibrillation on hemodialysis be anticoagulated?

Whether patients with end-stage kidney disease (ESKD) and non-valvular atrial fibrillation (AF) benefit from anticoagulation is a matter of controversy. 1,3 Although there may be some suggestion of benefit of warfarin for stroke prevention in this patient population, 2 there is also a higher concern for bleeding. 4-6 An increased risk of stroke among patients with ESKD and AF on warfarin has also been reported. 7

A 2018 Kidney Disease:Improving Global Outcomes (KDIGO) Controversies Conference concluded that there is “insufficient high-quality evidence” to recommend anticoagulation for prevention of stroke in patients with ESKD and atrial fibrillation. 8

However, the 2014 American College of Cardiology (ACC)/American Heart Association (AHA)/ Heart Rhythm (HRS) guideline states that it is reasonable to consider warfarin therapy in patients with ESKD and non-valvular AF with CHA2DS2 -VASc score of 2 or greater (Class IIa recommendation, level of evidence B).8 Of interest, the FDA recently approved the use of a direct oral anticoagulant (DOAC), apixaban, in ESKD potentially providing an alternative to the use of warfarin when anticoagulation is considered.10

Perhaps the decision to anticoagulate patients with ESKD for atrial fibrillation is best made on a case-by-case basis taking into account a variety of factors, including the risk of thromboembolic event, the risk of bleeding complications as well as patient preference.

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References

1. Genovesi S, Vincenti A, Rossi E, et al. Atrial fibrillation and morbidity and mortality in a cohort of long-term hemodialysis patients. Am J Kidney Dis 2008;51:255-62. https://www.ncbi.nlm.nih.gov/pubmed/18215703

2. Olesen JB, Lip GY, Kamper AL, et al. Stroke and bleeding in atrial fibrillation with chronic kidney disease. N Engl J Med 2012;367:625-35. https://www.ncbi.nlm.nih.gov/pubmed/22894575

3. Shah M, Avgil TM, Jackevicius CA, et al. Warfarin use and the risk for stroke and bleeding in patients with atrial fibrillation undergoing dialysis. Circulation2014;129:1196-203. https://www.ncbi.nlm.nih.gov/pubmed/24452752

4. Elliott MJ, Zimmerman D, Holden RM. Warfarin anticoagulation in hemodialysis patients: a systematic review of bleeding rates. Am J Kidney Dis 2007;50:433-40. https://www.ncbi.nlm.nih.gov/pubmed/17720522

5. Holden RM, Harman GJ, Wang M, Holland D, Day AG. Major bleeding in hemodialysis patients. Clin J Am Soc Nephrol 2008;3:105-10. https://www.ncbi.nlm.nih.gov/pubmed/18003768

6. Wizemann V, Tong L, Satayathum S, et al. Atrial fibrillation in hemodialysis patients: clinical features and associations with anticoagulant therapy. Kidney Int 2010;77:1098-106. https://www.ncbi.nlm.nih.gov/pubmed/20054291

7. Chan KE, Lazarus JM, Thadhani R, Hakim RM. Warfarin use associates with increased risk for stroke in hemodialysis patients with atrial fibrillation. J Am Soc Nephrol2009;20:2223-33. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2754104/

8. Turakhia MP, Blankestijn PJ, Carrero J, et al. Chronic kidney disease and arrythias: conclusions from a Kidney Disease:Improving Global Outcomes (KDIGO) Controversies Conference. Eur Heart J, ehy060. Published 07 March 2018. https://www.ncbi.nlm.nih.gov/pubmed/29522134

9. January CT, Wann LS, Alpert JS, et al. 2014 AHA/ACC/HRS guideline for the management of patients with atrial fibrillation. Circulation 2014;130:2071-104. http://circ.ahajournals.org/content/130/23/2071 

10. Moll S. Use of direct oral anticoagulants in patients on hemodialysis. Diffusion, October 11, 2017. http://www.hematology.org/Thehematologist/Diffusion/7794.aspx 

Contributed by Brad Lander, MD, Mass General Hospital, Boston, MA.

Should my patient with non-valvular atrial fibrillation on hemodialysis be anticoagulated?

Is there any utility to laboratory testing for inherited thrombophilia or antiphospholipid syndrome in my hospitalized patient with unprovoked acute pulmonary embolism?

There is virtually no utility to obtaining heritable thrombophilia testing in acute hospital setting. In fact, there are potential harms due to false-positive and false-negative results which in turn may lead to increasing anxiety in the patient and added cost due to repeat testing.

As many tests obtained as part of this workup are functional assays—eg, the protein S, C, or antithrombin activity, and activated protein C resistance (often used to screen for factor V Leiden)— they are easily impacted by the physiologic effects of acute thrombosis as well as all anticoagulants.1

More importantly, testing for inherited thrombophilia will not impact management in the acute setting, as decisions regarding duration of anticoagulation are often made later in the outpatient setting. The proper time to evaluate the patient for inherited thrombophilias (if indicated) is at least one week following discontinuation of anticoagulation (minimum 3 months from the time of the index event). 2 

Testing for antiphospholipid syndrome (APS) may be considered in this setting though it should be noted that the lupus anticoagulant assay is impacted by nearly every anticoagulant, resulting in frequent false-positive results1, and therefore should be performed before initiation of these agents (or delayed until later if anticoagulation has already begun). A false-positive result has downstream implications as many patients with acute, uncomplicated venous thromboembolism (VTE) are discharged on a direct oral anticoagulant (DOAC), and antiphospholipid syndrome is currently considered a relative contraindication to the use of DOACs in VTE.

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 References
1. Moll, S. “Thrombophilia: Clinical-practical aspects.” J Thromb Thrombolysis 2015;39:367-78. https://www.ncbi.nlm.nih.gov/pubmed/25724822
2. Connors JM. “Thrombophilia Testing and Venous Thrombosis.” N Engl J Med 2017; 377:1177-1187. http://www.nejm.org/doi/full/10.1056/NEJMra1700365 

 

Disclosures: The listed questions and answers are solely the responsibility of the author and do not necessarily represent the official views of Massachusetts General Hospital, Harvard Catalyst, Harvard University, its affiliate academic healthcare centers, or its contributors. Although every effort has been made to provide accurate information, the author is far from being perfect. The reader is urged to verify the content of the material with other sources as deemed appropriate and exercise clinical judgment in the interpretation and application of the information provided herein. No responsibility for an adverse outcome or guarantees for a favorable clinical result is assumed by the author. Thank you!

 

 

Is there any utility to laboratory testing for inherited thrombophilia or antiphospholipid syndrome in my hospitalized patient with unprovoked acute pulmonary embolism?

Should prothrombin complex concentrates be used to reverse anticoagulation from direct factor Xa inhibitors?

Due to insufficient and occasionally conflicting evidence, the use of prothrombin complex concentrates (PCCs) for reversal of direct factor Xa inhibitors (eg, rivaroxaban, apixaban, and edoxaban) is NOT recommended.1 This is because PCCs have no effect on the anti-Xa assay, the most accurate measure of anticoagulation for direct factor Xa inhibitors.

Although several in vitro and in vivo studies initially suggested that PCCs may be effective for this purpose, anti-Xa activity has not been measured in these studies2-4; PT and aPTT are not reflective of the anticoagulation activity of direct factor Xa inhibitors.

In fact, a 2014 study found no difference in the anti-Xa activity between 11 patients on rivaroxaban who were given a 4-factor PCC (Beriplex®, the European brand name for Kcentra®) and 12 patients on rivaroxaban receiving saline.5 Though small, this is the best published in vivo data to date examining the effect of 4-factor PCC on the anti-Xa levels of patients on direct factor Xa inhibitors.

A theoretical concern with the use of PCCs is increased risk of thrombosis when the therapeutic effect of these direct oral anticoagulant (DOACs) is gone (half-life ~12 h) while the thrombogenic effects of PCCs persist (eg, in critically ill, postoperative, or sedentary patients).

The good news is that more specific reversal agents are in the pipeline. 1 Stay tuned! 

 

References:

  1. Dzik WH. “Reversal of oral factor Xa inhibitors by prothrombin complex concentrates: a re-appraisal.” J Thromb Haemost 2015;13 (Suppl 1):S187-94. https://www.ncbi.nlm.nih.gov/pubmed/26149022
  2. Perzborn E, Heutmeier S, Laux V, et al. “Reversal of rivaroxaban-induced anticoagulation with prothrombin complex concentrate, activated prothrombin complex concentrate and recombinant activated factor VII in vitro.” Thromb Res 2014 Apr;133:671-81. https://www.ncbi.nlm.nih.gov/pubmed/24529498
  3. Eerenberg ES, Kamphuisen PW, Sijpkens MK, et al. “Reversal of rivaroxaban and dabigatran by prothrombin complex concentrate: a randomized, placebo-controlled, crossover study in healthy subjects.” Circulation 2011 Oct 4;124:1573-9. https://www.ncbi.nlm.nih.gov/pubmed/21900088
  4. Zahir H, Brown KS, Vandell AG, et al. “Edoxaban effects on bleeding following punch biopsy and reversal by a 4-factor prothrombin complex concentrate.” Circulation 2015 Jan 6;131:82-90. https://www.ncbi.nlm.nih.gov/pubmed/25403645
  5. Levi M, Moore KT, Castillejos CF, et al. “Comparison of three-factor and four-factor prothrombin complex concentrates regarding reversal of the anticoagulant effects of rivaroxaban in healthy volunteers.” J Thromb Haemost 2014;12:1428-36. https://www.ncbi.nlm.nih.gov/pubmed/24811969

Contributed by Hanny Al-Samkari MD, Mass General Hospital, Boston, MA.

 

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Should prothrombin complex concentrates be used to reverse anticoagulation from direct factor Xa inhibitors?

In my patient on oral anticoagulation about to undergo coronary stenting, will triple therapy (an oral anticoagulant plus two antiplatelet agents) be necessary or can I get away with double therapy (an oral anticoagulant plus a single antiplatelet agent)?

 

Patients with atrial fibrillation (AF) who need percutaneous coronary intervention (PCI) after acute coronary syndrome or for stable angina pose a treatment challenge as oral anticoagulants (OACs) and dual antiplatelet therapy (DAPT) are often used concurrently to decrease the risk of systemic thromboembolism and stent thrombosis. However, “triple therapy”, including aspirin, a P2Y12 inhibitor, and an OAC (eg, warfarin or a direct oral anticoagulant-DOAC), also increases the risk of bleeding, necessitating several recent landmark trials to better address the subject.

Two modest-sized RCTs (WOEST and ISAR-TRIPLE) reported that when compared to triple therapy (DAPT plus warfarin), double therapy (single antiplatelet agent plus INR-targeted warfarin) is associated with reduced risk of bleeding complications without an increased risk of thrombotic events. 1,2

Two larger RCTs, PIONEER AF-PCI and RE-DUAL PCI, studied rivaroxaban and dabigatran, respectively, in patients with non-valvular AF undergoing PCI and found a reduction in bleeding events in patients receiving double therapy (single antiplatelet agent plus DOAC) compared to triple therapy (DAPT plus warfarin), without an increased risk of thrombotic complications. 3,4

Collectively, these studies suggest that it may be safe to treat patients with increased risk of bleeding with double therapy (even immediately following PCI) without an increase in thrombotic events. If triple therapy is elected, duration should be minimized, clopidogrel should be preferred over more potent P2Y12 inhibitors, and a PPI should be considered.

 

References:

  1. Dewilde WJ, Oirbans T, Verheugt FW, et al. Use of clopidogrel with or without aspirin in patients taking oral anticoagulant therapy and undergoing percutaneous coronary intervention: an open-label, randomised, controlled trial. Lancet. 2013;381:1107-15. https://www.ncbi.nlm.nih.gov/pubmed/23415013
  2. Fiedler KA, Maeng M, Mehilli J, et al. Duration of triple therapy in patients requiring oral anticoagulation after drug-eluting stent Implantation: The ISAR-TRIPLE Trial. J Am Coll Cardiol. 2015;65:1619-29. https://www.ncbi.nlm.nih.gov/pubmed/25908066
  3. Gibson CM, Mehran R, Bode C, et al. Prevention of bleeding in patients with atrial fibrillation undergoing PCI. N Engl J Med. 2016;375:2423-2434. http://www.nejm.org/doi/pdf/10.1056/NEJMoa1611594
  4. Cannon CP, Bhatt DL, Oldgren J, et al. Dual antithrombotic therapy with dabigatran after PCI in atrial fibrillation. N Engl J Med. Published online, Aug, 27, 2017. http://www.nejm.org/doi/pdf/10.1056/NEJMoa1708454

 

Contributed by Amulya Nagarur, MD, Mass General Hospital, Boston, MA

In my patient on oral anticoagulation about to undergo coronary stenting, will triple therapy (an oral anticoagulant plus two antiplatelet agents) be necessary or can I get away with double therapy (an oral anticoagulant plus a single antiplatelet agent)?

Should I consider a direct oral anticoagulant for treatment of pulmonary embolism in my obese patient?

Evidence supporting the efficacy of direct oral anticoagulants (DOACs) in obesity is limited. A major concern is the possibility of subtherapeutic anticoagulation in obese patients when standard doses of DOACs are used.

The International Society on Thrombosis and Haemostasis recommends1:

  • Standard fixed dosing of DOACs for patients with BMI ≤ 40 kg/m2 or weight ≤ 120 kg.
  • Avoiding DOACs in patients with BMI > 40 kg/m2 or weight > 120 kg. However, if a DOAC is needed, laboratory confirmation of therapeutic drug concentrations (eg, by checking anti-factor Xa depending on the agent) should be performed, and if subtherapeutic, a vitamin K antagonist (eg, warfarin) is recommended instead.

Based on the individual comparison of DOACs with warfarin in patients with “high” body weight (cut-off of 90 kg or 100 kg, depending on the study) and limited data, apixaban may be more effective in preventing recurrent venous thromboembolism or its related deaths. However, other DOACs, such as rivaroxaban, dabigatran, and edoxaban have also been used in patients with high body weight2.  

To add to the controversy, the efficacy of fixed dose dabigatran in obese patients has been questioned3 and some have recommended avoiding DOACs altogether in patients with BMI ≥ 35 kg/m2 or weight > 120 kg, until more data become available4.

As in many situations in medicine, a case-by-case decision based on clinical judgment and patient preferences may be the best way to go!

References

  1. Martin K, Beyer-Westendorf J, Davidson BL, et al. Use of the direct oral anticoagulants in obese patients: guidance from the SSC of the ISTH. J Thromb Haemost 2016; 14: 1308–13. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4936273
  2. Di Minno MN, Lupoli R, Di Minno A, et al. Effect of body weight on efficacy and safety of direct oral anticoagulants in the treatment of patients with acute venous thromboembolism: A meta-analysis of randomized controlled trials. Ann Med 2015; 47: 61-8. https://www.ncbi.nlm.nih.gov/pubmed/25665582
  3. Breuer L, Ringwald J, Schwab S, et al. Ischemic Stroke in an Obese Patient Receiving Dabigatran. N Engl J Med 2013; 368: 2440–2. http://www.nejm.org/doi/pdf/10.1056/NEJMc1215900
  4. Burnett AE, Mahan CE, Vasquez SR, et al. Guidance for the practical management of the direct oral anticoagulants (DOACs) in VTE Treatment. J Thromb Thrombolysis 2016; 41: 206-32. https://www.ncbi.nlm.nih.gov/pubmed/26780747

 

Contributed by Mahesh Vidula, MD, Mass General Hospital, Boston, MA.

Should I consider a direct oral anticoagulant for treatment of pulmonary embolism in my obese patient?

Can novel oral anticoagulants (NOAC) be reversed?

Since their relatively recent introduction, a major concern over NOAC use has been the lack of available reversal agents akin to vitamin K or fresh frozen plasma used to reverse anticoagulation effect of warfarin.

Fortunately, there are currently 2 FDA-approved NOAC reversal agents (idarucizumab and andexanet alfpha) and 1 NOAC on breakthrough or fast-track status at the FDA (1,2):

  • Idarucizumab, a humanized mouse antibody fragment, or Fab, targeted specifically for reversal of dabigatran. FDA approved
  • Andexanet alfa, a class-specific antidote for reversal of direct factor Xa inhibitors (apixaban, rivaroxaban, edoxaban), as well as an indirect factor Xa inhibitor, enoxaparin. FDA approved
  • Ciraparantag (PER977), a synthetic water-soluble compound that reverses direct thrombin (dabigatran), direct factor Xa (apixaban, rivaroxaban, edoxaban), and indirect factor Xa inhibitors (enoxaparin). Currently under investigation.

 

1. Ansell JE. Universal, class-specific, and drug-specific reversal agents for the new oral anticoagulants. J Thromb Thrombolysis 2016;41:248-52.  https://www.ncbi.nlm.nih.gov/pubmed/26449414

2. Connolly SJ, Milling TJ, Eikelboom JW, etal.  Andexanet alfa for acute major bleeding associated with factor Xa inhibitors. N Eng J Med 2016;375:1131-41. https://www.nejm.org/doi/full/10.1056/NEJMoa1607887

Contributed in part by William L. Hwang, MD, Mass General Hospital, Boston, MA.

Can novel oral anticoagulants (NOAC) be reversed?

How should I choose between the direct oral anticoagulants (DOACs)?

Although warfarin has long been the standard treatment for venous thromboembolism (VTE) and thomboprophylaxis in atrial fibrillation (AF), the need for its frequent monitoring, potential drug interactions, and narrow therapeutic window made it far from ideal.

Since 2009, DOACs have become viable alternative agents owing to their more predictable and safer pharmacological profiles. DOACs include several direct factor Xa inhibitors (apixaban, rivaroxaban, edoxaban) and a direct thrombin inhibitor (dabigatran). Approved indications include: (1) thromboprophylaxis in nonvalvular AF; (2) treatment of deep venous thrombosis or pulmonary embolism; and (3) primary prevention of postoperative VTE. 

Compared to warfarin, DOACs are associated with a reduced risk of intracranial hemorrhage, and in the case of apixaban, lower risk of gastrointestinal bleeding; rivaroxaban and edoxaban have been associated with a higher risk of gastrointestinal bleeding.  

Apixaban is also the only NOAC whose dose can be safely reduced in chronic kidney disease, including those on hemodialysis. 

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References

 

1. Baber U, Mastoris I, and Mehran R. Balancing ischaemia and bleeding risks with novel oral anticoagulants. Nat Rev Cardiol 2014;11:693-703.  https://www.ncbi.nlm.nih.gov/pubmed/25367652 

2. Ansell JE. Universal, class-specific, and drug-specific reversal agents for the new oral anticoagulants. J Thromb Thrombolysis 2016;41:248-52. https://www.ncbi.nlm.nih.gov/pubmed/26449414

 

Contributed by William L. Hwang, MD, Mass General Hospital, Boston, MA

How should I choose between the direct oral anticoagulants (DOACs)?