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Choosing the right oral anticoagulant for your patient

Factors to consider when deciding whether a VKA or a DOAC is a better oral anticoagulant for your patient.

A female doctor smiling at her patient

When oral anticoagulants are indicated

Anticoagulants are often prescribed to people who have atrial fibrillation (AF) or artificial heart valves, or who have had a heart attack or other conditions that increase the risk of developing blood clots, such as deep vein thrombosis (DVT).

A woman nurse holding her patient's hand and smiling at her during a walk outside

Overview: vitamin K antagonists (VKAs)

Anticoagulation with VKAs (such as warfarin) is a long-established and proven treatment option. Moreover, there is a wealth of experience in the use of VKAs.

Patients receiving VKA therapy have very stable coagulation values, especially if they control the monitoring as coagulation self-testers and adjust their anticoagulant dosage themselves.

As far back as 2001, a major study revealed that self-managers were able to maintain 80% of their measured levels within the therapeutic range. In contrast, this percentage was only 65% in patients who received conventional care. The reasons for the difference were weekly monitoring and the ability to react quickly to INR deviations from the therapeutic range by an immediate dosage adjustment.1

Overview: DOACs/NOACs

In the last few years, several new drugs have been cleared for anticoagulation use. These direct oral anticoagulants (DOACs) offer the following benefits:2,3

  • No need for monitoring
  • Wider therapeutic index
  • Simpler kinetics
  • More rapid onset/offset
  • Fewer or no drug and food interactions

DOACs (sometimes also referred to as NOACs) such as dabigatran, rivaroxaban, apixaban, and edoxaban demonstrated non-inferiority to warfarin in prevention of stroke and systemic embolism. Secondary analyses demonstrated superiority for apixaban and dabigatran, at a 150 mg dose.

In each of these studies, the warfarin group was monitored using the usual care model. Warfarin patients who self-monitored once per week or every other week experienced dramatic increases in time in therapeutic range (TTR) with decreases in adverse events compared to patients managed under usual care.

A male doctor holding a tablet and smiling at his patient

Choosing the right anticoagulation therapy for your patient

The following patient-related factors are important when deciding between a VKA and a DOAC:

  • Risk of bleeding4,5
  • HAS-BLED score (≥ 3 points = high risk)4
  • A mechanical heart valve or hemodynamically significant valve disease5
  • Renal function5,6
  • Advanced liver disease6
  • Body weight7
  • Risk of coronary events7
  • Propensity to dyspepsia7
  • Patient compliance and preferences4
  • Abliity to safely sustain adjusted chronic anticoagulation4
  • Success on existing anticoagulation therapy6

Unlike with VKAs, the mode of action of DOACs does not need to be monitored. Though this can be regarded as an advantage, it has come under criticism from an increasing number of healthcare professionals because, especially with non-compliant patients, the absence of a control parameter can become a challenge for dosage adjustment.

For patients in the following subgroups, VKAs (such as warfarin) plus monitoring remain the standard of care:

  • There is a risk of non-compliance7-9
  • There are comorbidities (hypertension, heart failure, diabetes)9
  • The patient has renal impairment8
  • The patient has a mechanical heart valve9
  • The patient is elderly (> 75 years)9
  • The patient has an increased risk of bleeding10
  • Cost is an issue10
  • The patient is a child or adolescent10
  • The patient is intolerant to the new drugs11

Studies involving non-valvular atrial fibrillation indicate that DOACs are at least equivalent to VKAs. Although heavy, especially intracranial, bleeding is reported less frequently than with VKAs, a closer analysis revealed that with correct international normalized ratio (INR) adjustment, these advantages during the thrombosis prophylaxis disappear with VKAs. Furthermore, an increased risk of gastrointestinal bleeding has been shown with DOACs.11,12

When using VKA therapy, the right dose adjustments may be more easily attained when the INR checks are done in the form of patient self-testing.13

Physician perspective:
An interview with Dr. Christoph Sucker

Christoph Sucker

Dr. Christoph Sucker is medical and managing director of the COAGUMED Coagulation Center in Berlin, Germany. He is a board member of the German Society of Hematologists (BDDH), co-editor of Vascular Care, an advisory board member of Hämostaseologie and the Scientific Advisory Board of Die Gerinnung, and the author of multiple publications in clinical hemostasis.

DOACs have significantly expanded the therapeutic options for oral anticoagulation. How do you evaluate the routine applicabliity of DOACs?

We originally thought that there would be fewer side effects with the new anticoagulants, which is what the studies suggested. However, it is important to observe in daily practice just how these medications work in comparison with the situation described in the study. I think we have already learned a certain amount, and we have discovered that side effects occur even with DOACs.

Can you substantiate this?

An example is gastrointestinal bleeding. The reason for this is related to the mode of action of the DOAC, which, unlike VKAs, acts directly within the gastrointestinal tract and can thus produce bleeding in patients with previously compromised mucosa. But there are also some patients who develop non-specific adverse effects, like joint pain or nausea.

How do you evaluate the limited monitoring options in DOAC therapy?

This topic is being discussed in an increasingly critical manner. Just visualize a patient who is receiving treatment for hypertension. In this case, regular blood pressure checks are perfectly normal in order to see whether the adjustment is correct. The same applies to patients with diabetes where success monitoring is mandatory with each treatment, regardless of whether it involves testing glucose in the urine, blood sugar, or some other parameter.

I myself take a lipid-reducing drug, and of course I want to check periodically whether it is having the desired effect—lowering my cholesterol. With anticoagulation, we have exactly the same need.

In my experience, patients feel much safer when their treatment is monitored the way it is done with VKAs like warfarin.

Can you substantiate this?

Patients, especially those who have had a bleeding complication in the past, would be understandably anxious to know whether their dose adjustment is adequate or whether it might be too high, in which case they run the risk of suffering another bleeding complication.

To what extent do the monitoring options with oral anticoagulants offer any advantages?

For instance, for patients who are not very compliant, where we want to know whether they are taking any anticoagulants at all. Another example is surgery or an injury where the treating physician needs to know whether bleeding complications should be expected—where significant concentrations of this anticoagulant might still be in the body before a surgical procedure. When a DOAC is administered, we do not have a suitable measuring procedure in everyday clinical practice.

What is your personal conclusion about modern oral anticoagulant options?

You have to take a very close look whenever a patient requires a new adjustment. What is the situation regarding the approval of the medication in question, and what is the individual constitution of the patient? Furthermore—based on my long experience—VKA patients with a stable adjustment should not be switched to a DOAC.

Meet Bruce,* a patient with mechanical mitral valve replacement

A patient named Bruce

Bruce is a snowbird. At 63, he is a semi-retired accountant; as avid golfers, he and his wife like to spend their winters in warmer climates.
Two years ago, Bruce had a mechanical mitral valve replacement.

Concerns: Alternating concomitant medication

Treatment plan

Duration of anticoagulation: Long term

Therapy choice: Vitamin K antagonists (VKAs)

Rationale: In accordance with the guidelines, anticoagulation is necessary.

Monitoring recommendation: Bruce is a good candidate for patient self-testing. He is physically and mentally in a position to learn how to self-test, and self-testing is a good fit for his lifestyle. Additionally, studies have shown that patients who self-test remain within the INR target range for longer than with conventional VKA monitoring.1

A combination of VKA therapy, INR self-management, and dosage self-adjustment is the most suitable treatment plan for Bruce.

About patient self-testing

Meet Dorothy,* a patient with permanent atrial fibrillation

A patient named Dorothee

Dorothy is an 84-year-old widow. She still lives in her own home, though she is helped by her son and her granddaughter on a regular basis. Dorothy was diagnosed with permanent atrial fibrillation (AF) 10 years ago.

Risk factors: Impaired kidney function with a glomerular filtration rate (GFR) of 41 mL/min (CHA2DS2-VASc = 3)
Concerns: Alternating concomitant medication

Treatment plan

Duration of anticoagulation: Long term

Therapy choice: Vitamin K antagonists (VKAs)

Rationale: For this somewhat forgetful patient, a DOAC cannot be considered because of the short half-life: even one missed dose can limit the effects of the anticoagulant.

Monitoring recommendation: Although people older than 80 years can be trained in patient self-testing, it is not suitable for every patient and would not be an optimal choice for Dorothy. However, if visiting a clinic or pharmacy for monitoring increases the risk of contact with other viruses (for example, during cold and flu season, or if COVID-19 is present), Dorothy’s son or granddaughter could be trained to help her perform self-testing at home. This could improve her INR over time.1

Point-of-care INR testing is the best choice for Dorothy; however, patient self-testing remains an option if a caregiver is trained to help her.

About POC testing

NOAC: non-vitamin K oral anticoagulant (also known as novel oral anticoagulant and new oral anticoagulant)
*Fictional patient. May not represent all cases.


  1. Kortke H et al. Ann Thorac Surg. 2001;72(1):44–48.
  2. Kearon C et al. Chest. 2008;133(6 Suppl):454S–545S.
  3. Singer DE et al. Chest. 2008;133(6 Suppl):546S–592S.
  4. Camm AJ et al. Eur Heart J. 2010;31(19):2369–2429.
  5. Fuster V et al. Circulation. 2011;123:e269–e367.
  6. Cairns JA et al. Can J Cardiol. 2011;27(1):74–90.
  7. United Kingdom Clinical Pharmacy Association Position Statement on Introduction of the New Oral Anticoagulant.
  8. Wann LS et al. J Am Coll Cardiol. 2011;57(11):1330–1337.
  9. Fuster V et al. Circulation. 2011;123(10):269–367.
  10. Market research with 288 GPs and 29 experts from Australia, Germany, UK, USA; Q2 2011.
  11. Connolly SJ et al. N Engl J Med. 2009;361:1139–1151.
  12. Wallentin L et al. Lancet. 2010;376(9745):975–983.
  13. Heneghan C et al. Lancet. 2012;379(9813):322–334.