DOAC or VKA?

Oral anticoagulation

A patient-specific decision

Interview with Dr. Christoph Sucker

Direct oral anticoagulants (DOACs) have significantly expanded the therapeutic options for oral anticoagulation. How do you evaluate the routine applicability 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 vitamin K antagonists (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.

What you need to know about oral anticoagulation

Indications

Illnesses that necessitate anticoagulation

Treatment options

DOAC or VKA? Criteria for choosing the right treatment

VKAs

The importance of Coumadin derivatives

DOACs

A relatively new option

Patient profiles

Patient with mechanical mitral valve replacement

Patient with mechanical mitral valve replacement

Concerns: Alternating concomitant medication

Treatment plan

Duration of anticoagulation: Long term

Therapy choice: Vitamin K antagonists (VKAs) with the target of INR self-testing

Rationale: In accordance with the guidelines, anticoagulation is necessary.
Patient self-testing was advised for this patient because studies have shown that patients who self-test remain within the INR target range for longer than with conventional VKA monitoring.1,2 Since the patient is physically and mentally in a position to learn how to self-test, a combination of VKA, INR self-management, and dosage self-adjustment is the most suitable treatment option.

*Fictional patient. May not represent all cases.

References:

1. Kortke H et al. Ann Thorac Surg. 2007;83(1):24–29.
2. Heneghan C et al. Lancet. 2012;379(9813):322–334.

Patient with permanent atrial fibrillation

Patient with permanent atrial fibrillation, lives alone

Illness: Atrial fibrillation

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) with conventional monitoring in a doctor’s office

Rationale: For this somewhat forgetful lady, a DOAC cannot be considered because of the short half-life: even one missed dose can limit the effects of the anticoagulant. Despite the fact that people older than 80 years can be trained in patient self-testing, it is not suitable for every patient and would not be a good choice for this woman. On the other hand, her INR adjustment could be improved if a caring family member could be trained on how to perform the test.

*Fictional patient. May not represent all cases.

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