How well do the New Oral Anticoagulant (Blood Thinning) Drugs perform?
Referring to treatment options for patients with Atrial Fibrillation, Dr Ruff from Brigham and Women's Hospital in Boston says, "The new oral anticoagulants show a favourable balance between efficacy and safety compared with warfarin, which is consistent across a wide range of patients with atrial fibrillation known to be at high risk for both ischemic and bleeding events”.
According to a large (meta-analysis) study, the newer oral anticoagulant drugs including dabigatran, apixaban, rivaroxoban and edoxaban seem to be better than warfarin at preventing stroke in patients with nonvalvular atrial fibrillation, but they do cause more gastrointestinal bleeding.
Researchers in The Lancet reported that the newer drugs also reduced all-cause mortality relative to warfarin during follow-up, but had no effect on rates of ischemic stroke or myocardial infarction (MI). Intracranial haemorrhage was less frequent with the new anticoagulants. It is therefore suggested that these findings offer heart specialists with a better picture of the new oral anticoagulant drugs as a treatment option to reduce the risk of stroke.
Warfarin and other vitamin K antagonists have traditionally been the main drugs of choice for stroke prevention in atrial fibrillation patients, but these drugs require the patient to have frequent blood tests to ensure that levels required for anticoagulation remains within a safe and therapeutic range. The newer anticoagulant drugs don't require that monitoring. Three of the drugs have already been approved by the FDA -- dabigatran, rivaroxaban, and apixaban.
However, Dr Gregory Lip, from the University of Birmingham warns that the meta-analysis does not help clarify which of the newer agents is best. "Although indirect comparisons between novel oral anticoagulants have been both criticized and justified, these comparisons suggest that, ultimately, the drug could be fitted to the patient, or the patient to the drug, dependent on a focus on safety or efficacy, and on other patient factors, such as renal function and drug compliance," It is also pointed out that the more recent safety reports provide some reassurance that these drugs work well, if used correctly.
Senior UK Consultant Cardiologist, Dr Oliver Segal also points out that the need for blood thinning drugs varies according to the associated treatments. He says, "In most cases of ablation for typical atrial flutter, blood thinning medication can be stopped one month after a successful procedure. However, if there is another reason for taking blood thinning drugs, then they will continue. For instance, it is not uncommon for patients to have both atrial flutter and atrial fibrillation. If ablation is only performed for the flutter, then blood thinning drugs will continue according to a patient’s CHADS-VASc score."
CHADS-VASc Score
To identify patients who are at risk of stroke when they have atrial flutter, we use a scoring system called the CHA2DS2-VASc scoring system.
CHA2DS2VAScscore
The CHA2DS2VAScscore is an acronym. It stands for:
C = Congestive cardiac failure (or heart failure or impaired
ventricular function)
H = Hypertension (or high blood pressure)
A2 = Age over 75
D = Diabetes
S2 = Stroke or TIA (transient ischaemic attack, or ‘mini-stroke’)
V = Vascular disease (heart attack or other arterial disease)
A = Age below 65
Sc = Sex category (female = 1 point)
If you have or have ever had one of these conditions you score one point for each, except Age over75 or Stroke/TIA which count as 2 points, hence the CHA2DS2VASCscore.
If you have a CHA2DS2VASC score of 1 or more it is recommended that you take warfarin (or one of the newer types of anticoagulant medications) for life to reduce your risk of stroke, unless the atrial flutter is cured with a procedure called 'ablation'. So, if you are 65 or older and have atrial flutter, it is recommended that you are treated with an anticoagulant and not aspirin, which is now known not to be beneficial.
