Atrial fibrillation Dabigatran/Rivaroxaban/Apixaban

Choosing blood thinners for Atrial Fibrillation–a great summary

When you have 15 minutes, I’d recommend heading over to the Private Practice Blog of Dr Seth Bilazarian at Dr B has beautifully summarized both the clinical and real world factors that go into the difficult decision of which blood thinner to choose for prevention of stroke in patients with AF. Seth has a great talent for verbally presenting complex data.

I like his acronym: KISS-CRABI:

K- Keep

I- It

S- Simple

S- Silly

C- Prescription coverage?

R- Renal (kidney) function?

A- Early adopter?

B- Bleeding risk?

I- Instability on warfarin?

There are also two bonus features. One is a downloadable Powerpoint presentation.

The other is that after he finishes speaking, the video keeps filming. Here, we are treated to images of a busy cardiologist/blogger at work. You can almost see the neurons firing: “What’s my next blog going to be?”

Great job, Seth.


2 replies on “Choosing blood thinners for Atrial Fibrillation–a great summary”

YES – I agree that Dr. Seth Bilazarian DOES give a nice presentation – and has come up with a handy acronym of “CRABI” for assisting in decision to user warfarin vs one of the newer blood thinners. I do think of him (as I think of you) as a very high integrity excellent clinician who truly wants to do the best for his patients.

That said – “lower risk of stroke” was presented in Dr. Bilazarian’s presentation in a “slam-dunk” fashion – whereas in my view it is anything but. “Slam-dunk” is what the manufacturers have put their billions of dollars into – in the hope of encouraging marketing of their product.

My interpretation of the literature is different and more guarded. The ARISTOTLE Trial (NEJM 365:981,2011) was promoted as showing apixaban to be more effective than warfarin in preventing stroke, systemic embolism, bleeding and mortality. BUT – to get those results to achieve statistical significance – they needed no less than 1000 sites to get their 18,000 patients – with numbers like reduction in stroke from 5.04% with coumadin to 4.49% with apixaban. Yes – that’s a relative 10% improvement – but a NNT (Number-Needed-to-Treat) ~ 200 patients in order to benefit one. Similar small statistially significant differences were found in the other parameters stated, all of which sound much better with relative percentage reduction numbers than when absolute numbers of patients over the denominator of total patients in this study are used ….

This is THE BEST that it is going to get: i) manufacturer-supported study; ii) cards stacked in favor of apixaban (patients with renal insufficiency Cr <25 excluded) – AND – patients therapeutic on warfarin only 66% of the time (would seem excess bleeding clearly faciliated when warfarin is supratherapeutic – as often occurred in this manufacturer study …. ).

I am NOT saying warfarin is wonderful – because it is not. Credit to Dr. Bilazarian because he does acknowledge issues of cost, and also favors continuing warfarin in patients doing well on that drug, those with renal problems, and those who don't want to be "early adaptors". BUT – Isn't this scenario familiar with "great results" in a manufacturer-supported study initially, only to see the blemishes come out one-by-one several billion-dollars-spent later after a period of use … – and to me, results in Aristotle – while positive, are anything but "great" given small absolute number reductions, huge cost, GI upset, no monitoring (as a disadvantage), need for compliance given shorter-duration-of-action with no-way-to-monitor-if-patient-is-taking-the-drug – plus lack of reversibility.

I DO think the new blood thinners offer certain advantages – and for some patients they are a better choice than coumadin. THAT SAID – overpromotion and "slam-dunk-appearance" of "increased efficacy" makes me highly suspicious of the maker of the drug …

Thanks Ken. Great comment.

I am really thankful that you take the time to lay out these important messages. I agree that it’s critical for doctors to carefully evaluate the data–and then try to individualize. I like to lay out the pros, cons and alternatives of each blood-thinning option with the patient. I think one thing is certain about the emerging options for stroke prevention in AF: shared-decision making is critically important. There is no one right answer. In AF, variability reigns supreme.

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