Hi
Those guidelines indeed remain similar to the 2012 publication by ESC/EACTS so its timley to remind people that much of the developed world has been in this square for over 10 years now (
if I was being unkind I'd suggest that exceptions to this are nations who remain adherents of an outdated, inadequate, arcane and difficult to work with system of metrics called the "Imperial System" which belonged to an Empire that they fought a war to leave)
Guidelines on the management of valvular heart disease (version 2012)
The former is determined mainly by the target INR, the quality of anticoagulation control, the concomitant use of aspirin, and the patient’s risk factors for bleeding (p31)
it goes on to say:
11.2.2.2 Target INR
In choosing an optimum target INR, one should consider patient risk factors and the thrombogenicity of the prosthesis, as determined by reported valve thrombosis rates for that prosthesis in relation to specific INR levels (Table 20). Currently available
randomized trials comparing different INR values cannot be used to determine target INR in all situations and varied methodologies make them unsuitable for meta-analysis.
Certain caveats apply in selecting the optimum INR:
† Prostheses cannot be conveniently categorized by basic design (e.g. bileaflet, tilting disc, etc.) or date of introduction for the purpose of determining thrombogenicity.
† For many currently available prostheses—particularly newly introduced designs—there is insufficient data on valve thrombosis rates at different levels of INR, which would otherwise
allow for categorisation. Until further data become available, they should be placed in the ‘medium thrombogenicity’ category.
From my 2014 blog post
http://cjeastwd.blogspot.com/2014/05/inr-management-goldilocks-dose.html
In the past the goal INR was given as a range, however a new way of thinking about it is emerging in the literature, which is to simply have a 'target' INR and grasp the idea that consistency of dose is good and values too high increase your problems as do values too low. You can expect your INR to move around, as long as it stays within the window there is nothing to worry about.
To me the new method is wiser because for a start nothing stays in one place (least of all metabolism) and the reality is a continuum not a border. You will not suddenly burst if you go over a threshold (low or high) and so the idea of the range is a little misleading and (in my view) can encourage silly and wrong approaches: IE my Dr said my INR range was 2 ~ 3 so I'm going to sit on 2. This is dangerous because the reality is that you can't sit on 2, you'll dip low and increase your risk of a stroke.
Effective management of patients with unstable INR requires frequent in-clinic testing and dose titration.
for the non chemists titration here means determining by analysis. AKA INR measurement. This is exactly what I bang on about here ... for those who don't need any dose adjustment, good luck to you, I wish I was like that (but then, thinking like a Stoic I would not have learned as much)
Because of the lack of good-quality evidence, pharmacogenetic testing cannot be recommended to guide the dosing of VKAs.
by lack of evidence I expect they mean "we've looked real hard to find support of using this and found repeatably that it can't be relied on and thus
measurement is the gold standard for getting into the therapeutic window."
Best Wishes
