Posts Tagged ‘Anticoagulation’

A Replacement for Warfarin?

March 22, 2010

A lot of people dislike Warfarin. Also known by its brand name Coumadin, it is the most prescribed anticoagulant (Blood thinner) in North America. If you can get past the fact that you are taking something that is also used as rat poison, the constant monitoring and dosage adjustments are a pain in the butt. Every six weeks you must have a blood test, and it reacts with nearly everything. Other medications and even your choice of foods can make the drug more or less effective. This requires you to adjust your medication and have another blood test. It’s enough to make you yell!

But there are two new anticoagulants being developed that could replace Warfarin. The first is Dabigatran, which is marketed in Europe as Pradaxa. Dabigatran was approved for use in Europe and Canada in 2008 and is currently being considered here in the United States by the Food and Drug Administration.

Dabigatran has all the appearances of a wonder drug. It has done well in scientific studies: the RE-LY clinical trail shows that it performs better than Warfarin at some dosage levels; the RECOVER study proves that there is no need for the constant monitoring and no food/drug interactions.

If you’re waiting on the other shoe to drop, here it comes: Dabigatran is expensive. Great Britain’s National Health Service pays £4.20 per day for Dabigatran, and about £1 per day for Warfarin.

Ugh. Now that’s a problem.There are several theories that the cost difference can be recouped not only through the savings in monitoring costs, but the costs associated with stroke recovery. The simpler a medical therapy is to use, the more likely someone is to follow the instructions and benefit from it. Warfarin is difficult to maintain, while Dabigatran wouldn’t be. Just take your pill and go about your business.

The other new drug is Betrixaban, which is still being developed. It’s a joint venture between Merck and Co. and Portola, and like Dabigatran requires no monitoring and has almost no interactions. But it is still in Phase 2 testing, a long way from public use. Also, Portola is developing an “off switch”; another drug that can be administered in case of a heavy bleed and deactivate Betrixaban.

The potential market for any company that can develop a Warfarin replacement that has less interaction and less monitoring needs is wide open. Hopefully market forces will not only benefit the companies developing new drugs, but those of us who rely on them.

“At Night I’m a Junk Food Junkie…”

October 26, 2009

I have to go to the doctor’s office today to have my Prothrombin level checked, and I have a feeling that I’m going to be changing the amount of blood thinner I take. But overall, I think it is a good thing.

When you give the blood sample to have your anticoagulation level checked – a measure of the ability of your blood to clot – the results are your INR level. INR stands for International Normalized Ratio. At one time, there were many different systems and math formulas used to check anticoagulation, and lots of different results: This testing service may give you a result of 1.4, another might give a result of 73. It was too difficult to figure out if the systems were compatible, so finally the World Health Organization stepped in. A standardized system was determined along with a standard scoring system (the INR level). So now a reading of 2.6 means exactly the same thing, no matter if you have you test done in rural Virgina or downtown Toronto.

The rate at which your blood clots can depend on a lot of different factors: the availability of Vitamin K or Potassium are two of them. So when you start your anticoagulation therapy, they tell you to watch your intake of both and above all, be consistent.

I’ve been breaking that rule. Whoops!

All my life I have been a “Junk Fook Junkie”! That changed when I went on the low salt diet for Heart Failure, but I still ate poorly (Nutrition wise – it all tastes pretty good!) . I’ve recently decided that while I probably can’t just change completely, I can at least improve my diet.

So it’s been a bunch of little steps – and I’m a fan of the Eat This! Not That! series of books. They occasionally bump into my Low Sodium restrictions, and when that happens, the heart wins. Don’t take them as gospel, but rather as a guideline, and you’ll make better decisions. There are some Rules for Eating Well online at Everything Health that also make a lot of sense:

  • If you aren’t hungry enough to eat an apple, then you aren’t hungry!
  • Avoid snack food with the “OH!” sound (Doritos, Fritos, Cheetos…).
  • It’s easier to pay the grocer than the doctor.
  • Never eat something pretending to be something else (fake meat, fake butter, chocolate flavored drink…)
  • Make your own lunch whenever possible

But since I’m working on eating better, my diet is nowhere near consistent, and I have no clue how the Vitamin K and Potassium levels are doing. One thing you are told it “Try to eat about the same amount of green leafy vegetables that you usually do – big swings can mess up your INR.” Well I am not doing that, I am trying to increase the amount!

But they’ll just tell me to change the dosage of Warfarin that I take, and besides – you can’t really give a fellow a hard time for trying to take better care of himself, can you?

Moving Your Valves Around

September 29, 2009

Don’t be surprised to hear about more CHDers having the Ross Procedure to repair a damaged Aortic Valve. Invented by British surgeon Donald Ross in 1967, the Ross procedure is performed on roughly 1500 patients each year.

During the Ross Procedure, both the Aorta and the Pulmonary Artery are clamped and cut near the junction with the heart. The damaged Aortic Valve is then removed and discarded. The Pulmonary Valve is then removed and sewn into the Aortic Valve’s place. A frozen Pulmonary Valve (previously removed from a cadaver) is then reanimated and sewn into the opening left by the original Pulmonary Valve. In the final step, the Aorta and the Pulmonary artery are then sewn back into place. If this is a little confusing, here’s a helpful diagram.

It does seem a little strange – if you recall our memory trick for remembering the proper order of the valves, it’s “Three People Might Agree” – blood flows normally through the Tricuspid Valve, then the Pulmonary Valve, out to the lungs and back to the heart; through the Mitral Valve, and finally through the Aortic Valve and out to the body. T – P – M – A, or Three People Might Agree. If you follow the route after a Ross Procedure, you go through the Tricuspid, Pulmonary, Mitral, and another Pulmonary… Three People Might People! That makes no sense! But it works.

New research has shown that the Ross Procedure has a high survival rate, and the cadaver valve works well – after 20 years, 80% of Ross patients did not need replacement of either Pulmonary Valve. The operation also has the advantage of growing with the patient (great for children!) and no need for anticoagulation… Goodness knows, I wish I didn’t have to have an INR test ever few weeks!

New Blood Thinners!

September 28, 2009

The European Society of Cardiology held its annual big meeting recently, and the major news revolved around some new blood thinning medication coming to the market.

The two major blood thinners available now are Plavix, manufactured by Bristol-Myers and the second best selling drug in the world, and Coumadin, also known as Warfarin, which has been available for at least fifty years and is considered the “Gold Standard”. If you need to take a blood thinner, odds are you are on one of these two pills.

The new drug Pradaxa was compared to Warfarin and the results were roughly equal, with Pradaxa being slightly better. One advantage to Pradaxa is that the dosage is based on weight, not monthly blood tests, and there are fewer interactions with other foods and drugs. Not getting those pokes would be great!

Brilinta, another new anticoagulant, was tested gainst Plavix and found to be better at reducing heart attacks, strokes, and death. The study also found there were less bleeding problems with Brilinta.

A third drug, Dabigatran, was tested against Cumadin. In that study, Dabigatran seems to outperform Cumadin at higher doses and be roughly equal in lower doses.

All of these drugs are still in the testing phase – so it may be a while (quite a while!) before your doctor offers them to you for your anticoagulation needs.