Archive for the ‘Atrial fibrillation’ Category

Dabigatran approved!

October 21, 2010

For the first time in nearly 50 years, patients with Atrial Fibrillation (A-Fib) have a new blood thinning option: Dabigatran. The talk is already starting about how this could replace Warfarin (which is really RAT POISON… we’re just given it in doses too small to kill us!)

One can hope, but there is still a lot that we need to learn about the drug. The US Food and Drug Administration has approved it only as a preventive for stroke caused by A-Fib. Will it even work for anything else? The odds are that it will, but it still needs to be tested. How are people with mechanical valves going to react to it? Somebody’s going to have to take a deep breath and test it. Yet another problem is the cost. Dabigatran is estimated to cost $8 to $12 per day; Warfarin has been around so long that the cost is a pittance. But that is just the cost of the drug – with Warfarin, you also get the required monitoring, in the form of the INR Test. Dabigatran doesn’t require monitoring. Does the cost of Warfarin plus the cost of the test plus supplies make its cost roughly equal with Dabigatran?

There’s another major drawback for certain CHDers: Dabigtran is currently not recommended for “patients with the presence of a severe heart-valve disorder.” That sounds like Tricuspid Atresia patients, Hypoplastic Left Heart Syndrome patients, and those with several other defects are out of luck. Perhaps it is not for us because of lack of testing; if that is the case, the recommendation may change in the future.

At the moment, Dabigatran looks like a drug with a limited potential. Hopefully real world experience will change this.

Taken

June 13, 2010

A sad note from Dr. Wes:

A nationally renowned cardiologist, best known for his basic research on abnormal heart rhythms and the molecular structure of drugs to treat them, and a pioneer in applying nanotechnology to the study of biomedical problems, Morton F. Arnsdorf, professor emeritus and associate vice chairman of medicine and former section chief of cardiology at the University of Chicago, died June 9 in a motor vehicle accident in Indiana on his way home from work.

No in-depth post for you tonight, as I’m organizing the submitted links for Grand Rounds. See you tomorrow!

Is Robot Surgery worth the cost?

April 30, 2010

The coming thing in heart surgery – and almost any type of surgical procedure – is robotic surgery. Forget the popular image of R2D2 wearing a surgical cap and mask, there is ultimately a qualified surgeon at the controls of the robot. When you think of Robotic Surgery, you usually think of the da Vinci Surgical System, which has multiple uses in several medical fields. And just yesterday it was reported that a British citizen had an ablation using a robot to guide the procedure. And recently a computer was used to develop a model of a patient’s beating heart, which would allow a robot to perform a surgical procedure without use of the Heart-Lung machine.

But does Robotic Surgery provide better results or is it just the newest tool? The Robotic arm used in that British ablation cost £350,000. (Over $525,000 US Dollars; using today’s conversion rate) Who pays for the cost of that piece of equipment? Patients.

In a post on KevinMD’s website, Peggy Peck asks if Robotic Surgery for Prostrate Cancer offers any advantages. Disturbingly, the answer is “no”, despite claims to the contrary. In fact, men undergoing the minimally invasive procedure tend to have more problems in the long run.

The Law of Supply and Demand is a major factor in the use of Robotic Surgery options – with the patients providing most of the demand. The average Robotic Surgery costs about $2000 more than hands on surgery, but patients continue to demand it:

It’s come to a point where “patients interview you,” according to a urologist. “‘They say: ‘Do you use the robot? O.K., well, thank you.’ And they leave.”

And with healthcare finances shaky, a hospital almost has to invest in a Robotic Surgical System to keep up with the hospital across town. Patients undergoing any kind of surgery in which Robotic Surgery is an option should do their own research and determine if they would rather have all the bells and whistles or have their surgery done the old-fashioned way.

It isn’t working

April 11, 2010

Durn it!

Dronedarone, the Atrial Fibrillation drug that has been highlighted here before, isn’t living up to the hype. It was already known that it is not as effective as Amiodarone, but it doesn’t have the side effects that drug has. The hope was that if you developed A-Fib at an early age, or have a milder form of A-Fib, you could be switched from Amiodarone to Dronedarone. Amiodarone is an effective suppressor of A-Fib but the side effects can be terrible.

In fact, the last time I wrote about Amiodarone, I was accused of using “scare tactics” to get my point across. I wouldn’t do that – Heart Defects are  scary things; As any parent/CHDer knows. I’m not going to add to the hysteria. Behind every link on this blog is more information about a subject; click and read for yourself. HERE is the link I used the last time, it’s written by a Cardiologist. Obviously, he knows more about this drug than I do, and he isn’t a fan of Amiodarone, either.

Further testing has shown that Dronedarone is only half as effective in humans and doubles the rate of death! Dronedarone is recommended only as a second or third choice for people who can’t tolerate Amiodarone. Britain’s National Institute for Health and Clinical Excellence (NICE) gave the drug its approval after originally turning it down, based on its limited effectiveness and its price.

So while Dronedarone doesn’t look like it can be the answer everyone was looking for, perhaps it does have a place in the “medical toolbox”. For right now, the first drug of choice is still Amiodarone, and Cardiac Ablation is still an option.

And other researchers will continue to search for better answers.

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.

Flip the Switch

March 15, 2010

Nobody likes Amiodarone, not even the doctors who prescribe it. I recently wrote a post about it and all the side effects it can cause. A newer drug, Dronedarone, is usually recommended for younger patients. The longer you are on Amiodarone, the better the chances that the side effects will show. Dronedarone isn’t as effective as Amiodrone in controlling Atrial Fibrillation, but has less side effects.

New research released today at the ACC10 meeting in Atlanta shows that in two seperate trial studies, patients with controlled Atrial Fibrilation can safely switch from Amiodarone to Dronedarone in as little as two days.  If you have a slow heart rate (Bradyarrhythmia) or a long QT interval, the 48 hour guideline probably isn’t the best therapy for you. Your own cardiologist will be your best source of information.

New findings indicate source of A-Fib

December 29, 2009

Atrial Fibrillation, or A-fib, is one of the problems many CHDers will face. In a normal heart, an electrical signal is generated by the Sinoatrial node (also known as the SA node and is located near the top of the Right Atrium) and flows outward, causing the Atria to contract. When the electrical impulse reaches the Atrioventricular node, (AV node) it triggers its own electrical impulse which causes the Ventricles to contract, creating the “lub-dub” heartbeat we are all familiar with.

But when extra electrical impulses are moving through the heart’s electrical system, the Atria won’t contract, but rather fibrillate, or quiver. And if the electrical pulse isn’t strong enough the AV node won’t activate the Ventricles. A-fib is usually asymptomatic and painless, (though you can feel your heart beating out of rhythm) but there is a very real chance that the blood pooling in the not-quite-beating upper chambers can clot and cause a stroke.They can also lead to Congestive Heart Failure. (CHF)

One of the usual techniques used to stop A-fib is ablation. Before an ablation, the heart is examined closely and “mapped” to determine where the extra electrical impulses are coming from. Then a catheter is inserted through a vein in the leg or the neck and is guided to the heart. The sources of the extra electrical impulses are then “zapped” (or frozen) to knock them out, and the heart beat should be restored to normal. It doesn’t always work.

But researchers have recently determined that the cells that produce the heart’s electrical charge – and can cause Atrial Fibrillation – also express the protein DCT. DCT only originates from a couple of sources in the body, and only one inside the heart – the electrical current cells. So if scientists can learn a way to identify DCT cells in the heart, they’ll have a way to determine where electrical pulses can orgininate – and deaden the ones causing A-fib.

But this technology is a long way from being reality, if it works at all. Right now, studies are being conducted on mouse hearts. Mouse hearts are similar to human hearts, close enough to be used in research. But when it comes to transferring the results from a mouse to a man, there is a lot of difference!