Role of Fibrosis in Outcome of Atrial Fibrillation Catheter Ablation — Video Interview with Dr. Nassir Marrouche on Results of DECAAF Trial
June 11, 2013
- Summary: Video interview with Dr. Nassir Marrouche discussing DECAAF trial using MRI to determine role of fibrosis in atrial fibrillation ablation outcomes
- Reading and watching time is approximately 11 minutes
In this video interview, Dr. Nassir Marrouche discusses the results of the DECAAF (Delayed-Enhancement MRI Determinant of Successful Catheter Ablation for Atrial Fibrillation) trial, a multinational trial examining the role of atrial fibrosis in predicting patient outcomes from atrial fibrillation ablation. The DECAAF findings were presented as a late breaking clinical trial at Heart Rhythm 2013.
In the DECAAF trial, hypertension was the only predictor of the degree of atrial fibrosis in people with atrial fibrillation, and increasing amounts of fibrosis were associated with increased risk of afib recurrence following ablation. Based on these findings, Dr. Marrouche encourages a “look before you treat” approach, and sees MRI screening for fibrosis before afib ablation expanding to more centers.
View the video interview with Dr. Marrouche (approximately 11 minutes)
Also see our previous news stories and videos with Dr. Nassir Marrouche regarding the DECAAF trial:
- New Research Yields Insight into Stroke Mechanism for Atrial Fibrillation Patients
- Personalized Atrial Fibrillation Treatment Using New Method to “Stage” AF
- Interview with Dr. Nassir Marrouche on Personalized Atrial Fibrillation Treatment Through “Staging”
- Breakthrough: Use of MRI in Catheter Ablation for Atrial Fibrillation
About Nassir Marrouche, MD
Associate Professor, Internal Medicine
University of Utah
Salt Lake City, UT
Late-breaking Clinical Trial presented at Heart Rhythm 2013 – DECAAF
Dr. Marrouche: As you know, we talked a while ago about the use of atrial tissue structural remodeling as a guide to treat patients with atrial fibrillation—we have been a part of this for years now on a single center basis on an animal model basis—and the advantage of knowing the degree of atrial tissue disease, or fibrosis, before we treat patients with afib, and what that would mean in terms of patients responding to treatment, risk of stroke and beyond.
In 2009 we initiated a multicenter study—the idea came in 2009 and we started study at the end of 2010—where we used the MRI technology developed at the University of Utah on a multicenter basis to screen patients before they undergo an ablation of afib with the hypothesis that the more fibrosis, or atrial disease, detected in MRI, the less the chance the patient will stay in sinus rhythm after the afib ablation procedure. So, practically, we wanted to correlate the amount of atrial fibrosis, or atrial disease, in a patient with atrial fibrillation to the afib ablation procedure outcome.
So we initiated a multicenter [DECAAF] study, 15 centers around the world, in Australia, Europe, and the United States. We installed in every center this MRI image processing technology, called the MARREK Inc. software. We blinded the physicians to the data, and performed a one-year follow-up study (at least a one-year follow-up study).
We have 330 patients recruited into the study from 15 centers around the world, and patients underwent ablation. The majority of them underwent pulmonary vein isolation. By the way, DECAAF did not mandate the type of ablation used in this study, so the physician could choose any type of approach, any type of catheter, balloon, non-balloon, radiofrequency, cryo, whatever they wanted, but to work with them to ablate afib. They did the MRI before the procedure, looking at the fibrosis, and they would download the image to a centralized server, called the DECAAF study server, where the Core Lab analyzes the data and keeps them blinded until the study is done. At the end of the study, all of this data was analyzed and disclosed, and we presented the data here at the Heart Rhythm Society meeting in Denver.
At the end of the follow-up, what we could show was that from all the comorbidities that we have in DECAAF, we had 331 patients, and out of these 331 patients, we could analyze 261 patients in the follow-up and had good image quality of the MRI that we could use. From these patients, and after correcting again for all the comorbidities, a history of hypertension was the only predictor of the degree of atrial disease, or atrial fibrosis, in patients with atrial fibrillation. That’s a very important finding. And as you know, hypertension is correlated in a way to fibrosis.
To some, it’s surprising; to others, it’s not. For us, who’ve been dealing with this for years, it wasn’t surprising, but there was no correlation between the type [categories] of afib. This is an important message to your followers on StopAfib.org that they should never, ever give up on their disease treatment, and pursuing treatment of their disease. Always look before you treat. There was no correlation between duration and type of afib, and the amount of fibrotic changes or disease in the atrium.
This is important because in DECAAF, we showed that the more the atrium is diseased, and the more fibrosis you have, the less the chance of you staying in sinus rhythm if you undergo an afib ablation procedure. That means the less the chance the procedure will be successful. Specifically, the fibrosis was the only independent predictor in the multivariate analysis for afib ablation procedure outcome, with a hazard ratio of 1.063, meaning for every 1% increase in fibrosis you have a 6.3% chance of recurrence, or chance of procedure failure.
What we also could confirm in DECAAF, that based on the previously described Utah classification, or the staging of atrial fibrillation based on fibrosis, or atrial disease, we could confirm that if you are a stage one, or if you have less than ten percent of your atrium diseased, your chance of staying in sinus rhythm, at 415 days follow-up in this multicenter DECAAF study, is around 85%.
If you have between 10 and 20 percent fibrosis on presentation to the ablation procedure, your chance of staying in sinus [rhythm] at 415 days after the procedure is 66%. Then you have a 55% [chance] if you are between 20 and 30 percent, and if you have more than 30 percent, unfortunately, your chance of staying in sinus rhythm is very low, around 30%.
So, we are very excited about this finding in terms of helping our patients, and understanding, when we sit down with our patients and talk to them, that’s our expectation. Until now, we’ve just gone into the heart and see what we find, and do the ablation as best we can with what we find in the heart. Now we can, before we go into the heart, we can put our expectations with our patient, discuss it with them, and say, “This is great—you have a little disease, independent of how long you have been in afib, independent of what type of afib, independent of comorbidities—your chance of success is very high because you have a little disease. Or your chance of recurring is very high because you have a lot of disease, and you should either pursue other options, or maybe take the rate control option, or maybe try it, but the expectation is very low.”
Now finally, we have a modality to understand what to expect from the heart with a simple 20 minutes of imaging — it takes us 20 minutes to finish the MRI, and another 20 minutes to process the image. So, all of this together gives me an idea of what to expect going in.
As important from DECAAF—what we learned from DECAAF in this multicenter study—is that hypertension is an issue. We all know how important hypertension is; we all know how very powerful a risk factor for stroke and afib hypertension has been. Now, in DECAAF, we confirmed the association with tissue destruction, or disease in the atrium, in the afib population.
So we need to focus more and more on that hypertension, and the prevention of hypertension, hopefully to suppress the progression of fibrosis and atrial disease in our patient population, at least in those who are presenting with atrial fibrillation. So that’s another important finding that we need to highlight in DECAAF.
I’m very happy, and rather thankful for everybody who participated in these 15 centers; everybody was dedicated around the world. If you look at the DECAAF patient populations, the distribution was equally distributed around the world; we have European population, Australian, and American. And then the data was independent from the center—if you do it in a high experience center, or if you have somebody doing 30 ablations a year—that was exciting as well as the outcome was the same in terms of recurrence. The only predictor was atrial disease, or fibrosis.
Will MRI screening for fibrosis expand beyond the DECAAF study centers?
Dr. Marrouche: It’s obviously very important. We’d like to a have this as a standard tool in every single center in the world, and hopefully soon. It seems this has been outsourced by the University of Utah to be adopted, hopefully, in every center in the universe. Every patient should, in my opinion, every patient, and I hope you agree with me as in Mellanie True Hills, as a major player in this field, an advocate for treatment and prevention, what I like about StopAfib is the prevention of afib, that we start promoting “look before you treat” concepts. So get patients early on before the disease is too progressed, and to treat them or to avoid people being unnecessarily treated with afib ablation.
We have to accept the fact that some patients we can’t treat, unfortunately, and we have to live with that. It’s important for us, and hopefully this will be adopted very soon after this multicenter study that people have been waiting for for years. As you know, this has been out there for a while, but now we needed the multicenter study to prove the concept, and now it’s there, and it’s been presented. This is good, so we’re very, very excited about that.