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Circulation on the Run

Each monthly episode will discuss recent publications in the fields of genomics and precision medicine of cardiovascular disease.
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Sep 19, 2016

 

Carolyn:
Welcome to Circulation On The Run, your weekly podcast summary and backstage pass to the journal and its editors. I'm Dr. Carolyn Lam, Associate Editor from the National Heart Center and Duke National University of Singapore. Today we will be diving deep into issues of resistant hypertension, adherence to anti-hypertensive medication, and renal denervation. All this by looking closely at new data from the Renal Denervation for Hypertension trial. First, here are your summaries of this week's journal.

 
 
The first paper sought to answer these questions: How can we better re-stratify patients with long QT syndrome type 3? You will remember that as the type caused by a gain of function mutation in the SCN5A sodium channel, and the type that has a more lethal course than types 1 and 2. Another question is, are we sure that beta blockers are effective in type 3 long QT syndrome? Well the current study is by co-first-authors, Dr. Wilde of Academic Medical Center, Amsterdam, and Dr. Moss from University of Rochester School of Medicine and Dentistry, which is the largest multi-center long QT type 3 syndrome cohort described to date.

 
 
This study was designed to identify the risk and therapeutic factors associated with cardiac events in patients. The risk factors evaluated included clinical features such as age, gender, ECG measurements, the mutation type, and the therapeutic effects of beta blockers, other medications, and ICD. In almost four hundred patients with type 3 long QT syndrome, 30% experienced at least one cardiac event; that is syncope, aborted cardiac arrest, or sudden death. The risk of a first cardiac event was directly related to the degree of QT prolongation. Each 10 millisecond increase in QTC up to 500 milliseconds was associated with a 19% increase in cardiac events. Prior syncope doubled the risk of life threatening events. Beta blocker therapy was associated with an 83% percent reduction in cardiac events in females, however the efficacy in males could not be conclusively determined due to low number of events. The take-home message is, in your patients with long QT syndrome type 3, recognize the very high risk sub-population with prolonged QTC and a history of syncope.

 
 
The next paper is a basic science paper that reveals a novel way in which mitochondrial dysfunction may be targeted in heart failure. This paper is from first author Dr. Li, corresponding author Dr. Tian, and colleagues from the Mitochondria and Metabolism Center at University of Washington. These authors previously found that elevation in the NADH to NAD ratio induces mitochondrial protein hyperacetylation, and renders hearts highly susceptible to stresses, and they showed this in a mouse model of primary mitochondrial dysfunction caused by genetic defects. In the current study they defined the molecular intermediaries linking specific NAD sensitive hyperacetylation targets to the development of heart failure, and further demonstrated the relevance of these mechanisms in human heart failure. Specifically, they identified that hyperacetylation of the regulators of mitochondrial permeability transition poor and malate-aspartate shuttle, mediates the increased susceptibility to cardiac stresses. Further, expanding the cardiac NAD pool via pharmacological or genetic approaches normalized the NADH to NAD ratio, and thereby normalized protein acetylation in hypertrophied and failing hearts. Importantly, these measures improved cardiac function and reduced pathological hypertrophy in mice. Thus, the clinical implication is that restoring the NADH to NAD ratio may be an effective and translatable strategy to treat mitochondrial dysfunction in heart failure.

 
 
The next study broadens our considerations of the benefits versus risks of intensive anti-platelet therapy in patients with a prior myocardial infarction, and really suggests that more intensive anti-platelet therapy should be considered, not only to reduce the risks of coronary events, but also to reduce the risk of stroke. This is a paper from Dr. Bonaca and colleagues of the TIMI study group from Brigham and Women's Hospital in Boston, Massachusetts, who investigated the efficacy of ticagrelor, 60 milligrams twice a day, for reducing stroke in patients with a prior myocardial infarction from the Pegasus-TIMI 54 trial.

 
 
You will remember that in the Pegasus-TIMI 54 trial, ticagrelor was already shown to reduce the risk of major adverse cardiovascular events when added to low-dose aspirin in stable patients with prior MI. Of more than 14,000 patients randomized to placebo or Ticagrelor, 213 experienced a stroke, 85% of which were ischemic. 18% of strokes were fatal, and another 15% led to either moderate or severe disability at 30 days. Ticagrelor significantly reduced the risk of stroke, with a hazards ratio of 0.75, and this was driven by a reduction in ischemic stroke. Hemorrhagic stroke occurred in nine patients on placebo and eight patients on ticagrelor. Furthermore, a meta-analysis of four placebo-controlled trials of more intensive antiplatelet therapy in more than 44,800 patients with coronary disease confirmed a marked reduction in ischemic stroke, with a combined hazards ratio of 0.66. Thus this study really broadens our considerations of benefits versus risks of intensive antiplatelet regimens for the long-term secondary prevention in patients with patients with prior myocardial infarction. It really highlights the broader benefits in reducing ischemic stroke, and not just coronary events. In summary, overall, for 1,000 patients initiated on ticagrelor 60 milligrams twice daily for three years, 13 primary endpoint events would be prevented, including approximately five ischemic strokes. This benefit would come at a cost of nine TIMI major bleeds, but no hemorrhagic strokes or fatal bleeds.

 
 
That wraps it up for our summaries! Now for our feature paper. Our feature paper today discusses a really important issue that we face everywhere around the world, and that is the management of resistant hypertension. We're taking a very interesting look at the Renal Denervation for Hypertension trial, because we're actually looking at the adherence to anti-hypertensive therapy, and what we've learned in this trial. I'm so excited because I am sitting right here with first and corresponding author Dr. Michel Azizi, from Georges Pompidou hospital in Paris, France. Hello Michel, thank you!

 
Michel:
Hello, Carolyn. Thank you also for the invitation to discuss about the paper.

 
Carolyn:
We're also so lucky to have the associate editor who handled the paper, Dr. Wanpen Vongpatanasin, associate editor from UT Southwestern. Welcome, Wanpen.

 
Wanpen:
Hi, Carolyn.

 
Michel:
Hi, Wanpen.

 
Carolyn:
This whole issue of resistant hypertension, I'll tell you, to me that means someone who's adequately treated, and despite all the treatment that we can throw at them, they still have a blood pressure that is above a certain level, right?

 
Michel:
Yes.

 
Carolyn:
But your study seems to tell us that that assumption, that everyone's receiving treatment and still having high blood pressure, may need to be questioned, so please tell us a little bit more about what you found.

 
Michel:
This is a clinical trial where we compared the effect of renal denervation to medical treatment, optimal medical treatment. We standardized the anti-hypertensive treatment in the cohort of patients with resistant hypertension, and then we followed them on a monthly basis with home blood pressure monitoring. We also increased the intensity of the treatment every month after randomization between renal denervation against nothing, because this is a probe trial, it is not a double blind trial. We gave them the same treatment in both arms. At the end of the many study we demonstrated that there was 6 millimeter of difference, in terms of ABPM, in favor of renal denervation, against the same medical treatment alone.

 
 
However, because this trial was an open trial, it was open to a Hawthorne effect, and the possibility that patients or doctors behave differently in each arm of the study. Those having renal denervation may be more adherent to the treatment, and those not being given the new therapy, not being really adherent to treatment. This was an issue, so we specified analysis. We also measured drug levels in urine after six months of followup, and also assessed the exposure to each individual using a peptide in urine, which is N-acetyl-serylaspartyl-lysyl-proline (AcSDKP)/creatinine.

 
 
What we found after six months of followup in patients who really participated to this trial, they were willing to participate to the study, they signed an informed consent where it was written that, indeed, we will monitor drug levels. They knew that we would do this. They also knew that we will follow them very carefully every month, et cetera, that we'll provide them home blood pressure monitor for free. They had access to the same doctor, same nurse, same everything. They could arrive at the time they wanted in the morning for being investigated. After six months of followup we found that more than half of these patients did not take correctly their treatment, and even 15% of them, in reality, took zero medication over seven medications. This was a major, major surprise for us in this trial.

 
Carolyn:
I think that's one of the most significant findings, even in a trial setting, that is such a lot of non-adherents, anti-habitants, of therapy. It really makes us question when we say someone has resistant hypertension, is it really that, or do we have just a very non-compliant patient?

 
Michel:
Yes.

 
Carolyn:
Because it can only be worse in the real-world setting, isn't it? Congratulations, that was a very striking message to me as well. What was the other main finding that you wanted to ... ?

 
Michel:
The other finding was that the rate of non-adherence was similar in both arms. That there was absolutely no influence of being randomized to the renal denervation group or the medical treatment group only. This means that the patients were not influenced, and other physicians behaved similarly in both arms. Because at the end you have exactly the same rate of non-adherence to treatment. This is also very important.

 
Carolyn:
Yes, indeed. Wanpen, I was wondering what your thoughts were, and take-home messages from this paper. We definitely thought it was significant in the editorial board because you even commissioned a wonderful editorial by Dr. David Calhoun on this. What are your thoughts?

 
Wanpen:
In the United States, using the same technique, we found as much non-adherence. I think there is a lot that we need to do and to understand what caused non-adherence. The patient should not be the only party that's to blame. I think that the doctor's as much of a culprit here to try to tease out what's the barrier to the treatment. Also, as pointed out by Dr. Calhoun, is that although the trials show improvement in blood pressure in both groups, at the end number of medications of patients in resistant hypertension, they require to take four to five drugs to get the blood pressure under control. I think this is going to be a lifelong continuing medication treatment that the physicians have to face, and to deal with the adherence problem as well. Just lastly, I think that although people believe that doing drug levels is only for research purpose, but many people don't realize that actually many drug levels for anti-hypertensive drugs actually is clinical available and can be ordered. It takes a little bit more effort to order it, but it can be done, and actually our center has been doing that already anyway.

 
Carolyn:
Wow. I cannot say that my center has been doing that in Asia, but I really have to admit that this paper made me think about it. Especially the editorial when he highlights it, the very unique information that is provided by actually measuring the blood levels. Michel, you were nodding your head vigorously when Wanpen was saying that we should not just blame the patient. Tell me, what are your thoughts, and how does this affect your clinical practice?

 
Michel:
I fully agree with Wanpen. We have to now integrate the fact that it's accessible, you can measure drug levels through technology, with mass spectrometry, et cetera. This is very important to integrate and to change our paradigm that we have to put in our brain. We have to monitor drug levels. Using this technology we have to establish a partnership with the patient.

 
 
I think the truth, also, is somewhere, as Wanpen said, we are also culprits. If patients do not take their treatment, okay, there may be some benefit and e have to look why they are not taking pill treatment, but also we are culprits because we don't listen to them, we don't take enough time, et cetera, et cetera. But I think patients should not be only blamed, so it opens a new possibility to discuss with the patient about the fact that we didn't find the drug in levels in their urine, et cetera.

 
 
However, taking into account that there will be this toothbrush effect, that is, "Patient, brush your teeth when you go to see the dentist," you'll take the pills when you go to see the doctor so you can be treated. This is one of the difficulties. However I think it's a new possibility to discuss with the patient of his or her difficulties in taking the pills. It gives us the opportunity to discuss, to take time with our patients.

 
Carolyn:
It's really fascinating, you're talking from a system based in Europe. You're based in Paris.

 
Michel:
Yes.

 
Carolyn:
Wanpen just said that she's doing it, and she's based in the US. Do you now routinely, maybe, monitor these medication levels?

 
Michel:
Yes, yes, yes.

 
Carolyn:
Wow.

 
Michel:
In the hospital we have these mass spectrometer platforms, so we have access to this, and we are working with the house authority to have the reimbursement. Because I think it's important, because if it's not reimbursed there is also a problem.

 
Carolyn:
Of course.

 
Michel:
We are working to see how it could be reimbursed for labs doing these measurements.

 
Carolyn:
But this is for maybe selected resistant hypertensive patients that are difficult to ... ?

 
Michel:
Yes, absolutely. Those very difficult to manage. I think, as a rule of thumb, that after four or five drugs given to the patient, if the patient-

 
Carolyn:
Yeah, we should start questioning, are they taking it.

 
Michel:
If the patients do not have secondary hypertension, we should really start questioning ourself whether they are taking or not the treatment, even if they are looking right in your eyes and telling you, "Yes, doctor, I'm taking all the pills."

 
Carolyn:
Wanpen, how about the reimbursement issues and things like that in the United States? How are you getting it done in your institution?

 
Wanpen:
Actually the coding for doing drug levels, it's actually generic. It's the same coding for Digoxin or Cyclosporine. They actually don't care about what the name of the drug. Strangely, they're coded by the technique, so that's how we go with it, but we have to put in miscellaneous "other" for, we wanted to test for this. That's how we get around it.

 
Carolyn:
Do you do that again routinely, or in selected patients that are difficult to manage hypertensive?

 
Wanpen:
Obviously we have to be selective, so we select from people who we would suspect are non-adherent, but they say they're taking it. But if they already came in and made that they're not taking the drug, there's no point doing that for the clinical purpose. We're doing it for people who we suspect it, and we use it the way ... Actually we shall describe very well, not only just to find what drug they're not taking, because when they're not taking, only about 30% are not taking everything, about 20% not taking one or two drugs. When we drill down to that drug they say, "I have side effects to beta blocker and I don't want to tell my physician that I have problems taking it, but I just not take it." I think that's what led us to pinpoint the problem a little bit better with this technique.

 
Carolyn:
What a lot of practical advice, and congratulations once again for very, very meaningful findings. I learned a lot this time. I don't do this, and so I'm definitely going to think about this much more because of your work. Thank you very much Wanpen, Michel.

 
 
And thank you, listeners, for tuning in this time. Remember, you're listening to circulation on the run. Listen in again next week. Thanks.

 
 

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