[News] Special Safety Notice: ASV therapy for CSA patients with heart failure

[justMongo]

Special Safety Notice: ASV therapy for central sleep apnea patients with heart failure. From the American Academy of Sleep Medicine.

http://www.aasmnet.org/articles.aspx?id=5562

Abstract:
"On Wednesday, May 13, ResMed released a field safety notice that likely affects many of your patients currently being treated for central sleep apnea syndrome with adaptive servo-ventilation (ASV). In particular, if you have a patient with symptomatic, chronic heart failure (NYHA 2-4) and with a reduced left ventricular ejection fraction (LVEF ≤ 45%), using ASV to treat their moderate to severe central sleep apnea syndrome may be harmful..."

[Crimson Nape]

After reading(quickly) the article, I'm curious; Is this just the Resmed ASV or is it for all ASV manufacturers?

[DocWils]

No,sgearhart, it has nothing to do with Resmed itself, this is concerning ASV therapy on a narrow range of patients. The warning, which was passed on to our hospital as well through other channels, concerns the use of ASV in specific circumstances, not, for instance, if you have CSA but no current heart problems, or heart problems but no CHF with reduced LVEF. So arrhythmia is not included in this warning, for instance. The levels described are very specific and if you have this, then be warned, if you don't, for now you can disregard it.

Thanks Mongo.

[archangle]

...this is concerning ASV therapy on a narrow range of patients. The warning, which was passed on to our hospital as well through other channels, concerns the use of ASV in specific circumstances, not, for instance, if you have CSA but no current heart problems, or heart problems but no CHF with reduced LVEF. So arrhythmia is not included in this warning, for instance. The levels described are very specific and if you have this, then be warned, if you don't, for now you can disregard it.

Doc W makes a very good point here.

It's a very specific set of conditions that apply. Only a limited number of patients need be concerned.

We need to be careful to help people understand the limited range of people this applies to. I'm worried that there may be a tendency to deny ASV to everyone with heart problems, not just those with the required LVEF<45%.

Doc, is LVEF<45% a particularly bad level?

I need to look at the study a bit more myself. I notice the "33.5% increased risk of cardiovascular death" quote, but notice a few things. Even those without ASV had a 7.5% cardiac death rate, and the ASV group had a rate of 10% risk. It doesn't sound that scary stated that way. The people in this group were in pretty darn bad shape to begin with.

I suspect this is mostly lawsuit phobia on ResMed's part at this point.

While the warnings are appropriate, I wonder how significant the result is. I need to look at the sample size. I also wonder about selection bias. I suspect it wasn't a true random selection double blind. Maybe those who were in worse shape were more likely to get ASV.

I also wonder if the conclusion should be applied to T or S/T mode bilevel treatment as well.

I'll be very interested in the "mechanics" behind this when we figure it out, but it will probably be a while. Is there some sort of BP or blood flow effect from pressure of ASV? I do know there has been some discussion in the past that hypoxia causes angiogenesis and vascularization that may provide some degree of benefits in terms of having or surviving heart attacks.

[Sleeprider]

I'm sure the risk was significant enough to issue this warning, however chronic heart failure patients are on a one-way street in terms of the disease progress and eventual mortality. My dad died of CHF and was not on any CPAP therapy, but had oxygen supplemented. Since the research and Resmed couldn't counter the apparently increased risk with any benefits to quality of life, that kind of settled the matter. I'm sure the findings come as a surprise to many practitioners that believe the control of CA in CHF patients using ASV would be beneficial. On its face, it seems a logical conclusion, but not borne out by the research to date.

[retired_guy]

Mortality was slightly elevated in the test group. Not enough to issue a recall, but enough to justify a Surgeon General type warning on the ASV pack.

Most people, even CHF people using the ASV's don't die because of this. But a few do. Most people not treating their Central Apneas do not die. But some do.

[GP49]

The described condition, significant central sleep apnea with severe heart failure (NYHA III, BNP 2800, LVEF around 20), applied to me. I was prescribed ASV and experienced immediate improvement in sleep quality.

Two months later I underwent voluntary cardiac artery bypass graft surgery, a triple bypass. In the intervening nine months, LVEF has improved to around 50, BNP to 27, and other clinical signs of heart failure are no longer present (NYHA I). The cardiologist is of the opinion that I was lucky that little or no permanent heart damage was done (no coronary artery blockages were total and I did not suffer a heart sttack, only general tiredness and weakness) and that the heart muscle has recovered and strengthened to near normal with the improved blood supply.

So I guess I was lucky, and after the surgery and recovery the same conditions don't exist any more; but I still intend to consult my sleep specialist about this latest development.

[DocWils]

Okay, let's be a bit clearer on this - yes, the level of injection degradation is not good, and if your injection rate is over 50% this study does not address it. It is a narrow group of symptoms and conditions.
The risk is significant in medical terms. Enough to issue a warning. 35% mortality risk is significant to us. (odd in a way, sing real mortality risk in all people is 100%, but we look at a shorter window than that... our job is to try and keep you alive, after all....)
It is not a legal thing at all on Resmed's part - no one will sue Resmed for this, but they may sue the prescribing doctor. Resmed did these docs a solid and made sure they knew about this, although it should have disseminated through normal channels anyway. Good on them.
GP49, you were lucky as anything, and well done. Keep getting better. And yes, do consult your sleep specialist about this, and even your cardiologist, perhaps together, to see if an alternative therapy can be as effective. I would bet anything that getting those two together on this little bit of information will be interesting for both of them. Nothing like cross-discipline consultations to break up the routine and get the old grey cells working laterally.

[penuel]

DocWils, is it not ejection rate and not injection rate? In any case there is no mentioning how were these ASVs operating. If these ASVs were cycling as APAP machines then the American Sleep Board has warned since 2007 that APAP machines are contraindicated to be used by cardiac patients.

[DocWils]

DocWils, is it not ejection rate and not injection rate? In any case there is no mentioning how were these ASVs operating. If these ASVs were cycling as APAP machines then the American Sleep Board has warned since 2007 that APAP machines are contraindicated to be used by cardiac patients.

Sorry, that was a mistype on my part. Mea culpa. ejection is correct. I tend to be less careful writing on the board than on my patient reports, and I do apologise. Also often answering late at night or during a grabbed moment her or there between patients. And I might have had needles on the brain when writing that bit - looking at the date, I find that I was doing several procedures that involve long wide needle type thingies that make most common folk pass out when seeing them - I don't blame them, I run a mile if anyone came at me with one of them....