ST vs ASV - studies about risk

[Sleeprider]

Kiwii, I think the most revealing information is just to read the manufacturer's statement of intended use for those machines. This is what they were designed for, studied and demonstrated to provide efficacy and approved by the FDA to do. There is much more information at these links, and you can read more about the machines, but this is the simple summary answer. I think it's obvious which one fits your needs:

https://www.resmed.com/us/en/healthcare-...0-sta.html 

The AirCurve™ 10 ST-A provides effective non-invasive ventilation for patients with respiratory insufficiency such as neuromuscular disease, restrictive lung disorders, severe COPD and hypoventilation syndromes. It features iVAPS (intelligent Volume-Assured Pressure Support), ResMed’s proprietary mode that automatically adapts to each patient’s changing needs, and an intelligent Backup Rate (iBR)* that maximizes their opportunity to breathe spontaneously. The AirCurve 10 ST-A includes both fixed and adjustable alarms for added safety and built-in cellular connectivity to AirView™ for remote monitoring and the ultimate in patient care. 

https://www.resmed.com/us/en/commercial-...0-asv.html

The AirCurve 10 ASV offers truly personalized therapy for obstructive sleep apnea (OSA), central and/or mixed apneas, or periodic breathing. By treating central breathing disorders with auto-adjusting pressure support – and upper airway obstruction with auto-adjusting EPAP – the device works to rapidly stabilize respiration.

As the only one of its kind to target the patient’s own recent minute ventilation, ResMed’s ASV is the most clinically studied adaptive servo-ventilation therapy.

[kiwii]

Thank you so much, Sleeprider.

[Shin Ryoku]

The bolded words are from an article by experts and they cast grave doubt on this study's legitimacy.

The very last word in that article reads as follows:

Irrespective of the SERVE-HF results, ADVENT-HF will provide novel data regarding the effects of treating asymptomatic OSA in patients with heart failure, and will provide evidence as to whether the adverse effects observed in SERVE-HF were a class effect or were device specific.

So to conclude, those authors take seriously the increased mortality and hope to learn if it is a class effect (risk of all ASV therapy) or device specific (risk of the ASV device used in SERVE-HF).  They wouldn't wonder if the adverse effects (increased deaths) were a class effect or device specific if they thought those results were illegitimate.

ASV compliance was low, averaging only 3.4 h per night one year postrandomization. This low adherence suggests that subjects remained exposed to CSA during a substantial length of time when ASV was not worn.

This cuts both ways.  If they had used ASV for more hours per night, there may have been even more deaths.  We don't know.

There was substantial nonadherence to the study protocol: 29% of patients either discontinued or never used ASV, while 16% of patients randomly assigned to control crossed-over to positive airway pressure therapy. 

This is a standard, intention to treat analysis.  If you disqualify PAP studies due to non-adherence and dropout, then there aren't going to be a lot of PAP studies to look at.

ASV will most certainly prove to be a brick wall for LVEF<45% at this time.. 

Not all docs feel that way.  Some are willing to prescribe ASV anyway if the patient fully understands and accepts the risks.  For example, the specialist who gave this presentation - see "Patient example 3" on page 58):

Patient example 3
• Patient on ASV already, been doing well for years
• h/o severe CHF EF <25%
• Explained patient risks and turned his ASV machine to
CPAP mode
• Patient trialed for 2 months, felt much worse on CPAP,
decreased QOL
• Switched patient back to ASV as he was willing to take
the risk

[ajack]

ASV generally won't fix o2, it is for brain signals going wrong and forgetting to breathe. It sounds like you have more of a copd issue. Bilevel/bipap, S, ST or a/i VAPS would probably be the path. With supplemental o2 if needed.

Doesn't forgetting to breath sound like what I am doing (not inhaling?)

Sorry if I am misunderstanding you. I'm finding it very difficult to track what people are saying.

my mistake, I saw o2 problem and mistook inhale for exhale, o2 problem and exhale issues causing short of breath was what I was thinking.  I'll get my coat on the way out

[kiwii]

Oh good! I thought it was me. Being so dense is not my norm, and I'm finding it a hard pill to swallow.

[Sleeprider]

Kiwii, I think the most revealing information is just to read the manufacturer's statement of intended use for those machines. This is what they were designed for, studied and demonstrated to provide efficacy and approved by the FDA to do. There is much more information at these links, and you can read more about the machines, but this is the simple summary answer.  I think it's obvious which one fits your needs:

https://www.resmed.com/us/en/healthcare-...0-sta.html 

The AirCurve™ 10 ST-A provides effective non-invasive ventilation for patients with respiratory insufficiency such as neuromuscular disease, restrictive lung disorders, severe COPD and hypoventilation syndromes. It features iVAPS (intelligent Volume-Assured Pressure Support), ResMed’s proprietary mode that automatically adapts to each patient’s changing needs, and an intelligent Backup Rate (iBR)* that maximizes their opportunity to breathe spontaneously. The AirCurve 10 ST-A includes both fixed and adjustable alarms for added safety and built-in cellular connectivity to AirView™ for remote monitoring and the ultimate in patient care. 

https://www.resmed.com/us/en/commercial-...0-asv.html

The AirCurve 10 ASV offers truly personalized therapy for obstructive sleep apnea (OSA), central and/or mixed apneas, or periodic breathing. By treating central breathing disorders with auto-adjusting pressure support – and upper airway obstruction with auto-adjusting EPAP – the device works to rapidly stabilize respiration.

As the only one of its kind to target the patient’s own recent minute ventilation, ResMed’s ASV is the most clinically studied adaptive servo-ventilation therapy.

Thank you so much, Sleeprider.

I have one more thought on this. You mention elsewhere that you have asthma. That is a restrictive condition that might be considered for  treatment using ST, however if you have asthma and central apnea, then that shifts the preference back to ASV.  Mostly ASV is going to be a more comfortable therapy that will target your own minute vent and respiration rate to provide pressure support when needed, in the amount needed to normalize respiration.  ST lacks that intelligence and is a timed backup or allows spontaneous breathing with the set pressure support. ST is less suitable in the presence of CA.

[Spy Car]

The very last word in that article reads as follows:

Irrespective of the SERVE-HF results, ADVENT-HF will provide novel data regarding the effects of treating asymptomatic OSA in patients with heart failure, and will provide evidence as to whether the adverse effects observed in SERVE-HF were a class effect or were device specific.

Which seem to me as a recognition that the SERVE-HF study was deeply flawed and that it was urgent that a follow-up study be done to see if its conclusions--one that contradicted meta-data analysis and clinical experience--were valid, or not.

Thank goodness there are scientists following up.

So to conclude, those authors take seriously the increased mortality and hope to learn if it is a class effect (risk of all ASV therapy) or device specific (risk of the ASV device used in SERVE-HF).  They wouldn't wonder if the adverse effects (increased deaths) were a class effect or device specific if they thought those results were illegitimate.

Or if the low compliance rate was a factor. 3.4 hours average compliance would place the average study patient in the non-compliant category. Gauging efficacy or mortality using non-compliant subjects doesn't make sense.

Hopefully, the ADVENT-HF study isn't as sloppy as the SERVE-HF study.

This cuts both ways.  If they had used ASV for more hours per night, there may have been even more deaths.  We don't know.

We do know the subjects in the study not use the machines that are being judged in a compliant fashion on average. Not even close.

We need better science.

We also don't know that the ST machines are any less risky (assuming there is a risk).

This is a standard, intention to treat analysis.  If you disqualify PAP studies due to non-adherence and dropout, then there aren't going to be a lot of PAP studies to look at.

One could look at a meta-analysis of compliant users, and it seems those point to good outcomes.

Polluting study results with non-compliant user data doesn't make sense on a scientific level, and the excuse that it is difficult to get a compliant user-base doesn't change that truth.

Not all docs feel that way.  Some are willing to prescribe ASV anyway if the patient fully understands and accepts the risks.  For example, the specialist who gave this presentation - see "Patient example 3" on page 58):


Patient example 3
• Patient on ASV already, been doing well for years
• h/o severe CHF EF <25%
• Explained patient risks and turned his ASV machine to
CPAP mode
• Patient trialed for 2 months, felt much worse on CPAP,
decreased QOL
• Switched patient back to ASV as he was willing to take
the risk

Right. Because many consider SERVE-HF "junk science" and they see improved quality of life in their ASV patients. The risk warnings have to be broached due to risks of malpractice suits, but these doctors obviously don't believe they are endangering the lives of their patients.

Bill

[kiwii]

Thank you for that extra info, Sleeprider.

I'll be having some lung function tests in about a month. I'll wait for the results before setting up the overnight test, just in case there is something other than asthma going on.

I will write to the sleep doctor and ask why she is focusing on ST rather than ASV. Your links were very informative about the differences, but it does make me wonder about her choice (and shakes my confidence in her a little bit).

[SarcasticDave94]

This is in no way intended to throw gasoline on the ST vs ASV debate, but I do intend to throw my personal and serious two cents in.

1. Going on the assumption that either ST or ASV is indicated, both have the potential to treat with backup rates.

2. Further, with a possible added risk to the heart, and without entering in the debate ring of discussing LVEF, congestive heart failure, etc., I do agree that the heart echo test needs to be done when considering ASV.

3. After passing number 2 above, inclusive in a conversation with your doc should be your intended choice of machine, be it ST, ST-A, or ASV. YOU are the patient, this is the machine YOU will use, and it should to be YOUR informed decision to make.

4. For myself, I did educate myself to a moderate degree that ST or ST-A didn't sound suitable, even though it is indicated for COPD patients such as myself. FWIW my ASV plays well with COPD it seems. (not saying you have COPD too, just that COPD indicates ST typically)

5. My first conversation with medical staff about an ASV was where the nurse I saw at the pulmonary doc office asks: "Why aren't you on an ASV with these numbers on the BiLevel PSG?" Me: "I don't know either. How about we get me one?"

You deserve to be true to you. Be informed. Talk to the doc. Then do what's best for you.

No offense, but I personally don't care which you choose, except I do hope whatever YOU choose is best able to give you the most effective treatment possible. I chose ASV based on my informed decision due to the belief that it sounded like the best product available to treat me. And yes, once the decision was made for me and by me, I PUSHED to get it. Because I needed treated to the best available. OK end of the 2 cent rant. Coffee!!  

[kiwii]

Thanks, Dave. I appreciate your insights.