Historical perspective on PAP for CSA in patients with heart failure
I've been doing some more reading about studies of PAP therapy for CSA in patients with heart failure and found it very interesting to look at the reaction to the
CANPAP study published in 2005.
CANPAP remains the largest prospective trial of CPAP in CSA patients with heart failure. Interestingly, it was stopped prematurely, in part because the group randomized to CPAP had a significantly lower transplant-free survival rate in the first 18 months after randomization.
This led some experts at the time to conclude that
CPAP should not be used for CSA in CHF patients. Sound familiar?
I thought it was very interesting stuff to keep in mind when thinking about the questions raised by and raised about
SERVE-HF.
-Amin
Nothing I say on the forum should be taken as medical advice.
RE: Historical perspective on PAP for CSA in patients with heart failure
I've read the arguments on both sides. I have yet to see a cause for death agreed upon. If you have heart problems you have a more likely chance of dying. No secret there. Does the ASV cause the early death or the bad heart? Does Chemotherapy kill the patient when it doesn't work or does the cancer?
RE: Historical perspective on PAP for CSA in patients with heart failure
As I read it, one of the reasons the study was terminated was because changes in the drug treatment regimens meant that they would have needed three times the sample size to come to any definite conclusions as to efficacy or dangers - so there was no point in continuing that study. Up to that point, there was very little difference between the two groups.
Also of note, is that the CPAP usage averaged about four hours per night, and the average length of sleep was just five hours per night. This, according to Michael Walker in 'Why We Sleep' is sleep deprivation by two to three hours per night.
02-10-2018, 09:24 PM
(This post was last modified: 02-10-2018, 09:26 PM by Shin Ryoku.)
RE: Historical perspective on PAP for CSA in patients with heart failure
(02-10-2018, 08:45 PM)pholynyk Wrote: As I read it, one of the reasons the study was terminated was because changes in the drug treatment regimens meant that they would have needed three times the sample size to come to any definite conclusions as to efficacy or dangers - so there was no point in continuing that study. Up to that point, there was very little difference between the two groups.
This is straight from the study itself:
Quote:After the first 200 patients had been followed for a minimum of six months, the data and safety monitoring committee performed a prespecified interim analysis. It recommended termination of the study because of an early divergence of the transplantation-free survival curves favoring the control group, enrollment at only 50 percent of the predicted rate, and a falling rate of death and heart transplantation that precluded the ability to detect a difference in the primary outcome between the two groups with the originally predicted sample size. On the basis of this recommendation, the executive committee stopped the trial on May 21, 2004.
So yes, there were several stated reasons, one of which was the bolded one.
(02-10-2018, 08:45 PM)pholynyk Wrote: Also of note, is that the CPAP usage averaged about four hours per night, and the average length of sleep was just five hours per night. This, according to Michael Walker in 'Why We Sleep' is sleep deprivation by two to three hours per night.
Yes, this is a problem with almost all CPAP studies based on an intention-to-treat analysis. Hard to get a whole group of people using CPAP the way that the study authors would like them to do. It is possible to do an on-treatment analysis, but that comes with its own associated biases and limitations.
-Amin
Nothing I say on the forum should be taken as medical advice.
02-11-2018, 12:49 AM
(This post was last modified: 02-11-2018, 12:53 AM by ajack.)
RE: Historical perspective on PAP for CSA in patients with heart failure
"[..] CPAP showed improved left ventricular ejection fraction in patients who have obstructive sleep apnea with left ventricular systolic dysfunction[..] Similarly, in patients with diastolic heart failure, treatment of obstructive sleep apnea with CPAP has resulted in reverse remodeling of ventricular morphology and improved function."
From memory, it's a large improvement, It was from a video and hard to find again. I guess the question become whether this extends life or not. In this trial it seems it didn't and as it said it contrasts other trails that showed an improved rate.
I guess the heart transplant group would be the gold standard, in treatment for major failure.