What are the risks of waiting to use ASV as a sleep apnea treatment?

The risks of postponing ASV treatment depend on the severity of the problem. If you have a valid diagnosis of complex sleep apnea, I am concerned that your insurance company has not approved treatment. It sounds akin to waiting for an insurance company to approve the use of an antibiotic for a serious infection. The central apneas suggest impairment of the brain respiratory center either due to poor circulation from any cause, including heart failure, medication effect such as opiates or damage to the center from head injury, stroke or infection. Sometimes, no cause is obvious, but treatment is generally not too difficult if mask-fitting and tolerance are addressed. How much oxygen desaturation is one of many factors which influence the rapidity one should begin therapy. It has been there for awhile, so waiting a few days should not be too serious. The alternative and what to do in the meantime may include Bi Level PAP therapy which may require another sleep study, nocturnal oxygen if levels are low and, of course, looking for a cause which may be treatable.

Untreated sleep apnea that is severe puts one at increased for heart attack and stroke. The risk very slowly accumulates, so in the short term the risk is small. Waiting for the machine to be approved does not put you at great risk. The main thing is to become compliant once on it. There is no treatment to be had other than the ASV. Side sleep may be of help.