@Silencio - Sorry for not answering sooner. I hadn't logged into PR for a while.
You asked whether Systrom treats ME/CFS patients who are not willing to undergo the iCPET, I think the short answer is probably not.
The longer answer is that Systrom is not really a holistic ME/CFS specialist the way that Klimas, Peterson, Levine and Bateman are. He developed an interest in ME/CFS relatively recently. He is one of the pioneers in using the iCPET to understand the physiological causes of unexplained exercise intolerance. These can include ejection fraction-preserved heart failure, pulmonary hypertension, neuromuscular diseases (in rare cases), and what he calls preload failure/dysautonomia, which is what he commonly sees in the iCPET results of ME/CFS patients. His focus is on trying to increase exercise tolerance. His goal does not seem to be to treat the entire symptom complex of ME/CFS (e.g. cognitive dysfunction, unrefreshing/disturbed sleep, flu-like malaise, digestive problems, extreme allergies, headaches, noise/light sensitivity, etc.)
In my case, he recommended I undergo the iCPET at my initial consultation. He didn't offer to treat me experimentally with mestinon or other drugs that improve venous return. Of course, I could be wrong about this, but it seems that most of his patients who fit the profile of ME/CFS in terms of viral onset and current symptom profile end up doing the iCPET. He then follows up with a non-invasive CPET after about 6-8 months to see if the medication he prescribed has increased exercise tolerance, as measured by the objective parameters of the test.
If you don't want to undergo the iCPET or the follow-up CPET, then it seems like there must be easier and cheaper ways to skin this proverbial cat. You already trialed mestinon. The other drugs he uses, if mestinon does not work or causes too many negative side effects, are midodrine and florinef. Supposedly, he also considers using the drug northera, but that was never mentioned to me as an option. Maybe you can find a local doctor who is willing to prescribe these medications, though I realize that is easier said than done.
You also asked whether Systrom is using medications like Xolair in patients. Again, I am pretty sure the answer is no. His physician's assistant told me last fall that he tests patients for MCAS mostly out of an academic interest in it, but he doesn't really treat MCAS.
In any case, the approved indications for Xolair are uncontrolled allergic asthma and hives. No insurance company will pay for Xolair, which costs about $35,000 a year, unless the patient has one of these two conditions and other cheaper treatment options have failed. Obviously, MCAS is a new and still somewhat controversial diagnosis, in that not every MD believes it is a "real" clinical entity. My guess it that it will be at least another decade, if not longer, before insurers and Medicare authorize the use of Xolair or Dupixent, which might work even better than Xolair. to treat MCAS.
In patients who do not respond positively to mestinon or the other drugs used to treat dysautonomia (florinef, midodrine) after 6-8 months and who also have either clear signs of autoimmunity in their lab work or small fiber neuropathy confirmed by skin biopsy, Systrom has said he will consider the use of IVIG, Rituxan, or plasmapheresis. However, having spoken to his physician's assistants, I get the impression that the use of these treatments by Systrom hasn't really gotten off the ground yet. It is more in the "discussion stages" and is based on the recommendations and clinical experience of Anne Oaklander at Mass General and Peter Novak at Brigham & Women's, two neurologists who have treated small fiber neuropathy with IVIG.
My guess is that two problems stand in the way of Systrom using IVIG in his patients. The first is that small fiber neuropathy is not an approved indication for IVIG. If your insurance company won't pay for it, the out-of-pocket expense for the dose required would be astronomical. (Supposedly, Oaklander recommends using 2 grams of IVIG per kilogram of bodyweight every four weeks. That is about 5 times the dose used for immune deficiency.) My guess is that Systrom does not have the support staff to try to get insurers to approve IVIG for his patients. Another issue is that IVIG can cause pretty severe adverse events. The most notable is aseptic meningitis, which I believe requires hospitalization. Since a lot of his patients are travelling to see him, and are not local, he may be wary of prescribing IVIG if it could land his patients in the hospital.
