Suggest Treatment After Two Strokes While Diagnosed With Severe Sleep Apnea

Brief Answer:
Conditions predisposing for hypercoagulation

Detailed Answer:
I read your question carefully and I understand your concern. I know it must be frustrating undergoing test after test without getting any feedback.

As I have told you before in answering another query of yours, when it is the case of a young patient (under 65) it is preferred to look very thoroughly for conditions predisposing for stroke, especially in your case when it's a repeated case. There is a whole battery of tests which are done.
I would group them in 3 main groups: imaging tests to investigate blood vessels supplying the brain, tests to investigate for cardiac origins and laboratory tests for conditions predisposing coagulation.
From what you describe the first group (MRI/MRA, Doppler) and the second (echocardiogram, TEE, loop recorder study) seems to have been exhausted and I don't imagine there is anything that the stroke specialist might add really.
As for the lab studies they include antiphospholipid antibodies, proteins C and S, antithrombin III, Factor V Leiden or prothrombin G20210A mutations, homocysteine levels, tests for connective tissue disease, vasculitis (like ANA, anti-ds-DNA, ENAs, complement, XXXXXXX fibrinogen). It would take ages to explain each acronym individually and probably just add to your confusion, suffice to say it is about imbalances in coagulation pathways or inflammatory conditions predisposing to formation of thrombi.
So if these tests have not already been done the stroke specialist might require them.
There are also some less likely specific conditions like some infections, blood diseases, genetic conditions which might be considered if there are other findings suggesting them, but I doubt it, they would have produced more findings since it has been several months since your first stroke.

There is also the possibility that your neurologist has already considered those possibilities himself, has already done the lab tests as well, but since all has come back negative he simply wants a second opinion from someone sub-specialized in stroke to make sure he hasn't missed anything.

I remain at your disposal for further questions.

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Brief Answer:
Read below.

Detailed Answer:
Yes, I am not really surprised you had had those other tests, as I said they are standard ones.
Factor V Leiden is a common cause, but it is more commonly associated with thrombosis of veins rather than arteries and you would have been told if it was the case of a venous thrombosis (treatment would've been different as well), so I think it is right of the neurologist not to content himself with that as an explanation but to still search for other possibilities.
As we discussed in the past query sleep apnea is a factor for stroke and arrhythmia and loop recorder studies do unveil unknown atrial fibrillation which would explain a repeated stroke. To get an answer to that though, the end of the study has to be waited for.
If that comes back negative though I don't see any specific reason for him to be sending you to a stroke specialist other than as I said just to be sure.

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