new onset headache with vomiting after closing fenustrstion

[MomOfCarter]

Our 6 year old son has Tricuspid Artesia with HRHS and is 3 years post Fontan completion.  Four months ago his fenustration was closed via Cath.  During the Cath, a collateral was found and was unable to be coiled. It was accidentally directed a bit during the attempt. The SVC attachment area was angioplastied due to narrowing.  Our son was placed on Plavix for an expected six month time frame.

One week after the Cath, our son began getting severe headaches with vomiting.  CT scans were clear.  Headaches were occurring 3 times per month with more mild headaches occurring 3 times per week.

MRI was unremarkable except for the presence of what they considered to be old bleeds from surgery where he was on CPB.  

Periactin was prescribed daily for headaches.  Plavix was discontinued and 163mg daily aspirin prescribed.

Headaches are now daily, but headache with vomiting has not been present for a month.

Currently wearing a Zio Patch to determine if arrhythmia is present during headaches.

Any ideas?