I was about a month for an elbow AVF. Infiltrated once but that was at three months and more a technician problem than an AVF issue. They started with a larger gauge needle but migrated within a week.

«Maturation mostly occurs 4 to 6 weeks after the initial fistula surgery but that timeframe can vary with the average time ranging from 1 to 4 months. » • https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5989091/

Second Mapping

I believe they did a second vein mapping (dynamic ultrasound of the blood flow) that needed to reach a particular flow rate and possibly diameter before approving use.

Something like «The Rules of 6 (flow volume >600 mL/min, vein diameter >6 mm, vein depth <6 mm) »  • https://pubmed.ncbi.nlm.nih.gov/35227801/

Presumably if it failed to mature sufficiently they would follow up in another month or so.  

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A 'Fistula' is like a surfaced artery, except it immediately goes back to your heart.  Like a highway loop with no stops in between.

Apparently, this can happen naturally: some people have an artery that connects to a vein directly instead of going through capillaries first.  It can cause several problems due to the abnormal blood flow and pressures.  Large fistulas can be surgically fixed and removed.

Somehow nature inspired a doctor to do the opposite: create a fistula where none existed before.  Usually this is done in your arm, near your wrist or elbow.  The surgeon shunts an artery to the returning vein, so some of the blood flow immediately loops back through the shunt instead of continuing to your hand.  Since veins are on the surface and the blood is headed back to the heart, this creates an unusually good blood access point.  A vein on steroids.

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