Quad Bypass gone bad

what are the probable reasons for all 4 bypass' to go bad 8 weeks after surgery?

[ed34]

What do you mean by 'bad' ?  Have they closed up? or are they forming disease?

[GmBruner]

the veins did  not show up on a heart cath thus they were labeled "gone".
blood flow was seen through the original arteries.  total of 6 stints were installed.

[ed34]

Veins are not very reliable, the statistics for them are quite poor I think. The arteries used from the chest (Lima/Rima) have the best outcome. A grafted Lima/Rima has a 95% chance of still flowing after ten years.
Veins :-
Many factors determine the longevity of the grafted veins. If the coronary artery being bypassed has a lot of disease down the length, the vein won't last very long. The vein could be poor quality to begin with. The clearer the coronary artery being grafted to, the greater the flow through the vein, and the longer it tends to last. Sometimes veins close very quickly for no known reason. If a vein is flowing at 1 year, there is a high chance it will still be flowing for another 3-4 years. After that they start to form blockages like the coronary arteries but at an accelerated rate. Veins can last 10 years in some cases, or even 15 for the odd few.
It makes you wonder why they don't use stents in the first place. My 2 grafted veins lasted 3 months, and my LAD was then opened up using 5 long stents. They have so far remained open since sept 09. My first stent from feb 07 is still fully open. They have outlasted the grafts by a long way.