You assume the flowvolume has decreased, but did it? A residual lumen of 5 mm is large. And diameterchanges are common in the venous part. A residual lumen of 2 mm or smaller is becoming more important than PSV and/or PSV ratio's as a criteria for a significant stenosis. The venous wall differs and dilate much more and quicker than the arterial wall. So if you use criteria that are based on the criteria for arteries you can detect lots of stenosis. A diameterchange, curve, twist or valve, they all raise the PSV. And of course wall thickness and plaqueformation. In this case there is no plaque present, will the patiënt benefit if they perform a PTA based on your duplex findings? And you did not look at the outflow veins, when there are aneurysmatic dilatations it can be there is an outflowstenosis at for example in the subclavian vein, and while concentrating on this stenosis you might miss the actual cause of the decrease in flowvolume. And a flowvolume in the vein is of course not accurate, and must not be used. Measurement must take place in the brachial artery.
I too always measure flow in the brachial artery, all the references I've seen so far recommend that. Only when measuring flow of AVG I do it directly in the place of the graft
You assume the flowvolume has decreased, but did it? A residual lumen of 5 mm is large. And diameterchanges are common in the venous part. A residual lumen of 2 mm or smaller is becoming more important than PSV and/or PSV ratio's as a criteria for a significant stenosis. The venous wall differs and dilate much more and quicker than the arterial wall. So if you use criteria that are based on the criteria for arteries you can detect lots of stenosis. A diameterchange, curve, twist or valve, they all raise the PSV. And of course wall thickness and plaqueformation. In this case there is no plaque present, will the patiënt benefit if they perform a PTA based on your duplex findings? And you did not look at the outflow veins, when there are aneurysmatic dilatations it can be there is an outflowstenosis at for example in the subclavian vein, and while concentrating on this stenosis you might miss the actual cause of the decrease in flowvolume. And a flowvolume in the vein is of course not accurate, and must not be used. Measurement must take place in the brachial artery.
I too always measure flow in the brachial artery, all the references I've seen so far recommend that. Only when measuring flow of AVG I do it directly in the place of the graft