From Rob Daigle.
To play the devils advocate on the issue of physiologic segmental studies
versus duplex, I'd like to voice an opinion. This opinion has been sculpted
by my mentors in vascular surgery and radiology, experience in the trenches,
and by comments,criticisms, and attacks when I've lectured in support of
Duplex imaging of native arteries.
#1) Although a bilateral duplex scan from aorta to the ankles takes 5-10
minutes for those who have been scanning arteries since before sliced bread
was invented, for most of us it takes a lot longer. For a patient with
bilateral disease in the iliacs and fem -popliteal segments, a two hour exam
duration is more likely. (time flies when you're having fun). Sure, the exam
could take 30 minutes, but sometimes the quality of the test is severely
compromised. There is always a tendency to forget how much time it takes to do
the tough ones. The memory of pain is short!
#2 . For many of us, the iliacs are a bitch, in terms of scheduling time,
technical difficulty, bowel gas and frustration, one does not approach this
potentially very difficult segment without a good indication that you need to
scan there. Often the patient must return another day with bowel prep, NPO to
accomplish this exam.
The question posed by Jean Primozich, of why not take just take ankle
pressures and then scan, is important, for technical and reimbursement issues.
Ankle pressures, as long as the patient does not have calcific medial
sclerosis, and many do, will indicate normal versus abnormal, but if you want
to find where the disease is, with this protocol, you've got to scan the
entire limb(s). (Waveform analysis at the CFA is only good at detecting
severe aorto-iliac disease.) And the tibial arteries, all three of them, are
no picnic either!
#3) Reimburse is an issue for many that rely on medicare and insurance
carriers to keep their labs going. An ankle- brachial pressure index is not
reimbursable without other physiologic testing, waveforms etc. Many states
will not reimburse for a duplex exam unless surgery or intervention is
planned, nor will they reimburse for a normal duplex exam.
Guidelines have been written to suggest appropriate methods for arterial
testing. The Medical Policy manual from the mid western states (KA, MO NE),
reads "Duplex scanning and physiologic studies are reimbursed during the same
encounter if the physiologic studies are abnormal or to evaluate trauma,
thromboembolic events and aneurysms."
The guidelines further state " In most patients, segmental blood pressure
measurements (not just ABI, rd) before and after exercise should be the
preferred procedure in evaluating arterial insufficiency." Many states are
adopting similar guidelines. So what we feel is the best way to do things,
might not be the way we get paid for doing them. This is fine if you're funded
by grants or Powerball.
4) Physiologic segmental testing, when performed for appropriate indications,
is reimbursable in all states, whether the result is negative or positive.
It takes 15 minutes (ABI with waveform) - 60 minutes max (for a full test with
exercise) , regardless of tech experience.
Indirect testing accurately ( numerous articles) predicts whether the disease
is above or below the inguinal ligament, an important consideration for
It provides objective, physiologic information about the effect of stenosis
and occlusion on the patients' distal perfusion. Duplex data does not provide
It tremendously helps to differentiate vascular claudication from pseudo-
claudication, especially in referrals from non-vascular specialists.
And finally, unless the vascular surgeon is prepared to operate without a
preoperative angiogram (some do, but most do not) ( and I feel that Duplex
imaging in the hands of the true experts with many years experience, Bill
Schroeder comes to mind, is more accurate that angiography) duplex imaging of
the arteries is redundant to the angiogram, a waste of time ( a precious
commodity in a busy lab) and someones money. Ditto for angioplasty.
Duplex imaging is fun though.
Just an opinion from an average tech who is now an average product manager for
Nicoletvascular, manufacturer of physiologic testing equipment.