Bill,

ugh!

Comerota's article from the JVS compares duplex, PRG, and venography.  
Although the PRG part leaves some questions, the Duplex data is superb.  
It was 1990, I think (Terry just pulled it for our journal club).

I think it is a problem if you are expected to do DVT studies and are not 
available 24 hours.  We currently don't have that responsibility for 
in-patients but when we do, some sort of call will have to be worked out.

The basic problem, however, is that screeenig for DVT is flawed.  Unlike 
screening for and AAA or carotid stenosis, DVT is a more dynamic disease 
process.  I mean, if a patient sees you on Monday and has an 50-79% 
stenosis, that same stenosis will be present Tuesday, Wed, and thursday.  
Not so with DVT.  A normal study may be normal in the morning and 
positive 24 hours later.  The crux of the issue surrounding screening is 
that we don't know when the DVT starts,not to mention the significance of 
isolated calf vein thrombi, etc.  I believe that ANY DVT screening 
program will miss disease BECAUSE OF THE DISEASE not the test!

We recently did a study which we are preparing regarding a screening 
program.  We replaced Duplex with IPG.  A very specific protocol was 
followed for positive IPG (the issue around US is complicated because 
Radiology was giving the Orthopods 15% equivacol exams which were then 
progressing to venography).  Our endpoint was thromboembolic disease.  
Besides the fact that half of you will think I am crazy for using IPG, 
what we really found out was that the DVTs were occuring after the 
screening test when prophylaxis stopped.  The orthopods used a short 
course coumadin, discontinued then they left on day 4-5.  No serious 
sequelae occured in any patient with a negative IPG.  there were alot of 
false pos IPGs that got US.  More DVTs occured after discharge than while 
an in-patient.  (One patient with a pos IPG and neg Duplex died from a PE 
a week after discharge!) It confirmed my bias that screening was 
flawed and in fact, we have altered our prophylactic regimine.  If you 
are going to screen, you have to accept that some DVTs will be missed but 
that it does not mean the test is innaccurate.

Greenfield is preparing (resubmitting) a major multicenter study 
regarding DVT in trauma patients.  The endpoint for DVT (a screening 
protocol) is duplex ultasound.  Greenfield should know a little about DVT 
in trauma patients....

Good luck.

MAR


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Michael A. Ricci, MD			
Assistant Professor of Surgery			Phone:  (802) 656-8455
Vascular and Transplant Surgery			FAX:    (802) 893-0305
University of Vermont College of Medicine

Office: FAHC-University Health Center Campus
	One South Prospect Street
	Burlington, VT  05401
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