N. Labropoulos et al., THE ROLE OF VENOUS OUTFLOW OBSTRUCTION IN PATIENTS WITH CHRONIC VENOUS DYSFUNCTION, Archives of surgery, 132(1), 1997, pp. 46-51
Objective: To quantify the functional venous outflow obstruction with
different location and extent of obstruction attributed to previous de
ep vein thrombosis. Design: Case-control study. Setting: Vascular Labo
ratory, St Mary's Hospital Medical School, London, England. Patients:
Two groups: group 1, 25 case patients and 9 control subjects, and grou
p 2, 45 case patients and 30 control subjects. Interventions: Ascendin
g venography, duplex scanning, air plethysmography, and venous pressur
e measurements in the foot and the ann via a 21-gauge butterfly needle
. Main Outcome Measures: Venous outflow fraction (VOF), venous outflow
resistance (VOR), and arm-foot pressure differential (A-F PD) at rest
and after reactive hyperemia. Results: Venous outflow resistance was
evaluated in group 1. Twenty-two case patients underwent VOF testing,
and 16 had A-F PD measurement performed. Case patients in group 2 unde
rwent VOF testing. Signs and symptoms of chronic venous dysfunction me
re associated with the anatomical extent of obstruction, Limb swelling
and ache were present in most of the patients. Skin changes were note
d in about 30% and ulceration in 10% of patients. The results of all t
ests showed no evidence of obstruction in control subjects. In most ca
se patients with popliteal vein obstruction, test results were similar
to those in control subjects: the more proximal the veins involved, t
he mure severe the obstruction. In 16 case patients, all 3 tests were
performed and agreement between A-F PD and VOR test results was found
in 14 of them. The VOF test results agreed with the results of A-F PD
and VOR tests in 9 case patients. In group 2, 50% of the limbs with ob
struction proximal to the popliteal vein had a reduced VOF, which beca
me worst in the limbs with extensive obstruction, particularly when th
e iliac veins were involved. Of the 73 limbs tested for VOF in both gr
oups, only 7 limbs (9.6%) had their venous outflow markedly reduced by
occlusion of the superficial veins. Conclusions: The anatomical exten
t of venous obstruction and the development of collateral circulation
determine the hemodynamic severity of the chronic venous obstruction.
The deep collaterals seem to be more important than the superficial ve
nous system in bypassing the obstruction. The VOR and the A-F PD tests
can be used to identify those patients who have venous obstruction, w
hereas the use of the VOF test may reduce the need for performing the
above tests in 50% of the patients.