CVD is the result of venous reflux, obstruction or a combination
of both. So far, attempts to correlate venous hemodynamic measurements
with symptoms and sighs of chronic venous disease (CVD) have
produced poor results, probably because of lack of methods to quantitate
obstruction. Our hypothesis is that the combination of quantitative
measurements of (a) overall reflux (superficial and deep) and (b) overall
outflow resistance i.e. including the collateral circulation would provide a
hemodynamic index that should be related to the severity of the disease.
25 limbs with chronic venous disease and 1 limb from a
healthy volunteer (VCSS 0-13) were studied. The clinical CEAP classification
was C0 in one limb, C1 in 2 limbs, C2 in 10 limbs, C3 in
3 limbs, C4 in 1 limb, C5 in 6 limbs and C6 in 3 limbs. Air-plethysmography
was used to measure reflux (VFI in ml/sec) when the subject
changed position from horizontal to standing. Subsequently, with the
subject horizontal and the foot elevated 25 cm, simultaneous recordings
of pressure and volume were made on release of a proximal thigh cuff
inflated to 70 mmHg. Pressure change was recorded with a needle in the
foot and volume change with air-plethysmography. Flow (Q in ml/min)
was calculated at intervals of 0.1 seconds from tangents on the volume
outflow curve. Outflow resistance (R) was calculated at 0.1 second intervals
by dividing pressure by the corresponding flow (R = P/Q). R increased
markedly at pressures lower than 30 mmHg due to decrease in
vein diameter, so resistance at 30 mmHg (R30) was used in this study.
In a multivariable linear regression analysis with VCSS as
the dependent variable, both VFI and R30 were independent predictors
(P<0.001). Using the constant (0.333) and regression coefficients, the
regression equation provided a hemodynamic Index (HI) or estimated
VCSS = 0.333+(VFIx0.44)+(R30x158). Thus, HI could be calculated for
every patient by substituting VFI and R30 in the equation. HI or calculated
VCSS was linearly related to the observed VCSS (r=0.83).
The results indicate that the combination of quantitative
measurements of reflux and outflow resistance provide a hemodynamic
index which is linearly related to the VCSS. These findings need to be
confirmed in a bigger series. However, having quantitative information
on reflux and obstruction allows one to plan management, whether to
relieve obstruction, reflux or both.
