Kakkos SK, Szendro G, Griffin M, Sabetai MM, Nicolaides AN.
Improved hemodynamic effectiveness and associated clinical correlations of a new
intermittent pneumatic compression system in patients with chronic venous
insufficiency.
J Vasc Surg 2001 Nov;34(5):915-22

Irvine Laboratory for Cardiovascular Investigation and Research, Department of
Vascular Surgery, Imperial College School of Medicine, St. Mary's Hospital,
London, United Kingdom. s.kakkos@ic.ac.uk

PURPOSE: A new intermittent pneumatic compression device (SCD Response System)
has recently been shown in healthy volunteers to have the ability to detect the
postcompression refilling of the calf veins and to respond by initiating the
subsequent cycle when these veins are full. This has proven to be more effective
in expelling blood proximally than the conventional intermittent pneumatic
compression device (SCD Sequel System). The aim of this study was to test the
influence of venous disease on the postcompression refill time detected by means
of the SCD Response and the effectiveness of the new system in expelling blood in
patients who have venous reflux caused by post-thrombotic syndrome or varicose
veins. METHODS: This open, controlled trial was conducted in an academic vascular
unit with 10 patients who had post-thrombotic syndrome and 10 patients who had
varicose veins. The new SCD Response System was tested against the existing SCD
Sequel System in both legs in the supine, semirecumbent, and sitting positions.
The refilling time sensed by means of the device was correlated with the venous
filling index by using air plethysmography. The total volume of blood expelled
per hour during compression was compared with that expelled by the SCD Sequel
System in the same volunteers and in the same positions. RESULTS: An inverse
association was found between the mean postcompression refilling time in the
sitting position and the venous filling index of the apparently healthy or less
severely affected leg (r = -0.52, P =.019), the refill time being significantly
shorter in patients with advanced venous disease. The SCD Response System
increased the volume expelled per hour in the post-thrombotic leg, when compared
with the SCD Sequel System, by 109.9% (P =.005) in the supine position, by 85.1%
(P =.009) in the semirecumbent position, and by 40.2% (P =.005) in the sitting
position. The corresponding results in the more severely affected leg in patients
with varicose veins were 71.9% (P =.005) in the supine position, 77.9% (P =.005)
in the semirecumbent position, and 55.7% (P =.013) in the sitting position.
Similar improved results were also found in the contralateral leg in both groups.
CONCLUSIONS: The deflation settings of the new SCD Response System are able to be
adjusted selectively, correlating with the physiological severity of chronic
venous insufficiency. By achieving more frequent compression cycles, the new
system is more effective than the current one in expelling blood proximally,
confirming our earlier findings in healthy volunteers. Further studies testing a
possible improved efficacy in preventing deep venous thrombosis in this high-risk
group are justified.