Improved hemodynamic effectiveness and associated clinical correlations ofa new intermittent pneumatic compression system in patients with chronic venous insufficiency

Purpose: A new intermittent pneumatic compression device (SCD Response Syst em) has recently been shown in healthy volunteers to have the ability to de tect the postcompression refilling of the calf veins and to respond by init iating the subsequent cycle when these veins are full. This has proven to b e more effective in expelling blood proximally than the conventional interm ittent pneumatic compression device (SCD Sequel System). The aim of this st udy was to test the influence of venous disease on the postcompression. ref ill 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 postthrombotic syndrome and 10 patients who h ad varicose veins. The new SCD Response System was tested against the exist ing SCD Sequel System in both legs in the supine, semirecumbent, and sittin g positions. The refilling time sensed by means of the device was correlate d with the venous filling index by using air plethysmography. The total vol ume of blood expelled per hour during compression was compared with that ex pelled by the SCD Sequel System in the same volunteers and in the same posi tions. 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 d isease. The SCD Response System increased the volume expelled per hour in t he 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 semirecumben t position, and by 40.2% (P = .005) in the sitting position. The correspond ing results in the more severely affected leg in patients with varicose vei ns were 71.9% (P = .005) in the supine position, 77.9% (P = .005) in the se mirecumbent 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 cycle s, 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 thr ombosis in this high-risk group are justified.