title: Superficial venous reflux duration and cessation with two concurrent duplex probes.
abstract: BACKGROUND
  Venous reflux is the principal hemodynamic disorder and therapeutic target in patients with superficial venous insufficiency. To date, no studies have identified where or when it stops, anatomically or regionally, along the course of the refluxive conduit. Duplex measurements of reflux are performed invariably with a single probe. Because many anatomic locations are studied, repeated provocation maneuvers are required. However, this fails to appreciate reflux as a circulation. The use of two probes placed concurrently in different regions may address this limitation. The study compared venous reflux duration and cessation, above the knee and below the knee simultaneously, with two duplex probes.
  
  
  METHODS
  Seventeen legs from 17 consecutive patients (12 female, nine left) with great saphenous vein reflux were studied. Their median (range) age was 51 (28-71) years; weight, 76.8 (63.5-189) kg; height, 169 (153-180) cm; and Venous Clinical Severity Score, 5 (1-12). The clinical class of the Clinical, Etiologic, Anatomic, and Pathophysiologic (CEAP) classification was as follows: C2, 6; C3, 4; C4a, 5; and C4b, 2. After 2 minutes of elevation, the leg was assessed for reflux duration with duplex ultrasound. This occurred when the patient stood up during venous filling. One probe was positioned 10 cm below the saphenofemoral junction over the great saphenous vein (point A) and the other over a refluxive saphenous vein or tributary below the knee (point B). Concurrent images were displayed on adjacent monitors and recorded by a single video camera. Reflux duration was from the onset of dependency, indicated by the start of the video, to the termination of the red color (reflux) on video playback. The probes were swapped to negate for differences in machine sensitivity. Each leg was tested three times. Simultaneous was defined when there was <0.1 second difference between the two sites.
  
  
  RESULTS
  The median (range) vein diameters at points A and B were 6.1 (2.8-9.3) mm and 5.5 (2.5-8.1) mm, respectively, with an intertransducer distance of 41 (23-59) cm. There was no significant difference in reflux duration between point A with 27 (9-150) seconds and point B with 27 (10-149) seconds (P = .943 [Wilcoxon]). The correlation was excellent (r = .986; P < .0005 [Spearman]).
  
  
  CONCLUSIONS
  This is the first study to investigate reflux cessation by introducing a novel two-probe technique. It has demonstrated that reflux may stop simultaneously above and below the knee with use of the elevation to dependency maneuver to provoke reflux. It has shown that either site may be used to measure reflux duration. Furthermore, the two-probe technique confirms the belief that the mechanism of refluxive venous filling is through the descending path of a recirculation circuit.
authors.affiliation: Josef Pflug Vascular Laboratory, Ealing Hospital, Middlesex, United Kingdom; Department of Surgery and Cancer, Imperial College, London, United Kingdom; Department of Vascular Surgery, Northwick Park Hospital, Middlesex, United Kingdom. Electronic address: c.lattimer09@imperial.ac.uk.
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Lattimer
authors.affiliation: Venenpraxis, Wunstorf, Germany.
authors.forename: Erika
authors.initials: E
authors.lastname: Mendoza
mesh_terms: D005260:Female; D005764:Gastroesophageal Reflux; D006439:Hemodynamics; D006801:Humans; D007866:Leg / Q000098:blood supply; D012501:Saphenous Vein / Q000000981:diagnostic imaging* / Q000503:physiopathology; D018616:Ultrasonography, Doppler, Duplex; D014689:Venous Insufficiency / Q000000981:diagnostic imaging; D014690:Venous Pressure; D055422:Venous Valves