Roman A Tauraginskii1, Fedor Lurie2, Sergei Simakov3, Rishal Agalarov4. 1. Clinical and Scientific Department, International Institution of Health Care and Additional Education Research Institute of Clinical Medicine, Irkutsk, Russia; LLC Vein Center "Antireflux," Surgut, Russia. Electronic address: Rtaureg@mail.ru. 2. Jobst Vascular Institute, Toledo, Ohio; Division of Vascular Surgery, University of Michigan, Ann Arbor, Mich. 3. Department of Computational Physics, Moscow Institute of Physics and Technology, Moscow, Russia. 4. LLC Vein Center "Antireflux," Surgut, Russia.
Abstract
OBJECTIVE: The gravitational pressure gradient is considered the driving force of venous reflux. The results from our previous study demonstrated that gravitational force is not a necessary condition for the occurrence of venous reflux. We hypothesized that a force exists in addition to gravity that drives venous reflux. The present study was designed to test this hypothesis by measuring the acceleration of blood flow during venous reflux in a clinical study and by simulating reflux ex vivo in physical models. METHODS: A total of 80 lower extremities of 80 patients with primary incompetence of the great saphenous vein were included in the present study. The cross-sectional area of the great saphenous vein, peak velocity of venous reflux (PV), and time required to achieve the PV (Δt, seconds) were measured on duplex ultrasound scans taken with the patient in the standing rest position. Noncycling operator-dependent distal cuff inflation-deflation was used as the reflux provoking maneuver. The acceleration of venous reflux (areflux) was calculated as areflux = PV/Δt in m/s2. Physical models were used to demonstrate the difference in acceleration between the free-fall stream and the flow forced by suction. RESULTS: The magnitude of areflux was greater than gravity in 24 of 80 extremities (30%), with a range of 9.83 to 24.13 m/s2. The maximum observed value of areflux was approximately 2.5g (24.13 m/s2). The areflux weakly, but statistically significant inversely, correlated with the subject height (r = -0.26; P = .001). The difference in water flow acceleration was 2.5 times between the free-fall model and suction model (9.07 ± 0.2 m/s2 vs 23.32 ± 2.6 m/s2, respectively). CONCLUSIONS: The acceleration of blood flow during reflux exceeded the value of gravitational acceleration, suggesting the action of an additional nongravitational force. The calf muscle pump might create such force by negative pressure during muscle diastole.
OBJECTIVE: The gravitational pressure gradient is considered the driving force of venous reflux. The results from our previous study demonstrated that gravitational force is not a necessary condition for the occurrence of venous reflux. We hypothesized that a force exists in addition to gravity that drives venous reflux. The present study was designed to test this hypothesis by measuring the acceleration of blood flow during venous reflux in a clinical study and by simulating reflux ex vivo in physical models. METHODS: A total of 80 lower extremities of 80 patients with primary incompetence of the great saphenous vein were included in the present study. The cross-sectional area of the great saphenous vein, peak velocity of venous reflux (PV), and time required to achieve the PV (Δt, seconds) were measured on duplex ultrasound scans taken with the patient in the standing rest position. Noncycling operator-dependent distal cuff inflation-deflation was used as the reflux provoking maneuver. The acceleration of venous reflux (areflux) was calculated as areflux = PV/Δt in m/s2. Physical models were used to demonstrate the difference in acceleration between the free-fall stream and the flow forced by suction. RESULTS: The magnitude of areflux was greater than gravity in 24 of 80 extremities (30%), with a range of 9.83 to 24.13 m/s2. The maximum observed value of areflux was approximately 2.5g (24.13 m/s2). The areflux weakly, but statistically significant inversely, correlated with the subject height (r = -0.26; P = .001). The difference in water flow acceleration was 2.5 times between the free-fall model and suction model (9.07 ± 0.2 m/s2 vs 23.32 ± 2.6 m/s2, respectively). CONCLUSIONS: The acceleration of blood flow during reflux exceeded the value of gravitational acceleration, suggesting the action of an additional nongravitational force. The calf muscle pump might create such force by negative pressure during muscle diastole.