Venous outflow and inflow resistance in health and venous disease

Abstract

The application of calibrated photoplethysmography in conjunction with induced changes in leg hydrostatic pressure proved to be an effective physiologic method to noninvasively quantify venous hemodynamics in normal control subjects, patients with venous valvular insufficiency, venous obstructive disease, or both.

Noninvasive determination of venomuscular efficiency

“…Values are expressed in percent of optical reflectance (%OR), as described. 5 The TDV response was quite opposite, increasing from an initial 6.55% OR (Ϯ0.55) in the control group to 10.3% OR (Ϯ0.56) in the VVI group and 16.66% OR (Ϯ3.15) in the VVI plus TDV group. Table III presents the efficiency values in all three groups: 50.5% (Ϯ2.60) in the control group, 24.4% (Ϯ4.4) in the VVI group, and 8.8% (Ϯ2.1) in the VVI plus DVT group.…”

“…Briefly summarized, calibration is achieved with a defined decrease or increase of 5% in light intensity of the light-emitting diode incorporated in the PPG probe. 5 A tilt displacement volume (TDV) test is performed first. The PPG probe is placed 8 cm above the medial ankle, and the subject sits in a comfortable reclining chair with the knee joints angled at approximately 120 degrees.…”

Gravitational venous drainage is significantly faster in patients with varicose veins

“…Studies which used PPG with leg elevation whilst sitting were unable to discriminate between patients with venous valvular insufficiency and controls. 13,24 In this study the VDI has been used to investigate whether patients with SVI have poor venous drainage. The importance of a simple non-invasive test which can quantify venous drainage cannot be overestimated.…”

“…Studies which used PPG with leg elevation whilst sitting were unable to discriminate between patients with venous valvular insufficiency and controls. 13,24…”

Métodos de diagnóstico não-invasivos para avaliação da insuficiência venosa dos membros inferiores

“…O valor do TRV é uma medida indireta do retorno venoso e da incompetência das valvas 35 . Muitos pesquisadores utilizaram a FPG para avaliação da doença venosa dos membros inferiores 31,34,[36][37][38][39] e seguimento pós-operatório, com a finalidade de verificar a eficácia cirúrgica 25,[40][41][42][43][44] . A maioria dos autores considera como TRV normais valores acima de 20 s, como Gaitini et al 45 , Evangelista & Fonseca 28 , Sakurai et al 33 e Welch et al 11 .…”