Noninvasive determination of venomuscular efficiency

Area of Science:

• Vascular physiology
• Biomedical engineering
• Diagnostic imaging

Background:

• The venomuscular pump is crucial for venous return.
• Assessing its efficiency noninvasively is clinically important.
• Photoplethysmography (PPG) offers a potential method for such assessment.

Purpose of the Study:

• To quantitatively and noninvasively determine venomuscular pump efficiency using PPG.
• To establish a method for calculating efficiency by comparing exercise and passive limb movement volumes.
• To evaluate this method in control subjects and patients with venous diseases.

Main Methods:

• Photoplethysmography (PPG) was employed to measure limb volume changes.
• Exercise displacement volume (EDV) was recorded during dorsiflexion.
• Tilt displacement volume (TDV) was recorded during passive limb elevation.
• Venomuscular pump efficiency was calculated as the ratio of EDV to TDV.

Main Results:

• Exercise displacement volume (EDV) was significantly lower in patients with venous valvular insufficiency (VVI) and those with VVI plus deep venous thrombosis (DVT) compared to controls.
• Tilt displacement volume (TDV) was higher in patients with VVI and VVI plus DVT compared to controls.
• Calculated venomuscular pump efficiency was markedly reduced in patients with VVI (24.4%) and VVI plus DVT (8.8%) compared to normal subjects (50.5%).

Conclusions:

• The ratio of EDV to TDV provides a quantitative measure of venomuscular pump efficiency.
• This PPG-derived efficiency index may serve as a valuable tool for assessing venous hemodynamics.
• The findings highlight impaired venomuscular pump function in VVI and DVT patients.