Correlation between blood flow, tissue volume and microvessel density in the flap

Area of Science:

• Biomedical Engineering
• Surgical Research
• Vascular Biology

Background:

• Assessing flap viability is crucial in reconstructive surgery.
• Understanding the relationship between tissue volume and blood flow is essential for predicting flap success.
• Microvessel density (MVD) is a key determinant of tissue perfusion.

Purpose of the Study:

• To investigate the correlation between flap tissue volume and blood flow.
• To explore the relationship between blood flow and microvessel density in different flap types.
• To evaluate flap conductance as a measure of blood flow conductivity.

Main Methods:

• Utilized an animal model (Japanese white rabbit) to study jejunal and latissimus dorsi (LD) muscle flaps.
• Sequentially reduced flap volume and measured blood flow and blood pressure to calculate flap conductance.
• Quantified microvessel densities using immunohistochemical staining for CD31/PECAM1.

Main Results:

• A significant positive correlation was found between flap conductance and tissue volume in both jejunal and LD flaps.
• For every 1 cm³ increase in volume, conductance increased by 0.012 ml/min/mm Hg in jejunum and 0.0047 ml/min/mm Hg in LD.
• Mean MVD was higher in jejunal flaps (1.15 ± 0.52%) compared to LD flaps (0.37 ± 0.29%).

Conclusions:

• Flap conductance is proportional to tissue volume, with a distinct proportionality constant for different tissues.
• Differences in microvessel density likely account for the unique blood flow characteristics of various flap tissues.
• This study provides insights into the physiological basis of flap perfusion and viability.