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Valves in small veins and venules.
A Caggiati1, M Phillips, A Lametschwandtner
1Department of Anatomy, University La Sapienza, Rome, Italy. alberto.caggiati@uniroma1.it
Summary
Microscopic venous valves (MVVs) exist in small veins, challenging the belief they are absent. These valves are crucial for preventing blood reflux and play a significant role in venous hemodynamics.
Area of Science:
- Vascular Biology
- Anatomy
- Physiology
Background:
- Current understanding of chronic venous disease (CVD) pathophysiology focuses on large veins, assuming valves are absent in vessels <2mm.
- This overlooks the potential role of smaller venous structures in venous hemodynamics.
Purpose of the Study:
- To review existing literature and assess the functional relevance of microscopic venous valves (MVVs).
- To challenge the conventional view on venous valve distribution and its implications for CVD research.
Main Methods:
- Comprehensive literature review of personal collections and medical databases.
- Analysis of anatomical descriptions and functional implications of MVVs.
Main Results:
- Microscopic venous valves (MVVs) have been identified in small human veins and animal tissues since 1934.
- Their arrangement suggests a role in preventing reflux from venules and capillaries.
- Clinical evidence, such as skin grafting for leg ulcers, supports the haemodynamic function of MVVs in CVD.
Conclusions:
- Textbooks of anatomy require revision to include the presence and function of MVVs.
- Pathophysiology studies of chronic venous insufficiency (CVI) must acknowledge the role of MVVs in venous haemodynamics down to the venular level.