Revisit to Phlebolymphedema as Ultimate Outcome of Dual Outflow System Failure

Abstract

Venous and lymphatic systems are one interdependent, "inseparable" dual-outflow system of the circulation. Both systems are "mutually complimentary"; the insufficiency or overload to one of two systems allows the other to play an auxiliary role of fluid return through micro- & macro-anastomosis. But both systems are "mutually complimentary" only when they are with normal function; when the venous stasis exceeds this maximum lymphatic compensatory capacity, the insufficiency becomes "phlebo-lymphatic". When one of the two systems should fail to provide sufficient compensation to the other system, it would become a combined condition of chronic venous insufficiency (CVI)/chronic venous hypertension and chronic lymphatic insufficiency (CLI)/chronic lymphedema, known as “phlebo-lymphedema” (PLE). Hence, the ulcer of PLE origin represents an unavoidable outcome of the joint failure of this “inseparable” venous-lymphatic circulation system, presenting as a combined condition of veno-lymphatic edema caused by CVI and CLI. When the lymphatic system becomes damaged (mechanical insufficiency) or the ultrafiltrate load becomes greater than the ability of the lymphatic system to drain it (dynamic insufficiency), the lymphatic system would fail to handle the interstitial fluid load, and the proteins and macromolecules start to accumulate in the interstitium. This "presence of proteins in the interstitial space" further induces an inflammatory cascade to create a proinflammatory state leading to the irreversible changes. These proteins may serve further as a substrate for microorganisms to facilitate extending and intensifying infections. Increased scarring and trauma by these infections cause further damage to the vulnerable lymphatic collectors. Therefore, lymphatic system can be easily damaged not only by drainage overload but also by the inflammatory environment created by the fluid stasis so that this vicious circle created by the impairment of the venous and lymphatic system would cause the ulcer management more seriously complicating. Hence, a precise understanding of the nature of all the chronic "indolent" venous stasis ulcers as a combined condition of veno-lymphatic edema caused by CVI and CLI of various origins is mandated based on simultaneous evaluation of these two closely linked conditions/systems.