Foaming of blood in endovenous laser treatment.

This work is dedicated to a challenging issue of modern phlebology-establishment of a physical mechanism of the endovenous laser treatment (EVLT) against great saphenous vein incompetence (protuberant varicosities). Using optical and acoustical methods, we have studied the laser-induced formation of microbubbles in an aqueous solution of surface-active substances, serum, and blood directly in patients while conducting EVLT of the great saphenous vein in a clinical setting. We have used lasers with wavelengths 0.97 and 1.47 μm. Their radiation was transmitted through a quartz-quartz polymer fiber 600 μm in diameter. It has been found that in all cases, the laser beam with moderate power (1-10 W) supplied through an optical fiber leads to the formation of micro-bubbled foam. It has been shown that laser exposure during EVLT induces blood boiling, which results in heating of the venous walls (thermal destruction of the intima) and provides effective foam occlusion of the blood vessels (hemostasis). Necessary and sufficient conditions for a successful EVLT are associated with the thermal destruction of intima and laser-induced foam hemostasis.