Endovenous laser ablation: an experimental study on the mechanism of action

Abstract

In this experimental study, application of endovenous laser shows to be dominated by carbonization at the fibre tip. Although intraluminal laser-induced heat was heterogeneously distributed, with laser tip temperatures up to 1200 degrees C, heat dissipation was minimal. Continuous exposure of laser light appears to be better suited in EVLA than intermittent.

Heat conduction from the exceedingly hot fiber tip contributes to the endovenous laser ablation of varicose veins

“…Our results in Fig. 3 imply that a vein radius of 2.5 mm and a pullback velocity of 2 mm/s, the experimental conditions used by Disselhoff et al, would produce insufficient temperatures at the vein wall, reproducing their observation that "the diffusion of heat into the surrounding tissue was minimal" [9]. Laser power may be less critical, provided it is sufficient to reach tip temperatures of at least 800°C (Fig.…”

“…3), the vein radius used in the experiments by Disselhoff et al [9], and close to the tube radius of 3 mm used by Proebstle et al [11], and v=1 mm/s, 2 mm/s, and 3 mm/s. As an example (Fig.…”

Heat conduction from the exceedingly hot fiber tip contributes to the endovenous laser ablation of varicose veins

“…Our results in Fig. 3 imply that a vein radius of 2.5 mm and a pullback velocity of 2 mm/s, the experimental conditions used by Disselhoff et al, would produce insufficient temperatures at the vein wall, reproducing their observation that "the diffusion of heat into the surrounding tissue was minimal" [9]. Laser power may be less critical, provided it is sufficient to reach tip temperatures of at least 800°C (Fig.…”

“…3), the vein radius used in the experiments by Disselhoff et al [9], and close to the tube radius of 3 mm used by Proebstle et al [11], and v=1 mm/s, 2 mm/s, and 3 mm/s. As an example (Fig.…”

Endovenous welding: Basics and 5-year experience in the use of automatic thermal ablation in the treatment of patients with chronic vein diseases

“…After EVLA, coagulation of the endothelial, subendothelial, muscular and adventitial layers is observed against the background of minimal signs of venous spasm. 14,17 The changes that we observed after EVW have common features with the morphological picture after RFA: alteration mainly to the depth of the inner and middle layers of the venous wall with pronounced signs of spasm in the form of separation of the muscular layer from the adventitia. 9,10 As is known, reference values of vein diameter over 12 mm are associated with an exponential increase in the risk of recanalization when using EVLA and RFA, and an increase in the power or duration of thermal exposure potentiates the risk of injury to paravasal tissues.…”

Moving heat source in a confined channel: Heat transfer and boiling in endovenous laser ablation of varicose veins

“…The carbon layer that was deposited on the fiber tip heats up strongly through absorption of light even to temperatures high enough to cause melting of the silica. This melting has actually been observed at 25 W. Also in clinical situations melting of fibers has been reported [18].…”

Heat conduction from the exceedingly hot fiber tip contributes to the endovenous laser ablation of varicose veins

“…Our results in Fig. 3 imply that a vein radius of 2.5 mm and a pullback velocity of 2 mm/s, the experimental conditions used by Disselhoff et al, would produce insufficient temperatures at the vein wall, reproducing their observation that "the diffusion of heat into the surrounding tissue was minimal" [9]. Laser power may be less critical, provided it is sufficient to reach tip temperatures of at least 800°C (Fig.…”

“…3), the vein radius used in the experiments by Disselhoff et al [9], and close to the tube radius of 3 mm used by Proebstle et al [11], and v=1 mm/s, 2 mm/s, and 3 mm/s. As an example (Fig.…”

Endovenous welding: Basics and 5-year experience in the use of automatic thermal ablation in the treatment of patients with chronic vein diseases

“…After EVLA, coagulation of the endothelial, subendothelial, muscular and adventitial layers is observed against the background of minimal signs of venous spasm. 14,17 The changes that we observed after EVW have common features with the morphological picture after RFA: alteration mainly to the depth of the inner and middle layers of the venous wall with pronounced signs of spasm in the form of separation of the muscular layer from the adventitia. 9,10 As is known, reference values of vein diameter over 12 mm are associated with an exponential increase in the risk of recanalization when using EVLA and RFA, and an increase in the power or duration of thermal exposure potentiates the risk of injury to paravasal tissues.…”

Moving heat source in a confined channel: Heat transfer and boiling in endovenous laser ablation of varicose veins

“…The carbon layer that was deposited on the fiber tip heats up strongly through absorption of light even to temperatures high enough to cause melting of the silica. This melting has actually been observed at 25 W. Also in clinical situations melting of fibers has been reported [18].…”

Heat conduction from the exceedingly hot fiber tip contributes to the endovenous laser ablation of varicose veins

“…Our results in Fig. 3 imply that a vein radius of 2.5 mm and a pullback velocity of 2 mm/s, the experimental conditions used by Disselhoff et al, would produce insufficient temperatures at the vein wall, reproducing their observation that "the diffusion of heat into the surrounding tissue was minimal" [9]. Laser power may be less critical, provided it is sufficient to reach tip temperatures of at least 800°C (Fig.…”

“…3), the vein radius used in the experiments by Disselhoff et al [9], and close to the tube radius of 3 mm used by Proebstle et al [11], and v=1 mm/s, 2 mm/s, and 3 mm/s. As an example (Fig.…”

Endovenous welding: Basics and 5-year experience in the use of automatic thermal ablation in the treatment of patients with chronic vein diseases

“…After EVLA, coagulation of the endothelial, subendothelial, muscular and adventitial layers is observed against the background of minimal signs of venous spasm. 14,17 The changes that we observed after EVW have common features with the morphological picture after RFA: alteration mainly to the depth of the inner and middle layers of the venous wall with pronounced signs of spasm in the form of separation of the muscular layer from the adventitia. 9,10 As is known, reference values of vein diameter over 12 mm are associated with an exponential increase in the risk of recanalization when using EVLA and RFA, and an increase in the power or duration of thermal exposure potentiates the risk of injury to paravasal tissues.…”

Moving heat source in a confined channel: Heat transfer and boiling in endovenous laser ablation of varicose veins

“…The carbon layer that was deposited on the fiber tip heats up strongly through absorption of light even to temperatures high enough to cause melting of the silica. This melting has actually been observed at 25 W. Also in clinical situations melting of fibers has been reported [18].…”