Comparing venous wall effects using the empty vein ablation technique with VELEX catheter, endovenous laser ablation and foam sclerotherapy in an animal model

Abstract

Objective: To describe residual intima and the average media thickness persisted after the empty vein ablation (EVA) technique, endovenous laser ablation (EVLA), and foam sclerotherapy (FS) in a sheep in vivo model.

Methods: Six iliofemoral and two jugular sheep vein axes were treated as follows: four with EVA (using polidocanol [POL] 0.5% or 1% with 1 or 3 minutes as contact time), two with FS (FS-1 and FS during Valsalva maneuver [FS-Val], POL1% for 10 minutes), and two with EVLA (1470 nm radial, 80 J/cm²).

Results: The average percentage of residual intima layer was 2% (interquartile range [IQR]: 1%-4%) for EVA-POL0.5%-1 minute, 1% (IQR: 0%-3.5%) for EVA-POL0.5%-3 minutes, 2% (IQR: 0%-4%) for EVA-POL1%-1 minute, 0 for EVA-POL1%-3 minutes, 13% (IQR: 13%-15.7%) for FS, 1% (IQR: 0%-3%) for FS-Val, and 1% (IQR: 0%-6%) for EVLA. The average percentage of residual media thickness was 13% (IQR: 8%-15%) for EVA-POL0.5%-1 minute, 6% (IQR: 4%-9%) for EVA-POL0.5%-3 minutes, 13% (IQR: 10%-27%) for EVA-POL1%-1 minute, 6% (IQR: 5%-12%) for EVA-POL1%-3 minutes, 51% (IQR: 40%-62%) for FS, 29% (IQR: 23%-35%) for FS-Val, and 62% (IQR: 41%-75%) for EVLA.

Conclusions: EVA demonstrated better results in vein wall damage compared with EVLA and FS, both in intima and media layers.

Clinical relevance: This study provides crucial insights into the effectiveness of different vein treatment techniques, particularly the empty vein ablation method, in minimizing residual intima and media thickness. By evaluating these outcomes in a sheep model, it highlights how empty vein ablation may lead to more vein wall damage compared with endovenous laser ablation and foam sclerotherapy. For clinicians, understanding the comparative efficacy of these treatments is vital for optimizing patient care in managing venous diseases. As the field evolves, these findings could influence clinical decision-making, encouraging the adoption of techniques that promote better long-term outcomes for patients.

Keywords: Chronic venous disease; Empty vein ablation; Sclerotherapy; Varicose veins.

Fig 1

Empty vein ablation device. The zoomed box shows details of the selector for balloon inflation/deflation and sclerosing agent injection. CB, Central balloon; K1, posterior routable knobs; K2, anterior routable knobs; LB, lateral balloon; OP, opening for sclerosing agent release; Sync, synchronizer.

Fig 2

Empty vein ablation (EVA) technique summary steps. A, The catheter is inserted in the vessel to be treated by percutaneous access, through a 7F introducer sheath; three balloons are not inflated. B, Central balloon is inflated first, causing the blood to move and leave that vein segment. C, The two lateral balloons are subsequently inflated to isolate the segment of vein previously emptied from blood. In this way an empty and isolated vein segment is obtained. D, Medication injection is started, through the two openings, into the “central chamber” interposed between the two lateral balloons and through a partial deflation of the middle balloon. E, At the end of the vein treatment, the central balloon is inflated again, and simultaneously, the medication is recaptured to empty the vessel from it. F, At the end of the procedure, the three balloons are deflated simultaneously in order to return to the initial configuration, and the catheter is withdrawn.

Fig 3

A, Representative pictures of H/E-stained sections of the femoral vein. On the left, the inset shows the morphology of a stretch of the exfoliated intima layer at high magnification. On the right, the inset shows the morphology of a stretch of the residual intima layer at high magnification. B, The stretch of the residual intima layer was measured by Aperio Image Scope software. C, Measure of the vessel lumen perimeter, carried out by Aperio Image Scope software. Calibration bar 800 μm.

Fig 4

Representative images of Masson trichrome-stained femoral vein sections. Ten measurements of the media thickness were taken for each vessel at equivalent distances along the lumen. If the tunica media was completely absent at the measurement point, the thickness measurement was assigned to a value of zero. Calibration bar 700 μm. The inset shows the magnification of the indicated area; calibration bar 200 μm.

Fig 5

Median with interquartile range (IQR) of the average percentage of residual intima (A) or residual media thickness (B) layer after empty vein ablation (EVA)—used with polidocanol (POL) 1% or 3% for 1 or 3 minutes—foam sclerotherapy (FS)—with or without Valsalva (Val) maneuver—and endovenous laser ablation (EVLA). ∗P < .05, ∗∗P < .01, ∗∗∗P < .0001. ns, Not significant.

Fig 6

Evaluation of residual intima (A) or residual media thickness (B) along the vessel, dividing each treated segment into proximal, medial, and distal portion after empty vein ablation (EVA)—used with polidocanol (POL) 1% or 3% for 1 or 3 minutes—foam sclerotherapy (FS)—with or without Valsalva (Val) maneuver—and endovenous laser ablation (EVLA). Values are represented as median with interquartile range (IQR).