Fig. 11.1
The VenaSeal™ closure system
VariClose® Vein Sealing System
The VariClose® vein sealing system is similar to the VenaSeal™ closure system but uses a cyanoacrylate with a faster polymerisation rate. The process of venous access is as for other conventional endovenous methods. The delivery catheter has been designed with hydrophobic properties and features enabling easy visualisation under ultrasound. A 3 mL cyanoacrylate-containing syringe is connected to this 4Fr catheter, which is primed by slowly pulling the trigger gun over 5 s (delivering 0.3 mL of cyanoacrylate ) [19]. The catheter tip is exposed and positioned 3 cm distal from the SFJ. Pressure is applied over the SFJ with the ultrasound transducer. Treatment of the saphenous vein involves injecting 0.3 mL for every 10 cm of vein length. External compression is applied for 5 s following treatment of the first 10 cm of vein. The catheter is pulled back continuously at a rate of 2 cm per second with pressure from the ultrasound probe moving down the leg at the same rate. This carries on until the full length of the vein is ablated (Fig. 11.2).
Fig. 11.2
The VariClose® vein sealing system
An adhesive bandage is applied over the entry site, and as for the VenaSeal™ closure system, no compression stocking or bandage is necessary. Patients are advised to return to their normal activities as soon as possible but to wait until 1 day after their intervention before they start exercising (Fig. 11.3) (Tables 11.1 and 11.2).
Fig. 11.3
The VariClose® vein sealing system involves positioning of the catheter 3 cm distal from the sapheno-femoral junction, injection of 0.03 mL/cm of cyanoacrylate and continuous pullback of the catheter at a rate of 2 cm per second along with simultaneous application of pressure using the ultrasound probe
Table 11.1
Comparison of the VenaSeal™ closure and VariClose® vein sealing systems
VenaSeal™ | VariClose® | |
|---|---|---|
Country of origin | USA | Turkey |
Venous access | Vein cannulation and sheath insertion | Vein cannulation and sheath insertion |
Chemical used | Cyanoacrylate | Cyanoacrylate |
Delivery catheter | Connected to delivery gun | Connected to delivery gun |
Catheter pullback | Segmental | Continuous |
External compression | Segmental | Continuous |
Speed of polymerisation | Slow | Fast |
Distance from SFJ | 5 cm | 3 cm |
Post-intervention compression | None | None |
Table 11.2
Comparison of the cyanoacrylate characteristics of the two vein sealing systems
VenaSeal™ | VariClose® | |
|---|---|---|
Colour | Clear | Blue |
Consistency | Viscous (like ‘honey’) | Runny (like ‘water’) |
Polymerisation | Slow | Fast |
Texture post-polymerisation | Soft | Hard |
Cyanoacrylate in the Treatment of Varicose Vein Disease
Animal Studies
A plastic and a tissue model (common carotid artery of a swine) were used to investigate the process of polymerisation of cyanoacrylates, and three distinct stages were noted [20]. An initial stage (phase I), lasting less than 10 s, showed a linear rate of increasing tensile forces, while a second stage (phase II), lasting up to 1 min, was found to have a constant strength of tensile forces. Finally, the third and final step (phase III) follows phase II and involves complete polymerisation of the compound, characterised by an exponential rise in the tensile forces [20]. The strength of the binding forces as well as the rate of polymerisation is variable and dependent on the type and formulation of cyanoacrylate used [17, 20].
Evaluation of cyanoacrylate as a vein sealing method was conducted in the superficial epigastric veins (SEVs) in a swine model [21]. The SEVs were treated with the cyanoacrylate, and the swines were euthanised 60 days later. There were no sections of the SEVs which were patent. The segment treated was shown to be occluded with histological sections showing the presence of both inflammatory cells and fibrous tissue. This was consistent with a chronic foreign-body-type inflammatory reaction. No undesirable migration of the chemical or recanalisation of the treated veins was found.
Human Studies
VenaSeal™ Closure System
In the first clinical trial of CAE in the treatment of varicose veins, Almeida et al. (2013) recruited 38 patients [12]. They used the Sapheon closure system (Sapheon, Santa Rosa, California, USA) (eventually acquired by Medtronic, Minneapolis, Minnesota, USA) in which the catheter tip is placed 4 cm away from the SFJ. The incompetent GSV was treated, and patients were reviewed up at different time points over 24 months. Seventy-six percent of them were females, and the median age of patients was 51 years (range, 26–77 years) [12]. The mean length of GSV treated was 33.8 cm (standard deviation (SD), 9.1 cm), and the mean GSV diameter at the SFJ was 8.0 mm (SD, 2.2 mm). The complete occlusion rates were 100% at 2 days and 92.1% at the 12-month follow-up (three veins had recanalised). Using a Kaplan-Meier life table analysis, the occlusion rate was found to be 92% at the 24-month point [22]. Commonly encountered complications included post-operative thrombophlebitis (seven patients), thrombus extension into the common femoral vein (eight patients), cellulitis (one patient) and hyperpigmentation (one patient) [12].
A multicentre study in seven European centres looked at the use of CAE in the treatment of incompetent GSVs, but the distance of the catheter tip from the SFJ was modified to 5 cm [23]. This distance was thought to be more suitable as it could allow for glue propagation proximally towards the SFJ following cyanoacrylate injection and, at the same time, would provide for enough space to exert external pressure between the tip of the delivery catheter and the SFJ. As per Almeida et al. study, no compression hosiery was prescribed following treatment. In addition, no tributary treatment or reintervention was undertaken until after 3 months of post-ablation. Seventy patients were recruited in total, 78.6% of whom were females. The mean age was 48.4 years (range, 22–72 years). The mean length of GSV treated was 37.6 cm (range, 7–72 cm), and the mean GSV diameter at the SFJ was 7.8 mm (SD, 2.1 mm). The mean ablation time was 18.6 min (range, 8–74 min). At the 12-month follow-up, the complete occlusion (defined as no patent segment of more than 10 cm) rate using a life table method was 92.9% [23]. The Venous Clinical Severity Score (VCSS) improved from a mean of 4.3 at the baseline to 1.1 at the 12-month follow-up (p < 0.0001). The disease-specific Aberdeen Varicose Vein Questionnaire (AVVQ) also showed improvement from 16.3 at the baseline to 6.7 at 12 months (p < 0.0001). Phlebitis was noted in eight legs, and a single patient had thrombus extending into the common femoral vein. Treatment of this complication with 2 weeks of low molecular weight heparin led to resolution of the thrombus.
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