The patient is horizontally positioned in reverse Trendelenburg based on the location of the targeted vein, and the area is prepped and draped in a sterile manner (Fig. 10.4A). Local anesthesia is infiltrated at the site of the puncture. Under ultrasound guidance, the introducer wire and catheter sheath are inserted into the vein. For treatment of below-the-knee saphenous vein reflux, access can be obtained close to the ankle (Fig. 10.4B). The ClariVein catheter is then inserted through the lumen such that the tip of the wire is placed just below the saphenofemoral junction (SFJ) .

The ClariVein^® catheter is then connected to the motorized handle unit, and the distal end of the dispersion wire is unsheathed to expose the dispersion tip which is then positioned 1 cm distal to the SFJ or 1 cm proximal from the “fascia” as the small saphenous vein (SSV) angles toward the saphenopopliteal junction [11]. In the case illustrated, the catheter is advanced as close as possible proximally to the segment that was ablated prior (Fig. 10.5). Since the position of the catheter is steerable only with the cartridge wing at distal end, it is important to position the catheter tip at the desired position before attaching it to the motorized handle [12].

Once the location of the catheter is confirmed by ultrasound, the catheter is attached to the handle and the 2-cm-long angled tip is exposed. A 5 mL syringe filled with 1.5% sotradecol is then connected to the handle for delivery of the sclerosing agent. This step comprises full assembly of the device.

The access sheath is usually removed prior to initiation of treatment to ensure a smooth, continuous, uninterrupted pullback (Fig. 10.6). The first 2–3 cm is treated only with mechanical ablation to induce vasospasm and avoids propagation of the sclerosing agent into the deep venous system . Next, the activated catheter with rotating tip is gradually withdrawn at a speed of approximately 6–7 s per cm, while the sclerosant (polidocanol/sodium tetradecyl sulfate ) is injected at a rate of 0.2 mL per cm approximately. Ultrasound compression of the vein is not routinely used during treatment but is suggested for veins larger than 10 mm in diameter to enhance contact of the rotating tip with the wall of the vein. A white mark on the catheter indicates the last 5 cm of the catheter. An additional 2 cm of therapy can then be performed. The tip of the wire is re-sheathed and the catheter is withdrawn with pressure on the access site.

Immediately after procedure, an ultrasound should be performed to assess for patency of deep veins of the treated leg and examine the proximal ablation edge position, especially near the junction. The treated vein may still be compressible initially, but that does not indicate failure of treatment. Eventual thrombosis occurs subsequently with inflammation and continuous action of the sclerosing agent (Fig. 10.7).

There is a variation in the use of sclerosing agents (polidocanol/sotradecol) in terms of concentration and dosage. Some experts suggest that a higher concentration of polidocanol should be used near the junction, as it appears to be weaker than sotradecol [4]. In most cases the amount of sclerosant is calculated based on the patient’s weight, and the maximum amount should not exceed the amount mentioned on the drug insert. According to Tang et al. the maximum recommended treatment dose of sotradecol for one procedure should not exceed 10 mL of 3% strength (equivalent to 15 mL of 2% sotradecol) [13]. Currently, some surgeons also suggest the dose of sclerosant used should be 2 mL, 3% polidocanol for the first 10–15 cm, and 1.5% polidocanol for the remainder of the great saphenous vein (GSV) [4, 14, 15]. There is however no standard recommendation regarding choice of sclerosant, concentration, or dosage to date.

Ultrasound-guided foam sclerotherapy was one of the first nonthermal techniques developed but has not proved to be as effective as endovenous laser ablation (EVLA) and radiofrequency ablation (RFA) techniques, with a 5-year success rate of 74% [16]. Furthermore, it usually requires multiple treatment sessions and is associated with a small but well-documented risk of stroke using foam sclerotherapy [17, 18].

The first human study demonstrating clinical safety and efficacy of MOCA was conducted by Elias et al. in 2012 (Table 10.1). The study included 30 incompetent GSVs in 29 patients treated for primary venous insufficiency. The primary closure rate was reported as 96.7%, with no major adverse complications [19]. Although this was the first human study conducted, it was not the first one published as in 2011; van Eekeren et al. reported their experience on clinical efficacy of MOCA. In this study, 30 GSVs in 25 patients with venous insufficiency were treated in two centers. The immediate postoperative technical success rate was 100%. After a follow-up of 6 weeks, 26 (87%) remained occluded, three veins showed partial recanalization, and one vein completely recanalized. Patient satisfaction was reported at 8.5 on a 10-point scale, and the median VCSS decreased significantly from 3 to 1 [10].

The first prospective multicenter study on efficacy of MOCA in patients with chronic venous insufficiency was described by Bishawi et al. The study included 126 patients who were noted to be significantly older and with higher BMI compared to previous studies using endothermal techniques but reported high successful closure rates in the great saphenous vein at 1 week, 3 months, and 6 months (100%, 98%, and 94%), respectively. Also, there was a significant improvement in the venous clinical severity score (VCSS) post-procedure [20]. The following year, van Eekeren et al. published 1-year results for MOCA of GSV insufficiency in 106 patients. The initial technical success rate was 99% on duplex imaging immediately after treatment. Post-procedural pain scores were reported with mean pain during the first 14 days after treatment at 7.5 mm (0–100 visual analog scale). The time to return to daily life activities was noted as 1 day. At 1-year follow-up, the clinical success rate was 93% and 88.2% of the GSV remained occluded. Twelve patients were reported to have recanalization, of which eight were partial. The venous clinical severity score (VCSS) decreased significantly from 4.0 to 1.0 at 1 year [21].