CHIVA as an Alternative Procedure with Cyanoacrylate Ablation Exclusively for Non-cyanoacrylate Allergic Patients

Introduction, Objectives, and/or Purpose: CHIVA, sparing GSV, is based on understanding the hemodynamic factors that lead to the development of varicose veins. This requires the precise evaluation of where varicose veins arise secondary to a dysfunction in the venous drainage hierarchy, usually allowing venous flow to drain from tributaries or truncal veins to the deep venous system. In most cases, surgical interruption of the refluxing venous outlets is performed, but endovenous thermal ablation is also available recently. Cyanoacrylate ablation (CA) is a less invasive modality and provides an immediate closure throughout the length of refluxing truncal veins. However, cyanoacrylate hypersensitivity is an absolute contraindication, and indications of other allergies are still unknown, while subsequent phlebitis is another issue. A group of patients has a history of a single non-cyanoacrylate allergy that does not require medication and refuses thermal ablation.
To overcome the conflict of decision-making of procedures, we proposed introducing the CHIVA concept to CA, which reduces both the cyanoacrylate volume and the treated vein length. To achieve successful CHIVA, careful ultrasound examination of a venous escape flow from refluxing saphenofemoral junction (SFJ) or refluxing tributaries and venous drainage of the non-refluxing perforator must be necessary before procedures. A type 3 venovenous shunt (the main escape point would be from deep venous systems to saphenous truncal vein including SFJ, and the competent perforator exists as a re-entry to deep vein systems) is common, and CHIVA using CA for this shunt would be the goal in the initial study.
The present study aims to evaluate the short outcome of CA based on the CHIVA concept (CA-CHIVA) in patients with non-cyanoacrylate allergies and with type 3 shunts throughout GSV.

Methods: This multicenter retrospective observational study was conducted and reviewed the chart records concerning the CA-CHIVA procedure for incompetent GSVs. CA-CHIVA was indicated exclusively for the symptomatic patients with a history of single non-cyanoacrylate allergy without medication and refusal for thermal ablation simultaneously. Informed consent must be repeatedly obtained from the patients regarding a strong denial of thermal ablation, the possibility of a high incidence of the allergic response to cyanoacrylate at any time, and the requirement of surgical removal of cyanoacrylate in case of systemic hypersensitivities, which are resistant to medication. Anatomical indications included no or minimal SFJ incompetence, apparent truncal GSV reflux due to refluxing tributaries, re-entry perforators to the deep vein system, and peripheral refluxing tributaries in the calf. CA-CHIVA was avoided in patients with a greater GSV diameter >9 mm, suprafascial GSV, superficial vein thrombosis, and cyanoacrylate hypersensitivity. Transcatheter or percutaneously injecting CAs were used for the short GSV segment below the re-entry perforators and at the GSV segment in the calf, where refluxing tributaries were branching. Clinical outcomes were evaluated using the CEAP C class and VCSS. Patients were followed up for one year.

Results: Patients’ characteristics
Between June 2016 and June 2022, in a total of 745 consecutive CA procedures in 610 patients for symptomatic GSV or SSV refluxes, CA-CHIVA was performed only in 12 procedures (1.6%) in 12 patients with symptomatic GSV reflux. There were one man and eleven women with an average age of 64 years (SD 10) and a mean follow-up of 7.2 months (median eight months). The median CEAP clinical classification was 3, and all patients were symptomatic with a mean VCSS of 2.3 (SD 0.9). The average BMI was 24.0 (SD 2.9). All patients had a history of allergy without anaphylaxis and no daily medication: 6 atopic dermatitides, four drug allergies, and two food allergies.
Operating procedure
Eight patients underwent the catheter-direct CA, and four patients underwent the percutaneously-injecting CA. A median procedure time was 17 minutes, an average cyanoacrylate volume was 0.4 mL (range 0.2-0.8), and the median treated vein length was 8 cm (range 3-18). The treated zones were the calf GSVs with six patients, the upper thigh GSVs with three patients, tributaries only in the thigh with two patients, and GSV branching tributaries at the knee with one patient. Three patients who underwent upper thigh CA-CHIVA had a mild escape downstream to the trunk at the SFJ, while seven patients who underwent CA-CHIVA below the knee had no escape at the SFJ. Ultrasound-guided carbon dioxide foam sclerotherapy was simultaneously performed in three patients, and an ambulatory phlebectomy was done in one patient.
Change in ultrasound images (Figure 1)
The patients had their first follow-up duplex scan at week 1 as outpatients to the vascular laboratory. The median duplex follow-up period of this cohort of patients was 8 (range 2-14) months. The overall closer rates at week 1, month 1, and 6 were 100%, respectively. Vein diameter in the treated zone was decreased from 6.2 mm (SD 0.9) to 3.8 mm (SD 1.4) by a reduced rate of 39% (p < 0.001). The mean SFJ diameter, which was the proximal escape point, was decreased from 8.2 mm (SD 3.1) to 4.4 mm (SD 1.8) by a reduced rate of 47% (p=0.0021). The mean vein diameter distal to the treated zone was decreased from 5.8 mm (SD 1.0) to 3.3 mm (SD 1.0) by a reduced rate of 42% (p < 0.001). The untreated zone above CA-CHIVA was not thrombosed, and a reduced reflux flow was observed, which meant some drainage veins to the deep system existed. Tributaries branching from the CA-CHIVA zone disappeared gradually without thrombophlebitis. In addition, any de novo tributaries did not appear from the untreated truncal zone during follow-up.
Changes in patients’ symptoms
The mean CEAP clinical C score was improved from 3.2 (SD 1.4) to 0.1 (SD 0.4) (P < 0.001). The mean VCSS was also improved from 2.3 (SD 0.9) to 0.3 (SD 0.5) (p < 0.001). Thus, the clinical success rate was 100 % within the median follow-up range of eight months
Complications
None of our patients developed occlusive DVT, EGITs, or thrombophlebitis. However, a proximal cyanoacrylate cast at 3cm distal from SFJ was observed in one patient who underwent a short segment (5cm) CA with 0.3mL of cyanoacrylate above the knee by a catheter direct technique. Although all patients had non-cyanoacrylate allergies, there was no hypersensitivity and phlebitis-like abnormal reaction (PLAR) during the short-term observation.

Conclusion(s): CA is widely used and promises the mid-term outcome for the treatment of saphenous vein reflux as well as thermal ablation. However, adverse reactions to cyanoacrylate have been recognized, and many physicians are skeptical of its use because CA is permanent foreign body implantation. The major drawbacks in clinical settings are hypersensitivity and PLAR. The guideline of CA strongly prohibits performing this procedure in patients with a history of cyanoacrylate-related allergies, including cosmetics, any anaphylaxis, multiple allergies requiring daily medication, or autoimmune disorders. In contrast, controlled allergies without daily medication, such as occasional mild asthma, seasonal hay fever, or atopic dermatitis, might be relative contraindications but are still not well known. We usually recommended thermal ablation in such patients, because 156 out of 1425 patients, who were indicated for endovenous treatments, had non-cyanoacrylate allergies during the same observation period of this study. However, 12 out of 156 patients (7.7%) refused thermal ablation and strongly expressed a desire for CA. Fortunately, treated patients showed no hypersensitivity, no PLAR, and no surgical removal of cyanoacrylate during the short-term observation. Therefore, a low volume of cyanoacrylate and a shortly treated vein length might contribute to expanding the indication of CA for the non-cyanoacrylate allergic patient because a small amount of cyanoacrylate is advantageous to allow a minimal surgical intervention to remove it afterward.
In conclusion, anatomical and clinical success in the median follow-up period of eight months was achieved in all patients. CA-CHIVA, interrupting reflux in the truncal GSV downward to the calf and increasing the drainage flow through the competent perforator, led to significant clinical improvement with a diameter reduction of the untreated proximal zone of GSV and also the disappearance of peripheral tributaries in the calf. To perform this procedure, we must select the right patients, and clear explanations are required to obtain informed consent. Since the limitation of this study is the lack of long-term observation and the small number of patients, further investigation is required to obtain a precise conclusion.