CAC is the most recent endovenous option for treatment of VV and CVD and is the result of the development of cyanoacrylate catheter (CAC) directed technology. The techniques are known under their brand names, commonly referred to as VenaSeal™, VenaBlock™ or VeinOFF™. These techniques utilise medical grade cyanoacrylate glue (CAG) which is dispensed via a catheter along the length of the truncal veins (GSV and/or SSV)[13]. The major advantages of this technique over EVLA and RFA are that it does not use any thermal technology, hence does not require dilute local anaesthetic tumescent and does not carry the risk of thermal nerve injury or paraesthesia. Occlusion rates are comparable to EVLA, with two RCT reporting 12-month occlusion rates of 95.8-97.3% and estimated 3-year occlusion rates of 90-95%[13]. Long-term outcomes from an RCT comparing occlusion rates CAC and RFA, demonstrated the 5-year occlusion rate for CAC was higher at 91.4% and RFA 85.2%, but not statistically significant[17]. Other advantages CAC has over surgical, EVLA and RFA modalities is that it can be targeted via injection into perforator veins as well as large incompetent tributary veins[17]. Several case series have been reported demonstrating its safety and efficacy however it is a technique that is still undergoing development.
Complications of CAC relate to immediate and delayed hypersensitivity reactions and phlebitis, granuloma formation and complications of glue extension[13].
- Severe hypersensitivity causing anaphylaxis to CAG has not been reported, however there are case reports of documented CAG allergy that presented with symptoms including total body urticaria which can be delayed and transient, contact dermatitis or asthma after injection of CAG[13].
- Endovenous CAG treatment for VV/CVI results in phlebitis and hypersensitivity-type phlebitis in up to 20% of patients[13]. This is higher than EVLA and RFA. As with EVLA and RFA, inflammation of the treated vein(s) is initially treated with NSAIDs and if it responds it is consistent with phlebitis. However, inflammation in untreated sites or not responsive to NSAIDs is more consistent with hypersensitivity-like phlebitis and is commonly responsive to anti-histamines[13]. Studies have shown that up to one-third of phlebetic reactions post-CAC procedure is likely to be a CAG hypersensitivity reaction[13]. As such, current guidelines recommend that post-CAC phlebitis should be treated with NSAIDs and anti-histamines plus oral or intravenous steroids in severe cases.
- Granulomatous phlebitis has been reported but is a rare complication. Commonly it is asymptomatic but can result in suppuration, necrosis and ulceration in the affected segment. As such, CAC treatment is contraindicated in patients with previous CAG reactions, uncontrolled inflammatory, autoimmune and granulomatous conditions, such as sarcoidosis and should be used with caution in patients with active systemic disease or infection and other treatment options should be considered [13].
- DVT after CAC treatment is uncommon and pulmonary embolism has not been reported. Glue extension at the saphenofemoral junction into the common femoral vein have been well documented but a modification to the manufacturers’ recommended procedure to lengthen the starting distance from the saphenofemoral junction from 3cm to 5 cm has reduced/almost eliminated this risk. Extension of CAG into the common femoral vein can be treated with therapeutic anticoagulation [13].