Adverse neurological events after sodium tetradecyl sulfate foam sclerotherapy - A prospective, observational study of 8056 treatments.

BACKGROUND: Ultrasound guided foam sclerotherapy (UGFS) is a flexible and highly utilised tool in the treatment of varicose veins (VVs), both as a primary treatment and as an adjunct to other treatments. Concern remains regarding the risk of neurological adverse events (AEs) such as migraine, visual disturbance and serious adverse events (SAEs) such as cerebrovascular accident that have been reported after UGFS treatments. AIM: To determine the incidence of neurological AEs and SAEs after UGFS. METHODS: A prospective, multicentre, post-authorisation safety study across Europe (both private and government) was performed between January 2015-2020. Neurological adverse events after UGFS with Fibrovein® (Sodium Tetradecyl Sulfate) 1 and 3% physician generated foam. RESULTS: 8056 patients underwent treatment. There were 46 AE (including 5 SAEs), 30 (65%) SAEs were in female patients. Mean age was 55 years with mean body mass index (BMI) of 27. Univariable logistic regression demonstrate that UGFS only treatment (i.e. no adjunctive treatment), liquid-to-gas ratio, gas type and total foam volume (1% sodium tetradecyl sulfate, STS) were significantly associated with the odds of experiencing the outcome. Multivariable logistic regression model exhibits that migraine and total foam volume (1% STS) maintained statistical significance thus associated with the odds of adverse events. CONCLUSIONS: This study demonstrates that UGFS with Fibrovein is safe with a very low incidence of neurological AEs and SAEs. Past history of migraine, use of physiological gas (O2/CO2) and increasing volumes of 1% foam increase the risk of AEs.

The Addition of Lipid-Based Contrast Medium does not Inactivate the Detergent Sclerosant Sodium Tetradecyl Sulfate in-vitro.

PURPOSE: To investigate if the detergent sclerosant sodium tetradecyl sulfate (STS) is deactivated by the lipid-based contrast agent ethiodised oil. METHOD: 3% STS was mixed with ethiodised oil and room air in a 2:1:4 ratio in two luer lock syringes and a three way connector and agitated to make foam (the Tessari technique) to replicate the clinical use of the products. The assay of STS in the mixture was assessed using the British Pharmacopoeia method. Briefly this is a manual titration method where the solution of STS is mixed with an indicator solution and titrated with hyamine solution of known concentration; the concentration of the STS can then be calculated with the titration results. To further mimic the clinical environment with the presence of blood, the effect of adding increasing amounts of albumin to the STS-ethiodised oil mixture was assessed. RESULTS: The assay of STS in the solution after mixing with ethiodised oil was 3% indicating that the ethiodised oil did not deactivate the STS. The addition of albumin to the STS-contrast mixture resulted in near linear neutralisation of the STS with increasing concentrations in the same quantities as with STS alone. CONCLUSIONS: The mixture of the lipid-based contrast agent ethiodised oil with the detergent sclerosant STS did not affect the availability of the sclerosant. The continued use of STS-ethiodised oil in the management of vascular malformations can be supported.

Implication of foam sclerosant inactivation by human whole blood in a laboratory setting.

Background During sclerotherapy, it has been recommended to confirm intravenous placement of the needle by aspirating blood into the sclerosant syringe. This may inactivate some, or all of the sclerosant. Aims To quantify the volume of human blood needed to completely inactivate 1 ml of sodium tetradecyl sulphate, and comparing fresh blood and blood that has been stored in an ethylenediaminetetraacetic acid tube. Methods A series of manual titrations were carried out following a procedure developed at STD Pharmaceutical Products Ltd (Hereford, UK) and listed in the British Pharmacopeia. Three percent of sodium tetradecyl sulphate stock solutions were made with increasing volumes of blood and titrated against benzethonium chloride to determine the active concentration (% w/v) of sodium tetradecyl sulphate remaining in the solution. Results A calculated approximation showed 0.3 ml of blood is required to fully inactivate 1 ml of 3% sodium tetradecyl sulphate when made into a foam. A comparison was made between the use of fresh blood and blood stored in ethylenediaminetetraacetic acid tubes. Blood stored in ethylenediaminetetraacetic acid tubes showed more inactivation of sodium tetradecyl sulphate, but this was not significant at the P ≤ 0.05 level. Conclusion The data from our study have shown that a minimum of 0.3 ml of fresh blood is required to inactivate 1 ml of 3% sodium tetradecyl sulphate as a foam and it is not significantly affected by storing blood in an ethylenediaminetetraacetic acid tube. Our methodology suggests that during foam sclerotherapy treatment, blood should not be aspirated into the syringe to confirm position, and that ultrasound guidance is more appropriate for needle placement.

Physiochemical properties and reproducibility of air-based sodium tetradecyl sulphate foam using the Tessari method.

Objectives The objectives were to examine the density, bubble size distribution and durability of sodium tetradecyl sulphate foam and the consistency of production of foam by a number of different operators using the Tessari method. Methods 1% and 3% sodium tetradecyl sulphate sclerosant foam was produced by an experienced operator and a group of inexperienced operators using either a 1:3 or 1:4 liquid:air ratio and the Tessari method. The foam density, bubble size distribution and foam durability were measured on freshly prepared foam from each operator. Results The foam density measurements were similar for each of the 1:3 preparations and for each of the 1:4 preparations but not affected by the sclerosant concentration. The bubble size for all preparations were very small immediately after preparation but progressively coalesced to become a micro-foam (<250 µm) after the first 30 s up until 2 min. Both the 1% and 3% solution foams developed liquid more rapidly when made in a 1:3 ratio (37 s) than in a 1:4 ratio (45 s) but all combinations took similar times to reach 0.4 ml liquid formation. For all the experiments, there was no statistical significant difference between operators. Conclusions The Tessari method of foam production for sodium tetradecyl sulphate sclerosant is consistent and reproducible even when made by inexperienced operators. The best quality foam with micro bubbles should be used within the first minute after production.

Primary cesarean delivery among uncomplicated term nulliparous parturients: the influence of group practice within a community hospital.

In a community hospital, the rate of cesarean delivery varied significantly for uncomplicated nulliparous patients managed by four practice groups, although the rate of shoulder dystocia did not. Among four practice groups in a single center, our objective was to discern the rate of cesarean delivery (CD) among uncomplicated, term nulliparous parturients, and the likelihood of shoulder dystocia and admission to the neonatal intensive care unit (NICU). The inclusion criteria for this retrospective study were uncomplicated nullipara > or = 37 weeks. Multivariable models were used for analysis. Over 2 years, 1217 women met the inclusion criteria. The overall rate of primary CD was 21%, with rates of 15%, 24%, 17%, and 32% for the four groups. After controlling for confounding variables, the rate of primary CD was significantly higher for group 2 (odd ratio [OR] 1.68; 95% confidence interval [CI] 1.17, 2.42) and 4 (OR 1.83; 95% CI, 1.25, 2.68) versus groups 1 and 3 combined. Shoulder dystocia and admission to NICU did not vary between groups. Among uncomplicated term nulliparous patients, the rate of primary CD varied significantly by practice groups, without an effect on rate of shoulder dystocia or NICU admission.