Pattern of thermal damage and tissue carbonisation from endovenous radiofrequency ablation catheter - Using an in vitro porcine liver model

BACKGROUND

Successful endovenous thermoablation relies on transmural vein wall ablation. We investigated the pattern of thermal spread and tissue carbonisation from RadioFrequency-induced ThermoTherapy (RFiTT) at different powers and pull back methods, using a porcine liver model.

METHODS

We used a previously validated in-vitro porcine liver model. Different powers from 5-25 W were used to administer 150 J. We compared continuous and pulsed energy delivery. Length, lateral spread, and total area of thermal damage, together with any tissue carbonisation, was measured using digital analysis software.

RESULTS

All experiments used 150 J total energy. Total thermal damage area was smaller with lower power and pulsed energy. Continuous energy caused more tissue carbonisation than pulsed except at 25 W.

CONCLUSION

Reduced thermal damage with lower power or pulsed energy results from cooling due to increased time of treatment. Increasing the power increases tissue carbonisation. Optimal treatment is determined by the highest power used continuously that does not cause tissue carbonisation.

Five-year extension study of patients from a randomized clinical trial (VeClose) comparing cyanoacrylate closure versus radiofrequency ablation for the treatment of incompetent great saphenous veins

OBJECTIVE

The proprietary cyanoacrylate closure (CAC) system vs radiofrequency ablation (RFA) trial (VenaSeal Sapheon Closure System Pivotal Study [VeClose]) showed that CAC, a nontumescent, nonthermal, nonsclerosant ablation technique, was effective and noninferior to RFA in vein closure with good 36-month outcomes. Conducted under a separate protocol, the aim of this extended follow-up was to assess the long-term safety and effectiveness of CAC and RFA for the treatment of incompetent great saphenous veins (GSV) at 5 years (60 months) of follow-up.

METHODS

This 60-month extension study was conducted for all patients who completed the randomized VeClose study and who were willing to participate. The pivotal VeClose study included patients with symptomatic moderate to severe varicosities (Clinical, Etiology, Anatomy, and Pathophysiology [CEAP] class C2-C4b) and symptomatic GSV incompetence who were randomly assigned (1:1) to either CAC or RFA. The primary outcome measure of this 60-month extension study was complete closure of the target vein, with planned exploratory analysis of noninferiority. Secondary outcomes included CEAP class; completion of the Venous Clinical Severity Score, EuroQol-Five Dimension survey, and Aberdeen Varicose Vein Questionnaire; patient satisfaction with treatment; adverse events (AEs) related to target GSV; and details of adjunctive procedures.

RESULTS

A total of 89 patients completed the 60-month visit, which included 47 from the CAC group, 33 from the RFA group, and 9 CAC roll-in patients. No new recanalization events have been observed in the groups between 36 and 60 months of follow-up. At 60 months, Kaplan-Meier estimates for freedom from recanalization in the randomized CAC and RFA groups were 91.4% and 85.2%, respectively, demonstrating noninferiority of CAC compared with RFA. Both groups demonstrated sustained improvements in EuroQol-Five Dimension and quality of life measures through 60 months. Whereas patients assigned to C0 or C1 clinical class were excluded from the original study, more than half of all returning patients (64% [57/89]) were now assigned to C0 or C1, suggesting an improved clinical class from baseline. Furthermore, 41.1% of returning CAC patients and 39.4% of returning RFA patients are presently at least two CEAP clinical classes lower than at baseline. No long-term device- or procedure-related serious AEs occurred in either group between 36- and 60-month follow-up.

CONCLUSIONS

CAC and RFA were effective in achieving complete target vein closure of the GSV at long-term follow-up, with CAC demonstrating continued noninferiority to RFA. CAC was also associated with sustained improvements in symptoms and quality of life, lower CEAP class, and high level of patient satisfaction without serious AEs between 36 and 60 months.

Laser ablation versus mechanochemical ablation in the treatment of primary varicose veins: A randomized clinical trial

OBJECTIVE

to prospectively compare the surgical outcome of using endovenous laser ablation (EVLA) and mechanochemical ablation (MOCA) in management of patients with primary varicose veins (VV).

METHODS

The present study prospectively recruited 100 patients with primary VV. They were randomly and equally allocated to one of two treatment group: the EVLA group (n = 50) or the MOCA group (n = 50). Before intervention, all patients underwent to clinical and ultrasound assessment of the vascular system. The Venous Clinical Severity Score was used to assess clinical severity. In addition, patients completed the Chronic Venous Insufficiency Questionnaire. The primary study outcome was treatment success. After intervention, patients were followed up at 1 week, 1 months, 6 months, and 12 months.

RESULTS

Operative success was achieved in all patients. The MOCA group had a significantly shorter operative time when compared with EVLA group. The Venous Clinical Severity Score significantly improved in both groups over the follow-up period and showed significantly lower levels in the MOCA group. Perceived pain was significantly improved in both groups postoperatively with no significant differences. The Chronic Venous Insufficiency Questionnaire was significantly improved after 12 months of operation without significant differences between groups. MOCA patients had significantly lower rate of postoperative phlebitis and significantly shorter time to return to work.

CONCLUSIONS

MOCA for primary VV is a feasible, effective, and safe procedure with better clinical outcome and lower rate of postoperative phlebitis when compared with EVLA.

Influência da densidade de energia endovenosa linear no sucesso da termoablação endovenosa a laser como tratamento da insuficiência venosa crônica

Background

It is relevant to elucidate the influence that mean linear endovenous energy density (LEED) has on the success of endovenous laser ablation treatment for chronic venous insufficiency, in order to reduce the method’s adverse effects.

Objectives

To evaluate the influence of mean LEED on the prevalence of saphenous closure 30 days after the laser ablation procedure.

Methods

153 lower limbs from 118 patients seen at a tertiary hospital and treated for chronic venous insufficiency with endovenous 1470 nm laser ablation under local anesthesia were evaluated. The mean LEED used to treat patients was calculated to determine whether greater than average LEED was required for treatment success.

Results

A significant difference (p = 0.021) in saphenofemoral junction closure was associated with mean LEED used above the knee. Conversely, there was no significant difference in the thigh segment.

Conclusions

Linear intravenous energy density greater than the mean of 70.57 J/cm was associated with a higher rate of closure at the saphenofemoral junction. However, density did not have an influence on the result for the thigh segment, showing that an energy density exceeding 70.57 J/cm tends not to be required for treatment of this segment.

Influência da termoablação com baixa e alta densidade de energia na junção safeno-femoral, utilizando laser endovenoso 1470 nm

Contexto

Faz-se importante o conhecimento técnico dos ajustes de potência e de densidade de energia linear endovenosa (linear endovenous energy density, LEED) adequados para atingir o objetivo final da termoablação endovenosa (endovenous laser ablation, EVLA).

Objetivos

Avaliar a influência de diferentes LEEDs em termos de patência e presença de refluxo, bem como determinar a evolução clínica.

Métodos

Foram incluídas 60 veias safenas magnas (VSM). Os pacientes foram randomizados em dois grupos: EVLA com baixa potência (7 W e LEED de 20-40 J/cm) e com alta potência (15 W e LEED de 80-100 J/cm). O acompanhamento com eco-Doppler e escore de severidade clínica venoso (VCSS) foi realizado nos intervalos de 3-5 dias, 30 dias, 180 dias e 1 ano após o procedimento.

Resultados

Dezoito pacientes (29 membros) tratados com 7W de potência e 13 pacientes (23 membros) com 15 W completaram o estudo. Não houve diferença significativa considerando idade, tempo de cirurgia e o uso de analgésicos, lateralidade, gênero e presença de comorbidades. O LEED médio foi de 33,54 J/cm no grupo de 7 W e de 88,66 J/cm no de 15 W. Ambos apresentaram melhora no VCSS, redução significativa dos diâmetros da JSF e ausência de diferença significativa quanto ao aumento do comprimento do coto da VSM e de refluxo após o tratamento.

Conclusões

A utilização de maior densidade de energia mostrou-se mais efetiva em relação à estabilização do comprimento do coto da VSM e do refluxo em 6 meses. Fazem-se necessários estudos com um período de acompanhamento maior para fundamentar essa hipótese.