EL DISCURSO Y SUS DISCIPLINAS
2. LA SEMIÓTICA
In thesis we have demonstrated that MOCA is a safe, feasible and effective treatment in abolishing saphenous reflux. These good experiences with MOCA, still leave various questions to be answered and concerns to be resolved in the near future. Most interesting will be to monitor long term outcomes to determine if the good short term results of MOCA translate to good long term results as well. The tight and fibrotic collagen structures that were observed in the treated segment of MOCA after 1 year, justifies the thought that recanalization this area will be very unlikely15. On the other hand, treatment failures seem to increase over time with all endovenous procedures16. Therefore, long term results of MOCA are necessary to definitively place the position of MOCA among treatment options for varicose veins. Our study group will soon analyze the outcome after 3 years of follow-up in the prospective registry study. In this study 106 legs (92 patients) were treated with GSV insufficiency17.
When a new technology is introduced, development and standardization of the technique evolves over time. This is the case with RFA and EVLA, where catheters and tips are constantly perfected and adapted to new findings, and it will also be the case with MOCA. In MOCA there are several questions in standardization that need to be answered. The administration of the sclerosant dose is very pivotal. In our studies the dose of polidocanol was raised from 1.5% in the safety study to 3% in the proximal segment in the MARADONA study, to improve occlusion rates. The influences of different concentrations of sclerosant on outcome are studied in the ClariVein® dose finding trial (NTR3009), that randomizes patients with GSV insufficiency between treatment with polidocanol 2%, 3% and foam 1%18. In a previous study we already
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observed a higher anatomical success with polidocanol 2% compared with polidocanol 1.5%
(97% versus 87%)19. However, the difference between these was not statistically significant, probably because of the small number of patients.
In the hierarchy of research designs, the results of randomized controlled trials are considered to be evidence of the highest grade, whereas observational studies are viewed having less validity, because they might overestimate treatment effects. Therefore, we designed two multicenter randomized controlled trials (MARADONA trial, NCT01936168 and MESSI trial, NTR4613). The aim of both ongoing trials is twofold. First, it hypothesizes that anatomical success of MOCA is comparable with RFA in the treatment of GSV and SSV insufficiency. Secondly, it aims to demonstrate that MOCA is associated with less postprocedural pain than RFA. A cost analysis comparing MOCA with RFA will also be performed in the MARADONA study. In the background of increasing health resources, a rational cost analysis is necessary to determine the position of MOCA with other endovenous techniques. Nevertheless, the actual costs of treatment are influenced by several factors that should be encountered in the economic value of a new technique. For example, postprocedural pain leading to a longer recovery and delayed return to work;
the shorter time to perform the procedure; long term clinical and anatomical success;
and the number of re-interventions need to be evaluated as well. Our hypothesis, that adjunctive procedures are carried out less frequent after MOCA is an interesting point in terms of patient satisfaction and costs.
Also, a comparison in outcome between polidocanol and sotradecol would be very interesting to evaluate. Sotradecol is known to be a more potent sclerosant than polidocanol. Moreover, the outcome of MOCA with sotradecol appears to be slightly better than MOCA with polidocanol, as shown in chapter 2, but this observation is not evidence based. A randomized controlled trial that compares anatomical success of MOCA between patients treated with sotradecol versus polidocanol is an appropriate approach to study this issue. Unfortunately sotradecol is not registered in the Netherlands, and our study group is not able to design this study.
Histopathological outcomes are important in order to expose the mechanism of action of a technique and offers opportunities to improve the clinical results by adjusting details of the technique. There is only one study that has examined the effect of MOCA on the vein wall20. We have commenced an animal study that evaluates the histological effects of MOCA, sclerotherapy and mechanical abrasion without infusion of a sclerosant. Analysis of the specimens will be performed directly and six weeks after the procedure.
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