Strategy of Cyanoacrylate Closure Recanalization Case

Introduction, Objectives, and/or Purpose: Treatment method for recanalization case of cyanoacrylate closure (CAC) has been still unknown. Authors have reported that recanalization of CAC normally occurred in 7~12% cases. In our 205 cases experience, recanalization happened in 17 cases (8.3%) by 1 year after CAC and those were in different complicated morphologies. How should we treat the recanalization in complicated morphologies after CAC?
Sclerotherapy should be the first choice to consider. However, sometimes there are cases which cannot be occlusive even by sclerotherapy. Surgical resection is a safe and reliable method certainly, but it sometimes can be invasive and concerned about operative scars and adhesion around vein. Is endovenous thermal ablation (laser and radio frequency) safe and effective for CAC recanalization? To inquire this subject, we investigated our preliminary experiments in laboratory and 4 clinical cases which could be treated by endovenous thermal ablation.
Meanwhile, as operative technique for morphologically complicated varicose veins, we have over 5000 cases experience about laser multiple direct puncture ablation (MDPA) and over 100 cases experience of radio frequency (RF) MDPA. We also investigated these operative technique application and effect for CAC recanalization.

Methods: We investigated our 17 CAC recanalization cases retrospectively.
For 2 cases, we just observed, because of mild recanalization. We performed sclerotherapy for 13 cases. 11 cases could be treated. 2 cases could not be treated by sclerotherapy. We performed endovenous thermal ablation (EVTA) for these 2 cases. And in another 2 cases, recanalization occurred along the entire length of bilateral saphenous vein. For those cases, we performed EVTA without sclerotherapy. We investigated these operative cases retrospectively.
Moreover, we performed preliminary laboratory experiments. We already have enough information about normal ablation to vein wall. We need the information about ablation to coagulated cyanoacrylate (CA). Therefor experiments were performed with processed meat ham as alternative methods to animal experiments according to 1999 Bolognia declaration. We put experimenter’s blood to CA on the ham for coagulation. And we put 0.5% polidocanol on 8 specimens and ablated the coagulated CA by 1470nm laser slim fiber (LEED 65) and RF catheter (20 seconds) for 8 specimens each. We observed coagulated CA deformation, smell and other change.

Results: Case 1
In the first operative case, from 1 month to 9 months after CAC, we had tried 3 times sclerotherapy for bilateral small saphenous vein recanalization. But bilateral small saphenous veins reflux remained, therefor we decided endovenous laser ablation using MDPA technique. We ablated branches and bilateral small saphenous vein 3cm from saphenopopliteal junction by 1470nm diode laser bare tip fiber. No CA was observed in the ablated part. Post operative course was good without any complications.
Case 2
In the second operative case, 1year and half after CAC operation, we found that recanalization occurred along the entire length of bilateral great saphenous vein by ultrasonography. CA remained like wall thrombus. On the right side, residual CA reached closely to saphenofemoral junction. On both sides, lumen of great saphenous vein was patent widely along the entire length. We performed right side high ligation and both side RF ablation including residual CA. During high ligation, we recognized coagulated CA on the vein wall. Operation was done safely and post operative course was good without any complications.
Case 3
For the third operative case which could not be occlusive by sclerotherapy, we performed endovenous laser ablation for recanalized bilateral great saphenous vein. Before the operation, we planned operative methods against complicated and discontinuous recanalization pattern. Normal insertion method of laser catheter was impossible because of complicated shaped residual CA septum.
Meanwhile, we have performed laser MDPA against morphologically complicated varicose vein for over 5000 cases so far. Those cases had branching, meandering, grouped or discontinuous varicose vein. We treated those cases by only puncture ablation without incision. We performed collecting suture puncture and cross puncture depending on the varicose morphology.
This MDPA technique was effective for canulation of this third operative recanalized case. However, during operation by ultrasonography, we observed CA deformation by laser ablation. We stopped ablation at that point and changed plan. We ablated discontinuously only the part where we could observe no CA by ultrasonography. As a result, occlusion of great saphenous vein was good, and no complication happened.
We thought that deformation by laser ablation can be risk. Moreover, there is possibility that CA can remain thinly on the vessel wall, and we cannot recognize that by ultrasonography. We could deal with this case, but if cases will be accumulated, there will be some risk.
Meanwhile, although this laser MDPA method was useful with slim fiber, importantly there is the risk that slim fiber can be broken in 1% cases (our experience) during this MDPA method.
We investigated retrospectively traceable 26 cases about broken slim fiber. The reasons of slim fiber breakage seemed to be following 2 phenomena. First one was carbonization and adhesion around prism glass during big sized aneurysms ablation (15 cases). Second one was the external force to prism glass by plastic cannula distortion due to reefing puncture for strongly meandering aneurysms (16 cases). Laser MDPA can be performed safely without slim fiber breakage, if we select smaller diameter aneurysms than 6mm and make straight puncture effort as much as we can. We have never experienced slim fiber breakage after this effort. But this is the story for normal varicose vein, not about CA recanalization.
Preliminary experiments
After those 3 operations, we performed preliminary experiments in laboratory to investigate the potential risk about residual CA ablation.
How can laser ablation for coagulated CA influence safety and efficacy? Our laboratory preliminary experiments revealed laser ablation made hard deformation with some pointed parts and strong carbonization of coagulated CA with blood. And this carbonization cannot be removed from prism glass by gauze wipe because of strong adhesion. Processed meat ham wrapping coagulated CA showed no heat injury. It did not smell abnormally. We thought that carbonization adhesion around prism glass and hard deformation with shatp points of heated coagulated CA can make prism glass broken and tissue injury around vein. RF ablation made only soft and mild deformation. No carbonization, no adhesion and no abnormal smell occurred. Sclerotherapy liquid made no change for coagulated CA. This result suggests potential risk of laser ablation for coagulated CA that fiber prism glass breakage and tissue injury around vein. RF ablation can be safer than laser ablation for CAC recanalization.

Case 4
We think RF MDPA technique for branching or meandering varicose veins has potential for 2 kinds of cases. One is the strong meandering branches and big sized branches varicose vein which can make laser slim fiber prism glass broken. Another is the recanalization case of CAC.
This RF MDPA method is segmental sheathless ablation with 12G Angiocath puncture. We controlled duration time according to aneurysms size and depth from skin. No complications like burn and numbness were observed by this method in our 100 cases experience. Moreover, big sized aneurysms could shrink in short term, and number of punctures was smaller than laser MDPA. Importantly RF catheter is strong.
We tried radiofrequency ablation by MDPA technique for the 4th recanalized CAC case which sclerotherapy was unsuccessful for. We did not insert catheter in normal procedure with sheath, because there was the risk to push complicated shape residual CA or thrombus into deep vein. Under ultrasound observation, we insert 12G Angiocath needle into vein lumen or gap between residual CA and vein wall and sometimes penetrated residual CA septum. We ablated vein wall including residual CA segmentally each 7cm. We needed 4 punctures for above knee great saphenous vein. During operation, we observed the no deformation of CA by RF ablation. We performed ablation including residual CA part. Post operative course was good without any complications.

Conclusion(s): Treatment for recanalization after CAC has been unknown. And sometimes it can occur in a complicated morphology. First choice should be sclerotherapy and open resection can be a safe and reliable method. But morphologically complicated recanalization cases and cases of strong adhesion to the tissue around vein after CAC can be treated by RF MDPA. RF MDPA can be a good method for recanalized CAC case clinically without concern of heating CA and technical approach to complicated morphology recanalization. Laser MDPA can have the rsik for prism glass breakage and tissue injury around vein. We need more case accumulation for further investigation.