An Animal Experimental Study On Endovenous Radiofrequency Ablation Treatment

Objective:To observe the influences of endovenous radiofrequency ablation of varicose veins on coagulable states of blood and evaluate its safety and efficacy,and to provide a thechnique support and theory knowledge of endovenous radiofrequency ablation.Methods:Fourteen canines,weighing between 7 and 10kg,were divided randomly into two groups according to bandaging the operated legs(Group A, n=7)or not(Group B,n=7).A external jugular vein access was established using the seldinger technique,a 6-F radiofrequency catheter was inserted. Endovenous radiofrequency ablation was performed in left iliac-femoral vein.(1)GMP-140,t-PA and PAI-1 levels of plasma were monitored at nine different time points:before and after sheath entry,immediately,30 minutes, 12h,24h,48h,72h and one week after endovenous radiofrequency ablation.(2)The change of inner diameter of iliac-femoral veins in angiography was observed at four different time points:immediately,one week,two week and four week after endovenous radiofrequency ablation.(3)The sections of ablation were cut and stained by HE methods,and examined under light microscope at two different time points:immediately and four week after endovenous radiofrequency ablation. Results:(1)The expression of GMP-140 increased after sheath entry(P＜0.05)and much higher than after ablation.It reached its peak value at 48 hours and then begin to droped,remained at higher level than that at preoperation for one week.fore the treatment.Both t-PA and PAI-1 levels of plasma had no difference between before and after sheath entry,and increased just after ablation and droped to normal after one week(P＞0.05),t-PA reached its peak value just after ablation,while PAI-1 at 30mins after ablation.(2)Iliac-femoral vein showed patent in Venography before endovenous radiofrequency ablation.Venography after immediately ablation showed stenosis of left iliac-femoral vein in both group A and B.The stenosis of left external iliac and femoral vein was more obvious than that of left common iliac vein.The difference of venous had statistical significance(P＜0.05)at one week and two weeks after ablation.The degree of stenosis in left iliac-femoral vein of group A was obviously than that of group B.Due to more thrombsis in left iliac-femoral of group B,recanalizatioin of occlusion regment in group B was more common than that in group A at four week after ablation.(P＜0.05).(3)On gross examination,radiofrequency catheter ablation immediately after operation produced the endangium of vein wall obvious dropsy,hurt obviously,tissue necrosis,little mural thrombus was formed in the vessel.Four weeks later,group A displayed firm,irregularly contraction,harder than group B. (4)Histological examination revealed that intimal injury,necrotic myocardium and basophile infiltration immediately after ablation,but adventitia was integrity.Little mural thrombus was formed in the vessel.Four week later,group A displayed elastic lamina proliferation,haeder than group B. endovascular contraction,a great quantity of inflammatory cell infiltration in the vessel wall.Thrombus was partily lysis.Conclusions:(1)Endovenous radiofrequency ablation is a safe and effective micro-invasive method.(2)Exsanguinating the vien before and duiring radiofrequency ablation, pressure dressing the operated limb after operation were beneficial for curative effect.(3)Endovenous radiofrequency ablation of varicose veins could result in hypercoagulabale state.Prophylactic antiplatelet and anticoagulant after radiofrequency ablation are necessary to decrease the risk of thrombosis.