COMPARISON OF TWO SURGICAL METHODS USED FOR THE TREATMENT OF ACUTE THROMBOSIS OF ARTERIOVENOUS FISTULAS : THROMBECTOMY VERSUS DE NOVO CREATION OF ARTERIOVENOUS FISTULA

< e aim of this study was to evaluate effi cacy of two surgical methods used for the treatment of acute arteriovenous fi stula (AVF) thrombosis. Twenty two out of twenty fi ve patients that were admitted at the Clinic for vascular surgery in Sarajevo received successful surgical treatment for the salvage of acutely thromboses AVF from -. < ey were included in retrospective, descriptive clinical study. Based on the type of surgical procedures performed,  patients were divided into two groups. < e fi rst group included  patients and they had successful thrombectomy of thromboses AVF while  patients in second group underwent de novo creation of AVF using blood vessels already exploited for construction of thromboses AVF. Patency rate of salvaged AVF in analyzed groups was compared one month and  months after intervention. In the postoperative follow up there was no statistically signifi cant diff erence in patency rate of salvaged AVF between analyzed groups after one month, (  vs , Fisher exact test value =,, p= ,). Patency rate of salvaged AVF after six months of the follow up was signifi cantly better in group that received de novo construction of AVF when compared to thrombectomy group ( vs. , Fisher exact test value = ,, p=,). De novo construction of AVF in case of acutely thrombosed AVF off ered better patency rate of salvaged AVF when compared to surgical thrombectomy in the follow up period of six months.


Introduction
Although interventional radiology has become increasingly more present in the management of acute thrombosis of vascular access (arteriovenous fistula), conventional surgical treatment nevertheless plays signifi cant role in its treatment in many hospitals.Surgical thrombectomy of recently thrombosed arteriovenous fistula (AVF) is one method for AVF salvage but its successful outcome is signifi cantly jeopardized if it is performed  hours after occlusion ().Surgical thrombectomy may present itself as challenging procedure in terms of ability to remove occluding thrombus completely and that is the very reason why some authors make decision to create new vascular access ().
The aim of this study was to evaluate the efficacy of two surgical methods in salvage of thrombosed AVFthrombectomy of AVF with Fogarty catheter versus newly created AVF (de novo AVF) from the blood vessels that were used for the construction of mature and functional AVF until it failed due to acute thrombosis.

Materials and Methods
Twenty two out of twenty fi ve patients admitted to the Clinic for vascular surgery in Sarajevo, received successful surgical treatment for the salvage of acutely thromboses AVF from -.ey were included in retrospective, descriptive clinical study.All of  patients included in the study had matured and functional AVF until it became occluded.Based on the type of surgical procedures performed,  patients were divided into two groups.e fi rst group comprised  patients ( radio cephalic AVF and  cubit cephalic AVF) and they had successful thrombectomy of AVF in the period less than  hours from the moment of occlusion of AFV.Thrombectomy of AVF was performed with Fogarty catheter.All operations were performed in local anesthesia ( lidocaine).Operations were performed by specialist surgeon or by the resident under supervision of the specialist.For the purpose of thrombectomy, occluded AVF was dissected in scar tissue and venous limb of AVF was opened with transverse venotomy of suffi cient size to allow passage of catheter and extrac-tion of thrombus.If it was necessary, additional arteriotomy was created and repositioning of Fogarty catheter was made in order to remove extensive thrombus from arterial side.Patency of venous limb was confi rmed by unimpeded passage of heparins saline into the vein after removal of thrombus.Procedure was pronounced successful if thrill was palpated on venous limb of AVF.In the second group ( patients with radio cephalic AVF ) de novo creation of AVF was performed in the period less than  hours after thrombosis of AVF using blood vessels already exploited for construction of thromboses AVF but approximately - cm proximal to the site of previous anastomosis.Patency of AVF created in previously defined groups was compared one month and  months after intervention.Two patients with AVFs that were not salvaged with thrombectomy procedure and one patient from the second group whose AVF functionality was not salvaged with de novo creation of AVF were not included in study.

Results
Ten out of twelve AVF that underwent thrombectomy procedure were salvaged in the fi rst group of patients while  out of  AVFs were functional again after de novo creation of AVF.Patency of three AVF could not be restored surgically due to intensive proximal vein fibrosis changes and those AVF were not included in the study. of surgical interventions consisted of de novo construction of AVF and thrombectomy contributed to  of total operations (Figure ).Twenty one radio cephalic AVF and one cubit cephalic AVF were salvaged (Figure ).Patency of salvaged AVF, one month after intervention, was  in the fi rst group and  in the second group of patients (Figure ).Patency of AVF six months after performed procedure was  in the fi rst group of patients and  in the second group of patients (Figure ).There was no statistically signifi cant diff erence regarding obtained results between analyzed groups one month after intervention (Table , Fisher exact test value=,, p=,).e diff erence in patency rates of AVF between analyzed groups  months after the procedure was statistically signifi cant (Table , Fisher exact test value=,, p=,) in favor of better patency with "de novo" constructed AVF.

Discussion
While some authors do not favour surgical thrombectomy of acutely thromboses AVF (), others on the other hand when comparing surgical thrombectomy with endovascular treatment of this condition have obtained similarly good results with both methods and interestingly enough according to Tordoir et associates () primary and secondary patency in their study was even better in case of surgical thrombectomy method until .ereafter they report almost the same results for both methods ().Technical success of thrombectomy in our study equals  (/ thrombectomies) and it positively correlates with results published by Palmer et al () (). surgical thrombectomies were performed by specialist surgeon ( patients in group I and  patients from group II ), while the rest of operations performed physician in the residency program under supervision of the surgeon specialist.According to the study of Gundevia et al.()  there is no signifi cant diff erence regarding technical success of the operation when it was performed either by specialist or by the resident who was under supervision of the surgeon specialist().Primary patency of thrombectomized AVF in the study of Palmer et al. after  months was , while in our study patency of AVF salvaged by the same method was only .Although Palmer reports that thrombectomy may significantly prolong AVF life, our results failed to prove that since after  months only  of thrombectomized AVF were patent, while de novo constructed AVF prolonged usage of vascular access in case of  of patients with statistically signifi cant difference ( vs. , p=,).Our results of patency

TABLE 1 .
Statistical signifi cance (Fisher exact test and p value) of obtained results in relation to salvaged AVF patency rate one month after procedure SBOSNIAN JOURNAL OF BASIC MEDICAL SCIENCES 20010; 10 (SUPPLEMENT 1): S98-S99 NEDŽAD RUSTEMPAŠIĆ, EMIR SOLAKOVIĆ: OUTCOME COMPARISON OF TWO SURGICAL METHODS USED FOR THE TREATMENT OF ACUTE THROMBOSIS OF ARTERIOVENOUS FISTULAS: THROMBECTOMY VERSUS DE NOVO CREATION OF ARTERIOVENOUS FISTULA

TABLE 2 .
Statistical signifi cance (Fisher exact test and p value) of obtained results in relation to salvaged AVF patency rate six months after procedure of salvaged AVF after one month have shown no difference between AVF salvaged by either methods ( vs. , p=,).Ponikvar in his study also reported superiority of thrombectomy followed by creation of new AVF when compared to mere thrombectomy of AVF for the salvage of thromboses AVF.Diff erence in patency rate between two methods in his study after one year of follow up was  vs.  in favor of newly created AVF supposedly by virtue of reduced intima media thickness in case of already remodeled vein().