A Venotomy and Manual Propulsion Technique to Treat Native Arteriovenous Fistulas Occluded by Thrombi

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1 Vascular and Interventional Radiology Original Research Won et al. A Technique to Treat AVFs Occluded by Thrombi Vascular and Interventional Radiology Original Research Je Hwan Won 1 Anjali Basnyat Bista 1 Jae Ik Bae 1 Chang Kwon Oh 2 Sung Il Park 3 Jong Hyeog Lee 4 Gyeong Sik Jeon 5 Won JH, Bista AB, Bae JI, et al. Keywords: arteriovenous fistulas, dialysis fistulas, hemodialysis, thrombectomy, transluminal angioplasty DOI: /AJR Received November 22, 2010; accepted after revision June 22, Department of Diagnostic Radiology, Ajou University College of Medicine, San 5, Woncheon-dong, Suwon, Yeongtong-Gu , Republic of Korea. Address correspondence to J. H. Won (wonkwak@ajou.ac.kr). 2 Department of Surgery, Ajou University College of Medicine, Gyeonggi-do, Republic of Korea. 3 Department of Diagnostic Radiology, Yonsei University College of Medicine, Sedasemun-gu, Seoul, Republic of Korea. 4 Department of Diagnostic Radiology, Gangneung Asan Hospital, Gangneung, Republic of Korea. 5 Department of Diagnostic Radiology, Budang Cha General Hospital, Seongnam, Republic of Korea. AJR 2012; 198: X/12/ American Roentgen Ray Society A Venotomy and Manual Propulsion Technique to Treat Native Arteriovenous Fistulas Occluded by Thrombi OBJECTIVE. The objective of our study was to evaluate the efficacy and safety of a venotomy and manual propulsion technique that is performed to treat failed native arteriovenous fistulas (AVFs) with chronic organized thrombi. MATERIALS AND METHODS. For this study, we retrospectively reviewed a total of 69 venotomy and manual propulsion procedures performed from October 2005 to July 2009 in 56 patients for the treatment of native AVFs occluded by chronic thrombi. Inflow, anastomotic, and outflow veins were occluded using balloon catheters. Venotomy was made in the thrombi-bearing vein, and thrombi were propelled toward the venotomy site in a milking manner and were removed. After repair of the venotomy using simple interrupted sutures, the occlusion balloons were deflated. Angioplasty of the underlying stenosis was performed. RESULTS. Technical success was achieved in 95.7% of the procedures and clinical success was achieved in 91.3%. The follow-up duration was 1 50 months (mean, 16.7 months), with 3-, 6-, and 12-month primary patency rates of 92.5%, 80.8%, and 58.1%, respectively, and secondary patency rates of 98.1%, 96.2%, and 91.7%. The complication rate was 7.24%, with two major and three minor complications. CONCLUSION. The venotomy and manual propulsion technique is effective and safe for the removal of chronic and organized thrombi from occluded native AVFs. T he global incidence of end-stage renal disease has shown an increasing trend [1]. Consequently, the number of patients with endstage renal disease treated by hemodialysis is also increasing and adequate treatment to maintain vascular access is of growing importance. Thrombosis of an arteriovenous fistula (AVF) and graft is a commonly encountered severe complication that contributes to significant morbidity and hospitalization of hemodialysis patients. The incidence of thrombosis in native AVFs is lower than in prosthetic grafts, and the majority of thrombosed native AVFs can be recovered using percutaneous methods of mechanical thrombectomy, percutaneous infusion pharmacologic thrombolysis, and pharmacomechanical thrombolysis [2 10]. However, because of the large burden of thrombi or the risk of pulmonary embolism, AVFs with large aneurysms or diffuse aneurysmal degenerations can be relative contraindications to percutaneous treatment [10]. Furthermore, thrombi can be old, organized, and adherent to the venous wall, which will increase the difficulty of removal by conventional percutaneous methods. The purpose of this study was to evaluate the efficacy and safety of a venotomy and manual propulsion technique for the treatment of failed native AVFs with thrombosis. Materials and Methods Patient Population During the period from October 2005 to July 2009, 69 procedures were performed using a venotomy and manual propulsion technique in 56 patients for the treatment of failed native AVFs with thrombotic occlusion in which the thrombi were chronic and organized. Inclusion criteria were echogenic thrombi on sonography within a dilated native AVF with a minimum diameter of 15 mm. Exclusion criteria were an infected AVF, an immature native fistula, a stent placed at the target lesion, any contraindication to contrast medium, and pregnancy. This retrospective study was approved by the institutional review board and written consent was obtained from all patients before the procedure. The study included 31 men and 25 women who ranged in age from 32 to 83 years (mean, 55 years). The clinical characteristics of the patients are listed in 460 AJR:198, February 2012

2 A Technique to Treat AVFs Occluded by Thrombi TABLE 1: Patient Demographics Characteristic Value Sex, no. of patients (% of total) Men 31 (55) Women 25 (45) Age (y) Mean 55 Range Side of fistula, no. of patients (% of total) Left 42 (75) Right 14 (25) Type of fistula, no. of patients (% of total) Radiocephalic 32 (57) Brachiocephalic 23 (41) Radiobasilic with transposition of the basilic vein 1 (2) Table 1. The duration from fistula creation to performance of the procedure was months (mean, 51 months), and all patients were undergoing regular hemodialysis. Patients were referred for fistulography and angioplasty because of no flow in 52 patients, a progressive decline of the dialysis flow rate in two patients, a progressive increase in static venous pressure in one patient, and arm pain in one patient. One of the patients underwent a kidney transplant 17 months after the procedure and another patient received a kidney transplant just 1 month after the procedure. No patient mortalities occurred during the follow-up period. A total of 742 endovascular procedures of failed native AVFs were performed at our institution during the study period. Among them, 141 cases (19%) were clotted AVFs. A total of 69 procedures using the venotomy and manual propulsion technique were performed to declot and treat 94 stenotic lesions of native AVFs in 56 patients during the study period. The remaining 72 cases were treated with a simple balloon maceration and aspiration technique. Twenty-five patients had one stenosis, 25 patients had two stenoses, five patients had three stenoses, and one patient had four stenoses. The anatomic locations of the stenoses were allotted to one of the following categories: arterial anastomosis, juxtaanastomotic vein, forearm cephalic vein, upper arm cephalic vein, axillary vein, or subclavian vein as shown in Table 2. Sedation, Analgesia, and Patient Monitoring IV remifentanil (Ultiva, GlaxoSmithKline) was administered to all patients for sedation and analgesia during the procedure. Remifentanil was prepared as a 0.01 mg/ml solution (1 mg of remifentanil mixed with 100 ml of normal saline) and was administered via an infusion pump at a rate of 0.1 μg/kg/min as the loading dose, 0.05 μg/kg/ min as the maintenance dose, and 0.15 μg/kg/min as the maximal dose, through exclusive IV access made on the back of the contralateral hand [11]. Infusion was started with the loading dose approximately 5 minutes before venotomy, and the infusion rate was adjusted depending on the patient s level of pain during the procedure. Patients were monitored by a designated nurse who used noninvasive measurements of blood pressure and arterial oxygen saturation; checked venous lines, reactions, and emotional status; and provided support. After the procedure, patients were transferred to the recovery room and were monitored at 5-minute intervals by a nurse for at least 30 minutes or until the patients had fully recovered from sedation. No anesthesiologist was present during the procedures. Fistulography and Initial Thrombectomy Procedure After a thorough physical examination of the AVF and the draining vein, fistulography was performed using a digital subtraction angiography technique and iodinated contrast material (iodixanol [Visipaque 320, GE Healthcare]). At first, a 6- or 7-French proximal introducer sheath was placed in the venous limb retrograde of the native AVF. Next, anastomosis catheterization with a 5-French angiographic catheter was performed, and fistulography was performed to document fistular thrombosis or stenosis. When fistulography was incomplete using the proximal sheath approach because there was a massive thrombosis in a proximal vein, we performed fistulography via another distal antegrade sheath toward the venous outflow to document the venous thrombosis or stenosis. For the first 15 cases, aspiration thrombectomy was performed using an 8-French introducer sheath (Desilets-Hoffman introducer sheath, Cook) as an initial treatment, followed by the venotomy and manual propulsion method. We performed aspiration thrombectomy using introducer sheaths from two access sites, antegrade and retrograde puncture, and fistulography was also performed via these sheaths. If aspiration was not possible or there was a flow-limiting residual thrombus, we converted to the venotomy and manual propulsion method. In the remaining 54 cases, we performed venotomy and manual propulsion thrombectomy as the sole treatment when echogenic, chronic thrombi were shown on sonography. Thrombolytic agents were not used in any of the cases. Venotomy and Manual Propulsion Thrombectomy Procedure The venotomy and manual propulsion technique was initiated once adequate thrombosis assessment and patient comfort were established. A 6- to 7-mm conventional angioplasty balloon (Ultrathin or Bluemax, Boston Scientific) or an 8.5- mm occlusion balloon (Occlusion Balloon Catheter, Boston Scientific) was inserted through the proximally inserted introducer sheath toward the anastomosis. The balloon was positioned in the nonthrombotic peripheral vein or the anastomosis to occlude inflow. A second sheath was inserted antegrade in cases in which prior insertion was not required during the diagnostic procedure, and another balloon was advanced into the patent proximal vein through the sheath to occlude regurgitated venous flow. Placement of this second balloon ensured isolation of the segment of the draining vein occluded by thrombosis during the procedure and minimized blood loss and the risk of embolism. Entry sites for the venotomy were selected on the basis of the findings from the physical examination, fistulograms, and sonograms. The most dilated segment of the thrombi-bearing draining vein, which had a diameter of at least 15 mm, was selected as the venotomy site. The minimum distance between each puncture site was 6 cm and the minimal distance required between the puncture sites and venotomy site was 3 cm. After local administration of 5 ml of 1% lidocaine, a ve- TABLE 2: Stenoses Characteristics No. (%) of Lesions Location (n = 94) Arterial anastomosis 10 (10.6) Juxtaanastomotic vein 35 (37.2) Forearm cephalic vein 18 (19.1) Upper arm cephalic vein 26 (27.7) Axillary vein 2 (2.1) Subclavian vein 3 (3.2) AJR:198, February

3 Won et al. notomy of 7 10 mm long was made transverse to the course of the draining vein using an 11 blade. The venotomy was then widened using a curved hemostasis. Thereafter, intermittent and firm external manual pressure was applied to dislodge the thrombi from the vein wall and the detached thrombi were manually propelled toward the venotomy site in a milking manner. With respect to the venotomy site, thrombi in the proximal draining vein were squeezed out first, followed by thrombi in the peripheral draining vein. Additional venotomies were made at another site in four patients when thrombi apart from the initial venotomy site could not be milked out. In such cases, the first venotomy site was sutured before selecting the second site for venotomy. Sonography was performed to confirm complete removal of all thrombi and to rule out the presence of any remnant thrombi. After thrombectomy using the manual propulsion technique had been completed, the draining vein was flushed using normal saline through the side port of the introducer sheaths. The skin of the venotomy was then closed using simple interrupted sutures with 3 0 or 4 0 nylon suture material in 2- to 3-mm intervals. The needling was done deeply as close to the vein wall as possible without penetrating it. Separate suturing of the vein wall at the venotomy site and of the subcutaneous layer was not done. The occlusion balloon was then deflated and angioplasty of all significant stenoses was performed through the two sheaths. The balloon that was occluding venous backflow was deflated first, followed by the balloon occluding arterial inflow, to reduce pressure at the suture site. For stenosis, percutaneous transluminal angioplasty (PTA) was performed and stents were placed if indicated (Fig. 1). The total procedure time ranged from 60 to 90 minutes depending on the number of thrombi and degree of adherence to the vessel wall. The native AVF could be used for hemodialysis immediately after the procedure. Sutures were removed 2 weeks after the procedure and after oral antibiotic had been administered to all patients. All procedures were performed in the angiography room by interventional radiologists. Definitions and Statistics Technical success of the procedure was defined as restoration of flow and residual stenosis with a maximal diameter of less than 30% of the preprocedural diameter. Clinical success was defined as the resumption of normal hemodialysis via the treated native AVF for at least one session after the procedure. Patency estimates were calculated using the Kaplan-Meier life-table analysis, and patency rates were measured from the time of percutaneous intervention. Primary patency was defined as the interval after intervention until the next access thrombosis or repeated intervention, and secondary patency was defined as the interval after interventions until the access was surgically revised or abandoned because of various factors. Kidney transplantation and death with patent fistula were regarded as the end of the study. Complications were investigated and classified as major or minor according to the definitions established by the Society of Interventional Radiology [12, 13]. Primary and secondary patency rates were calculated using the Kaplan-Meier method. The Cox multivariate proportional hazard regression model was used to identify variables associated with patency rates. The variables considered for analysis included the sex of the patient, age of the patient, the location and type of AVF, and the number of stenoses. Statistical analyses were performed using SPSS software (version 15.0, SPSS). Follow-Up Follow-up was performed by review of patients records. Fistulography was performed to assess patency when restenosis or occlusion of the fistula was suspected during physical examination or hemodialysis. In addition, some of the patients were also contacted by telephone and were interviewed on the last date of follow-up. Results Technical success was achieved in 95.7% of the procedures (66/69) and clinical success was achieved in 91.3% of the procedures (63/69). Three technical failures, which subsequently led to abandonment of the AVFs and new access creation, were attributed to flow restriction resulting from residual, highly echogenic, calcified thrombi in two patients and failure to cross a calcified occlusion of a juxtaanastomotic area in one patient. Technically successful procedures followed by clinical failures were attributable to a case of early restenosis of the cephalic arch possibly as a result of recoil, infection at the surgical site in one patient, and reocclusion of the operated native AVF before performance of the next postprocedure hemodialysis session. The duration of follow-up was 1 50 months (mean, 16.7 months). The primary patency rates were 92.5%, 80.8%, and 58.1%, at 3, 6, and 12 months, respectively, and secondary patency rates were 98.1%, 96.2%, and 91.7%. A Cox hazard analysis showed that none of the variables considered for primary patency (patient sex, patient age, location of AVF, type of AVF) were significantly associated with stenoses. Secondary patency was also found to be independent of the factors considered, including the sex and age of the patient, the location and type of AVF, and the number of stenoses. A total of 24 of the 56 patients included in the study underwent reintervention to maintain secondary patency during the follow-up period. The total number of reinterventions performed was 38 procedures and included 19 PTAs, 16 revisions of the venotomy and manual propulsion technique, and three repetitions of the venotomy and manual propulsion technique along with stent insertions. One of the patients underwent the same procedure a total of four times over a follow-up period of 31 months. Primary patency was 13 months after the first venotomy and manual propulsion technique and repeated procedures were performed at an average interval of 7 months. On the last date of follow-up, the operated native AVF continued to be patent and was used for regular hemodialysis with no complications. The complication rate was 7.24% (5/69) with two major complications and three minor complications. One major complication was wound infection at the surgical site, a result of which the native AVF had to be abandoned and a new access created on the patient s opposite arm. Another major complication was a case of massive bleeding at the venotomy site during suture removal, which was surgically corrected by a surgeon. For the patient who was bleeding from the previous venotomy site of the AVF, the inflow vein near the anastomosis was separated from the adjacent tissue and controlled with a vascular clamp. Another skin incision was made at the site of bleeding, after which the previously opened vein was separated from the skin and closed with continuous running suture. Blood flow was established through the vein of the AVF after the clamp was removed. Minor complications included one case of local bleeding at the surgical site and two subcutaneous hematomas. The local bleeding was managed by application of an extra suture at the surgical site, after which the bleeding stopped. Discussion Thrombosis of AVFs and grafts is a commonly encountered severe complication and should be reopened as soon as possible for resumption of regular hemodialysis. Results of declotting of native fistulas are much more rewarding than those of grafts. However, several difficulties may be encountered during 462 AJR:198, February 2012

4 A Technique to Treat AVFs Occluded by Thrombi declotting of native fistulas that may be of less significance when declotting a prosthetic graft. The techniques must be adapted to large vessels and large clot burden and always carry a risk of potentially fatal iatrogenic pulmonary embo- A B D F C E G Fig. 1 Images of 52-year-old man with failed brachiocephalic arteriovenous fistula with thrombosis in right upper arm vein. A, Venography image obtained through antegrade access shows thrombosis is filling in draining vein. B, Fistulography image obtained through retrograde access reveals near total occlusion of juxtaanastomotic site. C, Conventional angioplasty balloon (7 mm 4 cm) is advanced to juxtaanastomotic draining vein for occlusion of inflow and dilatation of stenotic segment. Another 10 mm 4 cm balloon is inserted to axillary vein for occlusion of backflow. D, Drawing shows venotomy and manual propulsion technique. Two occluding balloons are in place and thrombi are being squeezed out from venotomy site. Manual propulsion is repeated until all thrombi have been completely removed. E, Both acute and chronic thrombi are removed by manual propulsion technique. Ruler shows inches (top) and centimeters (bottom). F, After complete removal of thrombi has been confirmed, venotomy is closed with 3 0 or 4 0 nylon suture using simple interrupted suture technique. G, Fistulography image reveals flow of brachiocephalic fistula has been restored and there are no residual thrombi. No leakage of contrast material is observed at venotomy site. lism. The volume of thrombus in a native fistula can be high, and it cannot be pushed into the lung. Difficulty is further added by the fact that venous anatomy varies; the locations of stenoses vary; and the locations of aneurysmal segments, which may contain thick, old thrombi, also vary. Because the immediate success rate is slightly lower, declotting of a native fistula may be more difficult than declotting a graft and may require greater skill and experience [2, 14, 15]. AJR:198, February

5 Won et al. The technique of manual thrombectomy by squeezing or milking the vessel has been used previously in various surgical thrombectomy procedures to treat arterial embolism [16], acute deep vein thrombosis of the lower extremities [17, 18], tumor thrombosis in the inferior vena cava [19, 20], and thrombosed native AVFs [21]. The procedure consists of a vasculotomy and manual milking of the vessel for removal of thrombi. When performing our technique, we made a venotomy of approximately 7 10 mm so that it would provide an adequate orifice for removal of thrombi and would also be larger than any available catheter for aspiration. The larger the orifice, the easier the removal of thrombi will be particularly when thrombi are hard and organized. At times, vigorous acts of rubbing, squeezing, and pushing the thrombi toward the venotomy site were required for the detachment of thrombi that were adherent to the venous wall. This part of the procedure could result in substantial pain to the patient if sufficient control of pain was not ensured. Hence, to secure patient comfort and compliance, it is mandatory to ensure adequate pain control during the procedure. Because the most dilated segment of the thrombi-bearing vein was selected for venotomy, some narrowing in this segment after the procedure would not result in significant stenosis. Separate suturing of the venous wall at the venotomy site was not performed after completion of thrombectomy using the venotomy and manual propulsion technique. Deep needling was performed while suturing the skin with simple, interrupted sutures to include as much subcutaneous tissue as possible without causing injury to the underlying venous wall. The venous segment of a native AVF is subjected to a high-blood-flow and lowblood-pressure environment, and various theories exist to explain the mechanism of thrombus and aneurysm formation in a native AVF [22, 23]. Venous wall remodeling of a native AVF with adhesions to the surrounding tissue has also been shown by numerous histopathologic and experimental studies [24 26]. Furthermore, when there is no obstruction to venous outflow, the direction and tension of fistulous high blood flow will be preferentially toward the proximal vein, which leaves little opportunity for a pseudoaneurysm to develop after the procedure. Even in the unlikely event that a pseudoaneurysm develops, suturing of the skin closely approximates both sides of the incised vein wall, resulting in a minimal neck of the pseudoaneurysm. We encountered only one case of subcutaneous hematoma development after skin suture in a patient with a thick subcutaneous layer, and it was controlled by simple manual compression. In our study, technical success was achieved in 95.7% of the procedures (66/69) and clinical success was achieved in 91.3% of the procedures (63/69). Primary patency rates at 6 and 12 months were 80.8% and 58.1%, respectively, and secondary patency rates were 96.2% and 91.7%. These results compare favorably with those of various other studies that used percutaneous methods in the salvation of thrombosed native AVFs. The various percutaneous methods available for declotting a thrombosed native AVF consist of pharmacologic thrombolysis, mechanical thrombectomy devices, or a combination of these techniques [27]. Technical success with local or systemic pharmacologic thrombolysis has been reported to range from 33% to 94% [8, 9, 28 31]. The numerous drawbacks of the pharmacologic thrombolytic agents even when used in conjunction with the mechanical thrombectomy techniques are their limited use as an outpatient procedure, bleeding as a result of reopening of recent dialysis puncture sites, inconsistent effectiveness due to collateral veins, and possible systemic complications of hemorrhage [27 31]. The recently introduced mechanical percutaneous thrombectomy techniques and devices include hydrodynamic thrombectomy catheters, the Arrow-Trerotola percutaneous thrombectomy device (PTD, Arrow), the rotating minipigtail catheter, the Castañeda brush catheter, and manual catheter-directed thromboaspiration [3 7, 14, 15, 32]. However, a considerable number of thrombi can remain after thrombectomy using these catheters, and their use is limited in large aneurysmal veins. Technical success rates for the hydrodynamic thrombectomy catheters range from 82% to 100%, with 6-month primary patency rates of 37 56% [5, 14, 15]. Technical success rates for the Arrow-Trerotola percutaneous thrombectomy device range from 87% to 100%, with 6-month primary patency rates of 38% and 60% [4, 32]. The rotating minipigtail catheter showed a 100% success rate and a primary patency rate of 47% at 6 months [6]. The technical success rate of the Castañeda brush catheter has also been reported to be 100%, with a 6-month primary patency rate of 62% [7]. The initial success rate reported for the manual catheter-directed thromboaspiration was 93% for forearm fistulas and 76% for upper arm fistulas, with 1-year primary and secondary patency of 49% and 81%, respectively, for forearm fistulas and 9% and 50% for upper arm fistulas [2, 3]. In comparison, the venotomy and manual propulsion technique produced commendable results and high primary and secondary patency rates. It is a simple, effective, and safe procedure for the removal of thick and organized thrombi. It can be performed as an outpatient procedure and allows immediate postprocedure hemodialysis if required. Furthermore, the venotomy and manual propulsion technique can also be applied for salvation of aneurysmal segments of veins that are usually resistant to treatment by other methods. This technique amalgamates conventional surgical methods with a modern approach and provides a time- and costeffective alternative for maintenance of the patency of thrombosed native AVFs. The limitations of this study are that it is retrospective, which means that not all of the patients underwent follow-up fistulography for the evaluation of the venotomy site, and that it requires long-term follow-up and reproduction of the study in other centers for confirmation of the results. Nonetheless, the venotomy and manual propulsion technique can be a novel approach for the salvation of native AVFs occluded with thrombi. References 1. Van Dijk PC, Jager KJ, Stengel B, Grönhagen- Riska C, Feest TG, Briggs JD. Renal replacement therapy for diabetic end-stage renal disease: data from 10 registries in Europe ( ). Kidney Int 2005; 67: Turmel-Rodrigues L, Pengloan J, Rodrigue H, et al. Treatment of failed native arteriovenous fistulae for hemodialysis by interventional radiology. 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