Mei-Jui Weng

Percutaneous Vein Graft Reanastomosis with Use of a Covered Stent to Salvage a Thrombosed Hemodialysis Graft

Technical success rates for percutaneous restoration of thrombosed arteriovenous grafts are high. However, in thrombosed grafts without restorable original outflow veins, percutaneous salvage is usually not possible. In this situation, patients are referred for bypass grafting or recreation of their vascular access sites. This report describes a patient in whom the original outflow vein at the venous anastomosis was completely obliterated and in whom vascular access was successfully salvaged by percutaneously reanastomosing the venous stump of the thrombosed graft with an adjacent patent vein. This procedure is technically feasible for the salvage of a thrombosed graft.

The usefulness of fast-spin-echo T2-weighted MR imaging in Nutcracker syndrome: a case report.

Nutcracker syndrome occurs when the left renal vein (LRV) is compressed between the superior mesenteric artery and the aorta, and this syndrome is often characterized by venous hypertension and related pathologies. However, invasive studies such as phlebography and measuring the reno-caval pressure gradient should be performed to identify venous hypertension. Here we present a case of Nutcracker syndrome where the LRV and intra-renal varicosities appeared homogeneously hyperintense on magnetic resonance (MR) fast-spin-echo T2-weighted imaging, which suggested markedly stagnant intravenous blood flow and the presence of venous hypertension. The patient was diagnosed and treated without obtaining the reno-caval pressure gradient. The discomfort of the patient lessened after treatment. Furthermore, on follow-up evaluation, the LRV displayed a signal void, and this was suggestive of a restoration of the normal LRV flow and a decrease in LRV pressure.

Use of angioplasty balloon-assisted Seldinger technique for complicated small vessel catheterization.

From: Matt Chiung-Yu Chen, MD Shih-Chin Chang, MD Mei-Jui Weng, MD Wen-Sheng Tzeng, MD Reng-Hong Wu, MD Huei-Lung Liang, MD Huay-Ben Pan, MD Department of Diagnostic Radiology (M.C.Y.C., S.C.C., W.S.T., R.H.W.) Chi-Mei Medical Center Yung-Kang Campus Yung-Kang City, Tainan County 806, Taiwan; and Department of Radiology (M.J.W., H.L.L., H.B.P.) Kaohsiung Veterans General Hospital Kaohsiung, and National Yang-Ming University Taipei, Taiwan

Short-term follow-up for percutaneous extra-anatomic intervascular anastomosis in salvage of a thrombosed native arteriovenous fistula.

Percutaneous extra-anatomic intervascular anastomosis (PEIA), i.e., the nonsurgical connection of two anatomically unrelated vascular lumina, has rarely been reported in peripheral applications. Chen et al. [1] recently described a PEIA technique applied in peripheral vascular intervention. Using the same technique, the authors successfully salvaged an occluded native arteriovenous (AV) fistula with obliterated outflow veins. The vascular access has been followed up for more than 6 months and access-related complications are reported here. A 54-year-old woman with a failed and diffusely thrombosed native radiocephalic fistula in the right forearm was referred for shunt salvage. The fistula had been used for about 13 years. Informed consent was obtained. The institutional review board was not required for this retrospective report in our hospital. On physical examination, a hard and dilated forearm cephalic vein was noted, terminating as a venous stump not far below the elbow crease. Using local anesthesia, a 7-Fr introducer sheath was inserted in antegrade fashion in the forearm cephalic vein about 4 cm downstream of the AV anastomosis. A 4.1-Fr angiographic catheter was advanced to the venous stump and a small test bolus of contrast material was injected. No outflow vein from the venous stump could be identified on fluoroscopy. Under sonographic guidance, small thrombosed veins were catheterized, but attempts to get access into the dilated venous stump failed (Fig. 1A). During the search for small thrombosed veins around the venous stump, an upper arm basilic vein near and medial to the venous stump was noted. The patent basilic vein was catheterized under sonographic guidance and the venogram revealed no direct anastomosis with the venous stump (Fig. 1B) and the finding was comfirmed by sonography. A new vascular access creation was therefore suggested but the patient refused surgery after a thorough explanation to her and her family. In order to restore sufficient shunt flow, a good outflow drainage tract from the venous stump was required. Therefore, we attempted to salvage the fistula using the technique reported by Chen et al. [1] by stent-graft insertion between the venous stump and an adjacent patent basilic vein. An 8 · 60-mm stent-graft (Wallgraft; Boston Scientific, Natick, MA) was used to bridge the two ends of the fistulous tract. The stent-graft was dilated with an 8mm ·4-cm PTA balloon catheter. Thrombolysis was performed thereafter using 500,000 IU of urokinase. Thromboaspiration was performed with an 8-Fr Desilets-Hoffman sheath (Cook, Bloomington, IN, USA). Before thrombolysis, a bolus of 5000 IU heparin was given through a peripheral intravenous line. The AV fistula was successfully salvaged and the immediate follow-up fistulography showed brisk flow with presumed compression of a segment of the runoff basilic vein by hematoma (Fig. 1C; arrow). No immediate complications were noted and the patient underwent successful hemodialysis the next morning. The patient was called back for a fistulography 1 month after M. C.-Y. Chen (&) R.-H. Wu W.-S. Tzeng S.-C. Chang Department of Diagnostic Radiology, Chi-Mei Medical Center, Yung-Kang Campus, No. 901, Chung Hwa Road, Yung-Kang City, Tainan County 806, Taiwan e-mail: jjychen@gmail.com

The pipeline technique: a simple endovascular technique for creation of a jump graft bypass.

Purpose The purpose of this study is to describe a technique by which a bypass was created percutaneously with two overlapping covered stents for salvage of a thrombotic right brachial-axillary arteriovenous graft without recanalizable outflow. Methods and results With the pipeline technique, a 16 cm bypass tract covered with two overlapping Viabahn stents between the hemodialysis graft and the right subclavian vein was created as an alternative access outflow. The hemodialysis graft was successfully salvaged without complications and functioned well for more than 6 months except for one thrombosis which occurred 147 days after its salvage. Conclusions We describe an endovascular bypass technique using a sheath-dilator set and two angiographic catheters to salvage a thrombotic hemodialysis graft.

Endovascular bypass for salvage of vascular access in hemodialysis catheter-consigned patients

Purpose: This study was performed to retrospectively assess the efficacy of percutaneous creation of an intervascular bypass with or without stent graft deployment (endovascular bypass) for salvage of abandoned vascular access sites in hemodialysis catheter-consigned patients. Methods: Salvage of abandoned vascular access sites was attempted in 16 patients with hemodialysis catheters. These vascular access sites were salvaged using endovascular bypass techniques to redirect the access flow to a nonarterialized vein as a new outflow conduit or cannulation segment. The postintervention primary, assisted primary, and secondary patency rates of the access site and bypass were calculated using the Kaplan–Meier method. Results: The procedural and clinical success rates were both 100%. The postintervention primary patency rate of the bypass and access site at 360 days was 75.7 ± 12.5% and 56.8 ± 14.9%, respectively. The mean follow-up period was 461.9 days (range: 121–900 days). No major complications were observed. One bare bypass tunnel rupture and one pseudoaneurysm were noted during the procedure. Conclusion: Salvage of abandoned vascular access sites for hemodialysis catheter-consigned patients can be technically feasible and clinically successful using endovascular bypass techniques in selected patients when surgical revision is not considered or is not possible.

Use of a portal vein localization sheath in the single-needle pass technique for creation of a portosystemic shunt

This study aimed to report a modification to the single-needle pass technique by use of a portal vein localization sheath for creation of a portosystemic shunt. The modification makes the single-needle pass technique a more straightforward procedure.

Treatment of Hemodialysis Vascular Access Rupture Irresponsive to Prolonged Balloon Tamponade: Retrospective Evaluation of the Effectiveness of N-Butyl Cyanoacrylate Seal-Off Technique

Objective The current study retrospectively evaluated whether the percutaneous N-butyl cyanoacrylate (NBCA) seal-off technique is an effective treatment for controlling the angioplasty-related ruptures, which are irresponsive to prolonged balloon tamponade, during interventions for failed or failing hemodialysis vascular accesses. Materials and Methods We reviewed 1588 interventions performed during a 2-year period for dysfunction and/or failed hemodialysis vascular access sites in 1569 patients. For the angioplasty-related ruptures, which could not be controlled with repeated prolonged balloon tamponade, the rupture sites were sealed off with an injection of a glue mixture (NBCA and lipiodol), via a needle/needle sheath to the rupture site, under a sonographic guidance. Technical success rate, complications and clinical success rate were reported. The post-seal-off primary and secondary functional patency rates were calculated by a survival analysis with the Kaplan-Meier method. Results Twenty ruptures irresponsive to prolonged balloon tamponade occurred in 1588 interventions (1.3%). Two technical failures were noted; one was salvaged with a bailout stent-graft insertion and the other was lost after access embolization. Eighteen accesses (90.0%) were salvaged with the seal-off technique; of them, 16 ruptures were completely sealed off, and two lesions were controlled as acute pseudoaneurysms. Acute pseudoaneurysms were corrected with stentgraft insertion in one patient, and access ligation in the other. The most significant complication during the follow-up was delayed pseudoaneurysm, which occurred in 43.8% (7 of 16) of the completely sealed off accesses. Delayed pseudoaneurysms were treated with surgical revision (n = 2), access ligation (n = 2) and observation (n = 3). During the follow-up, despite the presence of pseudoaneurysms (acute = 1, delayed = 7), a high clinical success rate of 94.4% (17 of 18) was achieved, and they were utilized for hemodialysis at the mean of 411.0 days. The post-seal-off primary patency vs. secondary patency at 90, 180 and 360 days were 66.7 ± 11.1% vs. 94.4 ± 5.4%; 33.3 ± 11.1% vs. 83.3 ± 8.8%; and 13.3 ± 8.5% vs. 63.3 ± 12.1%, respectively. Conclusion Our results suggest that the NBCA seal-off technique is effective for immediate control of a venous rupture irresponsive to prolonged balloon tamponade, during interventions for hemodialysis accesses. Both high technical and clinical success rates can be achieved. However, the treatment is not durable, and about 40% of the completely sealed off accesses are associated with developed delayed pseudoaneurysms in a 2-month of follow-up. Further repair of the vascular tear site, with surgery or stent-graft insertion, is often necessary.