Chieh Suai Tan

The Impact of Transvenous Cardiac Devices on Vascular Access Patency in Hemodialysis Patients

Creating a vascular access in the presence of a cardiovascular implantable electronic device (CIED) in a patient with or approaching end‐stage renal disease can be challenging. In this study, we aimed to evaluate the impact of a CIED on the outcomes of vascular access creation in hemodialysis patients and determine their effects on vascular access patency. This is a single‐center retrospective review of hemodialysis patients who underwent vascular access creation after CIED placement. Outcomes of vascular access creation and need for endovascular interventions were compared between patients with vascular access created ipsilateral and contralateral to the site of CIED. Comparing patients with arteriovenous (AV) access created ipsilateral to CIED placement (n = 19) versus the contralateral side (n = 17), the primary failure rate was 78.9% versus 35.3% (p = 0.02). For AV accesses that were matured, the median primary patency durations for AV accesses created ipsilateral to the CIED was 11.2 months compared to 7.8 months for AV accesses created contralateral to the CIED (p = 1.00). AV accesses created ipsilateral to a CIED have a higher primary failure rate compared with the contralateral arm and should be avoided as much as possible.

Safety of percutaneous tunneled hemodialysis catheter procedures in patients receiving concurrent clopidogrel therapy

Purpose Patients on clopidogrel are at increased risk of bleeding. This study was commenced to assess the incidence of bleeding in dialysis patients who underwent tunneled hemodialysis catheter procedures while on clopidogrel therapy. Methods This is a single center retrospective study of 25 (10 men, 15 women; median age 70) dialysis patients in whom clopidogrel could not be discontinued and underwent tunneled hemodialysis catheter insertion, removal or exchange between the period March 2010 to November 2011. The medical records of patients were reviewed and complications were classified according to the Society of Interventional Radiology system. Fifty-three procedures (22 insertions, 11 exchanges and 20 removals) were performed in these patients. The pre-procedural median platelet count, International Normalized Ratio and partial thromboplastin time were 195×103/dL (range 50-666), 1.1 (range 0.9-3.3) and 26.3 seconds (range 22.5-69.8) respectively. Results and Conclusions Forty-six procedures were performed in patients on clopidogrel and aspirin treatment. Five procedures were performed in patients while on clopidogrel in combination with aspirin and warfarin, and two procedures were performed with patients on clopidogrel alone. There were no documented bleeding complications from tunneled hemodialysis catheter procedures performed in patients on concurrent clopidogrel therapy in our study. Further prospective assessment with a larger cohort is necessary in order to validate these findings.

Coronary-subclavian steal syndrome in a hemodialysis patient, a case report and review of literature.

Dialysis vascular access associated coronary‐subclavian steal or hypoperfusion syndrome is an uncommon but potentially life threatening condition. Awareness of this syndrome is important in the management of vascular access in hemodialysis patients. We report a case of dialysis vascular access associated coronary‐subclavian steal syndrome and review the literature on its pathogenesis and therapeutic implications.

Approach to Patient with Arteriovenous Access Presenting with Hand Pain

A dialysis patient presenting with hand pain ipsilateral to the arteriovenous access warrants careful evaluation. In particular, ischemic monomelic neuropathy and distal hypoperfusion syndrome are two important entities that an interventional nephrologist should be familiar with. The pathophysiology, diagnosis, investigations, and management of these conditions are discussed in this chapter.

Non-tunneled Hemodialysis Catheter

While tunneled dialysis catheters are preferred over non-tunneled dialysis catheters, the use of non tunneled dialysis catheter is indicated when

Declotting of dialysis vascular access

Thrombosis of AV access can be considered a renal “emergency” that requires urgent intervention. With the advent of interventional nephrology as a subspecialty, declotting of the AV access can now be performed swiftly with minimal disruption to the dialysis schedule of the patients.

Endovascular Stent Placement

The use of stents, specifically covered stents or stent grafts, in the treatment of dialysis vascular access dysfunction has been increasing over the past decade. Several retrospective studies have investigated the role of stent versus angioplasty in the management of dialysis access interventions. Nevertheless, due to the lack of robust level 1 evidence, placement of stents in the AV access circuit has remained controversial.

Vascular Anatomy for Hemodialysis Access

The dialysis circuit can be considered as a closed loop system that begins and ends at the heart. Any obstruction or stenosis within this circuit can lead to access failure. A good knowledge of normal vascular anatomy and its variant in the upper limb, thorax and thigh is crucial in the management of dialysis vascular access.

Minimally Invasive Banding Procedure

The creation of a hemodialysis access is a non-physiological process that joins the high flow arterial circuit to the low-flow, low-resistance venous pathway. This creates the potential for a spectrum of problems, including high-output cardiac failure and vascular access-associated distal hypoperfusion ischemic syndrome (DHIS) or steal syndrome. High-output cardiac failure occurs when the cardiac function is unable to meet up with the demands created by the shunting effects of the AV access while DHIS results when the AV access diverts an excessive amount of blood away from the distal artery, resulting in tissue hypoperfusion. Banding of the AV access is a procedure that is used to reduce the blood flow to the access by creating a high resistance band to restrict the flow of blood into the AV access. Specifically, the MILLER (Minimally Invasive Limited Ligation Endoluminal-Assisted Revision) banding procedure is a technique that can be used to reduce blood flow to the access with the aid of fluoroscopy and endovascular equipments.

Angiographic Imaging Equipment

Since the accidental discovery of x-rays in 1895, technology has evolved so rapidly that minimally invasive endovascular interventions are routinely performed under radiological guidance. Having good fluroscopic is pivotal for endovascular intervention. This chapter aims to explain some of the fundamental principles of fluoroscopy and the commonly used terminology in radiology.