Vascular Access: Core Curriculum 2008

Scribner shunt. The invention that made long-term hemodialysis possible in the early days was the removable U-shaped Teflon shunt connecting an artery to a vein in the arm of a patient. Reproduced with permission from Blagg et al.²⁸

From pathogenesis to pathology to novel therapies. This figure identifies the different pathogenetic mechanisms that result in dialysis access stenosis and directs attention to potential novel therapies. Pathogenetic factors include hemodynamic and surgical stressors, inflammatory stimuli from dialysis needles and polytetrafluoroethylene (PTFE) graft material, and the unavoidable vascular injury that occurs at the time of angioplasty. Novel therapeutic modalities include perivascular drug delivery, drug-eluting stents, coated grafts, and novel balloons. Reproduced with permission from Roy-Chaudhury et al.²⁴

Anatomy of arteriovenous (AV) fistulas (AVFs). The brachial artery bifurcates at the antecubital fossa into the radial and ulnar arteries, which perfuse the forearm. The cephalic vein runs superficially from the wrist to the shoulder on the radial (lateral) side. The basilic vein runs deep from the wrist to the shoulder on the ulnar (medial) side. The cephalic and basilic veins merge into the axillary vein near the shoulder. (A) A radiocephalic fistula is created by anastomosis of the end of the cephalic vein to the side of the radial artery near the wrist. (B) A brachiocephalic fistula is created by anastomosis of the end of the cephalic vein to the side of the brachial artery near the antecubital fossa. (C) A transposed brachiobasilic fistula is created by anastomosis of the end of the basilic vein to the side of the brachial artery near the antecubital fossa. Because the basilic vein runs deep and medial, the surgeon creates a longitudinal incision from the antecubital fossa to the shoulder. The basilic vein then is teased out of its native bed and tunneled superficially and laterally before its anastomosis to the artery to ensure ease of cannulation.

Clinical approach to management of dialysis catheter–related bacteremia (CRB). In catheter-dependent patients with suspected CRB (fever or rigors), after blood cultures (BCs) are obtained, empiric antibiotic therapy (Abx) is started with vancomycin (for coverage of methicillin-resistant Staphylococcus species) and ceftazidime or gentamicin (for broad-spectrum gram-negative coverage). In conjunction, an antibiotic lock (Fig 4) is instilled into each catheter lumen at the end of the dialysis session. Abx is discontinued in patients with negative culture results. If culture results are positive for coagulase-negative Staphylococcus species or gram-negative bacilli, the 2 treatment options are to: (1) continue appropriate systemic Abx with an antibiotic lock or (2) exchange the infected catheter over a new one over a guidewire. If fever and bacteremia persist despite antibiotic therapy, the catheter is removed and workup (WU) is initiated for metastatic infection. In infections caused by Staphylococcus aureus or Candida species, catheter replacement is mandatory. Abbreviations: HD, hemodialysis; CVC, central venous catheter; ECHO, echocardiography; Ampho B, amphotericin B. Adapted with permission from Allon.²