Primary and secondary patencies of transposed femoral vein fistulas are significantly greater than with the HeRO graft.

INTRODUCTION: For access-challenged patients with bilateral upper extremity central venous stenosis, solutions include the Hemodialysis Reliable Outflow (HeRO) device or an autogenous AV fistula in the lower limb. We evaluated HeRO grafts and transpositions of the femoral vein in maintaining primary and secondary patency. METHODS: We retrospectively analyzed 40 patients with a HeRO device and 18 patients with superficial femoral artery to transposed femoral vein autogenous arteriovenous fistula (SFA-tFV). All patients had bilateral central venous obstruction. All procedures were outpatient performed by a single surgeon at one center between 2009-2015. Operative details, intraoperative flows, and flows at the first-week postoperative visit were analyzed, as were primary and secondary patency and intervention rates. Complications were compared between groups. RESULTS: The one-year cumulative primary patency was 30% for HeRO grafts and 79% for SFA-tFV fistulas (p = 0.0001); secondary patency was 71% for HeRO grafts and 93% for SFA-tFV fistulas (p = 0.03). To maintain patency, HeRO patients required a mean 2.1 interventions per year and thigh fistula patients required a mean 0.4 interventions per year. Thirty-seven percent of thigh fistula patients had a hematoma or seroma versus 5% of HeRO patients and 17% of thigh fistula patients experienced delayed wound healing versus 2.5% of HeRO patients (p<0.05). None of the thigh fistula patients had distal ischemia. CONCLUSIONS: HeRO patients had lower primary and secondary patency rates versus thigh fistula patients and HeRO grafts required five-fold more interventions to maintain secondary patency. However, patients with thigh fistulas had significantly more wound healing problems. Thus, the SFA-tFV has become our access of choice for patients with bilateral central venous stenosis.

First-week postoperative flow measurements are highly predictive of primary patency of radiocephalic arteriovenous fistulas.

PURPOSE: This study was conducted to determine whether volume flow rate at the first postoperative visit could predict early failure of radiocephalic arteriovenous fistulas (RCAVFs). METHODS: We retrospectively studied the records of 264 patients who received a RCAVF between 2007 and 2013 at our centers. Data collected included patient demographics, medical history, arterial and venous mapping, and volume flow rate intraoperatively after fistula creation but before closing the surgical incision. An intraoperative flow rate >100 mL/minute was targeted. We measured volume flow at the first postoperative visit 1 week after surgery and thereafter as needed. RESULTS: Intraoperative flow was not a significant predictor of primary patency (p = 0.44) but flow at the first postoperative visit was a statistically significant predictor of fistula primary patency (p = 0.002). No fistula with a blood flow <200 mL/minute at the 1-week postoperative visit reached maturity without receiving a maturation procedure. The hazard ratio for the first follow-up flow (mL/min) was 0.9973 (95% CI 0.9956, 0 .9989), indicating that for every 100 mL increase in blood flow the primary patency increases by 10%. CONCLUSIONS: Flow rate at the 1-week postoperative visit was the most important predictor of RCAVF patency. Thus, it should be possible to identify patients who would benefit from early intervention or closer follow-up as soon as the first postoperative visit. This should help reduce the use of bridging hemodialysis catheters and minimize the risks of catheter dependency.

An interesting clinical case: variant of the cephalic vein emptying into the internal jugular vein.

This case report describes a 45-year-old patient who was referred to our center for surgical creation of long-term vascular access. Angiographic mapping revealed the left cephalic vein draining directly into the internal jugular vein rather than the axillary vein. The patient was scheduled for an ulnar artery to cephalic vein fistula.

A sterile elastic exsanguination tourniquet is effective in preventing blood loss during hemodialysis access surgery.

PURPOSE: We report the first use of a sterile elastic exsanguination tourniquet (SET) in performing hemodialysis vascular access procedures in 27 patients. The main advantages of this tourniquet are the reduction of blood loss and need for possible transfusions. Additional benefits are the near-perfect exsanguination and excellent exposure of the operative field. METHODS: This SET is a sterile elastic stockinet device that rolls up the arm starting from the hand by pulling on two handles. The elastic silicone ring provides sufficient pressure (220 ± 30 mmHg) to block arterial flow into the limb. The stockinet can be cut to provide access to the incision area while providing an additional sterile cover over the rest of the limb. RESULTS: No transfusions were required in any patients. Minor adverse effects occurred in four patients, including a twisted vessel, a bleeding vascular branch, a tear in atrophic arm skin, and pain, all of which had resolved on subsequent follow-up. Operational recommendations to avoid these adverse effects are outlined. CONCLUSIONS: We conclude that this sterile elastic exsanguination tourniquet is effective and safe in preventing bleeding during upper extremity hemodialysis vascular access procedures.

High incidence of perigraft seroma formation with gelatin-coated polytetrafluoroethylene grafts.

We reviewed the effectiveness of a gelatin-coated polytetrafluoroethylene (PTFE) graft designed to reduce suture line bleeding and graft weeping. Twenty-nine adults with end-stage renal disease underwent implantation the graft (n = 30) in the arm. All had preoperative ultrasound vascular mapping to assess their options for an autogenous arteriovenous fistula and patients with a history of prior central venous devices or sternotomy underwent contrast venography. A 4- to 7-mm tapered graft (n = 10) was used if the inflow artery was <4.0 mm in diameter, and a 6-mm straight graft (n = 20) was used if the artery was ≥4.0 mm. Intraoperative volume flows were measured by duplex methodology. Precautions to prevent ultrafiltration and seroma development were taken. Eleven clinically significant seromas were detected in 30 sealed PTFE grafts (36.7%), 10 in the 6-mm grafts (50%), and 1 in a 4- to 7-mm graft (10%), a significant difference between graft types. There were no significant differences in flow between the graft types and between grafts with seromas versus no seromas. Five grafts were explanted and one was ligated, resulting in cannulation delays from 2 to 4 months. We conclude that the gelatin-sealed PTFE vascular graft is not the ideal prosthesis for hemodialysis access.

Cardiovascular and renal phenotype in mice with one or two renin genes.

We compared the phenotype of two common mouse models, C-57BL/6J (C57), which carries only the Ren-1c gene, and 129/SvJ (Sv-129), with both Ren 1d and Ren-2. We hypothesized two renin gene Sv-129 would have increased blood pressure and the renin-angiotensin system would be more influential in regulating renal function compared with one renin gene mice. Sv-129 consistently had higher blood pressure than C-57, whether conscious (128 versus 108 mm Hg, P<0.001) or anesthetized (102 versus 88 mm Hg, P<0.001). Plasma renin concentration in both conscious and anesthetized C-57 mice was 3- to 4-fold higher than in Sv-129 (P<0.05), whereas renal cortical renin content was 2.5-fold higher (P<0.005). Renal blood flow and renal vascular resistance were the same in C-57 and Sv-129. Exogenous angiotensinogen produced identical pressor and renal vasoconstrictor responses in both strains. Blocking AT1 receptors with losartan reduced blood pressure by 19 mm Hg in both strains. Nitric oxide synthase inhibition by l-NAME increased blood pressure by 29 mm Hg in C-57 and 35 mm Hg in Sv-129 mice, but the decrease in renal blood flow was 30% less in C-57 (P<0.025). We conclude that Sv-129 mice with two renin genes have higher blood pressure but lower plasma and renal renin than C-57 mice with one renin gene. Renin substrate may limit angiotensin II production in the mouse. In Sv-129, the influence of nitric oxide on renal but not systemic resistance may be exaggerated. Renin from Ren-2 may act independently of normal renin control mechanisms.