Proximal Radial Artery Research Articles

Early results of percutaneous arteriovenous fistula creation with the Ellipsys Vascular Access System

ObjectiveWe reviewed our initial experience creating a percutaneous arteriovenous fistula (pAVF) using a thermal resistance anastomosis device with proximal radial artery inflow. MethodsA retrospective review was conducted of all patients who underwent a pAVF creation procedure between May 2017 and October 2017. Primary end points of the study were technical success, patency by Doppler ultrasound examination or angiography, flow levels achieved, time to first use, and pAVF-related complications. ResultsA pAVF was attempted in 34 patients with technical success in 33 individuals (97%). Patency of the pAVF was 94%. Mean access flow was 946 mL/min (brachial artery measurement) at the latest follow-up visit (53-229 days; average, 141 days). At 6 weeks, all fistulas have been used or were ready for dialysis by clinical examination or ultrasound examination. Only one patient required superficialization of the upper arm cephalic vein by lipectomy. There were no adverse events related to the pAVF creation or use, nor was there need for further interventions. ConclusionsSuccessful pAVFs with proximal radial artery inflow were created with excellent initial results regarding technical success, patency, and safety. Advantages include avoidance of a surgical incision, short procedure times, good acceptance by patients, prompt access maturation, moderate flow, and low-pressure access, with possible reduction of risk for ischemic complications. Avoidance of vessel manipulation and side branch ligation might reduce risk of thrombosis and improve long-term patency and reduce need for further interventions. These early findings need to be confirmed in larger and longer follow-up studies.

Proximal radial artery ligation after distalization of a high flow brachio-cephalic fistula. A novel approach to inflow reduction.

High flow fistulae present a common challenge to vascular access (VA) surgeons and many strategies have been described, each with their benefits and limitations. There are no NK-DOQI guidelines for the management of high flow fistulae or indeed the management of those refractory to more conventional approaches. We discuss a novel technique to inflow reduction in a previously distalized brachiocephalic fistula and recommend the technique of proximal radial artery ligation.

The Pivotal Multicenter Trial of Ultrasound-Guided Percutaneous Arteriovenous Fistula Creation for Hemodialysis Access

PurposeTo evaluate safety and efficacy of arteriovenous fistulas (AVFs) created with a thermal resistance anastomosis device. Materials and MethodsA prospective single-arm trial at 5 sites enrolled 107 patients. Patients underwent ultrasound (US)-guided anastomosis creation between the proximal radial artery and perforating vein with the Ellipsys Vascular Access System (Avenu Medical, Inc, San Juan Capistrano, California) followed by separate maturation procedures. Primary endpoints were brachial artery flow volume ≥ 500 mL/min and target vein diameter ≥ 4 mm in > 49% of patients and absence of device-related complications at 90 days. ResultsAVFs with fused anastomoses were created in 95% (102/107) of patients. Maturation procedures included anastomotic balloon dilation in 72% (77/107), brachial vein embolization in 32% (34/107), cubital vein ligation in 31% (33/107), and surgical transposition in 26% (28/107) of patients. Primary flow and diameter endpoints were achieved in 86.0% (92/107) of patients, exceeding performance goal of 49% (P < .0001). No major adverse events were attributed to the device. Cumulative patency was 91.6%, 89.3%, and 86.7% at 90 days, 180 days, and 360 days. Target dialysis veins were cephalic, basilic, and brachial veins in 74% (73/99), 24% (24/99), and 2% (2/99) of patients. Two-needle dialysis was achieved in 88% (71/81) of patients on hemodialysis at a mean 114.3 days ± 66.2. Functional patency was 98.4%, 98.4%, and 92.3% at 90 days, 180 days, and 360 days. ConclusionsThe Ellipsys® Vascular Access System met primary safety and efficacy endpoint goals in the US pivotal trial.

Proximal ulnar artery arteriovenous fistula inflow is an uncommon but useful vascular access option.

A proximal ulnar artery arteriovenous fistula (PUA-AVF) is a logical vascular access option when the distal ulnar artery is occluded or inadequate in addition to other specific vascular anatomic variants. This study reviews a series of patients where the proximal ulnar artery was used for AVF inflow in establishing a reliable autogenous access for these uncommon patients. All new patients referred for vascular access with a PUA-AVF created during an eight-year period were evaluated. In addition to physical and ultrasound examinations, all patients had an Allen's test performed augmented with Doppler evaluation of the palmer arch. Analysis placed these patients into three anatomic groups: 1) A dominant radial artery with distal ulnar artery occlusive disease; 2) No cephalic or basilic vein option with an isolated and intact brachial vein originating from the ulnar vein for later staged transposition; 3) A proximal radial artery ≤2 mm in diameter and a normal Doppler augmented Allen's test. PUA-AVFs were created in 32 new patients during an eight-year period. Primary and cumulative patency rates were 80% and 94% at 12 months and 55% and 81% at 36 months. Follow-up was 2-62 months (mean 14 months). No patients developed steal syndrome during the study period. A PUA-AVF is a safe and reliable autogenous access. It is particularly important when the radial artery is the only or dominant arterial supply to the hand, in patients with small but patent radial arteries, and in selected individuals requiring a brachial vein transposition.

Forearm versus upper arm grafts for vascular access.

Forearm and upper arm arteriovenous grafts perform similarly in terms of patency and complications. Primary patency at 1 year for forearm arteriovenous grafts versus upper arm grafts ranges from 22%-50% versus 22%-42%, and secondary patency at 1 year ranges from 78%-89% versus 52%-67%), respectively. Secondary patency at 2 years, ranges from 30%-64% versus 35%-60% for forearm and upper arteriovenous graft, respectively. Ample pre-operative planning is essential to improved clinical success and the decision to place a graft at one location versus the other should be based solely on previous access history, physical exam, appropriate venous imaging, and other factors that make up the clinical picture. Operative implant strategies and risk of complications are very similar between the two configurations. Postoperative ischemia due to steal syndrome is a potential complication that requires immediate attention. Utilization of the proximal radial or ulnar artery for inflow for the graft can minimize risk of clinically relevant steal syndrome.

True aneurysm of proximal radial artery

True aneurysm of upper limb arteries is a rare entity with very few reported cases. Here, we report a case of true aneurysm of proximal radial artery starting from its origin at brachial artery bifurcation. A 50-year-old female presented with a painful pulsatile mass in the left cubital fossa of 1 year duration. Duplex examination revealed partially thrombosed large aneurysm of proximal radial artery. Aneurysmal segment was resected and end of distal brachial artery anastomosed end-to-end with ulnar artery. Radial artery was reconstructed with interposition reversed saphenous vein graft from side of brachial artery to end of radial artery.

Thermal Resistance Anastomosis Device for the Percutaneous Creation of Arteriovenous Fistulae for Hemodialysis

PurposeTo evaluate the safety and efficacy of arteriovenous fistula (AVF) creation with a thermal resistance anastomosis device (TRAD). Materials and MethodsFrom January 2014 to March 2015, 26 patients underwent ultrasound (US)-guided percutaneous creation of proximal radial artery–to–perforating vein AVFs with a TRAD that uses heat and pressure to create a fused anastomosis. Primary endpoints were fistula creation, patent fistula by Doppler US, two-needle dialysis at the prescribed rate, and device-related complications. ResultsTechnical success rate of fistula creation was 88% (23 of 26). Procedure time averaged 18.4 minutes (range, 5–34 min), and 96% of anastomoses (22 of 23) were fused. At 6 weeks, 87% of AVFs (20 of 23) were patent, 61% (14 of 23) had 400-mL/min brachial artery flow, 1 patient was receiving dialysis, 2 fistulae had thrombosed, and 1 patient had died unrelated to the procedure. Eighty percent (16 of 20), 70% (14 of 20), and 60% (12 of 20) of patients were receiving dialysis at 3, 6, and 12 months; 4 patients died, 3 fistulae failed, and one patient was lost to follow-up. Overall, 87% of AVFs (20 of 23) had an additional procedure at a mean of 56 days (range, 0–239 d), including balloon dilation in 43% (n = 10), brachial vein embolization in 26% (n = 6), basilic vein ligation in 17% (n = 4), venous transposition in 30% (n = 7), and valvulotomy in 4% (n = 1). There were no major complications related to the device. ConclusionsPercutaneous AVFs created with a TRAD met the safety endpoints of this study. Midterm follow-up demonstrated intact anastomoses and fistulae suitable for dialysis.

An unusual case of arteriovenous fistula-related venous hypertension: sonographic detection of a culprit perforating vein with movie and compact review

Venous hypertension is one of the critical complications of arteriovenous fistula (AV fistula). Here, we report an unusual variation of venous hypertension which was caused by retrograde outflow through a perforating vein of the elbow. A 79-year-old man with diabetic nephropathy had an AV fistula created at his left proximal forearm 2 years before referral. Shortly after the creation of the AV fistula, he developed swelling of the left hand and forearm. Six months prior to the referral, persistent pain of the left hand developed, and he visited the nephrology unit. An anastomosis of the AV fistula was located 5 cm distal to the elbow. Inspection, palpation, and auscultation did not suggest outflow stenosis. Ultrasound showed mature upper arm venous outflow without stenosis. His proximal radial artery had been anastomosed side-to-end to a nearby proximal forearm superficial vein. Color Doppler analysis revealed a retrograde outflow through an antecubital perforating vein, which drained into the deep portion of the forearm and then disappeared. Superficial veins of the left forearm had been exhausted due to a previous attempt to create a wrist AV fistula. Given the above, it was suspected that the unusual retrograde outflow through the perforating vein caused venous hypertension by interfering with the venous return of the forearm, which had been dependent on deep veins. The patient subsequently underwent ligation of the perforating vein. The day after the operation, the pain disappeared and swelling improved. The dialysis treatments were continued without problems. Retrograde outflow through a perforating vein can be a cause of venous hypertension in a patient with an AV fistula created using the proximal radial artery. Close sonographic examination of antecubital vessels should be done if a practitioner encounters unilateral whole forearm edema without apparent proximal outflow stenosis.

Creating arteriovenous fistulas using surgeon-performed ultrasound.

An arteriovenous fistulas (AVF) is the preferred vascular access for hemodialysis and is associated with lower mortality, morbidity and cost when compared with grafts and particularly with central venous dialysis catheters. This study reviews a series of new patients where an autogenous access was constructed for each individual utilizing surgeon-performed ultrasound (SP-US). Consecutive new patients referred for a permanent vascular access during an 11-year period were retrospectively reviewed. In addition to physical examination, each patient underwent SP-US evaluation for pre-operative vessel mapping and post-operative evaluation for access maturation. SP-US was also used in the evaluation of access dysfunction in mature AVFs. We identified 1874 patients. Ages were 8-94 years (mean 60 years). Of these, 51% were female and 59% were diabetic; 33% had previous failed access operations. Follow-up was 3-127 months (mean 23 months). An autogenous access was constructed for each individual. No grafts were used. Direct AVFs were constructed in 1240 (66%) patients and 634 (34%) individuals required a transposition or translocation procedure. Primary and cumulative patency rates were 60.0% and 93.0% at 12 months and 47.3% and 90.2% at 24 months, respectively. AVF arterial inflow was most commonly supplied by the proximal radial artery (67%). Creating a functional autogenous vascular access is possible for most patients. No grafts were used in this series of 1874 consecutive new patients. Important elements for success included SP-US evaluation, utilization of the many vascular access options available, establishing radial artery AVF inflow when feasible, and prompt intervention when indicated.

Combined Endovascular Treatment with Distal Radial Artery Coil Embolization and Angioplasty in Steal Syndrome Associated with Forearm Dialysis Fistula.

The present study was performed to define the results of the endovascular treatment with angioplasty and distal radial artery embolization in ischemic steal syndrome associated with forearm arteriovenous accesses. The cases referred to our interventional radiology unit with symptoms and physical examination findings suggestive of ischemic steal syndrome were retrospectively evaluated first by Doppler ultrasonography, and then by angiography. Cases with proximal artery stenosis were applied angioplasty, and those with steal syndrome underwent coil embolization to distal radial artery. Of 589 patients who underwent endovascular intervention for dialysis arteriovenous fistulae (AVF)-associated problems, 6 (1.01%) (5 female, 1 males; mean age 62 (range 41-78) with forearm fistula underwent combined endovascular treatment for steal syndrome. In addition to steal phenomenon, there were stenosis and/or occlusion in proximal radial and/or ulnar artery in 6 patients concurrently. Embolization of distal radial artery and angioplasty to proximal arterial stenoses were performed in all patients. Ischemic symptoms were eliminated in all patients and the AVF were in use at the time of study. In one patient, ischemic symptoms recurring 6months later were alleviated by repeat angioplasty of ulnar artery. In palmar arch steal syndrome affecting forearm fistulae, combined distal radial embolization and angioplasty is also an effective treatment method in the presence of proximal radial and ulnar arterial stenoses and occlusions.

Occlusion of acute distal brachial, proximal radial and ulnar arteries in a young thrower

Summary Acute arterial occlusion, a rare condition in throwers, requires early detection and treatment for avoiding further complications. Thus far, no study has mentioned the occurrence of distal brachial, proximal radial, and ulnar artery occlusion in baseball players. An adolescent baseball pitcher presented with acute occlusion of the distal brachial, proximal radial, or ulnar artery. The patient complained of a cold sensation in the hand, wrist, and distal forearm. On physical examination, decreased surface skin temperature, and no radial pulse in the wrist suggested arterial occlusion. Emergency angiography validated the clinical suspicion, and identified the arteries and sites of vascular occlusion. Surgery was performed to alleviate the occlusions, thereby resolving the preoperative complaints and abnormal findings. Furthermore, postoperative magnetic resonance imaging of the shoulder and elbow joint was conducted to determine the causes of arterial occlusion. The patient resumed pitching 4 months postoperatively, and has remained active and symptom free. Magnetic resonance imaging examination revealed no vascular abnormalities or bony or soft tissue in the shoulder or elbow region. With early detection and treatment, a favorable prognosis can be achieved in baseball pitchers with acute upper extremity arterial occlusion so that their pitching career is not jeopardized.

Access Flow Reduction for Cardiac Failure

High-flow in hemodialysis arteriovenous angioaccesses is frequent. It may result in high-output cardiac failure, which should be prevented by fistula flow reduction. The most frequently reported flow reduction procedure is banding but immediate and long-term results are questionable. Alternative techniques are related here with personal results. Juxta-anastomosis "Proximal Radial Artery Ligation" (PRAL) is a very simple and effective reduction technique for side-to-end radio-cephalic fistulas (82 patients; reduction rate [RR]: 54% ± 19%). For brachial artery-based fistulas flow reduction two variants of Revision Using Distal Inflow (RUDI) procedures are used: 1) RUDI-1 using a polytetrafluoroethylene (PTFE) graft or a greater saphenous vein, which we first described in 1989 as "Distal Report of the Arterial Inflow" (35 patients; RR: 53% ± 18%), 2) RUDI-2 procedure, "Transposition of the Radial Artery", which we described in 2009 (47 patients; RR: 66% ± 14%).

Previous Hemodialysis Access Improves Functional Outcomes of the Proximal Radial Artery Fistula in Males

The proximal radial artery fistula (PRA) has been established as an early viable surgical option for arteriovenous fistula creation. The overall assisted primary patency reported in the literature approaches 100% at 1 year. We hypothesize that this excellent patency does not represent a functional result when seen in light of successful cannulation and fistula utilization. We retrospectively queried our Veterans Administration Hospital operative database to identify 284 male patients who had 571 access procedures performed by a senior vascular surgeon attending (R.K.D.) from January 1, 2003, to December 31, 2008. Operative details, patient comorbidities, fistula maturation time (time to first cannulation), functional patency (date of access to abandonment, revision to another fistula type, conversion to a prosthetic graft, thrombosis of the fistula, conversion to peritoneal dialysis, renal transplant, or patient death), and total duration (creation of the fistula to the end of its functional patency) were collected and analyzed. A total of 144 PRAs were placed during the study period. In all, 87 patients underwent primary proximal radial artery fistula (P-PRA) placement in a limb without previous access; 57 patients had a secondary proximal radial artery fistula (S-PRA) after a failed previous fistula or graft in the same limb. There were no differences between the 2 groups in terms of age, comorbidities, and operative details. A total of 91 patients (63.2%) were receiving hemodialysis at the time of P-PRA or S-PRA placement. Outcomes of P-PRA and S-PRA populations on hemodialysis were examined. There was increased cannulation success (33% vs. 55%; P = 0.00354, Fisher's exact test), functional patency (755.2 ± 661.2 days vs. 405.4 ± 531.9 days; P = 0.0220, Wilcoxon two-sample test), and total duration (859.5 ± 650.7 days vs. 516.8 ± 547.2 days; P = 0.0361, Wilcoxon two-sample test) of S-PRA over P-PRA. There was no difference in endovascular interventions between the 2 groups (1.6 ± 1.0 interventions per access versus 1.1 ± 0.7 interventions per access; P = 0.2109, Wilcoxon two-sample test). Subgroup analysis (analysis of variance) of the S-PRA group indicated that a patent but failing previous access in the same arm was not superior in terms of successful cannulation, functional patency, or total duration when compared with a thrombosed previous access. The PRA remains a viable first access procedure undertaken at our institution. Compared with the reported 12-month assisted primary patency of this fistula type, we found a small percentage of PRAs actually being accessed for successful hemodialysis treatment. The S-PRA appears to have a significantly higher successful cannulation rate, functional patency, and total duration time when compared with the P-PRA in patients receiving hemodialysis treatments. The mechanism of these improved outcomes is not known; considering patency or thrombosis of a previous access in the S-PRA group did not predict future access success in the same extremity.

Distal tourniquet-facilitated radial arterial cannulation in adults--a double-blinded, prospective, randomized and controlled study.

Relatively small radial artery may be challenging for cannulation. We investigated whether a distal tourniquet would inflate the proximal radial artery and therefore facilitate cannulation in adults. There were two stages of the study. The first was to measure the characteristics of radial artery by ultrasound imaging before and after tourniquet in volunteers. The second was a prospective, randomized, double blind study. Forty patients (American Society of Anesthesiologists I-III) who needed artery cannulation during operation were enrolled. Patients were assigned into two groups: loosen or tightened tourniquet for proximal radial artery cannulation by traditional palpation technique. The primary endpoints were the success rates and time of first attempt success by traditional palpation technique. The time of success after two to three attempts, failure rates and complications were collected. For volunteers, the distal tourniquet significantly expanded the cross-sectional up-forward diameter (p<0.001) and the area (p<0.05), but had no effect on cross-sectional lateral-lateral diameter or circumference of proximal radial artery (p>0.05). The success rate of first attempt was higher in the tighten group (75%) than in the loosen group (15%, p<0.05), but the time for success of first attempt/two to three attempts was similar (19.33 ± 1.12/62.11 ± 37.03 sec loosen group vs. 19.07 ± 12.75/45.55 ± 8.98 sec tightened group, p>0.05). Both groups had same failure rates of 10%. No complication was observed. Distal tourniquet could inflate the proximal radial artery and facilitate palpation of radial artery cannulation.

Arterial Injury and Endothelial Repair: Rapid Recovery of Function after Mechanical Injury in Healthy Volunteers

Objective. Previous studies suggest a protracted course of recovery after mechanical endothelial injury; confounders may include degree of injury and concomitant endothelial dysfunction. We sought to define the time course of endothelial function recovery using flow-mediated dilation (FMD), after ischaemia-reperfusion (IR) and mechanical injury in patients and healthy volunteers. The contribution of circulating CD133+/CD34+/VEGFR2+ “endothelial progenitor” (EPC) or repair cells to endothelial repair was also examined. Methods. 28 healthy volunteers aged 18–35 years underwent transient forearm ischaemia induced by cuff inflation around the proximal biceps and radial artery mechanical injury induced by inserting a wire through a cannula. A more severe mechanical injury was induced using an arterial sheath and catheter inserted into the radial artery of 18 patients undergoing angiography. Results. IR and mechanical injury produced immediate impairment of FMD (from 6.5 ± 1.2% to 2.9 ± 2.2% and from 7.4 ± 2.3% to 1.5 ± 1.6% for IR and injury, resp., each P < 0.001) but recovered within 6 hours and 2 days, respectively. FMD took up to 4 months to recover in patients. Circulating EPC did not change significantly during the injury/recovery period in all subjects. Conclusions. Recovery of endothelial function after IR and mechanical injury is rapid and not associated with a change in circulating EPC.

Abstract 18953: Prevalence of and Risk Factors for Radial Artery Complications After Transradial Cardiac Catheterization

Background: In recent years, radial access for cardiac catheterization gains popularity. One of the most common complications is radial artery occlusion (RAO). There are various numbers for the prevalence of RAO in literature, ranging from 5 to 30% when using a 6F sheath. Our study was designed to investigate the prevalence of radial artery (RA) complications (RAO, false aneurysm, arteriovenous fistula) in a single center population using a 6F sheath. Methods: 415 patients* (pts) were examined clinically and with duplex sonography 4 - 68 weeks after cardiac catheterization (60.7% (n=254) male, median age 68 y (33 - 88). In n=103 pts (24.6%) an intervention had been performed immediately after the diagnostics. Results: Patient characteristics are summarized in table 1. RAO was found in 15/418 cases (3.6%, n = 10 female, n = 5 male). Of those 10 patients, 3 showed (transient) symptoms (dysaesthesia, feeling of heaviness of the hand), cases of critical ischaemia were not found. No false aneurysm was found, one pt showed an arteriovenous fistula in the proximal RA. One patient showed significant stenosis of the middle portion of the brachial artery in addition to RAO, another one showed a mild stenosis of the RA. Women showed a significantly higher rate of RAO (n = 10, 66.7% in the RAO group vs. n = 154, 40.3% in the comparison group, p = 0.03). Other risk factors seem to be diabetes (n = 6, 40% vs. n = 106, 26%) and renal insufficiency (n = 3, 20% vs. n = 43, 11%), although the risk was not significantly increased. Interestingly, a coronary intervention does not seem to increase the risk of RAO (n = 2, 13% vs. n = 101, 26%). Hypertension, dyslipidemia, present or past smoking, body height, age, and BMI did not have significant influence. Conclusion: Vascular complications, especially RAO, after radial access for cardiac catheterization are quite rare and remain usually asymptomatic. Women are at higher risk. Diabetic pts and pts with impaired renal function seem to be at slightly higher risk.

Radial artery complications occurring after transradial coronary procedures using long hydrophilic-coated introducer sheath: a frequency domain-optical coherence tomography study

This study was performed to analyze the impact of transradial intervention (TRI), performed by long (25-cm) hydrophilic-coated radial introducer sheath (HRS), on radial artery (RA). Both acute damages and chronic intimal modifications, occurring in RA, were assessed using frequency domain-optical coherence tomography (FD-OCT). FD-OCT evaluation of RA was performed in 51 consecutive patients, undergoing TRI by long (25-cm) HRS. FD-OCT was performed from RA ostium to the puncture site. Acute damages such as intimal tears and medial dissections together with chronic intimal modifications, assessed as intimal hyperplasia indexes, were observed and compared between proximal and distal RA segments. Intimal tears were detected in 37% of patients, especially located in proximal RA segment (p = 0.09). Medial dissections were imaged in 9.8% of patients with no significant difference between proximal and distal RA segments. Intimal hyperplasia indexes were higher in distal RA segment, with no significant association with a previous history of TRI. In the setting of TRI, performed by long HRS, intimal tears represented the main RA injury occurring in about one-third of patients, while medial dissections only occurred in a small proportion of patients. Distal RA segment was more prone to intimal thickening, although this phenomenon was not associated with repeated transradial procedures.

The effects of intra-arterial vasodilators on radial artery size and spasm: implications for contemporary use of trans-radial access for coronary angiography and percutaneous coronary intervention

Transradial access (TRA) offers advantages including decreased vascular complications, reduced length of hospital stay, and reduced cost. The size of the radial artery (RA) limits the equipment that can be used via TRA. Intra-arterial (IA) vasodilators prevent and treat RA spasm, yet are not uniformly used in TRA and their effect on the absolute size of the RA remains unknown. 121 patients undergoing TRA for cardiac catheterization were included. 78 patients underwent RA angiography prior to administration of IA vasodilators ('no vasodilator' group), 43 patients underwent radial angiography after administration of an IA verapamil and nitroglycerin cocktail ('vasodilator' group). Quantitative angiography was used to compare the RA diameters. Clinical characteristics were similar between the groups, except that patients in the 'no vasodilator' cohort were taller (1.67 ± 0.1 m vs. 1.73 ± 0.1 m, p=0.002), and heavier (84.9 ± 18.2 kg vs. 75 ± 17.1 kg, p=0.003). In the 'vasodilator' group the proximal RA diameter was larger (2.29 ± 0.47 mm vs. 2.09 ± 0.41 mm, p=0.02) as was the narrowest segment (1.83 ± 0.56 mm vs 1.39 ± 0.43, p<0.0001) compared to the 'no vasodilator' group. At the RA origin, 79.4% of those in the 'vasodilator' group were larger than a 6 Fr guide catheter, compared to 51.4% in the 'no vasodilator' group (p=0.004). At the narrowest segment a higher percentage of RAs in the 'vasodilator' group were larger than a 5 Fr guide catheter (65.1% vs 26.9%, p<0.001) and a 6 Fr catheter (34.9% vs 10.3%, p=0.001). IA vasodilators increase pre-procedural RA diameter in patients undergoing cardiac catheterization via TRA. This increase in diameter has important implications for procedural planning. Boyer et al. performed a blinded controlled clinical trial investigating the effects of intra-arterial vasodilators on radial artery size and spasm during cardiac catheterization. The study demonstrates that intra-arterial vasodilators significantly increased the radial artery size throughout the entire course of the vessel and significantly decreased the amount of radial artery spasm. The authors conclude that these findings support the use of intra-arterial vasodilators during cardiac catheterization and have important implications for emerging technologies such as larger bore sheathless radial procedures.

Mapping of the Snuffbox and Cubital Vessels for Percutaneous Arterial Venous Fistula (pAVF) in Dialysis Patients

Report on the anatomic qualification of the snuffbox radial artery (SBRA) and proximal radial artery (PRA) for pAVF. Retrospective analysis of upper extremity mapping in 64 limbs in 55 dialysis patients was performed. The radial artery was assessed for diameter, patency, flow and proximity to the adjacent vein to SBRA and PRA. Sites qualified for pAVF on a binary basis when the in situ radial artery and adjacent vein were straight, parallel, greater than 2 mm in diameter and within 1.5 mm of each other. Effect of age, sex, diabetes, systolic blood pressure and obesity were assessed with logistic regression. Mean, median and frequency distribution of vessel diameter and distance were analyzed. Radial artery sites were qualified for pAVF in 47.6% (30/63) at the SBRA and 87.9% (29/33) at the PRA. SBRA sites were disqualified for vessel size in 36.4% (12/33 overall, usually vein 11/12), distance in 24% (8/33) and both 36.4% (12/33). All (4/4) PRA sites were disqualified for vessel size alone. The adjacent vein was the median vein or cephalic vein for the SBRA, and the perforating vein or vena comitans for the PRA. Effects of age, sex, diabetes, systolic blood pressure, obesity and prior fistula did not attain statistical significance. Most dialysis patients meet the anatomic requirements for pAVF in the SBRA or PRA. Vessel size is the most common limiting variable followed by distance between vessels.

Blood flow dynamics in patients with hemodialysis access-induced hand ischemia

Hand ischemia may occur in the presence of a hemodialysis arteriovenous fistula (AVF), but its pathophysiology is partly unclear. The aim of this observational study was to investigate flow characteristics of forearm arteries in patients with a brachial artery-based AVF suffering from hemodialysis access-induced distal ischemia (HAIDI). A questionnaire scored hand ischemia in patients with HAIDI scheduled for revisional surgery (no symptoms of ischemia, 0 points; maximal ischemia, 500 points). Systolic index finger pressures (Pdig) and digital brachial index (DBI) were determined with open and compressed AVF. Blood flow direction and peak systolic velocity (PSV) were measured in radial and ulnar arteries using Doppler ultrasonography. Age- and sex-matched hemodialysis patients without HAIDI served as controls (CONT). Questionnaire scores were 258 ± 30 in patients with HAIDI (n = 10) compared with 31 ± 16 in CONT (n = 10; P < .01). Pdig and DBI with open AVF were lower in the HAIDI group than the CONT group (Pdig 22 ± 10 vs 102 ± 10 mm Hg; DBI 0.18 ± 0.08 vs 0.70 ± 0.04; both P < .01). Ulnar artery PSV was lower in HAIDI compared with CONT patients (38 ± 4 vs 56 ± 3 cm/s; P < .01). Mean ulnar artery PSV was significantly correlated to Pdig (r = 0.87; P < .01) in contrast to mean radial artery PSV (r = 0.06; P = .81). Ulnar artery blood flow direction was always toward the ischemic hand (n = 20). However, blood flow was reversed in just a short segment of the proximal radial artery in one HAIDI patient but also in two CONT patients. Hand ischemia in hemodialysis patients with a brachial artery-based AVF is not caused by a reversed blood flow direction in forearm arteries. However, forearm blood flow is diminished in these patients leading to critically reduced arterial pressures in the hand.