an autogenous arteriovenous fistula ( avf ) is the optimal form of vascular access for hemodialysis ( hd ) due to the longer duration of patency , fewer infections , and lower mortality [ 1 , 2 ] .
the presence of occlusive neointimal hyperplasia at the anastomosis and/or the outflow veins , which may be accelerated by chronic kidney disease , has been considered to be the leading cause of avf failure , while the major problem associated with the creation of an avf is the fact that fistulas do not necessarily mature into a usable vascular access , requiring subsequent revision and construction of another access . the caliber of the vessels used for fistula creation is a pivotal factor predicting the presumable maturation of the constructed fistula , and veins less than 2.5 mm in diameter have poor outcomes .
this report describes the balloon - assisted creation and maturation of an autogenous radial - cephalic arteriovenous fistula ( rcf ) in a patient with small - caliber veins and a radial artery of approximately 2 and 1.5 mm in diameter , respectively .
a 78-year - old female with end - stage renal failure caused by diabetic nephropathy had been undergoing hd treatment for 9 years .
her medical history included arteriosclerosis obliterans , an old myocardial infarction , and complete atrioventricular block , which was managed by the implantation of a definitive pacemaker via the right subclavian vein .
she first began undergoing hd through a left upper arm brachial - cephalic avf , since a forearm rcf created before initiating hd did not mature despite repeated surgical revisions .
the fistula failed 2 years later because of a thrombotic occlusion presumably induced by frequent postdialytic hypotension resulting from excessive interdialytic weight gain .
the patient underwent numerous vascular access interventions , including percutaneous transluminal angioplasty and stenting for thrombotic or stenotic lesions , not only in accessory veins , but also in the central venous system .
the peripheral venous access in the left upper extremity seemed to be exhausted 5 years after the initial intervention , and the right brachial artery was superficially repositioned .
the peripheral venous system in the right upper extremity also did not seem to be feasible to use as the return route , so the patient was dialyzed with a silicone tunneled cuffed catheter inserted through the right femoral vein .
however , thrombotic catheter occlusion developed 5 months after the insertion , and the catheter could only be used for the return route .
finally , a balloon - assisted procedure was used to try to create and expedite the maturation of the autogenous right forearm rcf
. small - caliber veins of approximately 2 mm and a radial artery of 1.5 mm in diameter were confirmed by preoperative digital subtraction angiography ( dsa ) .
the cephalic vein and radial artery were exposed through a transverse incision at the wrist using magnification glasses ( 3.0 ) .
the vein was then freed by wide dissection , and the collateral branch was ligated , followed by a longitudinal venotomy of the posterior wall .
the anterior wall of the radial artery was exposed without any dissection of its trunk , and a 5-mm longitudinal arteriotomy was made . a side - to - end , artery - to - vein anastomosis
palpation just after the creation of the anastomosis failed to confirm the patency of the fistula , and subsequent dsa revealed the stenosis of the juxta - anastomotic vein .
next , the stenotic lesion of the juxta - anastomotic radiocephalic vein was crossed with a 0.018-inch hydrophilic guide wire , and a 3-mm ( 40 mm long ) balloon catheter ( sterling balloon dilatation catheter , boston scientific , natick , mass . ,
usa ) was inflated to 6 atm for at least 1 min , with one overlapping angioplasty under direct visualization ( fig .
the patient underwent subsequent balloon angioplasty on days 20 and 60 to aid in the maturation of the radial artery and the usable portion of the rcf .
balloon angioplasty was performed under radiological guidance on day 20 , with a retrograde radial arterial approach using a 0.018-inch platform combined with a 4-mm balloon catheter for the radial artery ( inflated to 4 atm for 10 s ) , anastomotic region ( inflated to 6 atm for 20 s ) , and the juxta - anastomotic region ( inflated to 8 atm for 20 s ; fig .
angioplasty was performed on day 60 , using a 5-mm balloon catheter from the anastomotic to the juxta - anastomotic lesion .
follow - up fistulography was performed 3 months later , when the rcf became functional and the tunneled cuffed catheter was removed , revealing the matured radial artery and cephalic vein ( fig .
the right rcf has been functional for more than 6 months since the final fistulography .
a wrist avf including an rcf has been the first choice of vascular access for chronic hd , since it is simple to create and preserves more proximal vessels for future access placement with fewer complications than other fistula types .
however , a high level of surgical experience appears to affect the primary success and patency rate of an rcf , thus suggesting that the construction of such access is technically demanding . on the other hand
, the availability of a distal cephalic vein and radial artery will become even more limited for arteriovenous fistula construction with the increasing average age of the end - stage renal failure population .
the survival rate of a successfully created forearm autogenous rcf is excellent , and the 2-year complication - free survival of such a fistula is approximately 75% , while another study by miller et al .   demonstrated that the overall success rate of forearm rcf is rather poor .
therefore , it is not unusual that the left forearm rcf created in the current patient before initiating hd did not mature despite repeated surgical revisions .
several studies have evaluated factors that might predict fistula maturation , and preoperative vascular mapping has been shown to improve the rate of fistula placement and overall surgical success rate .
in addition , the criteria for the placement of an autogenous fistula have included a minimum artery diameter of 2 mm , a minimum vein diameter of 2.5 mm , and a lack of stenosis or thrombosis in the draining vein or central veins [ 3 , 8 ] .
the experience in the current patient with a suboptimal artery measuring approximately 1.5 mm in size and veins measuring 2.0 mm in diameter suggests the clinical benefit of balloon - assisted creation and maturation of an autogenous right forearm rcf .
although one may argue that perioperative radiological intervention could be dangerous due to the risk of disruption of the anastomosis , intraoperative interventions are not exceptional and are occasionally indicated in clinical settings .
the most common reason is limited percutaneous vascular access , such as with lesions proximal or distal to a stenosed or occluded portion that is simultaneously treated by vasculotomy . the directly visualized intraoperative procedure may avoid the development of several adverse events , such as vascular perforation or rupture
variability in the techniques used for creating avfs has made it difficult to objectively analyze the results and develop best practice recommendations , despite a large amount of literature on the subject and continued technological advances .
in addition , there are no clear protocols to address accessible vessel maturation with regard to an avf .
the application of intraoperative balloon angioplasty and the subsequent interventional approach has allowed the maturation of an autogenous avf with suboptimal vessels that otherwise could not have been used [ 13 , 14 ] .
the mechanisms of successful balloon angioplasty with vascular access stenoses involves vessel stretching and dissection , which are similar to the mechanisms that have been validated with morphological evaluation of arterial balloon angioplasty [ 15 , 16 ] . on the other hand ,
the vascular access portions dilated by repeated balloon angioplasty are thought to heal mostly by fibrosis , and eventually to become large - diameter fibrous segments [ 15 , 16 ] .
further studies and more extensive clinical experience are required to better determine the optimal interval and appropriate duration of balloon angioplasty not only for post - dilation healing , but also for expediting the maturation of an autogenous avf with small - caliber vasculature .
 the major problem associated with the creation of an arteriovenous fistula ( avf ) , which is the optimal form of vascular access for hemodialysis , is the fact that fistulas do not necessarily mature into a usable vascular access , requiring subsequent revision and construction of another access . 
 the caliber of the vessels used for fistula creation is a pivotal factor predicting the presumable maturation of the constructed fistula , and veins less than 2.5 mm in diameter have poor outcomes . 
 this report describes the balloon - assisted creation and maturation of an autogenous radial - cephalic avf in a patient with a small - caliber vein and a radial artery measuring approximately 2 and 1.5 mm in diameter , respectively . 
 the clinical impact of percutaneous radiological intervention for expediting the maturation of an autogenous avf with small - caliber vessels is also discussed . 
Introduction
Case Report
Discussion
Disclosure Statement