The Forearm’s Subcutaneous Venous Network to Accelerate Maturation of Native Arteriovenous Fistula: A Case Report

In patients with end-stage renal disease, adequate vascular access (VA) is critical for maintaining hemodialysis (HD). The radiocephalic arteriovenous fistula at the level of the wrist or direct fistula in snuff-box (SBAVF) stands out as the preferable VA for HD due to its reduced risk of infection and mortality compared with alternative options [1]. Despite their advantages, there are several disadvantage, including early failure, non-maturation, and the risk of thrombosis even after maturation period. Arteriovenous fistula (AVF) thrombosis is a serious incident that results in loss of VA or complicates its usage for HD, necessitating the creation of more proximal AVFs, such as a brachiocephalic or brachiobasilic fistula. HD access-induced distal ischemia, venous hypertension, and overload heart failure are all common and serious complications of arm fistulas [2]. Because of these reasons, the reconstruction of the fistula most distally on the upper limb is of the utmost importance but a challenging problem.

We describe an obese HD patient with primary SBAVF who was referred to our clinic due to thrombosis of a part of the superficialized cephalic vein (CV). In this case, the CV on the forearm and arm was patent and maintained the outflow. Unfortunately, this access could not be used due to inadequate fistula flow. In this case, we used one vein from the subcutaneous venous network to create a new AVF to improve blood flow through the forearm and arm veins. To the best of our knowledge, this is the first case in which the subcutaneous vein has been used to accelerate fistula maturation.

A 69-year-old HD patient with diabetes and obesity (weight 107 kg, BMI 41) was referred to our clinic with suspicion of thrombosis of superficialized section of the median vein in the forearm (MVF). His primary vascular access (VA) was SBAVF, followed by MVF elevation in the middle of the forearm. This last surgery was necessary due to the deep vein location and this portion of the AVF was regularly cannulated during HD sessions. Palpation revealed that the superficialized vein was rigid and noncompressible; however, a week of bruit could be heard in the wrist region. Doppler ultrasonography (DUS) confirmed a clinical finding of MVF thrombosis and multiple vein stenosis in the elevated part of MVF and in proximal region with a minimum cross-section diameter of 3 mm. Additionally, DUS revealed a patent 4 mm CV in the lateral region of the forearm, which maintained outflow (shown in Fig. 1a). This vein runs to the cubital fossa and connects to the CV in the arm. The vessels’ cross-sections were as follows: radial artery (RA) 4.6 mm, brachial artery (BA) 7.1 mm, CV 4 mm on the forearm, CV on the arm 6.8 mm. A 3.4 mm diameter subcutaneous vein (SV) was found in the distal forearm, near the RA site, which was later used to perform additional anastomosis. The blood flow rate on the BA was 435 mL/min. One unsuccessful attempt at vein cannulation in the elbow was made, but the blood flow was insufficient for effective HD. At the time, we considered thrombectomy, but it was rejected due to maintained fistula flow and accompanying multiple stenosis in the MVF. For this reason, a cuffed, tunneled central venous catheter was implanted, and next anastomosis was scheduled using the SV in distal part of the forearm (shown in Fig. 1a, b).

The procedure was carried out under local anesthesia with a 1% lignocaine solution. An oblique incision was made in the distal part of the forearm, approximately 4–5 cm proximal to SBAVF (shown in Fig. 1a). The appropriate vessel fragments were dissected. Over the ligature, the SV was severed and flushed with the heparinized saline. The radial artery was then clamped both distally and proximally and finally, and it was later incised longitudinally. Both vessels were sutured with a continuous suture, i.e., the end of the vein was anastomosed with the side of the artery using an insoluble polypropylene vascular suture of 6-0. The vein filled with blood when the clamps were released, and a typical murmur was noticed (shown in Fig. 1b). The wound was closed using skin sutures. Ultrasound examination confirmed that the fistula was patent immediately after the procedure. The patient had been discharged with a functional fistula.

The DUS performed 2 months later revealed that blood flow on the BA was 829 mL/min, and the diameters of the RA, BA, and CV on the arm were 5.2 mm, 8.1 mm, and 8.4 mm, respectively. The CV was located 10.2 mm beneath the skin. As a result, CV superficialization was performed on the arm (shown in Fig. 1a, c), followed by successful cannulation a month later with one needle (shown in Fig. 2a) and then two needles (shown in Fig. 2b). After 9 months of superficialization, the fistula was still patent.

Despite advances in surgical techniques and perioperative care, fistula maturation remains a challenging aspect of HD access. This was shown by Bylsma et al. [3], who conducted a meta-analysis that raised doubt on the AVF utility in addressing end-stage renal disease. They evaluated the outcomes of 62,712 AVF access formations and found 1-year primary, primary assisted, and secondary patency rates of 64%, 73%, and 79%, respectively. However, only 26% of created fistulas were reported as mature at 6 months and 21% of fistulas were abandoned without use. In another meta-analysis study based on 37 studies, the risk of primary failure was 23% and primary patency rate was 60% at 1 year and 51% at 2 years [4]. According to these findings, fistulas that are fully developed and functioning can nevertheless occlude. Vein stenosis is the most common cause of thrombosis, followed by intima media hypertrophy [5]; however, regular cannulation may have an additional effect.

In this report, we describe a case of a patient whose vascular access required rebuilding following thrombosis of superficialized MVF. The patency of the primary SBAVF was maintained by the collateral circuit, but it was insufficient for carrying out adequate HD. A key role in our approach was played by one of the SVN veins, which was used to create an additional anastomosis. In this technique, the main principle was to increase the blood flow to the CV in the arm and facilitate its distention. It should be noted that our patient ultimately had two independent fistulas with cumulative flow. Finally, the larger CV in the arm was superficialized and successfully cannulated.

The subcutaneous venous network stretches in the subcutaneous fat on the fascia proper and transports blood from the skin and superficial tissues of the forearm to larger superficial veins, such as cephalic and basilic. These vessels are small and delicate, and they are rarely used for creating AVFs due to technical difficulties and potential cannulation concerns. However, it is sometimes advisable to consider using these vessels. In this case, the subcutaneous vein was patent, located close to the radial artery, and connected to the CV in the elbow. Following the surgery, the collective arteriovenous flow doubled (increase from 435 mL/min preoperatively compared to 829 mL/min postoperatively), which resulted in dilation of CV and made them suitable for subsequent superficialization in the arm.

Our patient’s problem inspired discussion among our team members, raising the question of what other forms of treatment might be comparably useful; nonetheless, the following solutions were rejected:

• 1.

  In the case of AVF thrombosis, the first line of treatment is to remove the clots from the affected vessel (thrombectomy). This can be accomplished surgically, endovascularly, or pharmacologically using thrombolytic agents. Naturally, all these procedures require the subsequent stenosis repair, either surgically or by balloon angioplasty. Surgical procedures have the highest success rate, and in one systematic literature search, thrombectomy plus simple reanastomosis of the vein to the artery proximally had a greater 1-year secondary patency rate of 70–90%, compared with 44–89% after endovascular therapy [6]. We decided not to perform either surgical or endovascular thrombectomy because the superficialized vein is difficult to dissect due to adhesions, and additionally DUS showed several stenoses along the MVF.

• 2.

  The creation of a new brachiocephalic fistula (BCAVF) has also been rejected due to several disadvantages, including the risk of complications related to high fistula flow and HD access-induced distal ischemia.

• 3.

  When SBAVF fails, the majority of vascular access surgeons have a proximal anastomosis in the wrist. The procedure is frequently simpler since the vessels’ diameters increase as a result of the maturation of the primary SBAVF, as pointed out in a metaanalysis [1]. Our case is somewhat uncommon since the primary problems were superficialized MVF thrombosis and inadequate flow in the arm’s CV, even though the anastomosis was patent, and the flow was 435 mL/min. Simple reanastomosis is typically carried out as an end-to-side vein-to-artery anastomosis but is associated with the loss of the primary SBAVF. To increase arteriovenous flow, we believed it was better to perform an additional anastomosis without closing the previous one. In this case, this solution was effective as the flow reached 829 mL/min with increased flow through the CV arm and its diameter.

• 4.

  We also considered an arteriovenous graft (AVG), but on the one hand, the procedure is not technically simple, and on the other, there are several documented problems including higher rate of infectious and non-infectious complications in comparison to a native fistula. Furthermore, as several studies have demonstrated [7], patients with AVG have a poorer survival rate than those with native fistula. We ruled out AVG implantation since it would likely be the last vascular access in the upper extremity, limiting other options. Our procedure, however, did not prevent the formation of BCAVF or the implantation of AVG. The only advantage of AVG is that the patient may be saved by one superficialization procedure on the arm. This surgery was necessary due to severe obesity. In the literature, obesity has been associated with inferior AVF maturation outcomes, lower primary patency, and higher reintervention rates [8]. Our case clearly illustrates this rule, as instead of two anastomoses and two superficializations, the patient could have only one AVG procedure. However, as we mentioned earlier, this would be the last VA, so the policy in our department is to limit AVG implantation as much as possible because, in many, even more complicated patients, VA can be created without artificial materials (grafts).

To summarize, SNV may be used to perform additional anastomosis in situations where the addition of extra blood flowing between the artery and the venous system accelerates the maturation of the primary AVF.

The study was conducted in accordance with the Declaration of Helsinki and approved by the Ethics Committee at Wroclaw Medical University No KB-609/2019. Written informed consent was obtained from the patient for publication of this case report and any accompanying images. The CARE Checklist has been completed by the authors for this case report, attached as online supplementary material (for all online suppl. material, see https://doi.org/10.1159/000542903).

The authors have no conflicts of interest to declare.

The study is supported by the Wroclaw Medical University statutory funds (SUBK.C160.24.056). It was investigator-initiated research. The funder had no role in the design, data collection, data analysis, and reporting of this study.

Conception, all surgeries performed on the patient, and artwork design: T.G.; design of the work, analysis, and final approval of the version to be published: T.G. and M.K.; interpretation of data for the work: T.G., M.K., and M.C.; drafting the work: T.G. and M.G.; reviewing it critically for important intellectual content: M.K.; and funding: M.B.

The data that support the findings of this study are not publicly available due to their containing information that could compromise the privacy of research participants but are available from the corresponding author (T.G.).