Endovascular treatment has been widely used as a treatment for dysfunctional hemodialysis (HD) access, which includes balloon angioplasty, stent insertion, and thrombectomy/thrombolysis [1]. In addition to the conventional approach route for cannulation for HD, several alternative routes have been reported [2-6]. This review introduces various approach routes used for endovascular treatment of dysfunctional HD access and outlines their characteristics, advantages, and disadvantages.

The conventional approach involves cannulating the efferent vein of the HD access, which is the site used for needling during HD. Depending on the location of the target lesion, cannulation is performed in the antegrade or retrograde direction, and an appropriate sheath is inserted. It is advisable to avoid areas with aneurysmal dilation or mural thrombus. It the target lesion is present both distal and proximal to the cannulation site, an additional cannulation is performed in the opposite direction of the first cannulation. This technique is known as the bidirectional crossed-catheter technique.

For loop arteriovenous grafts (AVGs), after cannulating the apex of the graft, treating the distal (efferent) portion, and then appropriately retracting the sheath, it can be shifted to the proximal (afferent) portion to treat both the distal and proximal lesions using a single apex approach route (Fig. 1) [7]. This approach has the advantage of reducing the dead space, or perisheath-protected area, behind the sheath entry site. However, the operator should be cautious when manipulating the sheath to avoid damaging the opposite wall, and initial cannulation should ideally be performed horizontally rather than vertically to minimize this risk. A T-shaped angioplasty technique has been reported for treating lesions at the cannulation site (apex) [8].

Figure 1. A 78-year-old male patient with a left forearm brachiocephalic loop arteriovenous graft. (A) After cannulation of the apex (arrow) of the graft and treating the efferent vein, (B) the sheath was shifted to the arterial side and the arterial anastomosis site was treated.

Conventional approach routes are exposed to arterial pressure, necessitating careful attention to hemostasis after the procedure. Additionally, since these routes use the needling site for HD and involve relatively large sheaths, they may be challenging to use in immature arteriovenous fistulas (AVFs). There are also reports of new stenosis developed at the cannulation site even in mature fistulas [9]. To overcome this issue, various alternative approach routes are used, as described below.

Compared to conventional approach route, which involve direct cannulation of the HD access and insertion of a large sheath, transvenous alternative approach routes offer several advantages. These include utilizing systemic veins that is not directly exposed to the systemic arterial pressure, which makes hemostasis easier and reduces the complication risk of inserting relatively large diameter sheaths. Additionally, the complications such as bleeding and infection do not occur in the HD access site itself. Another advantage is that the operator’s hands are not included in the X-ray field [10].

The most commonly used route is the ipsilateral internal jugular vein (transjugular approach). While it may be challenging to advance the guidewire into the subclavian vein after cannulation, the operator can facilitate this process by bending the tip of the sheath to provide directionality and using catheters with reversed angles, such as RH (Rosch-Hepatic) or Omniflush. However, if there is stenosis in the ipsilateral subclavian vein-brachiocephalic vein area, transjugular approach may be difficult, and stent insertion in the direction of blood flow (from the subclavian vein to the brachiocephalic vein) via the transjugular approach is impossible. Additionally, transjugular approach may be challenging in patients who refuse to have the neck area cannulated. In such cases, other transvenous approach routes could be considered.

When selecting the common femoral vein as the approach route [4], it is important to consider the working length of the various devices to be used, as the distance to the target lesion is relatively long. Using a longer sheath can help ensure stability and improve back support during the entire procedure.

Another reported approach involves cannulating the ipsilateral basilic or brachial veins [5]. This method involves cannulating the vein in the direction of blood flow (centripetal), placing the sheath, and advancing guidewire and diagnostic catheter through the cephalic arch to reach the target lesion.

The major disadvantage of transvenous alternative approach is that the vessel must be selected in the reverse direction of blood flow, which often leads to incorrect selection of nearby vessels and makes it difficult to reach the target lesion. Methods for finding the appropriate vessel include repetitive fistulography and tracing the vessel with ultrasound guidance. However, repetitive fistulography increases the risk of contrast agent usage and radiation exposure, while tracing with ultrasound requires a skilled assistant, involves a large area to be draped before the procedure. Another reported method [11] involes using a 24-G scalp needle to cannulate the needling site (conventional approach route) in the direction of blood flow and placing a 0.014-0.018-inch guidewire of sufficient length. This guidewire can serve as a landmark for easy retrograde cannulation (Fig. 2). This method is useful as it facillitates passage through stenotic lesions and the cephalic arch entrance and minimizes the need for additional devices such as snare catheters.

Figure 2. A 83-year-old female patient with a left upper arm brachiocephalic native arteriovenous fistula. Access through the ipsilateral internal jugular vein (asterisk) was used to treat multiple stenotic lesions (arrowheads) in the left upper arm brachiocephalic arteriovenous fistula. Antegrade wire guidance using a 24-G micropuncture needle and a 0.014-inch guidewire facilitated easy retrograde cannulation of the cephalic arch. Hemostasis at the transjugular approach site and the HD access site was achieved with manual compression alone.

Compared to conventional approach, the advantage of transarterial alternative approach is that it allows for the treatment of the entire HD access circuit using a single approach route, eliminating the need to compress the venous limb and obtain angiography to visualize the anastomosis site (arterial anastomosis site in AVGs). In contrast to transvenous alternative approach, transarterial alternative approach allows for relatively straightforward visualization of the entire HD access circuit from the anastomosis site (arterial anastomosis site in AVGs) when performing angiography from the approach route.

Several reported approach routes include the radial artery [6,12] and brachial artery [13]. The radial artery approach is already a widely used route for percutaneous coronary artery intervention [14], and there have been reports on its complications and management strategies [15]. Before the procedure, the diameter of the radial artery should be confirmed to be at least 2-2.5 mm through ultrasound measurement. Complications such as radial artery occlusion may occur in 2-10% of cases during or after the procedure [16]. Therefore, it is recommended to perform the Allen test or Barbeau test before the procedure to assess palmar arch circulation through collaterals such as the ulnar artery. Puncture the radial artery under ultrasound guidance, and insert a sheath of 7 Fr or smaller. To prevent thrombus formation, heparin solution can be administered intravenously, and to avoid vasospasm, it is advisable to inject vasodilators (such as nitroglycerin or verapamil) through the sheath.

Compared to radial artery, the brachial artery has a relatively larger vessel diameter, which increases its utility and does not require additional spasmolytic medication. However, the brachial artery is located deeper, making hemostasis more challenging after the procedure, and acute thrombosis could result in a disastrous loss of both the radial and ulnar arteries distal to the approach site. Additionally, hematoma resulting from brachial artery approach site at the upper arm level could compress nerves within the compartment, potentially leading to medial brachial fascial compartment syndrome. Furthermore, even when using transvenous alternative approach routes, techniques such as antegrade wire guidance allow for positioning the diagnostic catheter to visualize the entire HD access circuit, thereby diminishing the benefits of transarterial alternative approach routes. Additionally, due to diabetic macroangiopathy or accelerated atherosclerosis, suitable arterial approach sites may be limited, and the need to insert a relatively large sheath can pose significant challenges, making it less commonly used as a primary approach route.

In the case of transvenous alternative approach, which is not directly exposed to systemic arterial pressure, manual compression alone after sheath removal is usually sufficient, even if anticoagulation was performed during the procedure. However, in the case of conventional approach, which is directly exposed to arterial pressure, manual compression alone is often insufficient, and hemostasis typically requires additional methods such as purse-string sutures upon sheath removal [17]. In the case of transarterial alternative approach, it is recommended to maintain antegrade arterial flow while achieving hemostasis to reduce the risk of distal arterial thromboembolism.

Choosing the optimal approach route is important for successful endovascular treatment of dysfunctional HD access. Knowledge on the advantages and disadvantages of both conventional approach routes as well as transvenous and transarterial alternative approach routes can help in managing issues encountered during the procedure.