CKD-Associated Complications: Progress in the Last Half Century. Группа авторов

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СКАЧАТЬ According to the NKF-K/DOQI guidelines, an autogenous AVF should ideally be placed in a peripheral-to-central sequence, and radiocephalic and brachiocephalic fistulas are the preferred types of AVF.

      The rapid growth of the aging population and the high prevalence of comorbidities, particularly diabetes mellitus and peripheral vascular disease, in patients requiring HD inevitably decrease the ability to construct and maintain a conventional AVF because of the lower vascular adaptability in these patients.

A prosthetic arteriovenous graft (AVG) is occasionally considered when suitable vascular anatomy is unavailable for fistula formation in areas such as the forearm and cubital fossa or when the superficial venous vasculature is inadequate for cannulable arterialization. However, evidence clearly shows that the AVF has superior patency, is associated with fewer complications, and requires fewer re-interventions than the AVG. The AVF also ultimately improves patient survival rates [1, 2]. Although proximal AVF construction is feasible, the inaccessibility of the arterialized vein because of its deep location in the upper arm is a matter of concern. Therefore, the availability of autologous vessels, including deeply located veins, should be carefully assessed when deciding the type of VA for AVF construction.

      AVF superficialization has been suggested as an alternative form of VA to maximize the availability of autologous veins and, when used for surgical revision, should improve the accessibility of arterialized veins. The procedures for superficialization include tunnel transposition, elevation, lipectomy, and liposuction. In the tunnel transposition approach, which is also simply termed “transposition,” the deeply situated vein is dissected free from its surrounding tissue, transposed to a superficial position through a subcutaneous tunnel, and anastomosed with the artery. In the elevation approach (also termed “elevation transposition” or the “fistula elevation procedure”), an AVF is constructed and the arterialized vein is raised and positioned in the pocket created in the subcutaneous space along the incision. In the lipectomy or liposuction approach, the subcutaneous fat layer above the arterialized vein is removed through 2 transverse incisions or using ultrasound guidance, respectively.

      Superficialization of the Basilic Vein for Autologous AVF Construction

      Transposed Brachial-Basilic AVF

The transposed brachial-basilic AVF (TBBAVF), which was introduced by Dagher in 1976, has been recognized as the most common alternative AVF that is established using venous superficialization. The basilic vein in the upper arm is relatively large, and because of its deeper location, it tends to be spared from the destruction caused by repeated iatrogenic venous punctures. Therefore, the use of the basilic vein for VA has certain advantages over the other arm veins [3–6]. In the NKF-K/DOQI guidelines, the TBBAVF is preferable to an AVG when establishment of the conventional AVF is not attainable [2].

The original method for establishment of a TBBAVF is a one-stage procedure. The basilic vein is mobilized from the ulnar aspect of the forearm to the axilla through a single continuous or interrupted longitudinal incision along the course of the vein. The brachial artery is then explored at the elbow. The mobilized basilic vein is transposed to the anterolateral arm through a subcutaneous tunnel and anastomosed end-to-side with the brachial artery [4]. In the two-stage procedure, the fistula-arterial anastomosis is simply performed first, followed by the second stage of tunnel transposition. Several weeks later, at the time of basilic vein maturation, the basilic vein is mobilized and transected near the anastomosis, placed inside an anterolateral subcutaneous tunnel, and re-anastomosed [7].

Although superficialization is typically accomplished by tunnel transposition in the TBBAVF procedure, elevation has been alternatively utilized by some research groups and also involves one- or two-stage procedures [8] (Figs. 1, 2). The risk of torsion or kinking of the basilic vein can be minimized using the elevation approach because it does not involve transection. In addition, a few research groups have preferred to employ a simpler elevation approach by relocating the vein to a location immediately beneath the incision [9, 10]. More recently, several reports have introduced modified tunnel transpositions of the basilic vein by adopting minimally invasive procedures, such as the use of an endoscopic vein harvesting device and catheter-mediated techniques or the performance of smaller incisions to avoid the postoperative complications that occur with larger incisions. The feasibility of these procedures is comparable with that of standard tunnel transposition, but they are yet to be widely recognized [3, 4].

Fig. 1. Elevation of the arterialized basilic vein. a Elevation of the arterialized basilic vein in two-stage AVF superficialization. b–d The arterialized basilic vein is raised and positioned in the pocket created in the subcutaneous space along the incision.

Fig. 2. Ultrasound images of the arterialized basilic vein. Ultrasound images before (a) and after (b) elevation of the arterialized basilic vein.

The clinical profiles and outcomes of the TBBAVF vary widely among individual studies. Overall, previous studies have revealed primary failure rates of up to 38% due to technical complications or unsuccessful maturation, 1-year primary patency rates of 23–90%, and secondary patency rates of 47–90% [4, 11].

In a review focusing on TBBAVF by Dix et al. [5], the rates of hematoma formation, transient arm edema, and aneurysm/pseudoaneurysm formation in the early postoperative period were 3.8, 3.7, and 1.9%, respectively, which seem higher than in other VA techniques because of the relatively extensive surgical procedure required for TBBAVF [5, 6]. In contrast, the most common long-term complication in a retrospective cohort study conducted by Beaulieu et al. [12] was stenosis, which occurred in 54% of fistulas. These authors also found that 74% of the stenoses were located at or near the area of the transposed basilic vein and that 50% of patients with stenoses required multiple interventions to ensure or re-establish conduit patency [12].

      Comparison between TBBAVF and AVG

Whether a TBBAVF or AVG is the preferential alternative to the conventional AVF remains controversial. In 2008, Lazarides et al. [13] СКАЧАТЬ