How to improve AV fistula maturationBy Laminate Medical
Arteriovenous fistulas are considered to be the most reliable long term form of vascular access in patients undergoing dialysis. AV fistulas are less susceptible to failure due to infection or thrombosis and patient survival rates are higher when an AV fistula is used.
AV fistulas require fistula maturation in order to allow for use of the fistula as an access point for dialysis. Successful fistula creation results in easy repetitive cannulation and adequate blood flow needed to support dialysis.
AV fistulas maturation rates
Between 25-40% of the AV fistulas do not mature, some of the reasons being genetic disposition, low shear stress, vascular injury, thrombosis, vessel inadequacy, hypotension and more.
Improving AV fistula maturation rates from the start:
The technique for AV fistula placement has not changed significantly since its introduction in 1966. Given the high failure rates and the lack of a better vascular access, there is a strong need for a new solution that addresses the root causes of access failure.
A new, innovative solution is found in VasQ™, an external support device in order to decrease the fistula’s early maturation failure rate caused by the issues described above.
During the initial fistula procedure a support device is placed proximal and distal to the anastomosis, where turbulent flow and intimal hyperplasia are most significant and where frequent occlusions occur. The decrease in the damaging turbulent flow near the anastomotic region allows for control of geometrical configuration and control of flow patterns, and the reduction of intimal hyperplasia allow for reduce of wall tension on the vein and an increase in wall shear stress, thus eliminating the main causes for lack of AV fistula maturation.
Surgical methods used to improve AV fistula maturation:
In cases when AV fails to mature there are surgical options, aimed at improving the AV fistula maturation. These surgical options require additional surgery, several weeks after initial fistula placement:
- Flow rerouting – a deliberate process of diverting blood flow into the veins that are known to have a straight line flow to the central circulation.
- Staged balloon angioplasty maturation – dilating the entire length of the fistula body with an angioplasty balloon in order to increase fistula target size for cannulation.
- Limited controlled extravasation – arterial inflow control technique utilizing an occlusion balloon or manual pressure.
- Vessel thickening angioplasty -deliberate fracturing of vessel wall causing inflammation of vein, resulting in wall thickening.
- Competing branch vein elimination – embolization or surgical ligation of competing branch veins over 3-8 mms in diameter.
What you can do in order to improve AV fistula maturation:
Early intervention may allow an opportunity to salvage an AV fistula that does not seem to be maturing. Patients with persistent edema two weeks after access placement should undergo testing to evaluate for central venous obstruction. In general, AVF evaluation should be done approximately 6 weeks after creation, in order to asses for lesions blocking the access circuit.
In addition to evaluation and testing most physicians routinely recommend a series of hand-arm exercises, in order to increase rate of fistula maturation. Forms of exercise include use of hand grips, stress balls, resistance bands, weighted wrist flexions, weights, clothes pins etc, and involve a series of repetitive movements aimed at increasing the blood pressure flowing through the fistula. It is also recommended to use other hand to squeeze the bicep of fistula arm, hindering blood return and causing fistula to dilate.