Named after the physician who created the procedure, a Cimino fistula is a connection between an artery and a vein in the forearm through surgical means. This connection creates a permanent access point for attaching a patient to a hemodialysis machine. Allowing a faster and easier hookup, this procedure is often used in patients receiving long-term dialysis.
The Cimino fistula is often chosen over other methods as it tends have a lower incidence of clotting and infection. It also results in increased blood flow, meaning fewer associated problems are likely. These factors help to improve the prognosis of the patient over the long term. The permanency of the fistula depends on the size and condition of the veins and arteries before the surgery. If they are too thin or in bad condition, the connection will fail sooner or not be possible at all.
Creation of the fistula is usually carried out under a local anesthetic and can be done on an outpatient basis without requiring the patient to stay overnight in the hospital. The procedure itself typically takes approximately 90 minutes to complete, although it takes four to eight weeks for the connection to be sufficiently healed to enable use. A Cimino fistula uses the cephalic vein and the radial artery. Preferably, the connection is closer to the wrist but can also be made further up the forearm just before the elbow.
To create the fistula, surgeons first isolate the artery and the vein. They then divide the vein and make a hole in the side of the artery. Next, they sew the end of the vein leading away from the hand to the arterial opening. As a result, blood continues to flow away from the heart in the artery and toward the heart in the vein, but some of the arterial blood also diverts into the vein.
The Cimino fistula subsequently increases blood pressure through the vein. This causes the vein to dilate and for its wall to become thicker in order to accommodate the change in pressure. The increased pressure minimizes the blood flow problems that can cause complications in dialysis, and the thickened walls make it easier for the vein to withstand repeated puncture.
There are a number of side effects that can occur with the Cimino fistula. Initially, there can be sensations of coolness and numbness, but these are usually temporary. There is also an associated feeling of turbulence, or rushing in the vein, caused by the increase in blood pressure. Other potential complications, though fairly uncommon, can result.
Although the risk is minimal, clotting, infection, and bleeding due to repeated puncture can occur. Insufficient dilation of the vein may result in poor blood flow. Blood flow can also be compromised by a narrowing of the vein. There can subsequently be a resultant shortage of blood to the hand, causing it to become cold, discolored, and prone to ulceration. Rarely, aneurysms can occur.