Vascular access refers to the method of inserting a tube into a patient’s bloodstream to facilitate vein access for haemodialysis. This allows blood to flow through the tubes into the dialysis machine where it is cleaned and returned to the bloodstream.
There are three types of vascular access:
- Central venous catheter
- Arteriovenous Fistula (AVF)
- Arteriovenous Graft (AVG)
Central venous catheter/permanent catheter (CVC):
This type of access is where a Y-shaped catheter is placed in a central vein to allow blood to be withdrawn from one lumen to enter the dialysis circuit, then to be returned via the other lumen. These catheters can be inserted in an outpatient clinic in a minimally invasive way.
There are two types of CVC, tunnelled and non-tunnelled.
- Non-tunnelled catheter access is for short-term access (up to about 14 days), and the catheter emerges from the skin at the site of entry into the vein.
- Tunnelled catheter (also known as Permanent Catheters) access is usually more long term and involves a longer catheter tunnelled under the skin from the point of insertion in the vein to an exit site some distance away. It is usually inserted in the internal jugular vein in the neck, and the exit site is generally on the chest wall. The tunnel prevents bacterial invasions by acting as a barrier. Although called a Perm Cath, such tunnelled catheters are designed for short- to medium-term access because the infection is still a frequent problem. We do not recommend placing a Perm Cath for more than six months.
Central Vein Stenosis (CVS) As A Result of Permcath Complication/Infection:
CVS is a serious, and not uncommon, a problem associated with the long-term use of Perm Caths. As the catheter is a foreign body in the vein, it often provokes an inflammatory reaction in the vein wall. This results in the vein becoming scarred and narrowing, which causes a blockage to the blood flow. CVS has been known to cause symptoms such as swelling in the face, neck, chest and/or the upper limbs.
Treatment of CVS requires a procedure known as a Venoplasty, a treatment used to open clogged veins. In this procedure, a balloon is inserted into the vein through a wire and inflated in order to open up the vein. Sometimes, if the narrowing is resistant to the balloon dilatation, then a stent (metal supporting strut) may be placed across it to keep the vein open. The Venoplasty and Stenting can be done under local anaesthesia or mild sedation and as a day surgery procedure.
Case Study 1
Patient was agreeable to fistula creation, and hence an arteriovenous fistula was created for increased accessibility for dialysis.
An incision was made, and the cephalic vein and brachial artery were isolated. The cephalic vein was truncated and attached to the brachial artery, creating a fistula. On release of clamps, good flow was observed.
Post-operation, strong thrill and flow rates were seen. When the patient returned after 3 weeks, good flow in the arteriovenous fistula was seen, with a diameter of 6mm.
Case Study 2
Patient is presented with a blocked arterio-venus hemodialysis graft. Unable to go for lifesaving dialysis.
The case was done under IV sedation and within 4 hours of graft blockage. Patient was able to return to hemodialysis within the same day.
The graft was unblocked using thrombolysis agents, angioplasty, and stenting.
