One third of arteriovenous fistulas develop complications including thrombosis (51.6%), stenosis (22.6%), aneurysm formation (6.7%) and infection (6.5%). Risk factors for these complications include: hypotension, hypertension, early puncture of the AVF, repeated puncture in the same site, external mechanical compression for hemostasis after removing needling. Pseudoaneurysm maybe thought as hemathomas communicating with the lumen of the access, which with time can develop a fibrotic sac(1,3,6,7,8).
If an aneurysm has ruptured or there is a risk of imminent rupture (skin ulceration and infection), like in our case, emergency ligation of the aneurysm is required.
We present an uncommon case in which aneurysm and pseudoaneurysm of the native fistula is caused by puncture, in both sides. Repeated punctures at the same site, may progressively weaken the venous wall resulting in dilation of the outflow vein.
Therefore it is demonstrated that even in long term AVF with aneurysm and pseudoaneurysm after needling it is advisable to try to salvage the access. At our patient we improved the quality of hemodialysis and no other venous segments or graft prothesis were used for the access salvage.
According to the Kidney Disease Outcomes Quality Initiative (KDOQI) recommendations, the fistula with a native ideal vein must present at least 6 mm in diameter and flow superior to 600 mL/min, and be at a depth of 0.5 to 1 cm of the skin.
After the surgery, has presented some problems that we solved immediately, tryng to avoid the need for a central venous catheter. The patient is feeling good, still performing the hemodialysis on her native fistula, on right side. We recommend her to change the needling site each time she perform hemodialysis.
To avoid loss of access and to prevent disartrous complications, the National Kindney Foundation Disease Outcomes Quality Initiative guidelines recommend that cannulation of the aneurysmal vein should be avoided. In our case, even thought the patient had aneurysmal outflow vein, she remained stable and asymptomatic, without compromising hemodialysis at all, till erosion and bleeding happened. She was afraid to loss her vascular access, therefore she was reluctant to notify the vascular surgeon despite the recommendation of the nephrologist(8,9,10,11,12).
Alternative treatment modalities for aneurysm of AVF inckude: excision and primary anastomosis, open plication with sutures and stapling devices to re-fashion the aneurysm and reduce the volume of the sac, excision and interposition of venous or prostethic graft, and ligation of access when patient have had renal transplantation. Some authors suggest ballon angioplasty for stenosis in some segments of outflow vein away from aneurysmal part.
Alternative treatment modalities for pseudoaneurysm of AVF include: thrombin injection or ultrasound compression for small pseudoaneurysms and surgical repair for large pseudoaneurysms to prevent local complications or enlargement.
Some patients may have a predisposition to aneurysm formation. We considered this as a possible condition to our patient, so we after surgery recommend needling sites changed and blunt needles used if possible(3,4,7).
There are several important factors and conditions to consider in maintaining long term function of the vascular access. It is very important to maintain a normal volume status. It is well known that hypotension from dehydration is one of the most common causes of thrombosis of vascular access. Local factors also contribute to thrombosis of vascular access, including mispuncturing and formation of hematomas, compression of hematoma, repuncturing with the same neddle causes contamination. Antiplatelet drugs such as dipyridamole, ticlopidine and prostaglandins may be used to prevnt thickening of the intima and occlusion of the draining vein(6,8,9,11).
The idea of our paper was that in patients we have predisposition for the formation of aneurysm and pseudoaneursym, the medical staff have more frequent meetings, so that such cases are treated more specifically, with more frequent visits to vascular surgeon, with more frequent measurements of draining vein diameter and flow of vascular access. The K/DOQI guidelines recommend a regular program of monitoring and surveillance of the vascular access. Color Doppler ultrasound s considered a valuable tool in the preoperative evaluation and in the follow-up.
Also, patients due to the general aggravated condition, receive a lot of parenteral therapy, which mainly nurses of hemodialysis patients should take into account, not to damage the large veins which in the future will be used to realize the vascular access.