Dialysis Flashcards
Higher 1yr patency rates:
Brachiocephalic or radio-cephalic?
Brachiocephalic arteriovenous fistulas offer several advantages over radiocephalic arteriovenous fistulas, including a higher maturation rate, decreased time to maturity, and higher primary patency and functional primary patency. Despite these benefits, radiocephalic fistulas are generally preferred if there is adequate conduit available to prolong sites for future access placement, as many patients are on long-term dialysis and need all access options preserved.
Access is patients with AICDs?
Arteriovenous accesses created ipsilateral to an AICD have a higher primary failure rate compared with the contralateral arm and should be avoided as much as possible. If adequate vein is unavailable in the contralateral arm, it would be appropriate to consider a venogram to assess patency of the central veins, although that is controversial.
Regional anesthesia in upper extremity fistulas
Regional anesthesia has been associated with longer operative time. Perioperative flow in the access has been shown to be higher and association with vasospasm has been shown to be lower. This translates to an improved short-term patency. Regional anesthesia has not been shown to affect major morbidity, including perioperative myocardial infarction and mortality.
Prolonged bleeding after hemodialysis?
Patients often have prolonged bleeding after dialysis due to an underlying venous outflow stenosis with relative venous hypertension. This patient needs a fistulogram and possible intervention.
Lower extremity dialysis access
Of lower extremity access studies have demonstrated the best outcomes for femoral vein transpositions. Patients undergoing femoral vein transpositions should have minimal to no peripheral arterial disease or ischemic symptoms of the lower leg can develop after the fistula is created. Saphenous vein transpositions are another option and have superior patency to synthetic grafts. The major concern with synthetic grafts is infection, which has been reported to be as high as 22% in one series. Overall long-term patency rates for lower extremity grafts is poor with approximately half patent at 6 months.
Dialysis Steal Grading
DRIL procedure
Differences between 1 and 2 stage brachiobasilic fistulas?
A recent systematic review and meta-analysis included data from 2 randomized controlled trials and 9 case control studies to evaluate the difference between one- and two-stage brachial-basilic arteriovenous fistula creation. It showed no difference in failure rates, primary or secondary 1-year patency, or secondary 2-year patency. There was no difference in infection rates, steal syndrome, hematoma, pseudoaneurysms, or stenosis. There was a significant improvement in 2-year primary patency in the two-stage group (relative risk, 2.50; 95% confidence interval, 1.66-3.74; p < .00001) and a trend toward increased postoperative thrombosis in the one-stage procedure, although that did not reach statistical significance.
Absolute contraindications to hybrid catheter-graft access
Addition to pic:
Graft patency is significantly compromised in patients with a low systolic blood pressure (< 100 mm Hg) or severely depressed ejection fraction (<20%).
Optimal timeing of fistula creation? AVG?
Ideal timing for autogenous arteriovenous access is 6 months prior to dialysis initiation, while prosthetic access should be delayed until about 3 to 6 weeks prior to dialysis initiation. Early autogenous access is associated with reduced sepsis and death risk compared to late access.
Risk of gadolinium contrast in those with CKD?
MRI should not be used due to the risk of nephrogenic systemic fibrosis with gadolinium administration in patients with a glomerular filtration rate less than 30-45 mL/min.
What is recirculation?
Venous outflow stenosis is the most common reason for arteriovenous graft failure. A low flow rate that fails to exceed the dialysis pump rate results in recirculation during the dialysis session.
What is significant arterial stemosis?
Greater than 50% stenosis of the inflow artery associated with a non-functioning AVF is considered significant and should be treated
Tapered vs non-tapered grafts
Tapered grafts are often used with the intent of decreasing the incidence of ischemic steal. Recent studies have demonstrated that tapered grafts for upper extremity access do not affect primary patency, development of steal, or complication rates. There was also no difference in the number of endovascular interventions performed in comparison to non-tapered grafts. Graft choice should be based on operator comfort and familiarity.
Most common cause of AVG thrombosis
Intimal hyperplasia and stenosis can lead to arteriovenous graft thrombosis. In prosthetic access, this most commonly occurs at the venous anastomosis. Central venous stenosis can also lead to graft thrombosis, particularly in patients with arm swelling and a previous history of central venous access.
Artery and vein criteria for access?
Signs of brachial shetah hematoma?
Clinical presentation
* The symptoms start with progressive pain, numbness and weakness. Then, the patient feels tingling of the thumb, index, middle, and half of the ring finger.
* Loss of sensation in the area where it is supplied by the median nerve in the hand (figure 1).
Source: Southern and Sloan, 2010
Figure 1. The area in the hand where its supplied by the median nerve sensory part.
* Loss or reduce the ability to move the thumb away from other fingers due to paralysis of the thumb muscles and inability to do a pinch grip (figure 2). Patient can not do things that required forearm, or wrist repetitive movements.
Source; Mathiowetz et al., 1985
Figure 2. The pinch grip become poor with the patient with median nerve palsy due to paralysis of the thumb muscles.
* In addition, median nerve compression at the elbow level, result in hand of benediction due to loss of the innervation of the median nerve at the second and third digits (figure 3).
