Arteriovenous Grafts: Early Ultrasonography Tells Their Fortune

Abstract

Background: The patency of arteriovenous grafts (AVG) for hemodialysis is mostly limited by growing stenoses that lead to decreasing of blood flow, thromboses and finally to access failure. The aim of this study was to find out if detection of any pathology by duplex Doppler ultrasonography (DDU) early after creation of AVG could identify those with lower survival. Methods: We retrospectively enrolled AVG examined by DDU in our center within 40 days after their creation during the last 10 years. The findings were divided into 4 subgroups: (1a) normal finding, (1b) DDU risk factor (low flow volume, medial calcinosis of the feeding artery, presence of intimal hyperplasia in the venous anastomosis), (2a) non-significant or (2b) significant stenosis. The primary outcome measure was the cumulative survival of people with AVGs, and the secondary was the primary (unassisted) survival. All patients underwent DDU surveillance every 3 months with pre-emptive treatment of significant stenoses. Results: Overall, 340 cases were found; the median follow-up was 565 days. Normal DDU finding had 60% cases, DDU risk factor 18% cases, non-significant stenosis 13% cases and significant stenosis 9% cases. Occurrence of early significant stenosis was associated with high risk of access loss (hazards ratio (HR) 14.73; 95% CI 5.10-42.58; p < 0.0001). Similarly, the presence of a DDU risk factor and of a non-significant stenosis were related to significantly shorter access lifespan (HR 2.86; 95% CI 1.10-7.40; p = 0.03 and HR 2.83; 95% CI 1.12-7.17; p = 0.03, respectively). Conclusion: DDU examination of AVG early after their creation can identify those at higher risk and may contribute to individualize the surveillance strategy.

Intra- and Postoperative Blood Flow Monitoring in a Sheep Model of Uterus Transplantation

“…Doppler sonography or unidirectional Doppler are standard methods for assessment of vascular anastomosis in surgery and for visualization of veins and arteries. These methods are widely applied, not only for proving patency of vessel anastomosis (30,31), but also for finding optimal vessels for a subsequent anastomosis (32). In our study, we used this method to identify the vessels around the uterus and to finally demonstrate the patency of the vascular anastomosis.…”

The role of Doppler ultrasonography in vascular access surveillance—controversies continue

“…DUS performed early after AVG creation can predict future complications and thus select patients who would profit more from ultrasound surveillance. 30 AVGs are generally more prone to later stenosis development than AVFs. The typical site of stenosis development is at the venous anastomosis and at the adjacent part of the outflow vein.…”

“…Moreover, DUS performed early after AVG creation can also predict future risk of AVG abandonment and thus select high-risk AVGs that could profit from the surveillance most. 30 DUS is even more frequently performed in AVFs after their creation, although the optimal criteria are discussed. 31 AVF/AVG thrombosis, however, can also develop not only because of stenosis progression, but also due to other mechanisms, such as hypotension, dehydration, unwished outer compression during sleep, thrombophilia, and so forth.…”

Briefly Noted

“…A retrospective study of the predictive value of duplex Doppler ultrasonography of AV grafts done within 40 days of graft placement was performed in 340 HD patients. A significant early stenosis (lumen size and blood flow criteria) was seen in 9% of cases and increased the likelihood of access loss during the follow‐up (median, 565 days) by 14.7 fold; a non‐significant stenosis (13% of cases) increased the risk by 2.9 fold .…”