Changes in duplex ultrasound parameters during maturation according to arteriovenous access types in incident hemodialysis patients

Background: Little is known about the changes in hemodynamic parameters during arteriovenous (AV) access maturation using duplex ultrasound according to radiocephalic fistula (RCF), brachiocephalic fistula (BCF), and AV graft (AVG) in incident hemodialysis (HD) patient. The objective of this study was to evaluate changes and differences in brachial artery flow rate (BAFR) and related parameters affecting maturation by duplex ultrasound in incident HD patients according to access type. Methods: This study was an observational study conducted from March 2019 to October 2020. During the study period, 109 incident patients underwent new AV access creation, of which 100 were included in the study. The duplex ultrasound was performed on the day prior to access creation, further, day 1, 2 weeks, and 4 weeks later after access creation in incident HD patients. Results: Among all the patients, 38 (38%) received BCF, while 26 (26%) underwent RCF. Of the patients with AVG, 18 (50%) had a forearm loop AVG. The overall mean age was 62.2 ± 13.8 years (range, 32–89). The BAFR increased about 6.9 times in the RCF, 17.4 times in the BCF, and 19.5 times in the AVG at day 1. The median BAFR measured on day 1 was 580.4 mL/min for RC, 1029.0 mL/min for BC, and 1133.0 mL/min for AVG. Relative to the values measured in week 4, the BAFR on day 1 was 69.5% in RCF, 90.6% in BCF, and 93.9% in AVG. The acceleration decreased most significantly on day 1( p < 0.05). The acceleration time increased significantly on day 1 ( p < 0.05) and beyond during maturation in the RCF and BCF. The BAFR of the RCF had a significantly negative correlation with the pulsatility index. The BAFR of the BCF showed a significantly positive correlation with the systolic and diastolic blood pressure but negatively correlated with pulse rate. The BAFR of the AVG showed a significant positive correlation with the diameter of the outflow vein. Conclusions: There were differences in the clinical and duplex parameters during maturation according to access type. The most dramatic changes of duplex parameters were on the day after AV access creation regardless of AV access types. Though RCF had a lower BAFR rate compared to BCF and AVG, it already had a sufficient BAFR required for adequate HD treatment the day after creation. The BAFR of BCF was not different from that of AVG.

Intra-access Pressure: Do We Really Need to Know? A Critical Review

Arteriovenous (AV) fistula and AV graft are considered superior to venous catheter access, remarkable success has been achieved in increasing prevalence of AV fistula. However, vascular access complications are common and result in increased hospitalization, mortality and expense. Guidelines suggest various methods to maintain patency of vascular access. Amongst these various methods used for vascular access monitoring and surveillance, intra-access pressure (PIA) is a simple tool which can be helpful in early detection and management of stenosis in vascular access. Intra-access pressure, although a very simple and quick method of vascular access evaluation, has a low diagnostic accuracy in prediction of vascular access stenosis as compared to other methods of access surveillance. We discuss here the physiology, methodology and the utility of intra-access pressure.

Endovascular treatment of arteriovenous graft dysfunction as a result of graft delamination and fracture

Background Graft thrombosis due to fabric delamination is a rare cause of delayed failure of arteriovenous grafts. Graft delamination is primarily an imaging diagnosis and is confirmed with the help of ultrasound which shows the separation of graft fabric layers. Only two such cases have been described in the literature so far. Case presentation We present a case of upper extremity arteriovenous graft thrombosis in a 79 year old COVID-19 positive patient with end-stage renal disease. The diagnosis was established on ultrasonography which revealed separation of the graft fabric layers with thrombosis within the “false” and “true” lumen of the graft. The patient was managed with angioplasty and embolectomy of the clot material followed by stent-graft placement across the delaminated portion of the graft. Post-procedural angiography confirmed brisk flow across the graft and patient could successfully have subsequent hemodialysis sessions. Conclusions Identification of graft delamination as a cause of graft failure is important as its management differs from other conventional causes since it requires stent-grafts to cover the area of delamination to re-establish flow and salvage the AV graft. The recognition of this phenomenon is essential to provide quality care and successful reuse of the AV graft. Level of evidence Level 4, Case Report.