Strategies for Hemodialysis Access: A Vascular Surgeon’s Perspective

Hemodialysis Access: US for Preprocedural Mapping and Evaluation of Maturity and Access Dysfunction

Patients with kidney failure require kidney replacement therapy. While renal transplantation remains the treatment of choice for kidney failure, renal replacement therapy with hemodialysis may be required owing to the limited availability and length of time patients may wait for allografts or for patients ineligible for transplant owing to advanced age or comorbidities. The ideal hemodialysis access should provide complication-free dialysis by creating a direct connection between an artery and vein with adequate blood flow that can be reliably and easily accessed percutaneously several times a week. Surgical arteriovenous fistulas and grafts are commonly created for hemodialysis access, with newer techniques that involve the use of minimally invasive endovascular approaches. The emphasis on proactive planning for the placement, protection, and preservation of the next vascular access before the current one fails has increased the use of US for preoperative mapping and monitoring of complications for potential interventions. Preoperative US of the extremity vasculature helps assess anatomic suitability before vascular access creation, increasing the rates of successful maturation. A US mapping protocol ensures reliable measurements and clear communication of anatomic variants that may alter surgical planning. Postoperative imaging helps assess fistula maturation before cannulation for dialysis and evaluates for early and late complications associated with arteriovenous access. Clinical and US findings can suggest developing stenosis that may progress to thrombosis and loss of access function, which can be treated with percutaneous vascular interventions to preserve access patency. Vascular access steal, aneurysms and pseudoaneurysms, and fluid collections are other complications amenable to US evaluation. ©RSNA, 2023 Supplemental material is available for this article. Test Your Knowledge questions for this article are available through the Online Learning Center.

The clinical journey and healthcare resources required for dialysis access of end-stage kidney disease patients during their first year of hemodialysis

BACKGROUND

Creation and maintenance of dialysis vascular access (VA) is a major component of healthcare resource utilization and cost for patients newly started on hemodialysis (HD). Different VA format arises due to patient acceptance of anticipatory care versus late preparation, and clinical characteristics. This study reviews the clinical journey and resource utilization required for different VA formats in the first year of HD.

METHOD

Data of patients newly commenced on HD between July 2015 and June 2016 were reviewed. Patients were grouped by their VA format: (A) pre-emptive surgically created VA (SCVA), (B) tunneled central venous catheter (CVC) followed by SCVA creation, (C) long-term tunneled CVC only. Clinical events, number of investigations and procedures, hospital admissions, and incurred costs of the three groups were compared.

RESULTS

In the multivariable analysis, the cost incurred by the group A patients had no significant difference to that incurred in the group B patients (p = 0.08), while the cost of group C is significantly lower (p < 0.001). Both the 62.7% of group A with successful SCVA who avoided tunneled CVC usage, and those with a functionally matured SCVA in group B (66.1%), used fewer healthcare resources and incurred less cost for their access compared to those did not (p = 0.01, p = 0.02, respectively) during the first year of HD.

CONCLUSION

With comparable cost, a pre-emptive approach enables avoidance of tunneled CVC. Tunneled CVC only access format incurred lower cost and is suitable for carefully selected patients. Successful maturation of SCVA greatly affects patients' clinical journey and healthcare cost.

Determinants of Tunneled Hemodialysis Catheter Implantation Time by Ultrasound Guidance: A Single-Center Cross-Sectional Study

BACKGROUND

We have previously reported that the ultrasound (US)-guided tip positioning is an accurate and safe procedure for placement of retrograde- and antegrade-tunneled hemodialysis catheters (HDCs). However, determinants of tunneled hemodialysis catheter implantation time by using US guidance have not been described yet. Therefore, we here report a comparative analysis to identify determinants of implantation time for retrograde- and antegrade-tunneled HDCs placement by US guidance.

METHODS

We performed a cross-sectional study to compare implantation time for US-guided tip positioning of retrograde- and antegrade-tunneled HDCs. We included a total number of 47 tunneled HDC insertions, including 23 retrograde tunneled and 24 antegrade-tunneled HDCs in patients requiring placement of an HDC for the temporary or permanent treatment of end-stage kidney disease (ESKD) in a single-center, cross-sectional pilot study.

RESULTS

We show that clinical and laboratory parameters did not differ between retrograde- and antegrade-tunneled HDC implantations. There was a tendency for shorter implantation time in antegrade-tunneled HDCs, although not statistically significant. Finally, we identified an independent inverse association between body weight (BW) and platelet counts with HDC implantation time specifically in antegrade-tunneled HDCs.

CONCLUSION

In this study, we identified determinants for tunneled HDC implantation time that might be relevant for patients and interventionists.

Early cannulation versus standard arteriovenous grafts in hemodialysis patients: a randomized clinical study

OBJECTIVE

Arteriovenous grafts (AVGs) are frequently needed in hemodialysis (HD) patients with unsuitable superficial veins. First cannulation of standard arteriovenous grafts (sAVGs) still require about 2 weeks after implantation. Early cannulation arteriovenous grafts (eAVGs) were suggested to overcome this shortcoming. The present randomized study proposed to compare the clinical outcomes of sAVGs and eAVGs in HD patients.

METHODS

The present single-center randomized clinical study recruited 477 HD patients indicated for AVG creation. They included 236 in the sAVG group and 241 in the eAVG group. Eligible patients were simply randomized and allocated to the studied groups using 1:1 allocation ratio. Blinding was secured using the sealed envelope technique. Enrolled patients were followed up for 12 months. The primary outcome in the present study was primary, primary assisted, and secondary patency rates at 12 months. Other outcome parameters included time to first cannulation, graft complications, and mortality.

RESULTS

Comparison between the studied groups regarding the primary outcomes revealed no statistically significant differences. Primary patency rate was 65.7% and 68.0% (P = .58) at 6 months and 53.8% and 56.4% (P = .57) at 12 months in the sAVG and eAVG groups, respectively. Primary assisted patency rate was 70.8% and 69.7% (P = .8) in patients with sAVG and eAVG, whereas the reported rates at 12 months were 59.3% and 61.0% (P = .71), respectively. Secondary patency rate was 78.4% and 73.9% (P = .25) at 6 months and 67.8% and 69.7% (P = .65) at 12 months in the sAVG and eAVG groups, respectively. As expected, patients in the eAVG group experienced significantly earlier cannulation when compared with patients in the sAVG group (median, 3.0 days; range, 1.0-9.0 days vs 19.0 days; range, 15.0-22.0 days; P < .001).

CONCLUSIONS

Patients in the eAVG group have comparable outcomes to those in the sAVG group at 12 months with the added advantage of earlier time to first cannulation.

Olfactory bulb - gateway for COVID-19?

Introduction: Anosmia and ageusia are one of the most common and characteristic symptoms of SARS-Cov-2 infection, with frequency of almost 50% in patients in Western countries. There are more and more hypotheses of potential central nervous system (CNS) affection by the virus. It is supposed that virus enters via nasal mucosa, and then via cribriform plate enters olfactory bulb, with further dissemination to the CNS. Case report: A 34-year old female patient experienced loss of smell and taste in July 2020, about two months before testing Covid-19 positive. Covid-19 presented with minor pneumonia, and worsening of anosmia and ageusia. After treatment, the patient recovered well, but anosmia and ageusia appeared again, varying in intensity, and since January 2021 became persistent. The case was evaluated by otorinolaryngologist, pulmologist, and finally neurologist. In the meantime, patient was tested Covid-19 negative and received two doses of Sputnik V vaccine. Brain MRI was performed and it clearly shows severe bilateral olfactory bulb atrophy. Thre patient has anosmia and ageusia up to this day, and future MRI follow-up is planned. Conclusion: Loss of smell and taste may be a predictor of further central nervous system dissemination of the virus, and possible neurological complications (which is still a subject of consideration). Olfactory bulb could be a gateway to Covid-19 intrusion into CNS, and its atrophy could be an indicator of that. Further investigation on this topic is required, including wide application of MR imaging in order to come to definite conclusions.

Agitated saline bubble-enhanced ultrasound for the positioning of cuffed, tunneled dialysis catheters in patients with end-stage renal disease

BACKGROUND

In patients with end-stage renal disease, the use of cuffed, tunneled dialysis catheters for hemodialysis has become integral to treatment plans. Fluoroscopy is a widely accepted method for the insertion and positioning of cuffed dialysis catheters, because it is easy to use, accurate and reliable, and has a relatively low incidence of complications. The purpose of our study was to evaluate the feasibility of tunneled hemodialysis catheter placement without the use of fluoroscopy but with a dynamic ultrasound-imaging-based guided technique.

METHODS

From January 2015 to December 2017, we performed an observational prospective cohort study of 56 patients with end-stage renal disease who required tunneled dialysis catheter placement.

RESULTS

The overall success rate for ultrasound-guided central access was 100%, with a mean number of 1.16 (±0.4) attempts per patient. There were no incidences of guide wire coiling/kinking, carotid puncture, pneumothorax, or catheter malfunction. Catheter flow during dialysis was 286 (±38) mL/min. The total number of catheter days was 7451, with a mean of 133 days and a range of 46-322 days. Life table analysis revealed primary patency rates of 100%, 96%, and 53% at 30, 60, and 120 days, respectively.

CONCLUSION

Dynamic ultrasound-based visualization of microbubbles in the right atrium is a highly accurate method to detect percutaneous implantation of large-lumen, tunneled, central venous catheters without the need for fluoroscopic guidance technology. Future research should further develop and confirm these initial findings.