Aneurysm Formation in Arteriovenous Grafts: Associations and Clinical Significance

Acute problems of hemodialysis access: Thrombosis, aneurysms, symptomatic high-flow fistulas, and complications related to central lines

Hemodynamic complications frequently affect vascular access and are important causes of morbidity and mortality. We present a review of acute complications affecting vascular accesses, focusing on classical and new treatments. Acute complications in hemodialysis vascular access are often underestimated and undertreated, and can present a challenge for both vascular surgeons and anesthesiologists. Accordingly, we considered different anesthesiologic approaches to both hemorrhagic and nonhemorrhagic patients. A strict collaboration among nephrologists, surgeons, and anesthesiologists can potentially improve prevention and management of acute complications and quality of life.

How to choose the appropriate cannulation technique for vascular access in hemodialysis patients

The cannulation technique is important for the survival of the arteriovenous access. Choosing the appropriate technique is a complex decision. Such choice must be customized to patients, considering their characteristics, the type of arteriovenous access and the experience of the hemodialysis team. We describe seven items that can help nurses to identify the appropriate cannulation technique: type of arteriovenous access; drainage vein; hygienic self-care profile; experience of the nursing staff in the cannulation technique and nurse-to-patient ratio; hemodialysis treatment method; patient's condition; and patient's decision. Such items can help nurses in decision-making on the "ideal" cannulation technique for each patient.

[Conservative aneurysmorrhaphy for hemodialysis arteriovenous fistula]

The aim of this study was to evaluate the results of conservative surgical treatment of the aneurysmal complications of arteriovenous hemodialysis fistulae and to determine the factors predictive of long- and mid-term patency of treated fistulae. The surgical treatment was mainly based on caliber reduction and reconstruction.

METHODS

This was a descriptive retrospective study with a five-year duration, going from January 2013 to December 2018. This study included 40 patients presenting aneurysmal complications of their hemodialysis vascular access who were treated with aneurysmorrhaphy.

RESULTS

The mean age of the aneurysmal-complicated hemodialysis vascular access was 42 months. The indications for treatment were puncture-related difficulties in 42.5% of cases, rapid increase of the aneurysmal diameter in 27.5%, skin thinning in 25% and aneurysmal rupture in 5%. The mean aneurysmal course was 6.6 months with an average diameter of 3.25cm at the moment of management. The initial technical success rate was 100%. Twenty patients had complications in the postoperative period. Patency rates at 3, 6, 12 and 24 months were 89.5%, 81.6%, 71% and 63.1%, respectively. Factors predictive of thrombosis were diabetes (P=0.001), peripheral arterial disease (P=0.003), number of punctures per week (P=0.003) and context of emergency presentation (P=0.001).

CONCLUSION

Aneurysmorrhaphy seems to be the best conservative surgical treatment for aneurysmal complications of hemodialysis vascular access fistulae. This surgical approach allows us to conserve the native autologous vascular access and spare the patient's venous network.

Emergency medicine evaluation and management of the end stage renal disease patient

BACKGROUND

End stage renal disease (ESRD) is increasing in the U.S., and these patients demonstrate greater all-cause mortality, cardiovascular events, and hospitalization rates when compared to those with normal renal function. These patients may experience significant complications associated with loss of renal function and dialysis.

OBJECTIVE

This review evaluates complications of ESRD including cardiopulmonary, neurologic, infectious disease, vascular, and access site complications, as well as medication use in this population.

DISCUSSION

ESRD incidence is rapidly increasing, and patients commonly require renal replacement therapy including hemodialysis (HDS) or peritoneal dialysis (PD), each type with specific features. These patients possess greater risk of neurologic complications, cardiopulmonary pathology, infection, and access site complications. Focused history and physical examination are essential. Neurologic issues include uremic encephalopathy, cerebrovascular pathology, and several others. Cardiopulmonary complications include pericarditis, pericardial effusion/tamponade, acute coronary syndrome, sudden cardiac death, electrolyte abnormalities, pulmonary edema, and air embolism. Infections are common, with patients more commonly presenting in atypical fashion. Access site infections and metastatic infections must be treated aggressively. Access site complications include bleeding, aneurysm/pseudoaneurysm, thrombosis/stenosis, and arterial steal syndrome. Specific medication considerations are required for analgesics, sedatives, neuromuscular blocking agents, antimicrobials, and anticoagulants.

CONCLUSIONS

Consideration of renal physiology with complications in ESRD can assist emergency providers in the evaluation and management of these patients. ESRD affects many organ systems, and specific pharmacologic considerations are required.

Vascular Access Complications: An Emergency Medicine Approach

Millions of central venous and arterial catheters are placed across the United States annually as mechanisms of obtaining advanced hemodynamic monitoring and facilitating acute resuscitation. Although presumably life saving or sustaining in many circumstances, current literature identifies the preprocedural and postprocedural complications of infection, thrombosis, embolism, and iatrogenic injury as resulting in patient morbidity and mortality. Today, through the application of aseptic technique, performance of operator training, and the utilization of ultrasound, emergency physicians may limit vascular access complications and improve patient outcomes.

Aneurysms in Vascular Access: State of the Art and Future Developments

A master class was held at the Vascular Access at Charing Cross (VA@CX2017) conference in April 2017 with invited experts and active audience participation to discuss arteriovenous (AV) vascular access aneurysms, a serious and common complication of vascular access (VA). The natural history of aneurysms in VA is poorly defined, and although classifications exist they are not uniformly applied in studies or clinical practice. True and pseudo aneurysms of AV access occur. Whilst an AV fistula by definition is an abnormal dilatation of a blood vessel, an agreed definition of 18 mm, or 3 times accepted maturation diameter, is proposed. The mechanism of aneurysmal dilatation is unknown but appears to be a combination of excessive external remodeling, wall changes due to injury, and obstruction of outflow. Diagnosis of AV aneurysms is based on physical examination and ultrasound. Venography and cross-sectional imaging may assist and be required for the investigation of outflow stenosis. Treatment of pseudo aneurysms and true aneurysms of VA (AVA) is not evidence-based, but relies on clinical experience and available facilities. In many AVA, a conservative approach with surveillance is suitable, although intervals and modalities are unclear. Avoidance of rupture is imperative and preemptive treatment should aim for access preservation, ideally with avoidance of prosthetic materials. Different techniques of aneurysmorrhaphy are described with good results in published series. Although endovascular approaches and stenting are described with good short-term results, issues with cannulation of stented areas occur and, while possible, this is not recommended, and long-term access revision is recommended.

A Case of Brachiocephalic Fistula Steal and the Emergency Physician's Approach to Hemodialysis Arteriovenous Fistula Complications

BACKGROUND

Chronic kidney disease is common in the United States, with many patients maintained on hemodialysis (HD). The process of HD requires vascular access through an arteriovenous (AV) fistula, AV graft, or central venous catheter. Today, as a result of the National Kidney Foundation's "Fistula First" initiative, nearly 55% of HD patients utilize an AV fistula. As there is significant morbidity and mortality associated with fistula placement and recurrent fistula cannulation, emergency physicians must be equipped to recognize and treat fistula complications.

OBJECTIVE

To detail a case study of vascular insufficiency (vascular steal) presenting to an emergency department (ED) and provide an evidence-based approach to the emergency assessment and management of HD AV fistula complications.

DISCUSSION

A 66-year-old man presented to the ED with left upper extremity pain, paresthesias, and loss of grip strength of 1-week duration 15 days after placement of left upper extremity brachiocephalic fistula. He was diagnosed with dialysis access-associated steal syndrome and taken to the operating room for revision. Patients with HD fistulas may experience several complications, including vascular insufficiency, hemorrhage, infection, stenosis, thrombosis, aneurysms, or pseudoaneurysms. Emergency physicians must be able to identify these complications and deliver timely treatment.

CONCLUSIONS

A comprehensive understanding of the appropriate management of AV fistula complications is paramount for the emergency physician. Early recognition and treatment of vascular insufficiency resulting from fistula creation, fistula hemorrhage, fistula infection, stenosis, thrombosis, and aneurysms or pseudoaneurysms is vital to reducing the morbidity and mortality associated with HD.

A modified stapling technique for the repair of an aneurysmal autogenous arteriovenous fistula

OBJECTIVE

An alternative surgical technique for the repair an aneurysmatic arteriovenous fistula (AVF) using a staple remodeling operation has been developed and the results are reported.

METHODS

All patients presenting with an aneurysmatic autogenous AVF of the upper extremities between January 2012 and December 2013 were included in the analysis. The AVF was approached laterally along the entire aneurysm and then remodeled using a stapler on the lateral side of the vein wall. All stenotic segments were excised. Follow-up included a clinical visit and echo color Doppler of the fistula and was performed 7, 15, and 30 days after the intervention and every 6 months thereafter.

RESULTS

We treated 14 patients (nine men [64.3%]) with a median age of 65 years (interquartile range [IQR], 62.5-69 years). Elective interventions were performed in 12 patients (85.7%), and two underwent emergency treatment because of postcannulation bleeding. Technical success was achieved in all cases. The mean duration of the intervention was 75 minutes (IQR, 61.15-83.45 minutes). No in-hospital deaths or major morbidities were observed. Median hospitalization time was 24 hours (IQR, 25-38 hours). Postoperative puncture was performed after a median delay of 12.5 hours (IQR, 12-17 hours). No patient was lost during the follow-up, which was a median of 16.5 months (IQR, 14-23 months). Primary functional patency was 12 of 14 (85.7%). Pseudoaneurysm, bleeding, hematoma, or infection was not observed.

CONCLUSIONS

In our experience, the stapling technique proved to be easy, fast, and safe. Early follow-up outcomes showed excellent primary patency and confirmed the effectiveness of the technique because local complications were never observed.

Patients on Hemodialysis Are Better Served by a Proximal Arteriovenous Fistula for Long-Term Venous Access

Patients with end-stage renal disease should have arteriovenous fistula (AVF) formation 3 to 6 months prior to commencing hemodialysis (HD). However, this is not always possible with strained health care resources. We aim to compare autologous proximal AVF (PAVF) with distal AVF (DAVF) in patients already on HD. Primary end point is 4-year functional primary. Secondary end point is freedom from major adverse clinical events (MACEs). From January 2003 to June 2009, out of 495 AVF formations, 179 (36%) patients were already on HD. These patients had 200 AVF formations (49 DAVF vs 151 PAVF) in arms in which no previous fistula had been formed. No synthetic graft was used. Four-year primary functional patency significantly improved with PAVF (68.9% ± SD 8.8%) compared to DAVF (7.3% ± SD 4.9%; P < .0001). Five-year freedom from MACE was 85% with PAVF compared to 40% with DAVF ( P < .005). Proximal AVF bestows long-term functional access with fewer complications compared to DAVF for patients already on HD.