**5. Vascular access morbidity and mortality**

Studies have shown a mortality risk dependent on access type, with the highest risk associated with central venous dialysis catheters, followed by AVGs and then AVFs [135–137]. Recently Hicks et al. [137] stated that this benefit of AVG over TCs may not apply to younger (18–48 years) or older (over 89 years) age-groups. Additionally, patients who had a catheter as the first VA had more complications and higher mortality [138]. The same results have been presented by Ng et al. [139], who examined hospitalization burden related to VA type among 2635 incident patients. The risk for vascular access complications is increased in intensive HD, with overall reported rates being lower in patients with AVF [140]. The CHOICE study examined mortality based on access type in 616 hemodialysis patients for up to 3 years of follow-up. Increased mortality was observed in CVCs and AVGs compared to AVFs in a rate of 50% and 26%, respectively, with greater prevalence in male and elderly patients [141, 142]. Despite these findings and the KDOQI recommendations, dialysis access data from 2002 to 2003 showed that only 33% of prevalent hemodialysis patients in the USA were being dialyzed via AVFs. On the contrary, in Europe and Canada, the majority of the patients [74% and 53%, respectively) were being dialyzed via AVFs [143], but a decreasing trend in the use of AVF seems to take place accompanied by an increasing trend in the use of TCs at the start and after the start of HD [144].

Vascular access admissions continue to fall, with more procedures now performed in an outpatient setting, and are 45% below than in 1993. Among African American patients, the relative risk of an all-cause hospitalization or one related to infection is almost equal to that of Caucasians; the risk of a vascular access hospitalization, however, is 24% higher [145]. Thrombotic occlusion remains a major event, leading to permanent failure in 10% of AVFs and 20% of grafts each year. Interventional (percutaneous transluminal angioplasty and/or stent implantation) or surgical revision of thrombosed accesses has similar outcomes with a high rate of reinterventions. Diabetic elderly patients suffering from peripheral arteriosclerotic obstructive disease are particularly prone to angioaccess-induced hand ischemia [146]. Patients with TCs and AVGs have higher chronic inflammation levels than those with AVFs and increased requirements in epoetin [147]. In our previous work with 149 hemodialysis patients with 202 vascular access procedures (177 Cimino-Brescia AVFs and 25 PTFE AVGs), Cimino–Brescia fistula was used in all patients as the first choice vascular access, except for one patient in the elderly group. Fifteen patients in the elderly group and 7 younger than 65 years old had PTFE AVGs as the third or second choice of VA, respectively. Vascular throm‐ bosis was the only reason of technique failure in both groups. Other complications were aneurysms (10/48 and 14/101), infections (0/48 and 2/101) and edema (0/48 and 6/101) (Table 1). AVF had a 5-year technique survival in two groups of 35% and 45%, respectively (Figure 13). According to our findings, there was no difference in VA complications across age-groups and the first AVF survival was independent of age [6]. Swindlehurst et al. [148] have published similar results, according to which the creation of AVF in the elderly is not only possible but also proved to have a short hospital stay, high patency rates, and an acceptable rate of further intervention. The outcome of AVF benefits more from acknowledging individual vascular conditions rather than age of the patient and therefore AVF creation should not be denied to elderly patients [149]. Among patients over 80 years of age, the AVF as vascular access for HD at the time of dialysis initiation was among the factors that benefit their survival [150].

indwelling CVC [126]. In the USA, no more than 800 pediatric patients receive maintenance HD therapy, while the majority of smaller patients, less than 10 kg or 2 years old, receive

However, hemodialysis can be performed successfully in infants and very young children, as well [130]. An evaluation of the vasculature of children who will undergo hemodialysis will indicate the appropriate vascular access. Because of the size of their vessels, there is limited use of AVF in children, although there is an effort to make nephrology society to consider AVF as the best access in pediatric HD patients [131]. According to a 2008 pediatric registry (NAPRTCS) annual report, vascular access for hemodialysis included external percutaneous catheter in 78% of patients, internal AV fistula in 12%, and internal and external AV shunt in 7.3 and 0.7%, respectively [125]. K/DOQI has encouraged greater use of AV fistulas in larger children receiving hemodialysis who are not likely to receive a transplant within 12 months, with a goal of achieving more effective dialysis with fewer complications than the ones occurring with catheters. Patient's size determines catheter size. An 8-F dual lumen catheter is well tolerated in 4- to 5-kg children, and as the child's size increases, a vascular access of larger volume can be placed [132]. Blood flow in pediatric patients varies due to the catheter size, which depends on the child's size. In most of the patients, a recommended blood flow of 3 to 5 ml/kg/min is acceptable [133], providing adequate dialysis with Kt/V equal or greater than 1.2. A recent study by Fadel et al. found a significant correlation between serum soluble vascular cell adhesion molecule 1 and ESA doses in thrombosed AVF, and this could have

Studies have shown a mortality risk dependent on access type, with the highest risk associated with central venous dialysis catheters, followed by AVGs and then AVFs [135–137]. Recently Hicks et al. [137] stated that this benefit of AVG over TCs may not apply to younger (18–48 years) or older (over 89 years) age-groups. Additionally, patients who had a catheter as the first VA had more complications and higher mortality [138]. The same results have been presented by Ng et al. [139], who examined hospitalization burden related to VA type among 2635 incident patients. The risk for vascular access complications is increased in intensive HD, with overall reported rates being lower in patients with AVF [140]. The CHOICE study examined mortality based on access type in 616 hemodialysis patients for up to 3 years of follow-up. Increased mortality was observed in CVCs and AVGs compared to AVFs in a rate of 50% and 26%, respectively, with greater prevalence in male and elderly patients [141, 142]. Despite these findings and the KDOQI recommendations, dialysis access data from 2002 to 2003 showed that only 33% of prevalent hemodialysis patients in the USA were being dialyzed via AVFs. On the contrary, in Europe and Canada, the majority of the patients [74% and 53%, respectively) were being dialyzed via AVFs [143], but a decreasing trend in the use of AVF seems to take place accompanied by an increasing trend in the use of TCs at the start and after

peritoneal dialysis [127–129].

256 Updates in Hemodialysis

clinical significance after further investigation [134].

**5. Vascular access morbidity and mortality**

the start of HD [144].

**Figure 13.** Cumulative survival of first VA according to the patients' age.


**Table 1.** Complications of vascular access

According to the 2010 USRDS Annual Data Report, in 2008, hospitalizations increased, to a point of 46% over 1993. Women on hemodialysis were 16% more likely to be hospitalized than men, overall, in 2007–2008. Also, they had a greater risk than men of cardiovascular, infectious and vascular access hospitalizations 11%, 14%, and 29%, respectively. Recently, in a retro‐ spective single-center analysis, our data varies to those we published in 1998. In 145 patients on HD, we found that female had more possibilities to start HD with double lumen catheter than male and also patients with heart failure independent of gender [115]. Patibandla et al. [151] in their logistic regression model found that increasing age, female sex, black race, lower body mass index, urban location, certain comorbidities and shorter pre-end-stage renal disease nephrology care are all associated with a significantly lower like hood of AVF placement as initial access predialysis. Additionally, there are geographic disparities in AVF creation with decreased rates of AVF placement as the first access in metropolitan, but not rural, populations compared with micropolitan communities [152]. Improvement in standardization of care according to practice guidelines is necessary. AVF rate could be increased by improving access to surgical resources and patients education [153]. Enhancing patient self-care abilities and working together with patients on proper vascular access care can prolong vascular access site viability [154]. Intraoperative blood flow measurements greater than 120 ml/min in AVF and less than 320 ml/min in AVGs may be predictive factors of early failure and fistulography is essential to access patency [155]. In addition to the clinical examination, there are numerous radiological assessments of vascular access pre- and postoperative that enrich our diagnostic armamentarium [156]. Recently, Remuzzi and Manini [157] presented a numerical model that in the clinical setting should allow to reduce the incidence of AVF nonmaturation as well as incidence of VA complications. Cannulation of VA is a crucial part of its management in HD patients and the proper use of the rotating site technique might still be the best approach to cannulation [158]. Evidence do not support the preferential use of buttonhole over rope-ladder cannulation [159]. However, according to systematic review of Muir et al. [160], buttonhole cannulation is associated with higher rates of infectious events, staff support requirements and no reduction in surgical AVF interventions compared with rope ladder in home HD patients.
