The total number of people actively treated with ESRD in the United States on December 31, 2012, was 636,905, of which 450,602 received dialysis and 186,303 had a functional kidney transplant; 88,638 patients with ESRD died between January 1 and December 31, 2012. Medicare spent $28.6 billion or 5.6 % of its total budget, providing ESRD care during this time period. Figure 4.2 places ESRD in context with other surgical diseases, including cancer and cardiovascular disease [6–8].
Each year, about 610,000 people suffer their first stroke, while 10,000 develop testicular cancer in comparison to the 110,000 who develop ESRD. About 40 % of those patients treated with ESRD with hemodialysis (HD) will survive for 5 years in comparison to 98 % of those diagnosed with prostate cancer, and 75 % treated for an abdominal aortic aneurysm. Almost 90,000 people with ESRD die every year, whereas 160,000 die annually from lung cancer, and 40,000 die from breast cancer.
Variation in ESRD Diagnosis
Southern states experience approximately twice the yearly incidence of ESRD in comparison to New England and the Pacific Northwest. Eggers, Rosansky, and colleagues reported this trend in 1990 [9]. Despite differing population characteristics, particularly density of African-American residents who demonstrated significantly higher ESRD frequencies, patient demographics could not completely account for variation in treatment. This finding was recapitulated in contemporary studies derived from recent USRDS and Medicare data [10, 11].
Variation in AVF Construction
Hemodialysis, rather than peritoneal dialysis, is the dominant renal replacement therapy in the United States. Surgeons occupy a key position in the initiation algorithm, namely, establishing reliable intravascular access. Arteriovenous fistulas (AVFs) are the preferred method. The prominent FFCL public policy campaign initiated in 2005 focused on increasing fistula-based access.
Incident and Prevalent Vascular Access
According to the FFCL Dashboard, approximately 63 % of all patients in the United States on hemodialysis use an AVF, a significant improvement over the early 2000s, when only 33 % of patients did so [12]. Malas et al. suggest approximately 99 % of ESRD patients are amenable to fistula creation based on demographic analysis [13]. Were incident fistula-based access to be pursued at this aggressive level, Malas et al. estimate saving $2 billion annually in 2010 dollars [13]. Most patients, however, still initiate dialysis with transcutaneous catheters – either temporary or permanent. Incident surgical access – either AVF or arteriovenous grafts (AVGs) – has not changed significantly since the Centers for Medicare and Medicaid Services (CMS) instituted the FFCL initiative in 2005 (Fig. 4.4) [14].
Furthermore, AVF construction for incident dialysis varies by nearly 100 % across the United States (Fig. 4.5) [15].
Nephrology care increases the likelihood of a patient beginning hemodialysis with a functional fistula by a factor of 11 [16]. This finding reemphasizes the necessity interdisciplinary coordination plays in optimal ESRD patient care.
Variation in Mortality Associated with Incident Vascular Access Type
Catheters and prosthetic graft material are hypothesized to subject patients to increased infection and cardiovascular event risks, accounting for this difference in mortality [17]. Furthermore, adjusted mortality hazard for patients varies by location within the United States (Fig. 4.7) [15].
Appraised together, these findings suggest that locoregional variation in surgical decision-making significantly impacts ESRD patient care at a systemic level.
Patient-Level Surgical Outcomes
The following section discusses patient-level AVF outcomes:
Fistula Maturation
Effective hemodialysis presupposes technical success in the operating room, defined as a patent fistula, graft, or catheter on concluding a procedure. Whereas catheters are immediately usable, AVG and AVF require – at a minimum – 2 and 4 weeks, respectively, to develop into viable intravascular access sites. Guidelines from the National Kidney Foundation Kidney Disease Outcomes Quality Initiative (NKF KDOQI) section 3.2.2 deem AVF mature when they display: (1) a 6 mm vein diameter, (2) a 600 mL per minute blood flow rate, and (3) a vein depth below the skin of 6 mm [18]. This process, usually appraised as maturation failure, varies between patients. Published frequencies in large series encompassing AVF at all upper extremity position range from 9 to 81 % [19–23]. The most compelling preoperative patient characteristics predicting failure to mature (FTM) include age, CAD, PAD, and race [19]. A scoring system developed by Lok et al. based on these preoperative patient characteristics categorized FTM risk into low, medium, high, and very high with frequencies of 24, 34, 50, and 69 %. Voormolen and coauthors identified postoperative hemodynamic risk factor assessment as 58 % sensitive and 88 % specific for maturation failure in a systematic literature review [21]. Fistula flow and fistula venous diameter as well as a composite value for both variables in addition to radial artery resistive index were employed together or individually as hemodynamic assessment variables in the examined studies. These parameters predicted maturation failure with better sensitivity and specificity than presurgical patient characteristics or preoperative hemodynamic assessment. Combined, these studies guide patient selection but also have implications into postoperative surveillance and intervention.
Cannulation
Preparing patients to receive renal replacement therapy is best practiced in a proactive fashion, as suggested by Fistula First Catheter Last guidelines. While selecting patients who will successfully mature fistulas is complex, predicting which patients ultimately progress to end-stage renal disease is a challenge in and of itself. Chronic kidney disease (CKD) progresses in a discontinuous fashion. An exact accounting of CKD patients within the United States does not exist. However, the National Health and Nutrition Examination Survey (NHANES) is a yearly cross-sectional study capturing, in addition to other variables, kidney disease prevalence and severity [24]. Between 2007 and 2012, about 0.5 % of the 50,000 NHANES participants demonstrated CKD stage 4 or 5 levels at which surgical referral is recommended by FFCL Change Concept 3 [6]. Extrapolating this finding to the US population as a whole, about 1.6 million of the estimated 320 million United States citizens in 2015 likely suffer from surgically actionable kidney disease. Figure 4.1 shows about 115,000 people progress to ESRD every year or about 7.2 % per year of those patients with CKD stage 4 or 5. Progression among patients receiving AVF prior to initiating HD – either due to selection bias, more aggressive disease, or non-initiator patients dying – appears to be significantly higher in reported cohorts. Solid et al. identified 550 non-ESRD patients who had received an AVF in the 2005 Medicare 5 % random sample; 71 % progressed to hemodialysis through their AVF within 2 years [25]. A large randomized trial corroborated this result with 81 % of patients not requiring renal replacement therapy prior to AVF creation, achieving successful cannulation within the study period [26]. Lastly, a recent retrospective cohort reported 65 % of patients proactively treated with an AVF eventually employed it on HD [27].
Patency
Once cannulated, fistulas must be durable. Hemodialysis is, philosophically, a bridge to kidney transplantation – the most efficacious ESRD treatment [6]. Practically, AVF must last for years and are often definitive therapy. Several meta-analyses published within the last 5 years improve on single-center results; Table 4.1 summarizes their findings.
Al-Jaishi et al. found pooled forearm and brachium fistula, 1- and 2-year primary patencies to be 60 % and 51 %, respectively [31]. Subgroup analysis demonstrates statistically fewer primarily patent lower arm fistulas at 1 year, 55 %, in comparison to upper arm fistulas, 65 %. At 2 years, both positions primary and secondary patencies were statistically similar, 46 % and 49 %, respectively. Focusing on radial artery-based fistulas, Wu and coauthors report 74 % and 71 %, 1- and 2-year primary patencies [30]. Brachiobasilic fistulas created in either a one-stage or two-stage fashion demonstrated no difference in primary patency, 57 % versus 59 %, respectively [28]. Finally, 82 % of brachiocephalic fistulas in elderly patients were patent at 1 year without reintervention [29]. Each meta-analysis reports significant heterogeneity associated with endpoint reporting and surveillance strategies employed by the primary studies; all call for randomized trial data to supplement their findings.
Maintenance
Medical Therapy
Preventing AVF thrombosis with an antiplatelet agent is a common strategy. Oral agents, including clopidogrel, aspirin, ticlopidine, and dipyridamole, reduce graft loss by half during the 6-month period after construction [32]. Major and minor bleeding events are not statistically different, and maturation appears unaffected. The meta-analysis authors state clearly that AVGs are not protected by antiplatelet agents.
Warfarin does not appear to have a beneficial effect on patency, possibly owing to the platelet-based thrombosis mechanism in arteries and arterialized veins. The 2008 Cochrane collaboration analysis on medical treatment to increase AVF patency reports a single randomized trial with low-dose warfarin resulting in a significant increase in bleeding for the treatment group with a concomitant increase in graft loss [33]. This result confirmed similar retrospective data from the Dialysis Outcomes and Practice Patterns Study (DOPPS) [34].
Surgical and Interventional Therapy
Clinical examination is integral in managing ESRD patients’ ongoing vascular access needs. Unlike other bypass surgeries, AVF and AVG are followed extremely closely often three times per week or more in local dialysis units. Monitoring cannulation and flow parameters during renal replacement therapy ensures failing intravascular access is identified and addressed. Routine multidisciplinary AVF assessments that discuss findings from the dialysis clinic improve primary and secondary patencies while decreasing morbidity experienced by patients [35]. A small series from Bountouris and coauthors in Malmö, Sweden, examined repeated angioplasty on AVF. Of the 50 % of fistulas in their cohort requiring more than one angioplasty, 85 % remained patent at 1 year [36]. Interventions on recently constructed fistulas and those with longer lesions demonstrate increased patency loss after balloon angioplasty, suggesting hemodynamic shear stress and fistula anatomy determine stenosis progression [37]. Likely, new fistulas that require an intervention are intrinsically disadvantaged, either due to a poor conduit, coagulation cascade abnormality, or technical error necessitating revision.
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