David Cull, Greenville, USA, writes that vascular access placement in the elderly needs to take into account patients’ physiological age in an effort to predict survival.
The Fistula First Breakthrough Initiative has placed substantial pressure on surgeons to create arteriovenous fistulae for patients on haemodialysis by linking arteriovenous fistula prevalence to surgical quality. The programme’s success is evidenced by the rapid growth of arteriovenous fistula prevalence in the USA. However, that change coincides with an increase in the use of dialysis catheters, arteriovenous fistula non-maturation, and early failure, events that can negate the benefits of arteriovenous fistulae over grafts. These complications have prompted efforts to identify factors that are predictive of early arteriovenous fistula failure and guide vascular access selection. Some have suggested that advanced age is one such factor and should be considered when evaluating a patient for vascular access type. This is an important issue because age-related problems such as disadvantaged arterial and venous anatomy, fragile skin, and comorbidities can influence vascular access outcomes and limit patient survival. Also, as more than half of patients on haemodialysis are older than 65 years of age, the prevalence of end-stage renal disease is increasing most rapidly in the elderly age group.
The conclusions of studies evaluating vascular access in the elderly are conflicting. These conflicts are likely due to varying definitions of “elderly” among studies. The elderly cohort of some studies includes patients older than 65 years of age, whereas others only include patients older than 75 or even 80 years of age. Furthermore, most agree that the physiological age, as measured by a tool such as the Karnofsky Performance Score, provides a more accurate definition of elderly than the chronological age. However, the studies addressing this issue exclusively use chronological age to define elderly.
The majority of studies reporting the primary and secondary patency rates of arteriovenous fistulae in the elderly suggest that the outcomes are equivalent to young patients. However, many of the studies also demonstrate that for many elderly patients, particularly those older than 80 years of age, life-expectancy is limited. This raises the question as to whether the early failures and interventions required to achieve arteriovenous fistula maturation are worthwhile for patients with a life expectancy of less than two years or whether those patients would be better served with a graft. This dilemma was addressed in a study from our institution which reported the outcomes of 32 arteriovenous fistulae in octogenarians (Claudeanos et al. Ann Vasc Surg 2015;29:98–102). The study comprised a carefully selected group of patients with excellent arterial and venous anatomy. The primary and secondary patency rates were 38% and 75% at two years and there were no infections. Those outcomes alone would suggest that arteriovenous fistulae in the elderly are equivalent to those of younger patients. However, we also noted that 10% of patients never required haemodialysis and therefore underwent an unnecessary operation. Twenty-one per cent failed maturation and 29% were never able to use their arteriovenous fistula for haemodialysis. The median patient survival was only 26 months. The median time to fistula cannulation was 109 days, which represented 21% of the survival time. Seventy-seven per cent of patients in the series required at least one subsequent intervention to either achieve maturation or to maintain access functionality. This study highlights the importance of looking at more than patency rates when evaluating outcomes of vascular access procedures as well as considering expected patient survival when selecting the optimal vascular access option. Although we have not used a specific measurement tool for predicting patient survival, an interesting 2003 study by Joly et al found that the combination of three factors—the Karnofsky Performance Score, body mass index, and late referral for haemodialysis—were highly predictive of one-year mortality for patients older than 80 years of age (Joly et al. J Am Soc Nephrol 2003;14:1012–21). This scale could be a valuable tool for deciding vascular access type for the elderly patient population.
Our approach to vascular access placement in the elderly is to assess the physiological age by considering the patient’s comorbidities and functionality in an effort to predict survival. Every patient undergoes a physical exam and duplex scan to evaluate the vascular anatomy. If the patient is on dialysis via a catheter, we favor arteriovenous graft placement unless the patient is both anatomically and physiologically an excellent arteriovenous fistula candidate. If the patient is referred to us prior to initiating dialysis, we will place a fistula. We prefer upper arm to radial-cephalic fistulae due to thinner skin of the forearm and the lower rates of maturation reported among some studies. If the skin is very thin and fragile, we prefer to place a graft in the upper arm and will tunnel that graft more deeply than usual.
In conclusion, efforts to obtain an arteriovenous fistula are justified in most elderly patients with favourable vascular anatomy, a life-expectancy exceeding two years, and who do not have a dialysis catheter. The patient’s physiological age and estimated survival time should be major factors in access procedure selection.
David Cull is professor of Surgery at the University of South Carolina School of Medicine, Greenville, USA, and is the founder and chief technical officer of CreatiVasc Medical