Association of Four Types of Vascular Access Including Arterial Superficialization with Mortality in Maintenance Hemodialysis Patients: A Nationwide Cohort Study in Japan

Abstract

Introduction: Vascular access usage varies widely across countries. Previous studies have evaluated the association of clinical outcomes with the three types of vascular access, namely, arteriovenous fistula (AVF), arteriovenous graft (AVG), and tunneled and cuffed central venous catheter (TC-CVC). However, little is known regarding the association between arterial superficialization (AS) and the mortality of patients.

Methods: A nationwide cohort study was conducted using data from the Japanese Society for Dialysis Therapy Renal Data Registry (2006-2007). We included patients aged ≥20 years undergoing hemodialysis with a dialysis vintage ≥6 months. The exposures of interest were the four types of vascular access: AVF, AVG, AS, and TC-CVC. Cox proportional hazard models were used to evaluate the associations of vascular access types with 1-year all-cause and cause-specific mortality.

Results: A total of 183,490 maintenance hemodialysis patients were included: 90.7% with AVF, 6.9% with AVG, 2.0% with AS, and 0.4% with TC-CVC. During the 1-year follow-up period, 13,798 patients died. Compared to patients with AVF, those with AVG, AS, and TC-CVC had a significantly higher risk of all-cause mortality after adjustment for confounding factors: adjusted hazard ratios (95% confidence intervals) - 1.30 (1.20-1.41), 1.56 (1.39-1.76), and 2.15 (1.77-2.61), respectively. Similar results were obtained for infection-related and cardiovascular mortality.

Conclusion: This nationwide cohort study conducted in Japan suggested that AVF usage may have the lowest risk of all-cause mortality. The study also suggested that the usage of AS may be associated with better survival rates compared to those of TC-CVC in patients who are not suitable for AVF or AVG.

Keywords: Arterial superficialization; Arteriovenous fistula; Arteriovenous graft; Central venous catheter; Vascular access.

Fig. 1.

Kaplan-Meier survival curves according to vascular access type. a All-cause mortality. b Infection-related mortality. c Cardiovascular mortality. AVF, arteriovenous fistula; AVG, arteriovenous graft; AS, arterial superficialization; TC-CVC, tunneled and cuffed central venous catheter.

Fig. 2.

Subgroup analyses of all-cause mortality according to the baseline characteristics. a Subgroup analyses according to age, sex, dialysis vintage, and cause of ESKD. b Subgroup analyses according to vascular access at hemodialysis and study initiation, myocardial infarction, cerebral infarction, cerebral hemorrhage, and limb amputation. Cox proportional hazard models were adjusted for age, sex, body mass index, cause of ESKD, dialysis vintage, and duration and frequency of dialysis, comorbidities (history of myocardial infarction, cerebral infarction, cerebral hemorrhage, and amputation of limbs), laboratory data (albumin, hemoglobin, albumin-adjusted calcium, phosphate, intact PTH, and ferritin), and proportion of AVFs within the four types of vascular access in each facility. Bars present 95% CIs. AS, arterial superficialization; AVF, arteriovenous fistula; AVG, arteriovenous graft; CI, confidence interval; ESKD, end-stage kidney disease; HR, hazard ratio; TC-CVC, tunneled and cuffed central venous catheter.