Coronary artery calcium burden and metabolic indices in relation to arteriovenous fistula functionality and post-functionality failure.

BACKGROUND

Autogenous arteriovenous fistula (AVF) is the preferred haemodialysis access, but functionality failure and subsequent post-functionality AVF failure remain common. Whether coronary artery calcium (CAC), a marker of systemic vascular calcification, is associated with either outcome is unclear; competing events are frequently ignored.

OBJECTIVE

To examine CAC and metabolic markers in relation to AVF functionality and post-functionality AVF failure.

METHODS

In this single-centre retrospective cohort, 645 patients with end-stage kidney disease underwent first-time radiocephalic AVF creation. The primary outcome was functionality failure (n = 139 events; assisted functionality or abandonment before cannulation), with unassisted functionality, death and transplantation as competing events. A secondary outcome was post-functionality AVF failure among 568 fistulas that achieved successful functionality, with death and transplantation as competing events. Fine-Gray subdistribution hazard models were fitted after multiple imputation (n = 20).

RESULTS

Independent predictors of functionality failure were age (subdistribution hazard ratio [SHR] 1.53, 95% confidence interval [CI] 1.22-1.93, P < 0.001 per 1 standard deviation [SD]), CAC score (SHR 1.21, 95% CI 1.06-1.38, P = 0.004 per 1 SD) and left ventricular diastolic dysfunction (SHR 1.44, 95% CI 1.02-2.04, P = 0.040). Categorically, CAC 1-100 and >100 vs. 0 yielded SHRs of 5.38 (95% CI 3.02-9.58) and 6.61 (95% CI 3.57-12.22), respectively, both P < 0.001. For post-functionality AVF failure, assisted functionality (SHR 1.68, 95% CI 1.25-2.25, P < 0.001), diabetes (SHR 1.42, 95% CI 1.07-1.89, P = 0.015), serum albumin (SHR 0.71, 95% CI 0.56-0.88, P = 0.002 per 1 SD) and C-reactive protein (SHR 0.78, 95% CI 0.64-0.97, P = 0.022 per 1 SD) were independently associated. The C-index was 0.746 (95% CI 0.70-0.79) at 180 days for the primary outcome and 0.677 (95% CI 0.632-0.725) at 2 years for the secondary outcome.

CONCLUSIONS

Older age and higher CAC burden are independently associated with AVF functionality failure, whereas the strongest determinant of subsequent patency loss is the need for assisted functionality. Preoperative static markers discriminate moderately; postoperative haemodynamic parameters are likely required for individual risk prediction.