A change of heart: the effect of high flow arteriovenous fistulas on cardiovascular outcomes - a systematic review and synthesis without meta-analysis (SWiM).

BACKGROUND AND HYPOTHESIS

Although arteriovenous fistulas (AVF) are widely accepted as the gold standard form of dialysis access for haemodialysis patients, high AVF flow may impose significant haemodynamic stress, potentially contributing to adverse cardiovascular events, including heart failure (HF). We hypothesize that higher AVF flow is associated with adverse cardiovascular outcomes including an increased incidence of heart failure. We sought to clarify this relationship as understanding this association is crucial for improving patient care.

METHODS

A comprehensive search of the PubMed, EMBASE, and Cochrane databases was used to identify observational studies and randomized controlled trials reporting an effect of AVF flow on cardiac outcomes (clinical, echocardiographic, and biomarker). Due to study heterogeneity, meta-analysis was not feasible. Synthesis without meta-analysis (SWiM) was performed using vote counting of direction of effect as the primary outcome.

RESULTS

Higher AVF flow rates were consistently associated with increased incidence of HF and worsening HF symptoms. Cardiac imaging revealed left ventricular dilation and reduced left ventricular ejection fraction in patients with high-flow AVFs. Elevated biomarkers, such as natriuretic peptides, corroborated the adverse cardiovascular effects of high AVF flow.

CONCLUSIONS

This systematic review and synthesis without meta-analysis showed a positive relationship between AVF flow and clinical, echocardiographic, and biomarker cardiovascular outcomes. The methodological heterogeneity of studies highlights the need for well-designed prospective research with standardised definitions of high flow AVFs and measures for reporting of cardiovascular outcomes.