Long-term Effects of Arteriovenous Fistula Closure on Echocardiographic Functional and Structural Findings in Hemodialysis Patients: A Prospective Study

Background

The arteriovenous fistula (AVF) provides an effective vascular access for hemodialysis; however, the associated hemodynamic effects may alter cardiac structure and function. The objective of this study is to evaluate the effect of AVF closure on functional and structural echocardiographic findings.

Study Design

Prospective observational study.

Setting & Participants

In a single center between 2003 and 2006, we enrolled 25 consecutive hemodialysis patients with AVF malfunction who underwent AVF closure and conversion to a tunneled central venous catheter because of exhaustion of alternative vascular sites and 36 matched controls with a well-functioning AVF.

Predictor

AVF closure.

Outcomes & Measurements

Outcomes were changes in findings on echocardiograms obtained before and 6 months after AVF closure for patients in the AVF-closure group and at baseline and 6 months later for controls. Echocardiographic measurements included left ventricular (LV) internal diastolic diameter, interventricular septum thickness, diastolic posterior wall thickness, LV mass (LVM), LVM index (LVMi), and LV ejection fraction (LVEF). Dialysis modality and scheme were unchanged.

Results

In the AVF-closure group, LVM decreased from 225 ± 55 to 206 ± 51 g (P < 0.001) and LVMi decreased from 135 ± 40 to 123 ± 35 g/m² (P < 0.001). LV internal diastolic diameter, interventricular septum thickness, and diastolic posterior wall thickness decreased significantly, whereas LVEF increased from 56% ± 7% to 59% ± 6% (P < 0.001). No significant changes were observed in controls. In patients with AVF closure, LV morphologic characteristics showed a decrease in both eccentric and concentric hypertrophy in favor of normalization or a pattern of concentric remodeling. No significant changes were observed in controls.

Limitations

Use of matched rather than randomized controls.

Conclusions

Closure of an AVF determines a significant decrease in LV internal diastolic diameter, interventricular septum thickness, and diastolic posterior wall thickness. This is associated with significant improvement in LVEF, a significant decrease in LVM and LVMi, and a more favorable shift of cardiac geometry toward normality.

Index Words: Arteriovenous fistula, hemodialysis, left ventricular hypertrophy, cardiac remodelling