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High arteriovenous fistula (AVF) flow (Qa) has been shown to increase cardiovascular burden in patients on chronic hemodialysis, in particular higher frequency of pulmonary hypertension and right ventricular dysfunction. However, most data came from studies that included only patients with Qa above 1500 – 2000 mL/min. Other studies documented the safety of AVFs with lower Qa (500-1000mL/min). To reveal the links between Qa and right heart dysfunction, we analyzed cross-sectional entry data from our ongoing larger longitudinal cohort study.
A cross-sectional analysis of prevalent patients on chronic hemodialysis. Qa was measured by ultrasonography and detailed echocardiography included also basic hemodynamic data. All examinations were performed at least 24 hours after the previous hemodialysis. Median Qa was calculated (including patients with catheters, when the Qa was set to zero) and patients with Qa below median were compared with those with Qa above median by the Wilcoxon matched pairs test. Results are presented as median (quartile range) and p-value <0.05 was considered significant.
We included 212 patients, 38 of them had a dialysis catheter, others an AVF. Median Qa was 990 mL/min. Comparison of echocardiographic data is presented in the Table as median (quartile range).
Dilatation of the right heart chambers and right ventricular systolic dysfunction occurred in patients with higher Qa despite no difference in the estimated pulmonary arterial systolic pressure. Therefore, the links between pulmonary hypertension, higher Qa and right heart changes are not straightforward and right heart changes may be more influenced by higher volume and not by pressure overload.