Haemodialysis and haemodiafiltration lead to similar changes in vascular stiffness during treatment

Haemodiafiltration (HDF) has been reported to cause less hypotension than haemodialysis (HD). We hypothesized that HDF causes less change in vascular tone, thereby reducing hypotension.

Aortic pulse wave velocity (PWVao) was measured in 284 patients, during a single dialysis session using cooled dialysate (117 HD, 177 HDF). Patient groups were matched for age, sex and cardiovascular comorbidity.

Systolic blood pressure (SBP) declined from 144 ± 26 to 133 ± 26 after 20 minutes, and to 131 ± 26 mmHg post HD, and for HDF from 152 ± 26 to 143 ± 27 after 20 minutes, then to 138 ± 27 mmHg post HDF. Net Ultrafiltration rates to achieve weight loss were similar; HD 0.13 ± 0.06 vs HDF 0.12 ± 0.05 mL/kg/min. PWVao did not change after 20 minutes HD 0.42(-0.7 to 1.3), HDF 0.5 (-0.6 to 1.8) or at the end of the session: HD -0.39 (1.5 to 1.2), HDF -0.41(-2.0 to 1.3) m/s. Aortic augmentation index (AiAxo), assessment of vascular tone fell significantly with both HD; 20 minutes by 6.2 (-2.5 to 14), end 5.6 (-6.7 to 13.9), and HDF 20 min by 4.2 (-2.5 to 10), end 7.8 (-0.8 to 19.3), with no difference between HD and HDF. The ultrafiltration rate correlated with % change in aortic SBP (r = 0.28 p = 0.004), but not with changes in PWVao or augmentation indices.

Blood pressure declined during both HD and HDF treatments, as did augmentation indices, unrelated to weight loss, suggesting a reduction in vascular stiffness occurs independently of treatment modality. We did not observe an advantage for HDF.