Expanded hemodialysis (HDx) could provide clearance of larger middle-molecule uremic toxins. We compared the effect of hemodialysis with medium cut-off membranes and high-flux (HFHD) membranes regarding changes in inflammation and vascular and left ventricular function. This was a single-center, prospective, parallel-group comparative study. Patients were divided into two groups (HDx: 25 patients and HFHD: 26 patients). All measurements were performed at baseline and 12 weeks. Serum c-reactive protein, interkelukin-18, pentraxin-3, β-2 microglobulin, and brain natriuretic peptide were measured. We used pulse wave velocity and augmentation index to assess arterial stiffness and echocardiography to evaluate left and right ventricular function. We enrolled 51 patients. Although serum c-reactive protein, interkelukin-18, pentraxin 3, and β-2 microglobulin were significantly decreased in the HDx group (p = 0.02, p < 0.001, p = 0.002, and p = 0.02, respectively), there was no significant change in HFHD group at 12th week. Serum c-reactive protein and interkelukin-18were significantly lower in the HDx group compared to the HFHD group in the 12th week (p = 0.007 and p = 0.03, respectively). We observed a significant decrease in pulse wave velocity in the HDx group at the end of the study (p = 0.03). Although there was no significant change in pulse wave velocity in the HFHD group, pulse wave velocity was similar between the HDx and HFHD groups in the 12th week. We detected a significant decrease in the mean isovolumetric relaxation time in the HDx group (p = 0.006). However, there was no significant difference in isovolumetric relaxation time between the HDx and HFHD groups in the 12th week. HDx provides better clearance of middle molecular uremic toxins and inflammatory biomarkers, and it may be associated with better central hemodynamic parameters and diastolic functions.