Long treatments showed more stability of peripheral systolic blood pressure ( change during HD4 , -21.715.6 mm Hg ; during HDF4 , -23.320.8 mm Hg ; during HD8 , -6.715.2 mm Hg [ P = 0.04 vs. HD4 ; P = 0.08 vs. HDF4 ] ; and during HDF8 , -0.514.4 mm Hg [ P = 0.004 vs. HD4 ; P = 0.008 vs. HDF4 ] ) .