A Doppler ultrasound utilized to evaluate renal allografts.
The resistive index is derived from the pulsatile flow-velocity waveform.
In natural kidneys, a higher resistive index is a predictor of progressive renal dysfunction and adverse cardiovascular events.
And increased intrarenal resistive index after kidney transplantation is associated with an increased risk of graft loss or recipient death.
Depends on the aortic pulse pressure and aortic stiffness.
Reflects central hemodynamic factors.
In a prospective study involving 321 renal-allograft recipients the measurement of resistive index at baseline and at 3, 12, 24 months reflects the characteristics of the recipient but not those of the graft (Naesems M et al).
In the above study that intrarenal resistive index is not associated with graft function, with acute inflammation, or chronic histologic damage, but instead reflects intrarenal disease processes, the recipients age and central hemodynamic factors.
In the above study intrarenal resistive index was associated with recipient survival but not with graft survival.