Steve,
I am sure you know most of this. This is what we look for with maturity of an AVF. The brachial or radial artery in flow is also a consideration and we look at a normal or resistive index ,, RI close to .70-1.0 is abnormal with a stenosis , occlusion or outflow obstruction. How soon after creation of the fistula? Cephalic or basilic? I would suspect outflow obstruction and look at the cephalic arch at the subclavian ,, or the basilic Axillallary Rt , subclavian and innominate . If too soon , repeat in 2-3 weeks for maturity,, Some but not often never mature. 6 weeks is the best to evaluate post creation . 45% of our practice is AVF and all types of hemodialysis grafts.. we had only one Brescia fistula that did not mature within several years of our practice. I know reimbursement will not cover if done too soon after creation unless they suspect DVT or occlusion.. would like to hear from others if they are using RI inflow ... Denise
I reviewed a case of an AVF exam that had very low Volume Flow Velocities reported (less than 0.06 L/min). The waveforms were obtained approx 5 cm distal to the arterial anastomosis in a straight uniform vein section one month post-op and looked normal in shape. Velocities were not impressively low. Diameter was about 2.2cm. 4 cardiac cycles were included in the calculation. The autotrace of peak velocity and mean velocity tracked the spectral profile without noticeable deviation. The series of beats measured did include a PVC with a low EDV. Also, the degree of fistula maturity may be a factor. I would like to hear others who do a lot of Vol Flow measurements of early dialysis fistulas weigh in here.
Thanks,
Steve K