Introduction: The CDU is a noninvasive vascular access (VA) monitoring technique that provides both structural and hemodynamic information from vessels.
Objective: The aim of this prospective study was to analyze some parameters of forearm vessels by CDU before and after RCF creation at the wrist.
Patients and methods: We explored by CDU the vessels of forearm in 34 CRF patients (pts) (mean age 63.915.1 yr, sex M:76.5%;F:23.5%, 26.5% diabetes, 73.5% already on HD at the time of RCF placement). Forearm CDU evaluation was planned twice: before RCF creation (first exploration FE) and after two months of successful RCF cannulation for HD by 2 needles at Qb>250 ml/min (second exploration SE). All CDU examinations were performed by the same radiologist with 5-10 MHz linear transducer (Doppler angle < or = 60 degrees) at two proximal and distal points of the forearm (the values were averaged) using the Aspen machine (Siemens-Acuson, Mountain View, CA). We measured by CDU parameters from radial artery RA (diameter RAd, peak systolic velocity PSV, resistive index RI, blood flow rate RAflow), cephalic vein CV (diameter CVd) and arterialized vein AV (diameter AVd, blood flow rate AVflow). RAflow or AVflow calculation by CDU: time average velocity (mean of three cardiac cycles) (m/s) x cross-sectional area (mm2) x 60. RCF outcome: functioning RCF (FRCF) suitable for routine HD 61.8% (mean age 61.214.5 yr, 23.8% diabetes), or non-functioning RCF 38.2% (mean age 68.215.5 yr, 30.8% diabetes) due to: early thrombosis (within 24 hours after operation, ETRCF) 14.7%, lack of RCF maturation (LMRCF) 5.9%, last thrombosis (between 24 hours after operation and SE by CDU, LTRCF) 17.6%.
Results: Between FE and SE by CDU at RA, overall mean RAd (3.2 +/- 0.3 vs 5.5 +/- 1.0 mm), mean PSV (59.9 +/- 12.4 vs 166.6 +/- 58.2 cm/s) and mean RAflow (67.9 +/- 27.4 vs 1297.1 +/- 683.1 ml/min) increased significantly (for all comparisons, p<0.001), and mean RI (0.9 +/- 0.2 vs 0.40. +/- 0.1) decreased significantly (p<0.001); we also found a significant difference when overall mean CVd (2.9 +/- 0.6 mm) and mean AVd (5.7 +/- 1.1 mm) were compared (p<0.001). Overall and distal mean RAflow at FE by CDU were lower in pts with ETRCF (33.6 +/- 19.6 and 26.0 +/- 16.7 ml/min, respectively) compared to pts with FRCF (67.9 +/- 27.4 and 48.0 +/- 21.3 ml/min, respectively) (p=0.015 and p=0.029, respectively). Pts with ETRCF and LMRCF considered together (20.6%), had lower overall mean RAd (2.80.4 mm) and distal mean RAflow (28.1 +/ 15.2 ml/min) at FE by CDU compared to pts with FRCF (3.2 +/ 0.3 mm and 48.0 +/- 21.3 ml/min, respectively) (p=0.015 and p=0.031, respectively). No significant differences between pts with LTRCF and FRCF were found when overall and distal mean RAd, PSV, RI, RAflow and CVd obtained at FE by CDU were compared (for all comparisons, p=NS), but all pts with LTRCF underwent HD at the time of RCF creation compared to 57.1% of pts with FRCF (p=0.049). Pts with FRCF who had overall mean AVflow = 800 ml/min (38.1%, mean AVflow: 602.5167.3 ml/min) showed lower overall mean RAflow at SE by CDU compared to pts with FRCF who had overall mean AVflow>800 ml/min (61.9%, mean AVflow: 1113.9 +/- 160.1 ml/min): 820.1 +/- 188.7 vs 1590.7 +/- 715.4 ml/min (p=0.002). We found a positive correlation between overall mean AVflow and mean RAflow obtained at SE by CDU (r = 0.52, p = 0.016).
Conclusions: 1) All parameters of forearm vessels measured by CDU changed after RCF placement. 2) Preoperative mean RAflow is predictive of RCF outcome. 3) Mean AVflow is related to mean RAflow obtained at SE by CDU.