Associations of Patient Morphology and Venous Anatomy with Early Changes in Upper-Extremity Venous Blood Flow Following PICC Placement in Patients with Cancer: A Prospective Cohort Study.

Purpose: Ultrasound evaluation of target vein diameter before peripherally inserted central catheter (PICC) placement is recommended to control the catheter-to-vein ratio, but early hemodynamic changes after PICC placement remain incompletely characterized. This study evaluated the associations of patient morphology and baseline venous anatomy with early changes in upper-extremity venous blood flow velocity after PICC insertion. Patients and Methods: In this prospective single-center cohort study, 519 adult patients with cancer requiring PICC insertion were enrolled. Body mass index (BMI), arm circumference, baseline vascular depth, and baseline vascular diameter were recorded before catheterization. Time-averaged mean venous blood flow velocity was measured by Doppler ultrasound before insertion and on day 1 after insertion under identical conditions. Multivariable linear regression was used to identify factors independently associated with day-1 flow velocity and with the change in flow velocity. Results: All 519 patients completed baseline and day-1 assessments. Mean blood flow velocity decreased from 14.87 ± 4.42 cm/s at baseline to 14.28 ± 4.87 cm/s on day 1 (mean difference, -0.59 cm/s; 95% CI, -1.08 to -0.10; p = 0.017); the effect size was small (Cohen's dz = -0.10) and the clinical significance of this change is uncertain. The mean catheter-to-vein ratio was 30.8% ± 6.6%, and 36.4% of patients exceeded a ratio of 33%. In multivariable analyses, baseline vascular diameter was independently associated with both day-1 flow velocity (adjusted β, 7.25 cm/s per cm; 95% CI, 2.85-11.64; p = 0.001) and the change in flow velocity (adjusted β, 8.33 cm/s per cm; 95% CI, 3.18-13.48; p = 0.002), with smaller veins showing lower post-insertion velocities and greater reductions. Body mass index was independently associated with day-1 flow velocity (adjusted β, 0.24 cm/s per kg/m Conclusion: Patient morphology and venous anatomy were associated with different patterns of early hemodynamic change after PICC insertion. This study evaluated hemodynamic changes only; catheter-related thrombosis was not assessed, and no conclusions regarding thrombosis risk can be drawn. The observed velocity reduction was small and of uncertain clinical significance. These findings are hypothesis-generating, and future studies incorporating thrombosis endpoints are needed.