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Innovation in catheter design for intra-arterial liver cancer treatments results in favorable particle-fluid dynamics.

van den Hoven AF, Lam MG, Jernigan S, van den Bosch MA, Buckner GD - J. Exp. Clin. Cancer Res. (2015)

Bottom Line: Here, we present first evidence of catheter design effect on particle-fluid dynamics and downstream branch targeting during microsphere administrations.Quantitative analyses confirmed a significantly more homogeneous distribution with the ARC; the mean DHD was 40.85 % (IQR 22.76 %) for the SMC and 15.54 % (IQR 6.46 %) for the ARC (p = 0.047).Catheter type has a significant impact on microsphere administrations in an in-vitro hepatic arterial model.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, Room E.01.132, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands. a.f.vandenhoven@umcutrecht.nl.

ABSTRACT

Background: Liver tumors are increasingly treated with radioembolization. Here, we present first evidence of catheter design effect on particle-fluid dynamics and downstream branch targeting during microsphere administrations.

Materials and methods: A total of 7 experiments were performed in a bench-top model of the hepatic arterial vasculature with recreated hemodynamics. Fluorescent microspheres and clinically used holmium microspheres were administered with a standard microcatheter (SMC) and an anti-reflux catheter (ARC) positioned at the same level along the longitudinal vessel axis. Catheter-related particle flow dynamics were analyzed by reviewing video recordings of UV-light illuminated fluorescent microsphere administrations. Downstream branch distribution was analyzed by quantification of collected microspheres in separate filters for two first-order branches. Mean deviation from a perfectly homogenous distribution (DHD) was used to compare the distribution homogeneity between catheter types.

Results: The SMC administrations demonstrated a random off-centered catheter position (in 71 % of experiments), and a laminar particle flow pattern with an inhomogeneous downstream branch distribution, dependent on catheter position and injection force. The ARC administrations demonstrated a fixed centro-luminal catheter position, and a turbulent particle flow pattern with a more consistent and homogenous downstream branch distribution. Quantitative analyses confirmed a significantly more homogeneous distribution with the ARC; the mean DHD was 40.85 % (IQR 22.76 %) for the SMC and 15.54 % (IQR 6.46 %) for the ARC (p = 0.047).

Conclusion: Catheter type has a significant impact on microsphere administrations in an in-vitro hepatic arterial model. A within-patient randomized controlled trial has been initiated to investigate clinical catheter-related effects during radioembolization treatment.

No MeSH data available.


Related in: MedlinePlus

Photograph of the experimental hepatic arterial model (model #2). For practical reasons, the model is oriented upside down (different to orientation in a patient). Abbreviations: PHA = proper hepatic artery; LHA = left hepatic artery; S4A = segment 4 artery; RHA = right hepatic artery
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Fig1: Photograph of the experimental hepatic arterial model (model #2). For practical reasons, the model is oriented upside down (different to orientation in a patient). Abbreviations: PHA = proper hepatic artery; LHA = left hepatic artery; S4A = segment 4 artery; RHA = right hepatic artery

Mentions: An in vitro hepatic arterial model was created to replicate hemodynamics and vessel geometry during microsphere administrations in the human hepatic arterial vasculature. The use of this model has been described before [16]. Central to this system was a rigid planar model fabricated by 3D printing. Two different models were used: a transparent model for the fluorescent microsphere administrations (experiments 1–3) to optimize the visibility of the microsphere flow, and a non-transparent model with a piece of surgical tubing inserted at the intended injection position to optimize vessel sealing by the ARC (experiments 4–7, Fig. 1). The geometry of both models was obtained from the branching pattern of three-dimensional CT imaging. The models consisted of a main bifurcation into left hepatic artery (LHA) and right hepatic artery (RHA), with the LHA terminating in six vessels (1.0 mm ID), and the RHA and segment 4 arterial (S4A) branch terminating in a total of ten vessels (1.0 mm ID). Hemodynamics was regulated by a closed-loop, dynamically pressurized system. At the proximal side of the vascular model, a fluid supply reservoir was connected to two parallel configured, computer-controlled pumps, a gear pump (Greylor Corporation, Cape Coral, FL) and a custom-made positive displacement pump that induced pulsatile pressurization of the hepatic arterial model to resemble the cardiac cycle. A blood pressure profile with a systolic/diastolic value of 140/60 mm Hg and 60 cycles/min was chosen as target (Fig. 2), based on previous simulations of the hepatic arterial blood flow [17]. One-way valves in the fluid lines near the pumps prevented backflow. The distal vessels drained into open collection reservoirs, mounted on USB-interfaced laboratory scales. Pumps connected to the collection reservoirs intermittently recirculated the fluid back to the fluid supply reservoir. Real time mass measurements were used to quantify the intra-vascular flow rates. All terminal vessels ran through pinch valves that were iteratively adjusted to keep the flow rates at target level and increase peripheral resistance. A target flow velocity of 10 ml/min for each vessel (total flow rate 160 ml/min) was chosen for all administrations. This choice was based on reported flow rates of the right hepatic artery with a range of 29–225 mL/min, constituting 60 % of the total hepatic arterial flow, yielding a range of 48.3-375.0 mL/min for the proper hepatic artery [18–20]. To replicate blood viscosity, with a reported value of 3.49 cP at systolic shear rates [21] (ex vivo measurements corrected for hematocrit level), a 25/75 % glycerin/water solution was used. Adequate fluid viscosity (3.48 ± 0.42 cP at a shear rate of 150 s-1) was confirmed by measurements taken with a HAAKE™ Viscotester™ 550 (ThermoFisher Scientific, Waltham, MA).Fig. 1


Innovation in catheter design for intra-arterial liver cancer treatments results in favorable particle-fluid dynamics.

van den Hoven AF, Lam MG, Jernigan S, van den Bosch MA, Buckner GD - J. Exp. Clin. Cancer Res. (2015)

Photograph of the experimental hepatic arterial model (model #2). For practical reasons, the model is oriented upside down (different to orientation in a patient). Abbreviations: PHA = proper hepatic artery; LHA = left hepatic artery; S4A = segment 4 artery; RHA = right hepatic artery
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4522078&req=5

Fig1: Photograph of the experimental hepatic arterial model (model #2). For practical reasons, the model is oriented upside down (different to orientation in a patient). Abbreviations: PHA = proper hepatic artery; LHA = left hepatic artery; S4A = segment 4 artery; RHA = right hepatic artery
Mentions: An in vitro hepatic arterial model was created to replicate hemodynamics and vessel geometry during microsphere administrations in the human hepatic arterial vasculature. The use of this model has been described before [16]. Central to this system was a rigid planar model fabricated by 3D printing. Two different models were used: a transparent model for the fluorescent microsphere administrations (experiments 1–3) to optimize the visibility of the microsphere flow, and a non-transparent model with a piece of surgical tubing inserted at the intended injection position to optimize vessel sealing by the ARC (experiments 4–7, Fig. 1). The geometry of both models was obtained from the branching pattern of three-dimensional CT imaging. The models consisted of a main bifurcation into left hepatic artery (LHA) and right hepatic artery (RHA), with the LHA terminating in six vessels (1.0 mm ID), and the RHA and segment 4 arterial (S4A) branch terminating in a total of ten vessels (1.0 mm ID). Hemodynamics was regulated by a closed-loop, dynamically pressurized system. At the proximal side of the vascular model, a fluid supply reservoir was connected to two parallel configured, computer-controlled pumps, a gear pump (Greylor Corporation, Cape Coral, FL) and a custom-made positive displacement pump that induced pulsatile pressurization of the hepatic arterial model to resemble the cardiac cycle. A blood pressure profile with a systolic/diastolic value of 140/60 mm Hg and 60 cycles/min was chosen as target (Fig. 2), based on previous simulations of the hepatic arterial blood flow [17]. One-way valves in the fluid lines near the pumps prevented backflow. The distal vessels drained into open collection reservoirs, mounted on USB-interfaced laboratory scales. Pumps connected to the collection reservoirs intermittently recirculated the fluid back to the fluid supply reservoir. Real time mass measurements were used to quantify the intra-vascular flow rates. All terminal vessels ran through pinch valves that were iteratively adjusted to keep the flow rates at target level and increase peripheral resistance. A target flow velocity of 10 ml/min for each vessel (total flow rate 160 ml/min) was chosen for all administrations. This choice was based on reported flow rates of the right hepatic artery with a range of 29–225 mL/min, constituting 60 % of the total hepatic arterial flow, yielding a range of 48.3-375.0 mL/min for the proper hepatic artery [18–20]. To replicate blood viscosity, with a reported value of 3.49 cP at systolic shear rates [21] (ex vivo measurements corrected for hematocrit level), a 25/75 % glycerin/water solution was used. Adequate fluid viscosity (3.48 ± 0.42 cP at a shear rate of 150 s-1) was confirmed by measurements taken with a HAAKE™ Viscotester™ 550 (ThermoFisher Scientific, Waltham, MA).Fig. 1

Bottom Line: Here, we present first evidence of catheter design effect on particle-fluid dynamics and downstream branch targeting during microsphere administrations.Quantitative analyses confirmed a significantly more homogeneous distribution with the ARC; the mean DHD was 40.85 % (IQR 22.76 %) for the SMC and 15.54 % (IQR 6.46 %) for the ARC (p = 0.047).Catheter type has a significant impact on microsphere administrations in an in-vitro hepatic arterial model.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, Room E.01.132, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands. a.f.vandenhoven@umcutrecht.nl.

ABSTRACT

Background: Liver tumors are increasingly treated with radioembolization. Here, we present first evidence of catheter design effect on particle-fluid dynamics and downstream branch targeting during microsphere administrations.

Materials and methods: A total of 7 experiments were performed in a bench-top model of the hepatic arterial vasculature with recreated hemodynamics. Fluorescent microspheres and clinically used holmium microspheres were administered with a standard microcatheter (SMC) and an anti-reflux catheter (ARC) positioned at the same level along the longitudinal vessel axis. Catheter-related particle flow dynamics were analyzed by reviewing video recordings of UV-light illuminated fluorescent microsphere administrations. Downstream branch distribution was analyzed by quantification of collected microspheres in separate filters for two first-order branches. Mean deviation from a perfectly homogenous distribution (DHD) was used to compare the distribution homogeneity between catheter types.

Results: The SMC administrations demonstrated a random off-centered catheter position (in 71 % of experiments), and a laminar particle flow pattern with an inhomogeneous downstream branch distribution, dependent on catheter position and injection force. The ARC administrations demonstrated a fixed centro-luminal catheter position, and a turbulent particle flow pattern with a more consistent and homogenous downstream branch distribution. Quantitative analyses confirmed a significantly more homogeneous distribution with the ARC; the mean DHD was 40.85 % (IQR 22.76 %) for the SMC and 15.54 % (IQR 6.46 %) for the ARC (p = 0.047).

Conclusion: Catheter type has a significant impact on microsphere administrations in an in-vitro hepatic arterial model. A within-patient randomized controlled trial has been initiated to investigate clinical catheter-related effects during radioembolization treatment.

No MeSH data available.


Related in: MedlinePlus