Can Detachable Embolization Coils Decrease the Cost of Materials for Portal Vein Embolization Procedures?

Research Article

Austin J Radiol. 2016; 3(3): 1051.

# Can Detachable Embolization Coils Decrease the Cost of Materials for Portal Vein Embolization Procedures?

Stecker MS1*, Fan CM1 and Dabydeen D1,2

1Department of Radiology, Harvard Medical School, USA

2Department of Radiology, Rochester Regional Health System, USA

*Corresponding author: Stecker MS, Department of Radiology, Harvard Medical School, Division of Angiography and Interventional Radiology, Brigham and Women’s Hospital, 75 Francis Street, Midcampus SR- 340, Boston, MA 02115, USA

Received: July 21, 2016; Accepted: August 19, 2016; Published: August 25, 2016

## Abstract

Rationale and Objectives: Preoperative Portal Vein Embolization (PVE) can induce hypertrophy of the Future Liver Remnant (FLR) prior to partial hepatectomy for malignancy. Beyond allowing better control during embolization, detachable coils are available in longer lengths, which could decrease the number of coils needed, and thus the cost of embolization materials. However, they are more expensive. The purpose of this study was to compare the use of Detachable Coils (DC) to Conventional Coils (CC) in PVE.

Materials and Methods: We retrospectively reviewed the clinical data from patients who underwent preoperative PVE, after obtaining IRB approval. Cross-sectional imaging was performed before and after PVE to assess the FLR. Demographics, liver volumes, particles and coils used, procedure times, contrast volumes, and radiation dose metrics were compared between the two groups.

Results: The study included 14 subjects in the CC group and 5 in the DC group. The right portal vein was embolized in all subjects, and 2 in the CC group also had segment 4 embolized. There was no significant difference between the groups for demographic data, volume of particles used, number of branches embolized, liver growth parameters, procedure time, contrast dose, and radiation dose metrics. A mean of 11.9 coils was used in the CC group versus 7.4 coils in the DC group (p=0.006), with a mean cost for embolization coils of $1,014 and$5,360 (p=0.0001) respectively.

Conclusion: Significantly fewer detachable coils are needed for a successful PVE procedure compared to conventional coils, but the total coil cost is much higher.

Keywords: Portal vein embolization; Embolization coils; Cost comparison

## Abbreviations

PVE: Portal Vein Embolization; FLR: Future Liver Remnant; IRB: Institutional Review Board; CC: Conventional fibered Coils; DC: Detachable fibered Coils; TELV: Total Estimated Liver Volume; sFLR: standardized FLR; RVG: Relative Volumetric Growth; DH: Degree of Hypertrophy; KGR: kinetic growth rate

## Introduction

Other than liver transplantation, major hepatic resection is currently the only potentially curative therapy for patients with hepatic malignancies. Increased postoperative morbidity and mortality is associated with a liver remnant that is too small [1]. Preoperative Portal Vein Embolization (PVE) of the diseased hepatic lobe has been used to induce hypertrophy in the remaining liver. The exact mechanism is not completely understood, but is believed to be related to apoptosis of the embolized segments, causing compensatory hypertrophy in the remaining liver [1,2]. With preoperative PVE a patient, whose disease is unresectable due to a Future Liver Remnant (FLR) that is estimated to be inadequate, may be converted to an operative candidate [3].

Many techniques have been used for PVE, but in general they all target portal vein occlusion at the sinusoidal level. Embolic materials used for PVE include particles, adhesives and many types of coils. One technique utilizes small particulate embolic material for the initial sinusoidal level occlusion followed by fibered coil embolization of the main lobar portal branches to prevent recanalization [4]. Conventional embolization coils available from multiple manufacturers have been used in many applications for several decades. Recently, detachable coils have become available with the potential advantage of being able to be retrieved or repositioned, improving the precision of deployment. Delivery platforms include 0.018-inch systems designed to be deployed via microcatheters, and more recently 0.035-inch systems that are deployed via standard diagnostic angiographic catheters were introduced. The retrievable design allows detachable coils to be produced in longer lengths than conventional coils, as the risk of maldeployment of a very long coil could be easily mitigated by recapture and redeployment. Due to the longer lengths, fewer detachable coils might be required for a successful PVE procedure, compared to conventional coils.

Cost containment continues to be strongly emphasized in medical practice. One disadvantage of minimally-invasive procedures is that many of the devices used are expensive and not reusable. Modified versions of conventional devices may cost several times that of the original, and in particular, detachable coils are more costly than conventional coils. This higher cost has a greater impact when multiple devices are required for a single procedure. Portal vein embolization is one such procedure and thus was used as a platform for cost comparison of detachable coils with conventional coils.

## Study design

This retrospective study was approved by the Institutional Review Board (IRB) for research limited to the use of health/medical records and was compliant with the Health Insurance Portability and Accountability Act. All patients gave written informed consent for the PVE procedure, but study consent was waived by the IRB. All patients underwent PVE by a single operator between July 2005 and December 2012. Initially, only 0.035-inch Conventional fibered Coils (CC) were used for these procedures, as they were all that were available. Beginning June 2011, 0.035-inch Detachable fibered Coils (DC) became available and shortly thereafter they were preferentially utilized. As the embolization materials are generally the largest part of the material costs, and since these new coils came in longer lengths, it was thought that fewer coils would be needed to complete a procedure, which could decrease the cost of the embolic materials. Other potential advantages of using fewer coils included reduced procedure time, contrast dose, and radiation exposure. Also, another benefit of these coils was that they could be removed prior to complete deployment if positioning was not acceptable. However, after a short period of time, it subjectively seemed that many coils were still being used for each procedure. Thus, their use was suspended, and a decision was made to perform this formal, IRB-approved review before continuing to use them in this application.

## Embolization procedure

The basic technique employed for PVE has been described elsewhere [4], but our adaptation is summarized here. Procedures were performed under intravenous moderate procedural sedation using midazolam and fentanyl. Prophylactic intravenous antibiotics (typically levofloxacin) were administered. Access was obtained via a right intercostal approach into a right portal venous branch as peripherally as possible under fluoroscopic guidance using a 21 gauge trocar needle, 0.018-inch mandril guidewire, and stiffened transitional dilatation system. A 6 French sidearm sheath was then placed via this access and portal venography performed in PA, and occasionally oblique, projection using a flush angiographic catheter and power injector.

Portal venous branches were then selectively catheterized and embolized with particles, followed by coil embolization of the segmental portal vein branches. Particles used in the CC group included Embosphere microspheres (BioSphere Medical, Roissy, France) in three subjects, Contour particles (Boston Scientific, Natick, MA) in three subjects, and Embozene microspheres (CeloNova BioSciences, Ulm, Germany) in four; Embozene particle were used in all five of the DC subjects. Only one type of particulate embolic agent was used in each patient, except for one subject in the CC group who received Embospheres to supplement the use of Embozene microspheres, and embolization of each branch commenced with small particles and size was increased stepwise. The endpoint for particle embolization of each branch was stasis, and was the same in both groups. (Figure 1) shows the amount and types of particles used for each subject.