Optimization of Peripheral Vascular Sizing with Conductance Guidewire: Theory and Experiment.

Hyo Won Choi,Ghassan S Kassab,Christopher D Owens,Matthew S Sulkin,Zachary C Berwick,Alain-Pierre Gadeau

doi:10.1371/journal.pone.0168886

Hyo Won Choi, Ghassan S Kassab + Show 4 more

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https://doi.org/10.1371/journal.pone.0168886

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Abstract

Although the clinical range of interventions for coronary arteries is about 2 to 5 mm, the range of diameters of peripheral vasculature is significantly larger (about 10 mm for human iliac artery). When the vessel diameter is increased, the spacing between excitation electrodes on a conductance sizing device must also increase to accommodate the greater range of vessel diameters. The increase in the excitation electrodes distance, however, causes higher parallel conductance or current losses outside of artery lumen. We have previously shown that the conductance catheter/guidewire excitation electrode distances affects the measurement accuracy for the peripheral artery lumen sizing. Here, we propose a simple solution that varies the detection electrode distances to compensate for parallel conductance losses. Computational models were constructed to simulate the conductance guidewire with various electrodes spacing combinations over a range of peripheral artery lumen diameters and surrounding tissue electrical conductivities. The results demonstrate that the measurement accuracy may be significantly improved by increased detection spacing. Specifically, an optimally configured detection/excitation spacing (i.e., 5-5-5 or an equidistant electrode interval with a detection-to-excitation spacing ratio of 0.3) was shown to accurately predict the lumen diameter (i.e., -10% < error < 10%) over a broad range of peripheral artery dimensions (4 mm < diameter < 10 mm). The computational results were substantiated with both ex-vivo and in-vivo measurements of peripheral arteries. The present results support the accuracy of the conductance technique for measurement of peripheral reference vessel diameter.

Highlights

Peripheral artery disease (PAD) is a common defect in the circulatory system in which occluded peripheral arteries reduce blood supply to the lower extremities such that the limbs are not adequately perfused
The percent error in diameter prediction was calculated as a function of the percent parallel conductance for three different peripheral artery diameters (i.e., D = 4, 7, and 10 mm) with a range of surrounding tissue conductivities using four different guidewire configurations with an identical excitation spacing or LEE = 17 mm (i.e., 7-1-7, 6-3-6, 5-5-5, and 4-7-4 or LDD = 1–7 mm)
The results demonstrate that an optimal ratio of detection to excitation distance can minimize the diameter measurement errors in a wide range of vessel diameters by enhancing the lumen conductance relative to parallel conductance

Summary

Introduction

Peripheral artery disease (PAD) is a common defect in the circulatory system in which occluded peripheral arteries reduce blood supply to the lower extremities such that the limbs are not adequately perfused. To accurately determine the CSA of the vessel lumen and the parallel conductance (Gp) through the vessel wall and surrounding tissue, a two bolus injections of saline solutions with different salinities (normal and half normal) has been proposed [3,4]. The design of the conductance guidewire requires a compromise between LEE to be large enough to maintain a cylindrical electric field and Gp to be small enough to maintain the accuracy of the two injection method. To our knowledge, this optimization has not been performed

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