Crossing Total Occlusions: Navigating Towards Recanalization.

Aimée Sakes,Evelyn Regar,Paul Breedveld,Jenny Dankelman

doi:10.1007/s13239-016-0255-0

Aimée Sakes, Evelyn Regar + Show 2 more

Open Access

https://doi.org/10.1007/s13239-016-0255-0

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Abstract

Chronic total occlusions (CTOs) represent the “last frontier” of percutaneous interventions. The main technical challenges lies in crossing the guidewire into the distal true lumen, which is primarily due to three problems: device buckling during initial puncture, inadequate visualization, and the inability to actively navigate through the CTO. To improve the success rate and to identify future research pathways, this study systematically reviews the state-of-the-art of all existing and invented devices for crossing occlusions. The literature search was executed in the databases of Scopus and Espacenet using medical and instrument-related keyword combinations. The search yielded over 840 patents and 69 articles. After scanning for relevancy, 45 patents and 16 articles were included. The identified crossing devices were subdivided based on the determinant for the crossing path through the occlusion, which is either the device (straight and angled crossing), the environment (least resistance, tissue selective, centerline, and subintimal crossing) or the user (directly steered and sensor enhanced crossing). It was found that each crossing path is characterized by specific advantages and disadvantages. For a future crossing device, a combination of crossing paths is suggested were the interventionist is able to exert high forces on the CTO (as seen in the device approach) and actively steer through the CTO (user: directly steered crossing) aided by intravascular imaging (user: sensor enhanced crossing) or an intrinsically safe device following the centerline or path of least resistance (environment: centerline crossing or least resistance crossing) to reach the distal true lumen.

Highlights

It is often stated that chronic total occlusions (CTOs) represent the ‘‘last frontier’’ of percutaneous coronary interventions (PCIs).[55]
This study explores the entire field, including the patented literature, and systematically reviews the state-of-theart of all existing and invented crossing devices and methods for crossing total occlusions, including acute occlusions (which are usually softer than CTOs, which are mainly characterized by heavy calcification), used in clinical practice and designs described in the patented literature
Several strategies can be applied:[51] (1) a second stiff guidewire can be placed proximal to the CTO, (2) a second balloon can be inflated proximal to the CTO, or (3) the balloon or microcatheter can be exchanged for a Tornus (Asahi Intecc, Nagoya, Japan) to enlarge the lumen

Summary

INTRODUCTION

It is often stated that chronic total occlusions (CTOs) represent the ‘‘last frontier’’ of percutaneous coronary interventions (PCIs).[55]. Several strategies can be applied:[51] (1) a second stiff guidewire can be placed proximal to the CTO (preferably in a side-branch), (2) a second balloon can be inflated proximal to the CTO (preferably in a side branch), or (3) the balloon or microcatheter can be exchanged for a Tornus (Asahi Intecc, Nagoya, Japan) to enlarge the lumen To overcome this problem altogether, multiple patents describe combined crossing and treatment tools (see Fig. 4 for the devices proposed by Samson et al.[47] and Gerberding et al.21).[14,21,24,29,46,47,48,56] In these designs, a cable-actuated or self-expandable cage-like structure is described that in collapsed state functions as a guidewire and in expanded state as a treatment device, similar to a stent. Mechanical Vibration (in Use for Peripheral and Coronary CTOs) In the mechanical vibration crossing method it is hypothesized that selective penetration depends on the difference in elasticity between the different tissue types Collagen rich structures, such as the blood vessel wall, are not damaged by vibrational energy as they are elastic and, FIGURE 5. In the electrical impedance approach, Lafontaine et al.[28] suggest using the difference in electrical impedance between the plaque and the blood vessel wall to distinguish between these two tissue types (see Fig. 8)

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CONCLUSION