Endovascular Crossing of Chronic Total Occlusions Using an Impulse: An Explorative Design Study

Aimée Sakes,Dimitra Dodou,Marleen Van Der Wiel,Paul Breedveld

doi:10.1007/s13239-017-0306-1

Aimée Sakes, Dimitra Dodou + Show 2 more

Open Access

https://doi.org/10.1007/s13239-017-0306-1

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Abstract

In this study we investigated whether exerting an impulse on a Chronic Total Occlusion (CTO) improves the success rate of CTO crossing as compared to the currently used method of statically pushing the guidewire against the CTO. A prototype (Ø2 mm) was developed that generates translational momentum using a spring-loaded indenter and converts it to an impulse during impact. Mechanical performance was evaluated by measuring the peak force and momentum for different spring compressions and strike distances in air and blood-mimicking fluid. Puncture performance, in terms of number of punctures, number of strikes to puncture, and energy transfer from the indenter to the CTO, was assessed for six tip shapes (stamp, wedge, spherical, pointed, hollow spherical, and ringed) on three CTO models with different weight percentages of gelatin and calcium. As a control, a Ø0.4 mm rigid rod was tested. A maximum indenter momentum of 1.3 mNs (velocity of 3.4 m/s), a peak force of 19.2 N (vs. 1.5 N reported in literature and 2.7 N for the control), and CTO displacement of 1.4 mm (vs. 2.7 mm for the control) were measured. The spherical and ringed tips were most effective, with on average 2.3 strikes to puncture the most calcified CTO model. The prototype generated sufficient peak forces to puncture highly calcified CTO models, which are considered most difficult to cross during PCI. Furthermore, CTO displacement was minimized, resulting in a more effective procedure. In future, a smaller, faster, and flexible clinical prototype will be developed.

Highlights

During Percutaneous Coronary Interventions (PCI), a small guidewire (Ø0.36 mm) is gradually driven through the vasculature from an incision point in the groin or wrist towards an occlusion in the coronaries
In an effort to pursue improved crossing ability, we investigated a new crossing method in which an impulse is applied onto the Chronic Total Occlusion (CTO)
The prototype was evaluated in terms of its mechanical performance and puncture effectiveness on CTO models made of gelatin and calcium

Summary

Introduction

During Percutaneous Coronary Interventions (PCI), a small guidewire (Ø0.36 mm) is gradually driven through the vasculature from an incision point in the groin or wrist towards an occlusion in the coronaries. Coronary Chronic Total Occlusions (CTOs), defined as heavily calcified, complete coronary occlusions of over 3 months old, represent the most challenging lesion type to be crossed during PCI, requiring a high skill level of the interventional cardiologists.. The development and use of several dedicated guidewires, such as the Confianza Pro (Asahi Intecc, Nagoya, Japan) and the Progress 200T (Abbott Vascular, Abbott Park, IL), dedicated crossing and support catheters, such as the Tornus (Asahi Intecc, Nagoya, Japan) and the Crossboss (Boston Scientific, Natick, MA), crossing tools, such as the Frontrunner XP (Ø0.76–1 mm; Cordis Corporation, Miami, FL), the Crosser Catheter (Ø0.6–1.5 mm; BARD Peripheral Vascular Inc., Tempe, AZ), and the Truepath (Ø0.43 mm; Boston Scientific, Natich, MA), and crossing strategies (see Sakes et al. for a comprehensive overview) have contributed to a steady increase in the technical success rate of PCI in CTOs (i.e., the ability to cross the CTO and to successfully reopen the artery), as well as in the overall procedural success rate of these interventions (i.e., the proportion of procedures with no nosocomial major adverse cardiac events).. Whereas experienced operators can achieve success rates of up to 90%, success rates of experienced operators not specialized in CTO PCI are

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