Hydraulic catheter device for treating chronic total occlusion

Abstract

Chronic total occlusion (CTO) occurs in approximately a third of all patients with coronary artery disease and is one of the most challenging types of conditions to treat. Minimally invasive methods like percutaneous coronary intervention (PCI) show a high treating potential as well as low costs, short hospital stay and fast recovery. However, their success rate is limited due to their mechanical force transmission, often leading to inability of crossing the hard proximal cap of the CTO. This study focuses on a promising non-mechanical concept for treating CTO using PCI. The proposed idea is based on energy transmission via hydraulic pressure waves in a liquid filled catheter tube. The aim of this project is to conduct a feasibility study for treating CTO by simulating a realistic situation based on the proposed concept. The first stage involved understanding the existing setup and dealing with its flaws and limitations. After the setup was improved and made appropriate for systematic experiments, a realistic scenario was simulated in the lab which led to a drop in force efficiency to one tenth of its original value, a useful result for estimating the required input force to puncture a real CTO. A CTO model was manufactured using gelatin and hydroxyapataite powder. In the final tests, the device was used to puncture effectively the CTO and demonstrate the feasibility of the concept in an ex vivo situation. Only one strike was enough to puncture the soft proximal caps whereas 2 to 4 strikes were needed for the hard caps. The input peak force was set to \SI{36}{N}. Finally, the sensing capabilities of the device were explored with the purpose of getting information on the compliance of the target in contact with the output tip of the catheter.