Navigation of a Tortuous “Epicardial-Type” Collateral in the Recanalization of an RCA CTO

Dr. Aiste Zebrauskaite

Introduction

Microcatheters are essential tools for crossing chronic total occlusions (CTO). Their use not only increases the success rate of recanalizing these lesions but also reduces procedure-related complications and enhances patient safety. Currently, there is a wide variety of microcatheters available on the market, each with unique profiles and specifications.
To optimize outcomes in CTO procedures and complex angioplasties, the operator must understand the key characteristics, advantages, limitations, and technical specifications of each microcatheter. Proper microcatheter selection, based on lesion characteristics, occluded segment anatomy, and the presence of collateral circulation, is a key factor in the success of the procedure.
This case describes the recanalization of an RCA CTO through a long, tortuous collateral with a morphology like an epicardial collateral, highlighting the fundamental role of the microcatheter in navigation and support during the procedure.

Patient Profile

Male, 68 years old.
Stable coronary artery disease with a history of:
- Previous myocardial infarction.
- Prior percutaneous intervention in the left coronary artery (LCA).
- Known RCA CTO since 2018.
Transthoracic echocardiography:
- Moderate ventricular dysfunction (LVEF 45%).
- Hypokinesia in the inferior wall.
Risk factors: Hypertension, dyslipidaemia, insulin-dependent type 2 diabetes mellitus with poor glycaemic control, permanent atrial fibrillation, obesity, and smoking.

Lesion Type

CTO in the mid-segment of the RCA.
Collateral circulation from the LAD and ipsilateral bridging collaterals.
Long and highly tortuous bridging collateral with a course similar to an epicardial collateral.

Procedure

The procedure was performed via femoral and bi-radial access, with an initial angiographic evaluation of the collateral circulation from the LAD and RCA bridging collaterals.
Initially, an anterograde approach was attempted with a Navitian microcatheter and a Fielder XT-A guidewire, but it was unsuccessful due to the extreme tortuosity of the collateral, which presented a 360° course.
Since the collateral anatomy was like an epicardial collateral, an Asahi Suoh 03 guidewire was selected, which enabled navigation through the tortuous course. The Navitian microcatheter then smoothly followed the guidewire, facilitating advancement through the loops of the collateral.
Upon reaching the distal cap of the CTO, severe calcification was noted, making penetration with the initial guidewire difficult. Crossing was attempted with an Asahi Gladius EX14 guidewire without success. Finally, an Asahi Gaia Third guidewire was used, successfully crossing the lesion and advancing the guiding catheter into the vessel.
Once the definitive guidewire was positioned in the distal RCA segment, the lesion was treated by implanting a drug-eluting stent in the mid-RCA segment.
Final angiography showed an excellent result.

Conclusion

The use of the Navitian microcatheter was key to the success of this procedure, providing robust support and smooth navigation through a highly tortuous collateral. Its ease of handling and ability to track the guidewire allowed safe advancement through a challenging course, facilitating CTO crossing and successful stent implantation.

Figures