New Catheter Tip Concept Providing Both Flexibility and Pushability: NIRxcell CoCr Coronary Stent System
Dr. Max Amor, Clinique Louis Pasteur, Nancy, FranceDownload Case Study
This case outlines the first in-patient implantation of the NIRxcell cobalt chromium bare metal stent system (Medinol). This challenging case involved a patient with flow-limiting lesions and extensive coronary aneurysms. The new NIRxcell stent system offers very good scaffolding properties while conforming to the vessel’s natural form and dynamic motion. In addition, the delivery system of NIRxcell includes an innovative metallic spring tip that was designed to enhance cross-ability by its superior flexibility and buckle resistance. Other stent delivery systems, typically having polymer distal tips, are prone to flare-out and buckling that may impact deliverability.
A 66 year-old male patient with a tight, heavily calcified lesion at the proximal RCA was treated at Clinique Louis Pasteur, Nancy, France. A guide wire was placed at the RCA (Figure 3).There were multiple attempts to cross the tight lesion with the following devices:
- Trek (Abbott) dilatation catheter (9 attempts with 9 different systems)
- Emerge (Boston Scientific) dilatation catheter (1 attempt)
- Sprinter (Medtronic) dilatation catheter (2 attempts with 2 different systems)
- NIRxcell (Medinol) delivery system used as a PTCA balloon after removal of the stent from the balloon (not optimal as a PTCA balloon in crossing profile and without hydrophilic coating on the balloon), 3 attempts with the same catheter, the third of which succeeded
- Two Integrity (Medtronic) stents were finally implanted in the proximal RCA following the successful crossing by the NIRxcell catheter.
The resulting angiography showed good revascularization of the proximal segment of the RCA with a non flow-limiting dissection at the mid segment and improved flow to the distal RCA (Figure 4).
Discussion and Conclusion
Multiple devices were used in an attempt to cross the lesion. Each of the systems was used only once, except for the NIRxcell catheter that was used three times and actually crossed the lesion in the third attempt. Following the procedure, the balloon catheter tips were visualized under low magnification light microscopy with the following findings: all the polymer tips (except for one) were deformed (Figure 5) in a way that would prevent them from crossing in a subsequent attempt. This finding supports our usual assumption that catheters after a failed attempt to cross a tight lesion should not be reused. The metallic spring tip of the NIRxcell delivery system showed no sign of deformation and the tip maintained its shape, even though the system was used three times while each of the other systems was used only once. Additionally, the visibility of NIRxcell’s metallic spring tip under fluoroscopy helped in visualizing the distal part of the catheter in the artery and pointed out the exact location of tip entry to the tight stenosis (Figure 6).
The notion that polymer tips are subject to flare-out and buckle did not receive enough attention, probably because until now only polymer tips were available and they in turn had to compromise between flexibility and buckle resistance, as mentioned above. Yet, most operators would not use a catheter that failed a challenging crossing attempt for a second attempt assuming it might be damaged.
The potential advantages of a delivery system with a flexible tip that does not buckle, such as the NIRxcell with the metallic spring tip, are apparent from this case. It could lead to stent and balloon-catheter systems with superior crossability and deliverability and could present a saving on equipment by using it in multiple crossing attempts without fear of tip buckling.
Disclosure of Commercial Conflict of Interest: Nothing to disclose