Recanalization of Chronic Total Occlusion Using a New Device: The Real-Time Intravascular Ultrasound Double-Lumen Microcatheter
Chronic total occlusion (CTO) of coronary arteries represents a significant challenge in interventional cardiology. Revascularization of CTO lesions can alleviate angina symptoms, improve cardiac function, and enhance clinical prognosis. However, percutaneous coronary intervention (PCI) for CTO revascularization is fraught with difficulties, including a high incidence of complications and prolonged X-ray exposure. Despite advancements in technology, devices, and anticoagulation strategies that have improved the success rate of PCI for CTO, complications such as coronary artery perforation and cardiac tamponade persist, limiting the application of these new tools. In response to these challenges, a novel device, the real-time intravascular ultrasound (IVUS) double-lumen microcatheter (RLS catheter), has been developed to enhance the safety and efficacy of CTO revascularization.
The RLS catheter combines the functionalities of an IVUS catheter and a microcatheter into a single device. The IVUS catheter serves as a monorail lumen, providing real-time cross-sectional images of the vascular wall, while the microcatheter functions as an over-the-wire (OTW) lumen, allowing the guidewire to be advanced through the lesion. The device is 1350 mm in length, with a side aperture located 20 mm from the distal tip of the microcatheter and an exit port 240 mm from the distal tip of the IVUS catheter. The widest part of the device is 3.6 Fr, and it features three radiopaque marks for enhanced visibility during procedures.
The RLS catheter is particularly useful in scenarios where the proximal cap of the CTO is ambiguous or when the guidewire is situated in the false lumen and cannot easily re-enter the true lumen. The device supports the guidewire in two critical ways: facilitating its entry into the occlusion and enabling its re-entry into the true lumen. The IVUS component of the RLS catheter provides real-time imaging, which helps identify the entry point, distinguish between true and false lumens, and define the relative position of the guidewire and the target lesion. This real-time guidance significantly improves the accuracy of the procedure, reduces the time required for guidewire passage, and minimizes the risk of complications.
In a study conducted at the Department of Cardiology of the 980 Hospital of PLA Joint Logistics Support Forces, 12 patients with CTO underwent PCI using the RLS catheter between February 2018 and May 2019. The median age of the patients was 54.0 years, with a median left ventricular ejection fraction of 62.0%. The cohort included nine males, and the most common comorbidities were hypertension (58.3%), diabetes (58.3%), and hyperlipidemia (41.7%). The most frequently affected vessels were the left anterior descending artery (75%) and the right coronary artery (50%), with 25% of patients having multivessel CTO lesions. The morphology of the lesions varied, including severely tortuous vessels (25%), stumpless CTO (41.7%), and in-stent occlusions (8.3%).
The RLS catheter was used in cases where conventional techniques failed to achieve guidewire entry or re-entry into the true lumen. The technical success rate and procedural success rate were both 91.7% (11/12). In one case, the RLS catheter was damaged during an attempt to re-enter the true lumen in a patient with an in-stent occlusion, resulting in technical failure. However, in the remaining 11 patients, the RLS catheter successfully facilitated guidewire passage through the CTO lesion with a median procedure time of 70.5 minutes. The median time for guidewire passage through the CTO lesion was 32.0 minutes, and after the RLS catheter was advanced, the median time for guidewire penetration through the target lesion was reduced to 3.0 minutes. The median time for guidewire passage through the CTO lesion after the RLS catheter was advanced was 9.5 minutes.
Importantly, all patients experienced relief from angina following the procedure, and no complications such as coronary artery perforation, pericardial tamponade, or acute myocardial infarction were observed during or after the procedure. The median follow-up time was 18.0 months, during which only one patient reported recurrence of angina pectoris at 17 months post-procedure. No other major adverse cardiovascular events were recorded.
The unique design of the RLS catheter addresses several limitations associated with conventional PCI for CTO. By integrating IVUS and microcatheter functionalities, the device eliminates the need for exchanging separate IVUS and microcatheter devices, streamlining the procedure and reducing the risk of complications. The double-lumen structure of the RLS catheter provides superior support for the guidewire, enhancing its directional accuracy during lesion penetration. Additionally, the real-time IVUS imaging capability of the RLS catheter allows for precise identification of the entry point and differentiation between true and false lumens, further improving the safety and efficacy of the procedure.
The RLS catheter’s compact design, with an external diameter of 3.6 Fr, allows it to be inserted through routinely used 6 Fr or 7 Fr guiding catheters, making it compatible with standard PCI equipment. This compatibility, combined with the device’s ability to reduce procedure time and minimize complications, positions the RLS catheter as a valuable tool in the treatment of complex CTO lesions.
In conclusion, the RLS catheter represents a significant advancement in the field of CTO revascularization. Its unique design and real-time IVUS imaging capabilities enhance the safety, accuracy, and efficiency of PCI for CTO, offering a promising solution to the challenges associated with conventional techniques. While the results of this study are encouraging, further research involving larger, multicenter trials is needed to confirm the efficacy and safety of the RLS catheter in a broader patient population.
doi.org/10.1097/CM9.0000000000001182
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