RAPID-HANDLE Technique for Catheter Retrieval From the Pulmonary Artery Using a Homemade Snare With Adjustable Loop.

Introduction
Misplaced intravascular foreign bodies can lead to serious complications, and immediate retrieval is recommended.1 Percutaneous retrieval of foreign bodies (PRFB) is the preferred method, often performed using a snare catheter.2 However, no standardised or universally safe method for PRFB is currently available, with interventionists typically relying on institution specific procedures. Two main challenges associated with PRFB are: 1) securely grasping and 2) safely retrieving the foreign body. Conventional snares are usually oval shaped and relatively small in diameter, making optimal deployment difficult, especially in areas such as the central veins, pulmonary artery, right atrium, and right ventricle. Consequently, undersized loops may hinder successful grasping of foreign bodies. Even when captured, retrieval through the sheath can be challenging and sometimes may require removing the entire system together with the sheath, increasing the risk of vascular injury or retention of the foreign body. To address these issues, a novel technique was developed using a custom made snare and an introducer sheath equipped with an adjustable diameter haemostatic valve, offering a safer, more reliable, and rapid procedure for PRFB. The authors obtained approval from the Ethics Committee of the Kyoto Chubu General Medical Centre.

Technique
A 75 year old man underwent implantation of a subcutaneous infusion port, an 8 F Argyle Fukuroi micro needle port (Cardinal Health, OH, USA), into the right subclavian vein for gastric cancer therapy (Fig. 1A and B). However, drug infusion through the port became difficult a few days after the procedure. A chest Xray acquired 102 days post-implantation showed a pinch off sign grade 1; however, the patient continued using the device (Fig. 1C and D). The port became completely occluded 238 days after implantation, and chest Xray revealed a catheter fragment in the pulmonary artery (Fig. 1E–G). The patient was referred to the Department of Cardiovascular Medicine. The patient's vital signs and physical findings around the infusion port site were unremarkable, and blood tests revealed a mildly elevated D dimer level of 4.9 μg/mL. Contrast enhanced computed tomography revealed a 10 cm long catheter fragment crossing the pulmonary artery, with the catheter tip migrating into a branch of the left pulmonary artery and the transected side floating in the right main pulmonary artery (Fig. 2A and B). Thrombus formation around the catheter was unclear. The patient was diagnosed with intravascular catheter remnants associated with pinch off syndrome.
The percutaneous retrieval of foreign bodies (PRFB) method was used to avoid catheter remnant related complications. The catheter tip had migrated into a branch of the left pulmonary artery, making it difficult to grasp. In contrast, the transected side had floated in the distal main trunk of the right pulmonary artery, measuring 27 mm × 20 mm. It was determined that grasping the transected side would be optimal for retrieving the catheter without causing vascular injury. However, using a conventional loop snare to grasp the transected side was challenging, as its short axis was relatively narrow and the loop did not always expand perpendicular to the axis of the foreign body. With a homemade snare, the loop could be spread outward, and the wider loop could compensate for slight misalignment. Additionally, because the folded silicone rubber catheter fragment grasped by the snare could not be removed through the 10 F sheath in preliminary in vitro experiments, an introducer sheath with an adjustable diameter haemostatic valve, the 14 F DrySeal Flex introducer sheath (Gore, DE, USA), was used to ensure safe retrieval. The DrySeal Flex sheath was inserted via the right common femoral vein, and pulmonary angiography was performed using a 5 F pigtail catheter (Nipro, Osaka, Japan) to confirm the position of the catheter in the pulmonary artery (Fig. 3A and B). A 7 F guiding catheter (JR4.0, ASAHI INTECC, Aichi, Japan) was advanced to the pulmonary artery trunk. A homemade snare was created using a 0.014 inch Cruise guidewire (GW) (ASAHI INTECC), a 2.5/20 mm Coyote balloon catheter (Boston Scientific, MA, USA), and a 6 F GUIDEZILLA II PV guide extension catheter (Boston Scientific) (Fig. 3C). The catheter was grasped with a snare loop on the first attempt by slowly dilating the loop to approximately 40 mm along the vessel wall (Fig. 3D and E). The guiding catheter and homemade snare were retracted together into the sheath and successfully retrieved from the body. Pulmonary angiography was performed to confirm the absence of serious complications, and the sheath was removed (Fig. 3F). The total operating time was 39 minutes. The post-operative course was uneventful, and the patient was discharged. Subsequent anticancer drug treatment was continued via peripheral infusion.
The authors confirm that written consent for the submission and publication of this case report, including the images and associated text, was obtained from the patient in accordance with COPE guidance.

Discussion
The frequency of misplaced intravascular foreign bodies is increasing due to the growing need for procedures such as percutaneous coronary intervention (PCI), endovascular treatment, invasive haemodynamic monitoring, fluid and drug infusion, parenteral nutrition, and haemodialysis.2 Most intravascular foreign bodies are reported to originate from venous catheters,3,4 and the rate of catheter transection among all central venous catheters is approximately 0.1–1%.5 Pinch off syndrome, as seen in this case, occurs when a central venous catheter inserted via the subclavian vein is compressed between the clavicle and the first rib, leading to obstruction or damage.6 The catheter should be removed at the onset of infusion difficulties to avoid catheter fracture and embolisation. In this case, early signs of pinch off syndrome were observed; however, the catheter was not removed, resulting in catheter transection.
Intravascular catheter remnants can lead to infections, such as infective endocarditis and lung abscess; as well as complications, including thrombus formation, pulmonary embolism, dysrhythmia, cardiac perforation, and cardiac tamponade, with secondary complications occurring in 71% of cases.1,7 Although immediate retrieval of catheter remnants is recommended, techniques vary among institutions.
The homemade snare technique, originally developed by Sumitsuji et al. for gripping a retrograde wire in PCI, uses a conventional 0.014 inch GW, PCI balloon catheter, and guiding catheter.8 A 0.014 inch GW with a relatively soft shaft is recommended to facilitate the spreading of the snare loop within the space.
A Cruise GW is a peripheral floppy wire with a tip load of 1 g. Its shaft consists of a stainless steel core, while maintaining relative flexibility. The balloon can be either a rapid exchange balloon or an over the wire balloon. The size of the snare loop can be adjusted by advancing or retracting the 0.014 inch GW to match the vessel diameter, making it relatively easy to grasp intravascular foreign bodies. While the conventional loop snare has limited spread in the short axis direction, the homemade snare can spread in any direction within the available space. The sheath or guiding catheter had to be positioned close to the foreign body to safely introduce the homemade snare. Therefore, the guiding catheter was advanced near the foreign body in this case. In addition, using a curved guiding catheter, such as the JR 4.0, outside the homemade snare facilitated snare rotation. However, the risk of vascular injury must be considered. Sumitsuji's homemade snare is a method designed for pulling through a retrograde wire and does not require extensive snare manoeuvrability. In contrast, the RAPID-HANDLE technique is a method developed for grasping foreign bodies and requires precise snare delivery performance. The main difference is that the homemade snare is constructed using a guide extension, which provides high manoeuvrability to position the homemade snare alongside the foreign body, enabling its rapid grasping. In addition, since the guide extension is used to assemble the homemade snare outside the body, it allows for shaping the loop. Technical tips for looping a foreign body require selecting or combining movements such as pulling the snare, rotating it, or narrowing the loop from its maximum size near the foreign body. These techniques must be chosen by the operator depending on the situation. The use of a Y connector is also recommended to minimise bleeding during snare operation.
The DrySeal Flex (Gore, DE, USA) is a sheath that has mainly been designed for endovascular treatment of abdominal and thoracic aortic aneurysms, available in sizes ranging 12–26 F. The size of the haemostatic valve can be adjusted by air infusion, and the valve size for the 14 F sheath can change up to 4.7 mm. In this case, the 8 F infusion port catheter fragment, with an outer diameter of 2.5 mm, was folded and grasped by the homemade snare; however, it could easily be removed from the sheath without resistance, resulting in minimal bleeding, reduced risk of blood vessel injury, and limited radiation exposure. It was later confirmed in in vitro testing that a 12 F DrySeal Flex introducer sheath could not retrieve the fragment, so at least a 14 F DrySeal Flex introducer sheath was required to remove the 8 F infusion port catheter fragment.
The homemade snare technique was developed and applied to create an intravascular foreign body removal system, combining a homemade snare and an introducer sheath with an adjustable diameter haemostatic valve, which was named the Reliable grAsPing and secure retrieval of Intravascular foreign boDies with a HomemAde sNare and an introducer sheath with adjustable Diameter haemostatic valve (RAPID-HANDLE technique). An additional advantage of the RAPID-HANDLE technique is that it allows the removal of foreign bodies of varying sizes using the same system. The procedure time for PRFB has been reported to range 6–153 minutes, with an average of 28.7 minutes, mainly for intravascular foreign bodies in the right atrium using an EN Snare.4
In this complex case involving the pulmonary artery, the time from grasping to removal was a few minutes. It is believed that the RAPID-HANDLE technique can reduce procedure time and minimise intercase variability. Complications associated with the loop snare technique are rare; however, they may include cardiac dysrhythmias, ventricular perforation, and arterial spasm if the loop is too wide.9 Additionally, the snare cannot be used without a free end on the foreign body, which must be confirmed by imaging before the procedure.
Given the increasing variety of devices that can migrate, including intravascular stents, wires, haemostatic plugs, leadless pacemakers, and catheter fragments, it is believed that the RAPID-HANDLE technique will prove valuable in many cases requiring PRFB.

Funding
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Conflict of interest
The authors declare that they have no competing interests.