An Enhanced Device for Transluminal Retrieval of Vascular Stents Without Surgical Procedures: Experimental Studies

Successful Retrieval of a Torn KUSABI Trapping Balloon Catheter From the Coronary Artery and Verification of the Reproducibility of Trapping Balloon Catheter Shaft Tears

The balloon trapping technique is frequently used during percutaneous coronary intervention, which is a common treatment for ischemic heart disease. A 68-year-old man with induced ischemia, stenotic lesions, and arterial calcifications underwent catheterization of the circumflex artery and debulking of lesions. During the removal of the catheter, the tip of the balloon catheter used in the procedure dislodged and entered the circumflex artery. After successfully retrieving the catheter, we conducted a bench test of the balloon catheter to determine the cause of the tear. The results suggested that the tearing of the KUSABI balloon might have been caused by manual pulling of the shaft quickly at an inflation pressure of 14 atm and that twisted wires were not involved in balloon tearing. The tensile strength of the balloon catheter was 5N. We believe that the balloon tore owing to excessive force applied to dislodge the tip and because the trapping balloons were not properly deflated. As KUSABI trapping balloons have had a rupture rate of just 0.003% since their launch in 2013, we recommend paying attention to KUSABI balloon deflation within the guiding catheter before its retrieval in order to ensure that only a gentle pull is needed. If resistance is felt during the removal of the KUSABI balloon, it should be confirmed that the tip is in place after removing it.

Application of an enhanced device to transluminal retrieval of malappositioned coronary stents: An experimental study

OBJECTIVES

This study investigated the application of a novel enhanced device to retrieval of deployed stents in a porcine coronary model.

BACKGROUND

Recurrence of in-stent restenosis and stent thrombosis still remains to be resolved. Under these conditions, it is sometimes necessary to retrieve malfunctional stents responsible for thrombosis. However, few data exist regarding the feasibility and safety of retrieval device use in previously deployed coronary stents.

METHODS

We have developed an enhanced device consisting of an asymmetric forceps, conducting shaft (1.6 mm diameter, 150 cm length), and control handle. Bare-metal stents (3 mm diameter) were implanted in four pigs to create a malapposition model. Coronary artery injury was evaluated by intravascular ultrasound (IVUS) and histological imaging on the first and 14th days.

RESULTS

The device was delivered to the coronary artery using the existing catheter (7 Fr). After opening the forceps, the blade was forced into the space between the vessel wall and the stent, and the stent struts were then grasped with the forceps. This was then pulled back into the catheter, still grasping the stent struts with the forceps. All stents were successfully retrieved by this method (n = 4). On the first day, no apparent vessel wall injury was detectable by IVUS, although histological findings revealed damage to endothelial monolayer on retrieval of deployed stent. On the 14th day, mild intimal thickening was observed by IVUS and histology.

CONCLUSIONS

These results demonstrate that the present device can be applied to transluminal retrieval of acquired malappositioned coronary stents.

Percutaneous Retrieval of Foreign Bodies Around Vital Vessels Aided with Vascular Intervention: A Technical Note

OBJECTIVE

To describe a new interventional technique to remove foreign bodies (FBs) embedded in soft tissues around vital vessels.

METHODS

Under fluoroscopic guidance and using local anesthesia, percutaneous removal of FBs was performed using forceps in nine patients. All patients suffered from a metallic soft tissue FB located in close proximity to important vessels and one also had a small traumatic pseudoaneurysm adjacent to the FB. Prior to removal of the FB, the position of the nearest vessel was identified using a guide wire or catheter placed into the vessel. Balloon catheter was also simultaneously used to temporarily stop the blood flow of the nearest artery during the FB removal in three of the nine patients.

RESULTS

All of the nine FBs with 0-2 mm interval to the nearest vessel were successfully removed in the nine patients without any serious complications. The removed FBs measured 3-12 mm in length and 1-3 mm in width. The total fluoroscopic time of retrieval of each FB was 5-9 min (mean, 6.4 min). The volume of intraoperative bleeding ranged from 5 to 12 ml (mean, 7.5 ml). The length of hospital stay for each patient ranged from 4 to 8 days (mean, 5.5 days).

CONCLUSION

Vascular intervention-aided percutaneous FB removal is minimally invasive and an effective method for removal of FBs around vital vessels.