136-40: Successful retrieval of a Micra™ leadless pacemaker after 3 months

Abstract

Introduction: Single chamber leadless pacemakers (PM) are a new alternative to conventional VVI PM eliminating the risk of pocket or lead problems. Currently available systems use either a helical wire screw (Nanostim™, St. Jude Medical) or nitinol tines (Micra™, Medtronic) for endocardial fixation. There is some concern that device retrieval in case of infection or battery depletion may be a problem with these new PM. Data on extraction of leadless PM beyond the immediate postoperative phase are very limited. Methods: Since European market release in June 2015 we successfully implanted Micra PM in 8 pts. (mean age 75.5 yrs. (20 – 92 yrs.); 5 females). Indications for implantation of Micra where bilateral PM pocket infection (n = 1), central vein occlusion or stenosis (n = 3), severe pocket problems (n = 1) or other reasons (n = 3). There were no acute complications in any patient; in 2 pts. up to 3 positions had to be tested to reach adequate sensing and/or pacing threshold. Mean radiation duration was 7,56 + 7,37 min. In one of these pts. the Micra device was explanted after 12 weeks. He received the system due to symptomatic bradyarrhythmia and permanent atrial fibrillation with moderately reduced left ventricular function (LVEF 45%) and planned implant of a phrenic nerve stimulator to treat his central sleep apnea which was successfully performed 3 weeks after the Micra implant. Nine weeks later the pt. was successfully resuscitated from ventricular fibrillation. The patient recovered well and a coronary angiogram after the event showed no new coronary stenoses. The decision was made to extract the leadless VVI PM and exchange it for an implantable defibrillator for secondary prevention of sudden death, combined with cardiac resynchronization therapy (CRT-D) to prevent left ventricular desynchronisation by right ventricular apical pacing. After placement of the ICD lead, a left femoral venous access was used to place a new 23 French (F) introducer system into the right atrium. Using a 8.5 F steerable catheter and a 25 mm snare the Micra pacemaker could be fixed in the neck section of the device and retrieved from endocardial fixation with permanent traction for 18 seconds without any hemodynamic compromise. The whole system could then be retracted into the 23 F sheath and removed without problems. Conclusion: This case report illustrates that retrieval of the Micra leadless PM is possible beyond the immediate postoperative phase by using a femoral approach with a large introducer sheath and a snare catheter, capturing the neck of the PM and using gentle traction (as opposed to “screwing off” with the Nanostim device). It cannot be excluded that retrieval may be more difficult by strong fixation of the Micra nitinol tines and tissue overgrowth years after implant. In this situation, the implantation of an additional leadless PM while leaving the first device in place may be an alternative.