Permanent pacemaker lead extraction

Magnetic resonance conditionality of abandoned leads from active implantable medical devices at 1.5 T

PURPOSE

During MR scans, abandoned leads from active implantable medical devices (AIMDs) can experience excessive heating at the lead tip, depending on the type of termination applied to the proximal contacts (proximal end treatment). The influence of different proximal end treatments (ie, [1] freely exposed in the tissue, [2] terminated with metal in contact with the tissue, or [3] capped with plastic, and thereby fully insulated, on the RF-induced lead-tip heating) are studied. A technique to ensure that MR Conditional AIMD leads remain MR Conditional even when abandoned is recommended.

METHODS

Abandoned leads from three MR Conditional AIMDs ([1] a sacral neuromodulation system, [2] a cardiac rhythm management pacemaker system, and [3] a deep brain stimulator system) were investigated in this study. The computational lead models (ie, the transfer functions) for different proximal end treatments were measured and used to assess the in vivo lead-tip heating for four virtual human models (FATS, Duke, Ella, and Billie) and compared with the lead-tip heating of the complete MR Conditional AIMD system.

RESULT

The average and maximum lead-tip heating for abandoned leads proximally capped with metal is always lower than that from the complete AIMD system. Abandoned leads proximally insulated could lead to an average in vivo temperature rise up to 3.5 times higher than that from the complete AIMD system.

CONCLUSION

For the three investigated AIMDs under 1.5T MR scanning, our results indicate that RF-induced lead-tip heating of abandoned leads strongly depends on the proximal lead termination. A metallic cap applied to the proximal termination of the tested leads could significantly reduce the RF-induced lead-tip heating.

Radiofrequency-induced heating of broken and abandoned implant leads during magnetic resonance examinations

Purpose

The risks of RF‐induced heating of active implantable medical device (AIMD) leads during MR examinations must be well understood and realistically assessed. In this study, we evaluate the potential additional risks of broken and abandoned (cut) leads.

Methods

First, we defined a generic AIMD with a metallic implantable pulse generator (IPG) and a 100‐cm long lead containing 1 or 2 wires. Next, we numerically estimated the deposited in vitro lead‐tip power for an intact lead, as well as with wire breaks placed at 10 cm intervals. We studied the effect of the break size (wire gap width), as well as the presence of an intact wire parallel to the broken wire, and experimentally validated the numeric results for the configurations with maximum deposited in vitro lead‐tip power. Finally, we performed a Tier 3 assessment of the deposited in vivo lead‐tip power for the intact and broken lead in 4 high resolution virtual population anatomic models for over 54,000 MR examination scenarios.

Results

The enhancement of the deposited lead‐tip power for the broken leads, compared to the intact lead, reached 30‐fold in isoelectric exposure, and 16‐fold in realistic clinical exposures. The presence of a nearby intact wire, or even a nearby broken wire, reduced this enhancement factor to <7‐fold over the intact lead.

Conclusion

Broken and abandoned leads can pose increased risk of RF‐induced lead‐tip heating to patients undergoing MR examinations. The potential enhancement of deposited in vivo lead‐tip power depends on location and type of the wire break, lead design, and clinical routing of the lead, and should be carefully considered when performing risk assessment for MR examinations and MR conditional labeling.

Pacemaker lead tip heating in abandoned and pacemaker-attached leads at 1.5 Tesla MRI

PURPOSE

To assess the risk of RF-induced heating in pacemaker-attached and abandoned leads using in vitro temperature measurements at 1.5 Tesla as a function of lead length.

MATERIALS AND METHODS

Five custom lead lengths, 20-60 cm, were exposed to a uniform magnitude and phase radiofrequency electric field to examine the effect of lead length on pacemaker lead tip heating for pacemaker-attached and abandoned pacemaker leads.

RESULTS

Abandoned and pacemaker-attached leads show resonant heating behavior and maximum heating occurs at different lead lengths due to the differences in termination conditions. For clinical lead lengths (40-60 cm) abandoned leads exhibited greater lead tip heating compared with pacemaker-attached leads.

CONCLUSION

Current recommendations for MRI pacemaker safety should highlight the possible increased risk for patients with abandoned leads as compared to pacemaker-attached leads.

Percutaneous transcatheter repositioning of displaced permanent pacemaker atrial lead with a simple system

A 48-year-old man who was implanted with a DDD-R pacemaker because of sick sinus syndrome eight days ago presented to our institute with a syncopal attack. Fluoroscopy showed a dislodged active fixation atrial pacemaker lead. With a snare system simply improvised from a 0.014 inch guidewire and a NIH catheter, the lead was repositioned via percutaneous transfemoral approach. The procedure was easy and completed without any complication. Follow-up controls after two weeks and three months showed stability of the lead position with normal pacing and sensing functions.

Successful use of an acceleration rate response pacemaker with a transvenous steroid-eluting screw-in lead for third-degree atrioventricular block in a labrador retriever

Permanent pacemakers are commonly used in veterinary practice and can have a dramatic effect on the treatment of heart block. A Labrador Retriever dog suffering from exercise intolerance secondary to third degree atrioventricular block was treated with a new pacemaker system. A steroid-eluting screw-in type lead that has the advantage of being more fixed to the myocardial wall without increasing the pacing threshold was used. The heart rate was regulated with an acceleration sensing pacemaker generator that included several automatic modulation systems. Nineteen months after implantation, the dog has a normal level of activity. The present case suggests that this pacemaker design may offer important advantages for canine patients.

Percutaneous transcatheter repositioning of displaced permanent pacemaker lead

In three patients, two with a pacemaker and one with an implantable cardioverter defibrillator, hospitalized for dislodgement of a passive fixation J-shaped atrial lead, a percutaneous transcatheter repositioning was successfully attempted thus avoiding surgical revision. This procedure, performed through the femoral vein, is easy and safe. The stability of the lead position and of the pacing and sensing parameters was confirmed 1 and 6 months after the transcatheter repositioning.

Percutaneous extraction of an abandoned coiled pacing lead

Abandoning redundant pacing leads has been an accepted practice in most cases. Late migration of a lead is a rare, unpredictable, and potentially lethal complication of this approach and requires immediate removal. We report the case of an atrial pacing lead that had migrated and was found coiled in the right atrium. It was removed by a snare catheter via a femoral approach.

Teletronics 330-801 atrial lead extraction via the subclavian approach

BACKGROUND

The Telectronics 330-801 atrial J (801) lead was recalled after reports implicated lead fracture/retention wire protrusion in patient mortality and morbidity. Recent reports suggest that 801 lead extraction may be associated with substantial morbidity and, possibly, excess mortality. We hypothesized that the 801 lead could be extracted using the subclavian approach with a high success rate and acceptable morbidity.

METHODS

We analyzed the clinical outcomes in 60 consecutive patients who underwent 801 lead extraction.

RESULTS

Sixty patients (34 women) with a mean age of 67 +/- 14.8 years had 18 class I, 13 class II, and 29 class III fractures. The lead age was 39 +/- 17 months. The subclavian approach was successful in 58 of 60 patients (96%). Complications, three major and eight minor, occurred in 10 of 60 patients (16%). All complications were successfully treated. There were no deaths. Only concurrent ventricular lead extraction was associated with complications (p = 0.008 by Fisher's exact test).

CONCLUSIONS

Telectronics 801 leads can be successfully extracted using the subclavian approach with acceptable short-term morbidity, low mortality, and excellent long-term results.

Three-year experience with a stylet for lead extraction: a multicenter study

INTRODUCTION

The extraction of chronically implanted and infected pacemaker and defibrillator leads is an important issue. This article describes the experience gathered between 1990 and 1994 by seven European centers regarding a locking stylet that is uniformly applicable for a wide variety of internal pacing coil diameters. This interventional locking stylet for lead extraction has an outer diameter of 0.4 mm (0.016 inches). The stylet consists of a hollow shaft in which an inner traction wire is embedded. At the tip of the inner traction wire an anchoring mechanism, which can be opened by retraction, is applied. Removal attempts were made for 150 leads, 110 in ventricular and 40 in atrial positions.

RESULTS

Complete removal was possible in 122 cases (81%). Partial removal was possible in 18 cases (12%). Failure to remove the lead with the extraction stylet was experienced in 10 cases (7%). In seven patients, the leads were removed by cardiothoracic surgery; 3 defective leads were left in place. There were no serious complications associated with the procedure. None of the patients died.

CONCLUSION

The experience with this extraction stylet for lead removal has shown good results. Despite a low complication rate thus far, each case for lead removal should be judged on the individual basis of benefit-to-risk ratio.

Catheter aided repositioning of a displaced permanent pacemaker lead

A 91-year-old woman, who had a pacemaker implanted in 1977, underwent replacement of a pulse generator and lead in 1995 because of recurrent syncope. The new lead dislodged the next day and migrated to the pulmonary artery. Because of her dependence on continued pacing, repeated resuscitation was required. Considering her advanced age and the impact of cardiopulmonary resuscitation on her general condition, we attempted catheter aided repositioning of the pacemaker lead. The procedure was technically successful; lead position was stable and optimal pacing parameters were attained. She was discharged in good condition.