Device Lead Management and Laser Lead Extraction
Due to the dramatic increase in the use of cardiac implantation devices such as pacemakers and implantable defibrillators, there is an increased need to monitor and replace leads that are wearing out or causing problems. Lead removal has progressed from a fairly primitive procedure to a sophisticated undertaking that involves telescoping sheaths with tips powered by laser energy.
The sheaths are designed to remove leads from fibrous tissue without doing damage. Lead-removal procedures range from cardiopulmonary bypass to transvenous, and are most often performed to remove infected material. Although the procedures are delicate, the mortality rate at experienced centers is less than .2 percent.
Reasons for Laser Lead Extraction
Although theoretically designed for permanent implantation, there are a number of reasons device leads must be extracted. Even where there is no clear design flaw in the device, leads wear out at a somewhat predictable rate, which is estimated to be as high as 20 percent over the course of 10 years.
Reasons for a laser lead extraction include the following:
- Infection of an implanted cardiac device
- Mechanical failure of the device
- Predictable failure of the device, based on its age and design
- Damage (fracture) of the lead
- Need for venous access for revision or upgrade
- Excessive scar tissue (exit block)
- Patient discomfort
Very rarely, a laser lead is extracted for cosmetic reasons. Assessing the need for laser lead extraction relative to the risks involved is often a complicated and highly individualized process. The patient's age and any comorbidities, as well as the age, size and design of the lead, have to be taken into consideration.
Laser Lead Extraction Procedure
A laser lead extraction takes between 2 and 6 hours. The patient is sedated, and a local anesthetic is administered. During the process, the patient may experience a pulling sensation as the leads are removed, but typically does not suffer any pain.
Lead extraction can take place through one of two sites: the subclavian vein or the femoral vein. The subclavian vein, which is in the upper chest, is used most frequently; a small incision is made in the chest just above the vein. When it is not possible to gain access through the subclavian vein, the femoral vein, which is in the groin, is used instead. In this case, a small puncture, rather than an incision, is made above the femoral vein to gain entry.
Whichever site is used, a sheath is inserted in the vein, and guided to the point at which the tip of the lead attaches to the heart. The sheath holds the heart muscle while the lead is removed. A laser may be used to target and remove scar tissue left by the lead. After the lead is removed, a guidewire may be placed through the sheath to retain access for subsequent lead reimplantation. In some cases, a new lead is immediately implanted.
Risks of Laser Lead Extraction
Because lead extraction is a complex procedure with inherent risk, the procedure is best performed by someone who is highly skilled and experienced. Statistics show clear evidence that danger to the patient is greatly lessened when the extractor has performed the procedure many times.
Risks of laser lead extraction include the following:
- Heart tamponade
- Deep vein thrombosis
- Pocket hematoma
In institutions in which the lead extractor is not a cardiothoracic surgeon, it is necessary to have such a surgeon, and bypass equipment, at the ready to tackle any complications.