Transvenous Lead Extraction- An Overview

Introduction

Implantable cardiac pacemakers, biventricular pacemakers, cardiac loop recorders, implantable cardioverter-defibrillators (ICD), and other cardiac implantable electronic devices (CIED) are designed to assist patients diagnosed with heart rhythm abnormalities and heart failure. These devices gather data on the cardiac rhythm as soon as they are implanted, thereby regularly tracking irregular heartbeats. Implantation rates of cardiac implantable electronic devices, which have proven to be a helpful tool in cardiology, are on the rise. Because of this, the quantity of these devices in use and the complications they inevitably cause have grown.

What Is a Transvenous Lead Extraction (TLE)?

Thin wires called leads attach a cardiac implantable electronic device (CIED), such as pacemakers, and implantable cardioverter-defibrillators, to the heart. The leads keep track of the heart’s electrical activity and can pace it if it is beating too slowly. An implantable cardioverter-defibrillator can send an electrical signal to the heart, which causes a shock and brings the heart’s normal rhythm. These leads are removed if they are not functioning appropriately, which is frequently the result of a mechanical failure, such as a lead fracture, or the infection of the device or the leads. The surgery that involves the removal of these leads is known as transvenous lead extraction. The removal and replacement of the leads is an easy process. However, removing the leads is challenging if they have been in place for a long time since the surrounding scar tissue may have covered the leads. Scar tissue is the tissue that forms after a healing process.

What Situations Call for the Removal of Leads?

The clinical scenarios that call for the removal of leads can be broadly classified under two categories: infections and non-infectious.

Infectious causes include-

• Infection with or without bacteremia.

• Left-sided endocarditis in a cardiac implantable electronic device carrier.

• Infective endocarditis that is not associated with the cardiac implantable electronic device.

Non-infectious causes include-

• Arrhythmias (irregular heartbeats) generated by the leads.

• Inappropriate positioning of the leads.

• Physical damage to the leads (for example, breakage or fracture of the lead).

• Dysfunctional leads.

• Dysfunctional cardiac implantable electronic device.

• Excessive scar tissue formation on or around the leads (scar tissue hampers the normal functioning of the leads as it impedes electrical conduction).

• Thrombus or clot formation that impedes blood flow in the vessels.

• Chronic or severe pain at the device or lead insertion site.

• To upgrade to a newer model or different cardiac implantable device.

What Are the Prerequisites for Transvenous Lead Extraction (TLE)?

Before the procedure, a variety of tests are conducted. They include -

• Blood Tests: Blood tests give an overview of an individual’s health. They include a variety of tests, such as tests for clotting disorders, liver function tests, kidney function tests, thyroid function tests, etc.

• Echocardiogram (ECHO): An echocardiogram produces images of the heart’s internal structures using high-frequency sound waves, known as ultrasound. The chambers, walls, valves, and blood vessels associated with the heart are depicted in these images.

• Electrocardiogram (EKG/ECG): It is a non-invasive medical procedure used to measure the heart’s electrical activity using electrodes placed on the skin. The electrodes detect tiny electrical changes on the skin that arise from the heart during each heartbeat. These electrodes are placed on the skin of the chest, arms, and legs.

How Is the Procedure of Transvenous Lead Extraction (TLE) Performed?

The procedure of transvenous lead extractions can last anywhere between two to six hours. There are two sites from which the leads can be extracted. They are-

• Subclavian Vein: It is the most common site and is accessed by an incision in the chest, under the clavicle (collarbone).

• Femoral Vein: This approach is considered when the previous approach cannot be used. The femoral vein is accessed by making an incision in the groin.

Transvenous lead extraction (TLE) is performed in the following way -

• The patient is administered with general anesthesia. Once it is effective, a breathing tube is inserted into the mouth. The tube is attached to the ventilator (a machine that aids the patient’s breathing process throughout the procedure).

• A small incision (2 to 3 inches long) is made on the insertion site.

• Once the insertion is made, a specialized tube (sheath) is inserted into the vein (blood vessel). This sheath is slowly threaded over the concerned lead and is guided to its tip. The tip of the lead refers to the part of the lead that is attached to the heart.

• Surgeons employ the use of fluoroscopy to guide the sheath. Fluoroscopy, often called an interventional x-ray system, is a medical imaging technique that displays internal organs and tissues of the body moving in real-time on a computer screen or monitor. It uses short bursts of x-ray beams (known as pulses). Traditional X-rays are static images, whereas fluoroscopy provides a video.

• Specialized and intricate tools are used to remove the scar tissue, ensuring that no blood vessel gets injured. Occasionally, the surgeon can also use laser devices to remove the scar tissue. The device is attached to the sheath’s tip, generating heat to remove the scar tissue.

• Once everything is in place, the surgeon slowly removes the leads and the sheath.

• The surgeon sews the surgical site using sutures. Bandages further protect the sutures.

• The patient is transferred to ICU for monitoring. Recovery may take up to a week.

• Patients may experience swelling, bruising, and soreness at the surgery site.

• If there are any signs of infection, the patient is prescribed antibiotics.

• If the old leads are replaced with new ones, a chest x-ray is done to check the positioning of the leads.

What Are the Advantages of Transvenous Lead Extraction (TLE)?

Several advantages are associated with transvenous lead extraction, such as -

• The removal of malfunctioning or broken leads helps in the proper functioning of the cardiac implantable electronic device.

• It improves the efficiency of the devices, especially when the primary reason for inefficiency is an exit block (exit block refers to the phenomenon in which the leads do not function properly because of the formation of scar tissue over them).

• Helps restore regular heart rhythm.

• Helps restore blood flow, especially when the cause of the malfunction is the formation of a thrombus (blood clot).

What Are the Risks Associated With Transvenous Lead Extraction (TLE)?

Surgeries and their invasive nature are always associated with certain risk factors, irrespective of how major or minor the procedure might be. The risks associated with transvenous lead extraction include -

• Lead fracture.

• Perforation of the nearby blood vessels.

• Perforation of the heart.

• Complications associated with anesthesia.

• Excessive bleeding that requires a blood transfusion.

• Pericardial effusion (buildup of excess fluids, such as blood around the heart).

• Hemothorax (accumulation of blood in the pleural cavity - the space between the chest wall and the lungs).

• Myocardial avulsion (tearing the heart tissue and its associated structures).

Conclusion

Transvenous lead extraction (TLE) is a surgical procedure for treating the complications associated with cardiac implantable electronic devices (CIED). They are devices that help control and monitor heart rhythms. The leads or wires of these devices are removed if they are not functioning appropriately, which is frequently the result of a mechanical failure, such as a lead fracture, or if the device or the leads get infected. Removing and replacing the leads is an easy process, but the presence of excessive scar tissue makes it a complicated procedure. The surgery can last for as long as eight hours, and the patient recovers within a week.