Left atrial appendage (LAA) ligation, or exclusion, is a procedure pioneered by cardiologist and electrophysiologist Randall Lee, M.D., Ph.D., and his colleagues at UCSF Medical Center. It reduces the risks of thrombus formation within the LAA — which may lead to embolic stroke associated with atrial fibrillation (AF) — while minimizing the risks associated with other therapies for the same clinical indications.

Seeking Safer Alternatives

Atrial fibrillation is one of the most frequent causes of embolic stroke in patients over the age of 75, and the left atrial appendage is often the source of stroke-causing clots associated with AF.

Numerous therapies are available to reduce those risks, but the new LAA exclusion procedure helps address concerns with the interventions used to date.

• Oral anticoagulation therapy is contraindicated in some patients, due to numerous side effects, including life-threatening bleeding.
• Surgeons have used open-heart surgery to tie off the LAA for decades, but it remains an invasive, open-chested procedure.
• Catheter-based LAA occlusion devices are less invasive than an open-heart procedure, but studies have shown a risk of perforation and embolization of the plug used to occlude the LAA.
Catheter ablation of electrical activity in the LAA is limited by the risk of tamponade and electromechanical dissociation with the potential for thrombus formation.

In contrast, Lee's percutaneous LAA exclusion procedure uses a lasso-like suture delivery device to tie off the LAA from the rest of the circulatory system, leading to necrosis and atrophy of the LAA. This means it effectively achieves the same results as the above therapies, with considerably less risk.

How It's Performed

During a percutaneous LAA exclusion, doctors insert guide wires through a small hole in the patient's pericardium and via a catheter positioned in the left atrium. These wires, fitted with magnets, establish a track to the LAA. The cardiologist then slips a pre-tied suture over the LAA and, with the help of X-ray or ultrasound, tightens the loop to fully exclude the pouch.

In addition, the LAA exclusion procedure now allows teams to percutaneously replicate the Cox maze IV surgical ablation for AF. It increases the success rate of the catheter ablation by eliminating focal LAA triggers for AF.

"What Dr. Lee has developed involves closing the LAA from the outside, without any need to move inside the heart," says cardiologist and electrophysiologist Nitish Badhwar, M.D.. "We have done a lot of these procedures here at UCSF, and it is an effective stroke prevention measure for patients with atrial fibrillation, with a very minimal complication risk. A second benefit is that for patients whose arrhythmias come from the LAA, the procedure stops the irregular rhythms; the argument could even be made that LAA ligation offers patients greater freedom from atrial fibrillation, and makes them more comfortable getting off blood thinners."

To contact Dr. Randall Lee or Dr. Nitish Badhwar, call (415) 353-2554.

 

Heart & Vascular Center News, Winter 2013 Index