Percutaneous endoscopic laser balloon pulmonary vein isolation for atrial fibrillation

Evidence-based recommendations on percutaneous endoscopic laser balloon pulmonary vein isolation for atrial fibrillation in adults. This involves destroying the tissue causing atrial fibrillation using laser energy.

# Recommendations
Current evidence on the safety of percutaneous endoscopic laser balloon pulmonary vein isolation for atrial fibrillation shows there are serious but wellrecognised complications. Evidence on efficacy is adequate in quantity and quality to support the use of this procedure provided that standard arrangements are in place for clinical governance, consent and audit. Find out what standard arrangements mean on the NICE interventional procedures guidance page.
Clinicians should ensure that patients fully understand the potential complications, the uncertainty about the success of the procedure in the short term and the risk of recurrent atrial fibrillation. In addition, the use of NICE's information for the public is recommended.
Patient selection and treatment should be carried out only by interventional cardiologists with expertise in electrophysiology and experience of doing complex ablation procedures.
This procedure should be done only in units with arrangements for emergency cardiac surgical support.
Clinicians should enter details about all patients having percutaneous endoscopic laser balloon pulmonary vein isolation for atrial fibrillation onto the UK Central Cardiac Audit Database and review local clinical outcomes.# Indications and current treatments
Atrial fibrillation (AF) is the most common type of cardiac arrhythmia. It is caused by the uncoordinated electrical stimulation of the atrial walls, which stop contracting as they fibrillate. This causes the ventricle to beat at an irregular and sometimes rapid rate. Patients with AF may be asymptomatic or have palpitations, dizziness, shortness of breath, fatigue and chest pain.
AF is associated with increased risk of embolic stroke from atrial thrombus, and death. Depending on risk stratification, oral anticoagulation treatment may be indicated. Such treatment is associated with risk of haemorrhage and requires longterm followup. Drugs may be used to prevent AF and maintain sinus rhythm (antiarrhythmics) or may be used to control the ventricular rate when AF occurs (usually beta blockers).
Ablation procedures are typically done in patients with nonpermanent AF when drug therapy is either not tolerated or is ineffective.# The procedure
Percutaneous endoscopic laser balloon pulmonary vein isolation for atrial fibrillation (AF) aims to maintain normal heart rhythm. It uses laser ablation to isolate the electrical impulses originating in the pulmonary veins, which are thought to be responsible for triggering AF.
The laser balloon catheter comprises an inflatable balloon mounted on a catheter shaft, an endoscope lumen, and an optical fibre that can also deliver laser energy.
The procedure is done with the patient under general anaesthesia or sedation. A deflectable sheath introducer is inserted in the femoral vein and advanced into the left atrium through a transseptal puncture. A circular mapping catheter is introduced, which may need a second transseptal puncture. A balloon catheter is passed through the deflectable sheath and the balloon is inflated at the ostium of the target pulmonary vein. The endoscope tip is positioned at the proximal end of the balloon, allowing direct visualisation of the cardiac tissue and assessment of the degree of contact between the balloon and cardiac muscle. Laser energy is delivered around the circumference of the pulmonary vein to isolate the source of the abnormal electrical activity. The circular mapping catheter is then used to assess whether electrical isolation of the pulmonary vein has been achieved. Ablation and assessment are repeated for each pulmonary vein. During ablation of the rightsided pulmonary veins, phrenic nerve pacing is done from the superior vena cava to monitor for phrenic nerve injury.# Efficacy
This section describes efficacy outcomes from the published literature that the committee considered as part of the evidence about this procedure. For more detailed information on the evidence, see the interventional procedure overview.
In a randomised controlled trial of 342 patients with atrial fibrillation (AF) treated by laser balloon pulmonary vein isolation or radiofrequency ablation, 61% and 62% of patients (actual numbers not reported) respectively (p=0.003 for noninferiority) did not have protocoldefined treatment failure (documented symptomatic AF of 1 minute or more; ablationinduced left atrial flutter or atrial tachycardia; failure to acutely isolate all pulmonary veins; use of any antiarrhythmic drug; or left heart ablation or surgery or implantable cardioverterdefibrillator placement for AF) at 12month followup. The percentage of patients who were drugfree at 12 months and free from symptomatic AF or atypical atrial flutter or atrial tachycardia was 64% (106/167 and 106/166) in both treatment groups (p=0.94). In a case series of 200 patients, 60% (95% confidence interval  53% to 67%) of patients were free from AF and were off antiarrhythmic drugs (class I or III) at 12month followup.
In a nonrandomised comparative study of 140 patients treated by laser balloon pulmonary vein isolation or cryoballoon ablation, AF recurred between 90 and 365 days after the procedure in 27% (18/68) and 37% (24/65) of patients respectively (p=0.18). In a nonrandomised comparative study of 80 patients with early persistent AF treated by laser balloon pulmonary vein isolation or radiofrequency ablation, AF recurred in 28% (11/40) and 23% (9/40) of patients respectively (p=0.79) after a single procedure at 12month followup. In a case series of 194 patients, 82% (130/158) of patients with paroxysmal AF and 75% (9/12) of patients with persistent AF were free from AF at 12month followup. For patients with paroxysmal AF, 76%, 76% and 75% of patients were free from AF at 24, 36 and 48month followup respectively.
In the nonrandomised comparative study of 80 patients, 25% (10/40) and 23% (9/40) of patients treated by laser balloon pulmonary vein isolation or radiofrequency ablation respectively had a repeat procedure. In the case series of 194 patients, 6% (11/194) of patients had a repeat procedure.
The specialist advisers listed key efficacy outcomes as persistent isolation of pulmonary veins, freedom from AF, freedom from atrial arrhythmias, freedom from atrial arrhythmias when off antiarrhythmic drug therapy, the single or multiple procedure success rate and improvement in quality of life.
Sixteen commentaries from patients who had experience of this procedure were received, which were discussed by the committee. The commentaries supported the procedure and reported improved quality of life after the procedure.# Safety
This section describes safety outcomes from the published literature that the committee considered as part of the evidence about this procedure. For more detailed information on the evidence, see the interventional procedure overview.
Stroke was reported in 2 patients treated by laser balloon pulmonary vein isolation (1 before discharge and 1 a week after discharge) and in 1 patient treated by radiofrequency ablation (p=0.56) in a randomised controlled trial (RCT) of 342 patients. All 3 strokes completely resolved. Transient ischaemic attack was reported in 1 patient treated by laser balloon pulmonary vein isolation in a nonrandomised comparative study of 140 patients. Stroke or transient ischaemic attack was reported in 1 patient in a case series of 194 patients; the patient showed symptoms of verbal confusion 2 hours after the procedure, but this resolved within 24 hours.
Cardiac tamponade, perforation, or significant effusion was reported in 1% (2/170) of patients treated by laser balloon pulmonary vein isolation and 2% (3/172) of patients treated by radiofrequency ablation (p=0.66) in the RCT of 342 patients. Cardiac tamponade was reported in 1 patient in the nonrandomised comparative study of 140 patients; this was treated by drainage of 300 ml of blood. Pericardial effusion was reported in 3% (6/200) of patients in a case series of 200 patients; 4 patients developed haemodynamic compromise or cardiac tamponade. All of these tamponades occurred during the procedure and were successfully drained. Cardiac tamponade or pericardial effusion was reported in 1 patient in the case series of 194 patients.
One patient died suddenly 6 days after the procedure, in the case series of 200 patients. The patient was found to have unrecognised critical triple vessel coronary artery disease. An independent Data Safety and Monitoring Board considered that this event was not related specifically to the laser ablation catheter.
Diaphragm paralysis persisting beyond 90 days was reported in 4% (6/170) of patients treated by laser balloon pulmonary vein isolation (3 persisted at 12 months, 1 resolved after 12 months) and 1% (1/172) of patients treated by radiofrequency ablation (persistent at 12 months; p=0.05) in the RCT of 342 patients. Phrenic nerve palsy was reported in 4% (3/70) of patients treated by laser balloon pulmonary vein isolation and 6% (4/70) of patients treated by cryoballoon ablation in the nonrandomised comparative study of 140 patients. Phrenic nerve injury was reported in 3% (5/200) of patients in the case series of 200 patients (1 remained unresolved at 12month followup). Acute phrenic nerve injury was reported in 2% (4/194) of patients in the case series of 194 patients; none persisted beyond 6 months.
Thermal lesions in the oesophagus, identified by endoscopy, were reported in 82% (33/40) of patients treated by laser balloon pulmonary vein isolation and 85% (17/20) of patients treated by radiofrequency ablation in a nonrandomised comparative study of 60 patients. Ulceration was reported in 10% (4/40) of patients treated by laser balloon pulmonary vein isolation and no patients treated by radiofrequency ablation.
A patient with pulmonary vein stenosis 6 months after laser balloon pulmonary vein isolation was described in a case report. The first attempt to isolate the pulmonary vein was unsuccessful and additional energy applications were needed. Significant pulmonary vein stenosis (more than a 50% decrease in diameter on CT or cardiac MRI) at 3month followup was reported in no patients treated by laser balloon pulmonary vein isolation and 3% (5/172) of patients treated by radiofrequency ablation (p=0.03) in the RCT of 342 patients. Pulmonary vein narrowing (more than 20% but not more than 50% decrease in diameter) evaluated on a pervein basis was reported in 22% and 25% of patients respectively, in the same study (p value not reported). The mean decrease in pulmonary vein diameter was 4% at 3month followup in the case series of 200 patients. Mild narrowing (1% to 25% decrease in diameter) was present in 44% of pulmonary veins and moderate narrowing (26% to 50%) in 6% of pulmonary veins.
An endoscopically visible steam 'pop' was described in a case report. During ablation at the antrum of the left superior pulmonary vein, a sudden steam pop was witnessed, with displacement of the laser balloon catheter. The left superior pulmonary vein antrum showed a red discolouration, most likely a haematoma in the antral wall. The discolouration was still present 1 hour after the procedure. The patient did not develop any symptoms related to the steam pop and echocardiography did not reveal any abnormalities.
Laceration of the right femoral vein by mechanical trauma was reported in 1 patient in the nonrandomised comparative study of 140 patients. This was treated by surgery. In the same study, minor vascular complications (false aneurysms or haematoma) were reported in 4% (3/40) of patients treated by laser balloon pulmonary vein isolation and 3% (2/70) of patients treated by cryoballoon ablation. False aneurysm was reported in 1 patient treated by laser balloon and 1 patient treated by radiofrequency ablation in a nonrandomised comparative study of 80 patients. Vascular injury was reported in 3% (6/194) of patients in the case series of 194 patients; 2 patients had surgical repair and 4 patients had prolonged hospitalisation because of bleeding.
Cardioversion for atrial arrhythmia was reported in 8% (14/170) of patients treated by laser balloon pulmonary vein isolation and 9% (16/172) of patients treated by radiofrequency ablation (p=0.73) in the RCT of 342 patients.
Asymptomatic cerebral lesions were detected by MRI 1 to 2 days after the procedure in 24% (8/33) of patients treated by laser balloon pulmonary vein isolation, 24% (8/33) of patients treated by radiofrequency ablation and 18% (6/33) of patients treated by cryoballoon ablation (p=0.8) in an RCT of 99 patients.
In addition to safety outcomes reported in the literature, specialist advisers are asked about anecdotal adverse events (events which they have heard about) and about theoretical adverse events (events which they think might possibly occur, even if they have never done so). For this procedure, specialist advisers listed the following anecdotal adverse event: catheter failure needing a minor surgical procedure to remove it safely from the femoral vein. They considered that the following were theoretical adverse events: atrialoesophageal fistula, myocardial infarction and death.# Further information
For related NICE guidance, see the NICE website.

# Information for patients
NICE has produced information on this procedure for patients and carers. It explains the nature of the procedure and the guidance issued by NICE, and has been written with patient consent in mind.
ISBN: 978-1-4731-1978-9