Percutaneous endoscopic laser balloon pulmonary vein isolation for atrial fibrillation

5.1 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 non‑randomised 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.

5.2 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 non‑randomised 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.

5.3 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.

5.4 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 non‑randomised 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 12‑month follow‑up). Acute phrenic nerve injury was reported in 2% (4/194) of patients in the case series of 194 patients; none persisted beyond 6 months.

5.5 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 non‑randomised 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.

5.6 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 3‑month follow‑up 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 per‑vein 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 3‑month follow‑up 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.

5.7 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.

5.8 Laceration of the right femoral vein by mechanical trauma was reported in 1 patient in the non‑randomised 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 non‑randomised 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.

5.9 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.

5.10 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.

5.11 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: atrial‑oesophageal fistula, myocardial infarction and death.