NATIONAL INSTITUTE FOR HEALTH AND CLINICAL EXCELLENCE

Interventional procedure consultation document

Percutaneous occlusion of the left atrial appendage in non-valvular atrial fibrillation for the prevention of thromboembolism

 

1       Provisional recommendations

1.1  Current evidence suggests that percutaneous occlusion of the left atrial appendage (LAA) is efficacious in reducing the risk of thromboembolic complications associated with non-valvular atrial fibrillation (AF). With regard to safety, there is a risk of life-threatening complications from the procedure, but the incidence of these is low. Therefore this procedure may be used provided that normal arrangements are in place for clinical governance, consent and audit.

1.2  Patient selection should be carried out by a multidisciplinary team including a cardiologist and a cardiac surgeon. Patients should be considered for alternative treatments to reduce the risk of thromboembolism associated with AF, and should be informed about these alternatives.

1.3  Percutaneous occlusion of the LAA is a technically challenging procedure which should only be carried out by clinicians with specific training.

1.4  This procedure should be carried out only in units with on-site cardiac surgery.

1.5  There are plans for the UK Central Cardiac Audit Database to include a dataset for percutaneous occlusion of the LAA, and when this becomes available clinicians should enter details about all patients undergoing this procedure (www.ccad.org.uk).  

2       The procedure

2.1    Indications and current treatments

2.1.1  Atrial fibrillation is the irregular and rapid beating of the atria. Patients with AF may be asymptomatic or may have symptoms such as fatigue, palpitations, chest pain, shortness of breath and fainting. They also have an increased risk of thromboembolic stroke. In non-rheumatic AF, thrombi largely develop in the LAA.

2.1.2  Patients with AF who are considered to be at a high risk of thromboembolic stroke are often treated with warfarin anticoagulation therapy. Surgical intervention may involve obliteration of the LAA through an open or thoracoscopic approach.

2.2    Outline of the procedure

2.2.1  Percutaneous occlusion of the LAA is usually performed with the patient under general anaesthesia. Using fluoroscopic guidance, a catheter is advanced through the femoral vein into the right atrium and then into the left atrium via a transseptal puncture. The location of the LAA is confirmed and the size of the LAA orifice may be established by transoesophageal echocardiography (TOE). An appropriately sized device is selected and deployed in the mouth of the LAA where it is expanded to fit the space.

2.2.2  The position and patency of the occlusion device may be confirmed postoperatively using echocardiographic imaging.

Sections 2.3 and 2.4 describe efficacy and 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 overview, available at www.nice.org.uk/IP310aoverview.

 

2.3    Efficacy

2.3.1  A randomised controlled trial (RCT) of 707 patients treated by percutaneous closure of the LAA or warfarin reported 2.3 and 3.2 strokes (all cause) per 100 patient-years respectively (rate ratio 0.71, credible interval [CrI] 0.35 to 1.64).

2.3.2  A case series of 111 patients reported stroke in 2 patients at 173- and 215-day follow-up. Echocardiography at 1 and 6 months revealed a stable device in both patients and no thrombogenic layer on the surface of the device.

2.3.3  Transient ischaemic attack was reported in 2 patients in the case series of 111 patients (not otherwise described).

2.3.4  The RCT of 707 patients treated by the procedure or warfarin reported successful closure in 88% (408/463) of patients randomised to the procedure.

2.3.5  The Specialist Advisers listed key efficacy outcomes as freedom from stroke, other neurological and cardiac events.

2.4    Safety

2.4.1  Cardiac tamponade requiring median sternotomy, pericardiocentesis and ligation of the LAA occurred 4 hours after the procedure in 1 patient in the case series of 111 patients. The patient later developed deep vein thrombosis and died 27 days after the procedure (attributed to cerebral haemorrhage associated with anticoagulation therapy).

2.4.2  Cardiac arrest 30 minutes after the procedure because of device embolisation was reported in 1 patient,, who subsequently died, in a case series of 73 patients.  

2.4.3  Device embolism was reported in 0.6% (3/463) of patients in the RCT of 707 patients: 1 detected during the procedure, and 2 detected on transoesophageal echocardiography at 45-day follow-up (1 was removed percutaneously and 2 underwent surgery; not otherwise described). Device embolisation in the left atrium a few minutes after implantation occurred in 1 patient in a case series of 16 patients (attributed to incorrect sizing of the device). The device was removed surgically.

2.4.4  The case series of 73 patients reported that one implant required open heart surgery because the device was unstable.

2.4.5  Delivery wire fracture requiring surgical removal was reported in one patient in the case series of 75 patients.

2.4.6  The RCT of 707 patients reported pericardial effusion successfully treated surgically or with pericardiocentesis in 5% (22/463), pericardial effusion not requiring drainage in 2% (8/463), oesophageal tear in 0.2% (1/463) and procedure-related arrhythmia in 0.2% (1/463) of patients treated by percutaneous occlusion.

2.4.7  Laminar growth on the superior edge of the occluder treated by aspirin and clopidogrel for 6 months after the procedure (no other details provided) was reported in 1 patient in the case series of 111 patients.

2.4.8  Perforation of the right femoral artery when accessing the right femoral vein and left atrial thrombus at the time of the procedure preventing the implantation of the device was reported in 1 patient each in the case series of 111 patients.

2.4.9  Femoral pseudoaneurysm was reported in 3% (2/66) of patients in a case series of 75 patients (not otherwise described).

2.4.10  The Specialist Advisers considered theoretical adverse events to include the inability to recover an incorrectly positioned device by endovascular means, so requiring emergency surgery; and persistent atrial septal defect.

2.5   Other comments

2.5.1  The Committee noted that the published reports included different occlusion devices and were mindful that clinical outcomes may not necessarily be the same with all devices. 

2.5.2  The Committee noted that new pharmacological products are under development for use in reducing the risk of thromboembolism associated with AF.

3     Further information

3.1  This procedure is a review of IPG181 published in 2006.

3.2  For related NICE guidance see www.nice.org.uk.

Bruce Campbell
Chairman, Interventional Procedures Advisory Committee
February 2010

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