MAIN SESSION

Thromboembolic risk factors after cardioversion for atrial fibrillation Barcelona, 3 September 2006 A main session was devoted to the role of echocardiography in atrial fibrillation and for assessing thromboembolic risk after cardioversion for atrial fibrillation. The chairmen of this session were W.G. Daniel (Erlangen, Germany) and S.B. Olsson (Lund, Sweden).

a

The first presentation was by A. Cohen (Paris, France), who discussed the role echocardiography plays in detecting some of the causes of atrial fibrillation, namely mitral valve disease, pericardial disease and hypertrophic cardiomyopathy. Atrial pressure elevation is an important cause of atrial fibrillation and can be estimated in patients with atrial fibrillation using Doppler echocardiography. Furthermore several transthoracic echocardiography (TTE) variables are useftil for determining the risk of recurrence of atrial fibrillation (left atrial size) and risk ofthromboembolism (left ventricle ejection fraction). In the SPAF III (Stroke Prevention in Atrial Fibrillation) trial, transoesophageal echocardiography (TEE) variables such as left atrial thrombus, spontaneous echo contrast, low velocity in the left atrial appendage and complex aortic plaques were identified as risk factors for thromboembolism. These echocardiography variables contribute to the clinical risk factors in atrial fibrillation associated with thromboembolism such as age >75 years, previous stroke, TIA or systemic embolism, history of systemic hypertension, diabetes mellitus and rheumatic valvular disease or valvular prothesis.

Next, R. Zahn (Ludwigshafen, Germany) addressed the subject of embolic events in patients with atrial fibrillation and the value ofTEE. The risk of thromboembolism after direct-current cardioversion is 5 to 7% without oral anticoagulation and 1 to 2% with oral anticoagulation. Current guidelines recommend the use of anticoagulation three weeks before and four weeks after direct-current cardioversion. A new development is the use of TEE to guide anticoagulation strategies for direct-current cardioversion. H.C. Groonewegen P.P. Van Geel Department of Cardiology, University Medical Centre Groningen, Groningen, the Netherlands E-mail: [email protected]

12

Then third speaker was C. Stellbrink (Bielefeld, Germany), who discussed the ACUTE (Assessment of Cardioversion Using Transoesophageal Echocardiography) trial. In this trial patients were randomised to conventional anticoagulation treatment (603 patients) and TEE-guided anticoagulation (619 patients). Ofthe patients in the conventional group, 55% received cardioversion. Patients in the TEE-guided group were stratified according to the presence or absence of thrombus. Ofpatients in the TEE-guided group with absence ofthrombus, 69% received early cardioversion. In patients with thrombus the cardioversion was postponed or no cardioversion was performed. In the TEE-guided group there was a similar rate ofembolic events compared with the conventional group; however, patients had a shorter time to cardioversion and a lower rate of haemorrhagic events in the TEEguided group. In the Ludwigshafen Observational Cardioversion Study 357 patients were randomised to conventional anticoagulation and 719 to TEE-guided anticoagulation (all patients had INR >2). Cardioversion was performed in 355 patients in the conventional group (successfully in 78%) and in 586 patients in the TEE-guided group (successfully in 86%). There was no difference between the two groups in the rate of thromboembolic events (both 0.8%).

The last presentation was by P. Colonna (Bari, Italy), who addressed the issue of echocardiographic postcardioversion evaluation of left atrial appendage stunning. After it was demonstrated in two large trials (RACE and AFFIRM) that some patients with sinus rhythm but a history of atrial fibrillation have a substantial embolic risk, life-long anticoagulation was suggested for these patients. However, a balance between thromboembolic and haemorrhagic risk is advocated. It is known that embolic events are almost always derived from the left atrial appendage. So left atrial appendage dysfunction (atrial stunning) could be a link between clinical risk factors and thromboembolic events. Left atrial stunning has been evaluated by measuring left atrial appendage flow velocities and spontaneous echo contrast. Left atrial stunning has been reported after spontaneous, chemical and directcurrent cardioversion and is worse in patients with a longer duration ofatrial fibrillation. Some studies have also found that patients with atrial fibrillation and a normal left atrial appendage function after cardioNetherlands Heart Journal, Volume 14, Supplement 2, November 2006

^|pc

28th Congress of the European Society of Cardiology / World Congress of Cardiology

version have a low embolic risk. Also the development of a new transthoracic parameter (M-mode ofleft atrial appendage) means that TTE in the future can be used for measurement of left atrial appendage velocities. In conclusion, TEE before cardioversion is not needed in patients who have had effective anticoagulation for at least three weeks. In patients with a normal TEE, early cardioversion can also be performed safely. Bleeding complications are lower with TEE-guided echocardiography; however, thromboembolic events and mortality are unaffected. In the ACUTE cost-effectiveness study there was no difference in patient costs between the TEE-guided strategy and the conventional

q|PC

Netherlands Heart Journal, Volume 14, Supplement 2, Novenber 2006

strategy. The value ofTEE-guided anticoagulation is that it is more convenient for physicians and patients: both TEE and cardioversion can be performed during a single visit. Patients with the following characteristics might be better suited for the TEE-guided approach: new onset AF, uncertain anticoagulation status, higher risk for bleeding, potential noncompliance with anticoagulation and high risk for left atrial thrombus. Evaluation of left atrial function using TEE or TTE might be useful for the selection of some patients postcardioversion with a low embolic risk (eliminating the need for lifelong anticoagulation, while giving antiaggregation instead), however more research is needed to confirm this. U

13

Thromboembolic risk factors after cardioversion for atrial fibrillation: Barcelona, 3 September 2006.

Thromboembolic risk factors after cardioversion for atrial fibrillation: Barcelona, 3 September 2006. - PDF Download Free
244KB Sizes 0 Downloads 8 Views