Percutaneous left atrial appendage transcatheter occlusion to prevent stroke in high-risk patients with atrial fibrillation: early clinical experience

Role of transesophageal echocardiography in the evaluation of patients with stroke

This review article summarizes recent advances in the care of patients presenting with neurologic events, in which transesophageal echocardiography plays an important role in diagnosis, prognosis, and treatment. New research on the use of transesophageal echocardiography in patients with stroke and atrial fibrillation is discussed, including left atrial clot formation, maintenance of sinus rhythm after cardioversion, and techniques of left atrial appendage occlusion. A discussion of developments in the diagnosis and management of thoracic aortic plaque follows. The association of patent foramen ovale and atrial septal aneurysm with stroke is outlined, and possible reasons for this association are discussed. Recent literature on the use of percutaneous closure devices for patent foramen ovale is reviewed.

Long-term outcome after stroke due to atrial fibrillation

Atrial fibrillation (AF) is the most common cardiac arrhythmia. AF is paroxysmal or persistent and becomes permanent when it does not convert to sinus rhythm spontaneously or when attempted cardioversion fails. The prevalence of AF is 0.4% in the general population and increases with age up to 6-8% in octogenarians. In men, the age-adjusted prevalence is generally higher than in women. During AF, synchronous mechanical atrial activity is disturbed, resulting in haemodynamic impairment. This can give rise to thrombus formation and embolism to the systemic circulation. Thrombus associated with AF arises most frequently in the left atrial appendage. Cerebrovascular emboli in AF patients most often manifest as transient ischaemic attacks or ischaemic strokes. The overall rate of ischaemic stroke among patients with nonrheumatic AF averages 5% per year, but the rate increases with age. Patients with AF are at higher risk of cerebrovascular events from all causes. Of all strokes, one in every six occurs in patients with AF. Including transient ischaemic attacks and silent strokes detected radiographically, the overall rate of all cerebrovascular events in AF patients rises to more than 7% per year, although approximately one third of these are due to causes that are only secondarily or incidentally associated with AF or related anticoagulant therapy. Antiarrhythmic therapy is useful to improve cardiac rate and function in AF. However, to reduce first or recurrent emboli, antithrombotic therapy is of paramount importance. Results from several randomized clinical trials of antithrombotic therapies have shown that adjusted-dose warfarin reduces first or recurrent stroke by about 60% compared with placebo. When patients with nonvalvular AF are anticoagulated, the odds against ischaemic stroke and intracranial bleeding favour an INR between 2.0 and 3.0. Acetylsalicylic acid is less efficacious than warfarin in AF patients, reducing the risk of stroke by about 20%. Therefore, this antiplatelet agent should be used only for AF patients at low risk. Anticoagulation is the current treatment modality in AF patients at high or intermediate risk, i.e. patients with history of transient ischaemic attack or stroke, those aged >65 years, those with a history of hypertension, diabetes, heart failure or structural heart disease, valvular disease or significant systolic dysfunction. The benefit of dual antiplatelet regimens in AF patients is unknown, and combining antiplatelet agents with different mechanisms of action is an important topic for future investigation.

An endovascular approach to cardioembolic stroke prevention in atrial fibrillation patients

This report is of a 62-year-old woman presenting with a 3-year history of chronic atrial fibrillation (AF) and unable to tolerate chronic warfarin therapy due to bleeding episodes and unstable INR values. Additional high risk factors for stroke are a history of congestive heart failure and previous embolic stroke. Percutaneous left atrial appendage transcatheter occlusion (PLAATO ) was performed to seal the LAA. A transesophageal echocardiography (TEE) at the 1- and 6-month follow-up showed no device migration and no new thrombus related to the implant. The patient has been doing well on postprocedure aspirin with no embolic events.

Cardioembolic stroke: an update

Embolism of cardiac origin accounts for about one fifth of ischaemic strokes. Strokes due to cardioembolism are in general severe and prone to early recurrence. The risk of long term recurrence and mortality are high after a cardioembolic stroke. Cardioembolism can be reliably predicted on clinical grounds but is difficult to document. MRI, transcranial doppler, echocardiogram, Holter monitoring, and electrophysiological studies increase our ability to identify the source of cardioembolism. Non-valvular atrial fibrillation is the commonest cause of cardioembolic stroke. Despite its enormous preventive potential, continuous oral anticoagulation is prescribed for less than half of patients with atrial fibrillation who have risk factors for cardioembolism and no contraindications for anticoagulation. Alternatives to oral anticoagulation in this setting include safer and easier to use antithrombotic drugs and definitive treatment of atrial fibrillation. Available evidence does not support routine immediate anticoagulation of acute cardioembolic stroke.