Atrial fibrillation and stroke. Revisiting the dilemmas

Cardiac CT angiography after percutaneous left atrial appendage closure: early versus delayed scanning after contrast administration

PURPOSE

Cardiac computed tomography angiography (CCTA) is increasingly used for device surveillance after left atrial appendage closure (LAAC). While CT protocols with delayed scans are useful to diagnose thrombus in the LAA, an optimal protocol for post-procedural CCTA has not been established. Therefore, we assessed the role of delayed versus early scans for device surveillance.

METHODS

We retrospectively reviewed patients who underwent LAAC at Vancouver General Hospital who had follow-up CCTAs using standard (early) and delayed scans. Scans were performed on Toshiba 320-detector (Aquilion ONE). Image quality was interpreted by 2 independent observers for anatomy, LAA contrast patency, and device-related thrombus (DRT) using VitreaWorkstationTM. A Likert scale of 1-5 was used (1= poor quality, 5= excellent) for assessment.

RESULTS

We included 27 consecutive LAAC patients (9 Amplatzer, 18 WATCHMAN) with mean age 76.0±7.7 years, mean CHADS2 score 2.8±1.3, CHA2DS2-VASc score 4.4±1.6 and HAS-BLED score 3.4±1.0. Subjective quality assessments by both reviewers favored early scans for assessment of anatomy (reviewer 1: 4.63±0.63 [early] vs. 1.74±0.71 [delayed]; reviewer 2: 4.63±0.63 [early] vs. 1.89±0.64 [delayed]) and DRT (reviewer 1: 4.78±0.42 [early] vs. 3.11±1.16 [delayed]; reviewer 2: 4.70±0.47 [early] vs. 3.04±1.29 [delayed]). Inter-rater variability showed good correlation between reviewers (intraclass correlation 0.61-0.95). Mean LAA/LA attenuation ratios were significantly different between scans, with larger mean percent reduction of contrast opacification from LA to LAA in the early scans (57.0±36.6% reduction for early vs. 29.1±30.8% for delayed; p < 0.001) CONCLUSION: For CT device surveillance post-LAAC early phase imaging provides superior image quality objectively and subjectively compared with delayed scanning.

Pharmacotherapy of Atrial Fibrillation

Atrial fibrillation is the most common sustained arrhythmia of clinical significance. Its prevalence rises with age. It is a significant cause of thromboembolic phenomena. We describe briefly the etiology and classification of atrial fibrillation, the risk factors for thromboembolism and stroke associated with it, the indications for hospitalization, and the therapeutic goal. We discuss in depth the management strategies for such patients and compare the impact of rate versus rhythm control in reducing morbidity and mortality attributed to arrhythmia, in light of past and present trials. A brief overview of the drugs used in the management of atrial fibrillation, their pharmacology and dosage, their effects and use in rhythm versus rate control with important side effects are also included. Finally, the prevention and treatment of thromboembolism in patients with atrial fibrillation, an important aspect of therapy, is revisited in light of recent advances.

Extracranial Carotid Artery Disease: Risk Factors and Outcomes in Patients With Acute Critical Hemispheric Ischemic Stroke

OBJECTIVES

The prevalence of carotid disease in stroke patients has been underestimated because most stroke patients who receive carotid sonography have already survived the acute event. Little is known about the extracranial carotid arteries of patients with acute stroke who need intensive care. This study reviewed color-coded carotid duplex sonographic examinations of the extracranial carotid arteries of patients with acute critical hemispheric ischemic stroke.

METHODS

We retrospectively reviewed 30 consecutive patients who had acute critical hemispheric ischemic stroke and received color-coded carotid duplex sonography in the intensive care unit. The presence of occlusive carotid artery disease was correlated with clinical features, vascular risk factors, and outcomes.

RESULTS

Overall, 57% of the patients (17 of 30) had an occlusive internal carotid artery, and 44% of patients with atrial fibrillation (7 of 16) also had occlusive carotid disease. Eventually, 73% of the patients (21 of 30) had poor outcomes, and 57% (17 of 30) died. The contributing factors to a poor outcome were older age, an initial conscious disturbance, endotracheal intubation, and occlusive carotid disease, with the most significant factor being older age (P = .022; odds ratio, 27.76). The factors contributing to death were endotracheal intubation, occlusive carotid disease, and reversed ophthalmic flow, with the most significant factor being occlusive carotid disease (P = .014; odds ratio, 11.38). Soft homogeneously echogenic thrombi filling the lumen of the internal carotid artery and moving forward and backward with the carotid pulse were found in 3 patients. A small segment of ruptured plaque that was floating forward and backward with pulsation was found in 1 patient.

CONCLUSIONS

Occlusive carotid artery disease is not uncommon among Chinese patients who have had an acute critical hemispheric infarction. Older age is the factor most significantly correlated with a poor outcome, and occlusive carotid disease is the factor most significantly correlated with death.

Usefulness of brain natriuretic peptide for predicting left atrial appendage thrombus in patients with unanticoagulated nonvalvular persistent atrial fibrillation

BACKGROUND

The CHADS2 scoring system is simple and widely accepted for predicting thromboembolism in patients with nonvalvular atrial fibrillation (NVAF). Although congestive heart failure (CHF) is a component of the CHADS2 score, the definition of CHF remains unclear. We previously reported that the presence of CHF was a strong predictor of left atrial appendage (LAA) thrombus. Therefore, the present study aimed to elucidate the relationship between LAA thrombus and the brain natriuretic peptide (BNP) level in patients with unanticoagulated NVAF.

METHODS

The study included 524 consecutive patients with NVAF who had undergone transesophageal echocardiography to detect intracardiac thrombus before cardioversion between January 2006 and December 2008, at Hiroshima City Asa Hospital. The exclusion criteria were as follows: paroxysmal atrial fibrillation, unknown BNP levels, prothrombin time international normalized ratio ≥2.0, and hospitalization for systemic thromboembolism.

RESULTS

Receiver operating characteristic analysis yielded optimal plasma BNP cut-off levels of 157.1 pg/mL (area under the curve, 0.91; p<0.01) and 251.2 pg/mL (area under the curve, 0.70; p<0.01) for identifying CHF and detecting LAA thrombus, respectively. Multivariate analyses demonstrated that a BNP level >251.2 pg/mL was an independent predictor of LAA thrombus (odds ratio, 3.51; 95% confidence interval, 1.08-10.7; p=0.046).

CONCLUSIONS

In patients with unanticoagulated NVAF, a BNP level >251.2 pg/mL may be helpful for predicting the incidence of LAA thrombus and may be used as a surrogate marker of CHF. The BNP level is clinically useful for the risk stratification of systemic thromboembolism in patients with unanticoagulated NVAF.

Antiplatelet drugs: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition)

This article about currently available antiplatelet drugs is part of the Antithrombotic and Thrombolytic Therapy: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). It describes the mechanism of action, pharmacokinetics, and pharmacodynamics of aspirin, reversible cyclooxygenase inhibitors, thienopyridines, and integrin alphaIIbbeta3 receptor antagonists. The relationships among dose, efficacy, and safety are thoroughly discussed, with a mechanistic overview of randomized clinical trials. The article does not provide specific management recommendations; however, it does highlight important practical aspects related to antiplatelet therapy, including the optimal dose of aspirin, the variable balance of benefits and hazards in different clinical settings, and the issue of interindividual variability in response to antiplatelet drugs.

Warfarin versus aspirin in patients with reduced cardiac ejection fraction (WARCEF): rationale, objectives, and design

BACKGROUND

Warfarin is widely prescribed for patients with heart failure without level 1 evidence, and an adequately powered randomized study is needed.

METHODS AND RESULTS

The Warfarin versus Aspirin in Reduced Cardiac Ejection Fraction study is a National Institutes of Health-funded, randomized, double-blind clinical trial with a target enrollment of 2860 patients. It is designed to test with 90% power the 2-sided primary null hypothesis of no difference between warfarin (International Normalized Ratio 2.5-3) and aspirin (325 mg) in 3- to 5-year event-free survival for the composite endpoint of death, or stroke (ischemic or hemorrhagic) among patients with cardiac ejection fraction < or =35% who do not have atrial fibrillation or mechanical prosthetic heart valves. Secondary analyses will compare warfarin and aspirin for reduction of all-cause mortality, ischemic stroke, and myocardial infarction (MI), balanced against the risk of intracerebral hemorrhage, among women and African Americans; and compare warfarin and aspirin for prevention of stroke alone. Randomization is stratified by site, New York Heart Association (NYHA) heart class (I vs II-IV), and stroke or transient ischemic attack (TIA) within 1 year before randomization versus no stroke or TIA in that period. NYHA class I patients will not exceed 20%, and the study has a target of 20% (or more) patients with stroke or TIA within 12 months. Randomized patients receive active warfarin plus placebo or active aspirin plus placebo, double-blind.

CONCLUSION

The results should help guide the selection of optimum antithrombotic therapy for patients with left ventricular dysfunction.

Platelet-Active Drugs: The Relationships Among Dose, Effectiveness, and Side Effects

This article discusses platelet active drugs as part of the Seventh American College of Chest Physicians Conference on Antithrombotic and Thrombolytic Therapy: Evidence-Based Guidelines. New data on antiplatelet agents include the following: (1) the role of aspirin in primary prevention has been the subject of recommendations based on the assessment of cardiovascular risk; (2) an increasing number of reports suggest a substantial interindividual variability in the response to antiplatelet agents, and various phenomena of "resistance" to the antiplatelet effects of aspirin and clopidogrel; (3) the benefit/risk profile of currently available glycoprotein IIb/IIIa antagonists is substantially uncertain for patients with acute coronary syndromes who are not routinely scheduled for early revascularization; (4) there is an expanding role for the combination of aspirin and clopidogrel in the long-term management of high-risk patients; and (5) the cardiovascular effects of selective and nonselective cyclooxygenase-2 inhibitors have been the subject of increasing attention.

Thoracoscopic extracardiac obliteration of the left atrial appendage for stroke risk reduction in atrial fibrillation

OBJECTIVES

We evaluated left atrial appendage obliteration in high-risk patients with atrial fibrillation (AF).

BACKGROUND

Left atrial appendage thrombosis and embolization is the principal mechanism of stroke in AF. Anticoagulation is underutilized and often contraindicated.

METHODS

Thoracoscopic Left Appendage, Total Obliteration, No cardiac Invasion (LAPTONI) was undertaken with a loop snare in eight patients and a stapler in seven patients, median age 71 years, with clinical risk factors for stroke and with an absolute contraindication to or failure of prior thrombosis prevention with warfarin. Eleven patients had a history of prior thromboembolism. One patient took sustained warfarin during follow-up.

RESULTS

The LAPTONI procedure was completed in 14 of 15 patients, and 1 patient required urgent conversion to open thoracotomy because of bleeding. Patients have been followed up for 8 to 60 months, mean 42 +/- 14 months. One fatal stroke occurred 55 months after surgery, and one non-disabling stroke three months after surgery. Two other deaths occurred, one after coronary bypass surgery and the other from hepatic failure. The subgroup of 11 patients with prior thromboembolism had an annualized rate of stroke of 5.2% per year (95% confidence interval [CI] 1.3 to 21) after LAPTONI, which compares to a rate of 13% per year (95% CI 9.0 to 19) for similar aspirin-treated patients from the Stroke Prevention in Atrial Fibrillation trials (p = 0.15).

CONCLUSIONS

The LAPTONI procedure appears technically feasible without immediate disabling neurologic morbidity or mortality, and it demonstrates low post-operative event rates and a statistical trend toward thromboembolic risk reduction in high-risk AF patients.

Antithrombotic Secondary Prevention After Stroke

In patients with transient ischemic attack (TIA) or ischemic stroke of noncardiac origin, antiplatelet drugs are able to decrease the risk of stroke by 11% to 15%, and decrease the risk of stroke, myocardial infarction (MI), and vascular death by 15% to 22%. Aspirin leads to a moderate but significant reduction of stroke, MI, and vascular death in patients with TIA and ischemic stroke. Low doses are as effective as high doses, but are better tolerated in terms of gastrointestinal side effects. The recommended aspirin dose, therefore, is between 50 and 325 mg. Bleeding complications are not dose-dependent, and also occur with the lowest doses. The combination of aspirin (25 mg twice daily) with slow-release dipyridamole (200 mg twice daily) is superior compared with aspirin alone for stroke prevention. Ticlopidine is effective in secondary stroke prevention in patients with TIA and stroke. For some end points, it is superior to aspirin. Due to its side-effect profile (neutropenia, thrombotic thrombocytopenic purpura ), ticlopidine should be given to patients who are intolerant of aspirin. Prospective trials have not indicated whether ticlopidine is suggested for patients who have recurrent cerebrovascular events while on aspirin. Clopidogrel has a better safety profile than ticlopidine. Although not investigated in patients with TIA, clopidogrel should also be effective in these patients assuming the same pathophysiology than in patients with stroke. Clopidogrel is second-line treatment in patients intolerant for aspirin, and first-line treatment for patients with stroke and peripheral arterial disease or MI. A frequent clinical problem is patients who are already on aspirin because of coronary heart disease or a prior cerebral ischemic event, and then suffer a first or recurrent TIA or stroke. No single clinical trial has investigated this problem. Therefore, recommendations are not evidence-based. Possible strategies include the following: continue aspirin, add dipyridamole, add clopidogrel, switch to ticlopidine or clopidogrel, or switch to anticoagulation with an International Normalized Ratio (INR) of 2.0 to 3.0. The combination of low-dose warfarin and aspirin was never studied in the secondary prevention of stroke. In patients with a cardiac source of embolism, anticoagulation is recommended with an INR of 2.0 to 3.0. At the present time, anticoagulation with an INR between 3.0 and 4.5 cannot be recommended for patients with noncardiac TIA or stroke. Anticoagulation with an INR between 3.0 and 4.5 carries a high bleeding risk. Whether anticoagulation with lower INR is safe and effective is not yet known. Treatment of vascular risk factors should also be performed in secondary stroke prevention.

Neurologic manifestations of cardiogenic embolism: an update

Cardiogenic embolism is increasingly appreciated as an important and preventable cause of stroke. Several potential sources of embolism have been identified with the advent of transoesophageal echocardiography. Their role as independent risk factors for stroke and management implications based on recent evidence, along with characterization of schemes for antithrombotic management of patients with atrial fibrillation are reviewed.

Antithrombotic Secondary Prevention After Stroke

In patients with transient ischemic attack (TIA) or ischemic stroke of noncardiac origin, antiplatelet drugs are able to decrease the risk of stroke by 11% to 15%, and decrease the risk of stroke, myocardial infarction (MI), and vascular death by 15% to 22%. Aspirin leads to a moderate but significant reduction of stroke, MI, and vascular death in patients with TIA and ischemic stroke. Low doses are as effective as high doses, but are better tolerated in term of gastrointestinal side effects. The recommended aspirin dose, therefore, is between 50 and 325 mg. Bleeding complications are not dose-dependent, and also occur with the lowest doses. The combination of aspirin (25 mg twice daily) with slow release dipyridamole (200 mg twice daily) is superior compared with aspirin alone for stroke prevention. Ticlopidine is effective in secondary stroke prevention in patients with TIA and stroke. For some endpoints, it is superior to aspirin. Due to its side effect profile (neutropenia, thrombotic thrombocytopenic purpura ), ticlopidine should be given to patients who are intolerant of aspirin. Prospective trials have not indicated whether ticlopidine is suggested for patients who have recurrent cerebrovascular events while on aspirin. Clopidogrel has a better safety profile than ticlopidine. Although not investigated in patients with TIA, clopidogrel should also be effective in these patients assuming the same pathophysiology than in patients with stroke. Clopidogrel is second-line treatment in patients intolerant for aspirin, and first-line treatment for patients with stroke and peripheral arterial disease or MI. A frequent clinical problem is patients who are already on aspirin because of coronary heart disease or a prior cerebral ischemic event, and then suffer a first or recurrent TIA or stroke. No single clinical trial has investigated this problem. Therefore, recommendations are not evidence-based. Possible strategies include the following: continue aspirin, add dipyridamole, add clopidogrel, switch to ticlopidine or clopidogrel, or switch to anticoagulation with an International Normalized Ratio (INR) of 2.0 to 3.0. The combination of low-dose warfarin and aspirin was never studied in the secondary prevention of stroke. In patients with a cardiac source of embolism, anticoagulation is recommended with an INR of 2.0 to 3.0. At the present time, anticoagulation with an INR between 3.0 and 4.5 can not be recommended for patients with noncardiac TIA or stroke. Anticoagulation with an INR between 3.0 and 4.5 carries a high bleeding risk. Whether anticoagulation with lower INR is safe and effective is not yet known. Treatment of vascular risk factors should also be performed in secondary stroke prevention.

Antiplatelet therapy in the elderly. Aspirin, ticlopidine-clopidogrel, and GPIIb/GPIIIa antagonists

Antiplatelet agents including aspirin, dipyridamole, the thienopyridines, and the GPIIb/IIIa antagonists have collectively demonstrated their ability to have a significant impact on the incidence of recurrent MIs, strokes, and other vascular ischemic events in the geriatric population. Low-dose aspirin also seems to be effective and safe for the primary prevention of ischemic heart disease in men considered at high risk. There is no evidence that the recommendations from these studies had increased relevance to younger adults, and the studies considering age as a variable found antiplatelet agents had either similar or increased benefit in older patients. In view of the relatively reduced adverse effects of these agents when compared with their potential therapeutic benefit, it is important that they be considered in all older patients for secondary prevention and in certain high-risk groups for primary prevention of cardiovascular morbidity and mortality.

Stroke prevention: anti-platelet and anti-thrombolytic therapy

In patients with TIA or ischemic stroke of noncardiac origin antiplatelet drugs are able to decrease the risk of stroke by 11-15%, and the risk of stroke, MI, and vascular death by 15-22%, but not mortality. Low doses of aspirin (50-325 mg) are as effective as high doses and cause less gastrointestinal side effects. Severe bleeding complications are not dose-dependent. The combination of aspirin with slow release dipyridamole is superior to aspirin alone for stroke prevention. Ticlopidine is superior to aspirin but has slightly more serious adverse effects (neutropenia). It will be replaced by clopidgrel which has a better safety profile. Anticoagulation with an INR between 3.0 and 4.5 is too dangerous. Whether anticoagulation with lower INR is safe and effective is not yet known.

Second Copenhagen Atrial Fibrillation, Aspirin, and Anticoagulant Therapy Study (AFASAK 2): Methods and Design

Background: Seven randomized trials have demonstrated that anticoagulant therapy is effective for primary and secondary prevention of stroke and other thromboembolic events in patients with chronic nonvalvular atrial fibrillation. The effect of aspirin is still not clarified. Conventional anticoagulant therapy is inconvenient as a primary preventive therapy as it requires frequent blood tests and implies a risk of bleeding complications. Purpose and methods: The Second Copenhagen Atrial Fibrillation, Aspirin and Anticoagulant Therapy Study (The AFASAK 2 study) is a randomized, one center, primary prevention trial. Its purpose is to investigate the effect of four antithrombotic regimens in patients with atrial fibrillation (1) fixed dose warfarin 1.25 mg per day, (2) a combination of warfarin 1.25 mg per day and aspirin 300 mg per day, (3) aspirin 300 mg per day, and (4) conventional warfarin therapy (INR 2.0-3.0). The primary endpoint is a stroke or a thromboembolic event in viscera or extremities. Secondary endpoints are transient ischemic attack, myocardial infarction, or death. The study will evaluate outcome events on intention-to-treat principles. The rate of bleeding complications is evaluated. The aim is to obtain an antithrombotic therapy for patients with nonvalvular atrial fibrillation that is effective, safe, easy to administer, and inexpensive. The methods and design of the study are presented in this paper.

Antiplatelet therapy. Aspirin, ticlopidine/clopidogrel, and anti-integrin agents

Aspirin is the most widely employed antithrombotic agent in use today and has a proven role in the prevention and acute management of atherosclerosis-associated arterial thrombotic events. More recently developed antiplatelet agents have been found to have specific prophylactic roles associated with percutaneous coronary intervention and other clinical settings. This article outlines pharmacologic considerations and current clinical knowledge relevant to the use of aspirin, ticlopidine, clopidogrel, and the GPIIbIIIa antagonists in the management of thrombotic disorders.

Eversion versus conventional carotid endarterectomy: a prospective study

OBJECTIVES

To analyse comparatively eversion and conventional CEA for later association with restenosis, perioperative stroke/death and ipsilateral cerebrovascular events (early, late, disabling and non-disabling).

DESIGN

Prospective non-randomised clinical study.

MATERIALS AND METHODS

A total of 469 patients underwent 514 procedures; 274 (53%) eversion CEA and 240 (47%) conventional CEA. Perioperative monitoring was carried out by clinical evaluation under local anaesthesia or by transcranial Doppler under general anaesthesia. Follow-up was carried out by clinical evaluation and Duplex scanning.

RESULTS

Clamping time was significantly shorter in the eversion group (25.5 +/- 7.4 vs. 28.3 +/- 10.1 min; p = 0.0001; CI delta 4.40/1.12). The perioperative disabling stroke/death rate was 0.7% for eversion vs. 1.2% for conventional CEA, p = 0.6; odds ratio (OR), 0.58. There were two early carotid occlusions (within 30 days) in both groups. According to life-table analysis, after 3 years the probability of > 50% carotid restenosis was significantly lower in the eversion group (2.2% vs. 6.9%, p = 0.03; relative risk reduction 67%). There were no significant differences between the two groups relative to new cerebrovascular events (92% in both groups, p = 0.6). Using multivariate analysis (Cox regression), eversion CEA, and to a lesser extent standard CEA with patch, appeared to protect the vessel from restenosis.

CONCLUSIONS

The eversion technique was associated with reduced clamping time and probability of restenosis. However, because of the nature of a non-randomised study, the present analysis should be confirmed by a multicentre randomised trial.

Atrial fibrillation with left atrial spontaneous contrast detected by transesophageal echocardiography is a potent risk factor for stroke

Nonrheumatic atrial fibrillation (AF) frequently coexists with other risk factors for cerebral ischemia. This study was originally designed to determine which combinations of clinical and echocardiographic abnormalities were most closely associated with the risk of cerebral ischemic events. Patients with cerebral ischemic events (n = 214) and community-based control subjects (n = 201) underwent transesophageal echocardiography and carotid artery imaging. Adjusted odds ratios (ORs) were determined using multiple logistic regression analysis. Independent risk factors for cerebral ischemia included diabetes, carotid stenosis, aortic sclerosis, left ventricular dysfunction, left ventricular hypertrophy, left atrial (LA) spontaneous contrast, and proximal aortic atheroma. Nonrheumatic AF in combination with LA spontaneous contrast and LA enlargement showed a strong association with cerebral ischemic events (OR 33.7 [95% confidence interval 4.53 to 251]). In subjects with sinus rhythm or nonrheumatic AF, LA enlargement was not associated with an increased risk of cerebral ischemic events in the absence of LA spontaneous contrast. However, only 2 patients and 1 control subject had nonrheumatic AF without LA spontaneous contrast or LA enlargement. Therefore, study of a larger number of subjects is required to address the issue of whether nonrheumatic AF itself carries increased risk. The combination of nonrheumatic AF with LA spontaneous contrast is a potent risk factor for cerebral ischemia. Ascertaining the risk factor in nonrheumatic AF requires adequate examination for underlying cardiac, aortic, and carotid vascular disease. Transesophageal echocardiography may contribute to this assessment.

Management of atrial fibrillation in adults: prevention of thromboembolism and symptomatic treatment

Because of its prevalence in the population and its associated underlying diseases and morbidity, atrial fibrillation (AF) is an important and costly health problem. Advancing age, diabetes, heart failure, valvular disease, hypertension, and myocardial infarction predict the occurrence of AF within a population. The management of AF is complex and involves prevention of thromboembolic complications and treatment of arrhythmia-related symptoms. Stroke occurs in 4.5% of untreated patients with AF per year. Independent risk factors for stroke in nonrheumatic patients with AF are advanced age; a history of prior embolism, hypertension, or diabetes; and echocardiographic findings of left atrial enlargement and left ventricular dysfunction. Warfarin decreases stroke by two-thirds and death by one-third; aspirin is only about half as effective overall and is insufficient therapy for those with risk factors for stroke. Options for thromboembolic prophylaxis are use of warfarin for all in whom it is safe or, alternatively, warfarin for those with risk factors and aspirin for those without risk factors. One-half of the patients with AF are 75 years of age or older. The uniform applicability and relative safety of warfarin therapy in this age-group are controversial. Specific therapy for the arrhythmia should be dictated by the need to control symptoms. Symptomatic treatments include rate-control medications and strategies designed to terminate and prevent arrhythmia recurrence. Digoxin, beta-adrenergic blockers, verapamil, and diltiazem slow excessive ventricular rates in patients with AF and may favorably manage comorbid conditions. The efficacy of anti-arrhythmic medications is only 40 to 70% per year in preventing recurrences of AF, and these agents, except amiodarone, may increase the risk of sudden death in patients with certain types of organic heart disease and AF. The use of nonpharmacologic symptomatic therapies such as atrioventricular node modification or ablation with a rate-response pacemaker or surgical intervention is increasing.

Appendage obliteration to reduce stroke in cardiac surgical patients with atrial fibrillation

BACKGROUND

Left atrial appendage obliteration was historically ineffective for the prevention of postoperative stroke in patients with rheumatic atrial fibrillation who underwent operative mitral valvotomy. It is, however, a routine part of modern "curative" operations for nonrheumatic atrial fibrillation, such as the maze and corridor procedures.

METHODS

To assess the potential of left atrial appendage obliteration to prevent stroke in nonrheumatic atrial fibrillation patients, we reviewed previous reports that identified the etiology of atrial fibrillation and evaluated the presence and location of left atrial thrombus by transesophageal echocardiography, autopsy, or operation.

RESULTS

Twenty-three separate studies were reviewed, and 446 of 3,504 (13%) rheumatic atrial fibrillation patients, and 222 of 1,288 (17%) nonrheumatic atrial fibrillation patients had a documented left atrial thrombus. Anticoagulation status was variable and not controlled for. Thrombi were localized to, or were present in the left atrial appendage and extended into the left atrial cavity in 254 of 446 (57%) of patients with rheumatic atrial fibrillation. In contrast, 201 of 222 (91%) of nonrheumatic atrial fibrillation-related left atrial thrombi were isolated to, or originated in the left atrial appendage (p < 0.0001).

CONCLUSIONS

These data suggest that left atrial appendage obliteration is a strategy of potential value for stroke prophylaxis in nonrheumatic atrial fibrillation.