Left Atrial Appendage Occlusion Does Not Eliminate the Need for Warfarin

Abstract

A trial fibrillation (AF) is the most common sustained heart rhythm disorder. It is increasing in incidence, which has major societal implications for our aging population. [1][2][3] It is estimated to affect 1% to 1.5% of the developed world, and the incidence increases with age to a rate of 19.2 per 1000 patient-years in those 65 years of age and older. The most important aspect of the treatment of patients with AF is the prevention of stroke. The average annual stroke rate across risk groups is 5%, and AF-associated strokes confer worse outcomes than those occurring in the absence of AF. 1,4 Furthermore, Stroke Prevention in Nonrheumatic Atrial Fibrillation (SPINAF) data suggest that 15% of patients with AF suffer silent cerebral infarctions on computed tomography, the implications of which are unknown. 5 Response by Holmes and Schwartz on p 1932Oral anticoagulant (OAC) therapy with warfarin has been established as the standard for stroke prevention in patients with AF and more than 1 risk factor for stroke. 6 Hart et al have summarized this literature in meta-analyses that include 29 trials and 28 044 patients. 7,8 Compared with placebo, warfarin reduced the rate of stroke by 64% (95% confidence interval [CI], 49% to 74%), and in trials of warfarin versus antiplatelet, warfarin reduced the rate of stroke by 37% (95% CI, 23% to 48%). This is a large treatment effect when compared with other drug therapies in cardiovascular medicine. Further, even with an absolute risk increase in intracerebral hemorrhage and major hemorrhage of 0.2% per year over antiplatelet therapy, warfarin still produces a statistically significant 26% reduction in overall mortality compared with placebo. 7 Despite its demonstrated benefit, warfarin therapy is administered to as few as 25% of patients with AF and only to 70% of patients who are considered to be "ideal" candidates for warfarin. 9 -15 In the Canadian Cardiovascular Outcomes Research Team AF study, using prescription claims databases in Alberta, British Columbia, and Ontario from 1997 to 2000 (pre-AFFIRM [Atrial Fibrillation Follow-up Investigation of Rhythm Management] trial), less than one half of patients with AF filled a prescription for warfarin within 90 days of discharge for an AF hospitalization. 13 Also concerning is the rate of warfarin discontinuation, which has been documented in the the Fibrillation Registry Assessing Costs, Therapies, Adverse events and Lifestyle (FRACTAL) as 20% over a 2.5-year period. 14 Many patient, prescriber, and system barriers have been identified. However, the main limitation of warfarin is concern about bleeding, and this often prevents its use in potentially suitable patients. 16,17 In study patients assigned to warfarin therapy, it has been noted that patients are in the therapeutic range on only 50% to 68% of monitored days. 18 The relationship between international normalized ratio (INR) and outcomes has been well documented: that low INR results in an increased risk of stroke and high INR is associated with increased risk of ble...

Evaluation of the Left Atrial Appendage With Real-Time 3-Dimensional Transesophageal Echocardiography

“…It has been postulated that residual leaks may be a risk for thrombi formation and embolic events in patients with partially occluded LAAs, therefore leading to the need of continued anticoagulation therapy. 28,29 This suggests that among AF patients with nondilated and elliptical LAA orifice, devices may need to be elliptical to adequately occlude the LAA orifice.…”

Predictors of early and late stroke following cardiac surgery

“…With this information, clinicians could optimize medical therapy for stroke risk factors such as hypertension, 10,11 improve the evidence-based use of oral anticoagulation in patients with atrial fibrillation and evaluate intraoperative surgical strategies (e.g., removal of the left atrial appendage 12 ) in patients whose clinical characteristics predict an increased risk of stroke. We examined the rate and predictors of long-term stroke within 2 years after cardiac surgery.…”

Interventional Closure of the Left Atrial Appendage for Stroke Prevention

“…Whitlock et al suggested a local approach might be insufficient to prevent the systemic prothrombotic state, which increases the chance of thrombosis and embolism from multiple sources in addition to the LAA, such as the aorta, the LV and the cerebral vasculature. 29 Because the efficacy of LAA closure for stroke prevention in AF will depend on the patient's background, clinicians have to evaluate LV function, presence of patent foramen ovale, disorders of coagulation, or underlying disease that could lead to atherosclerotic changes and modification of the bleeding risk. However, this new technique is an emerging and viable clinical strategy for stroke prevention in AF patients, and should be considered as an alternative for patients who have contraindications for, or have been ineffectively treated with, OACs.…”