Elizabeth A. Lieber

Role of CHADS2 score in evaluation of thromboembolic risk and mortality in patients with atrial fibrillation undergoing direct current cardioversion (from the ACUTE Trial Substudy).

The CHADS(2) (congestive heart failure, hypertension, age >75 years, diabetes mellitus, stroke or transient ischemic attack [2 points]) scoring scheme has been found to be a good predictor of stroke risk in patients with nonvalvular atrial fibrillation (AF). However, the value of the CHADS(2) scoring system in the risk stratification of patients with AF who undergo direct-current cardioversion has not yet been specifically investigated. In this study, a subgroup of 541 patients from the Assessment of Cardioversion Using Transesophageal Echocardiography (ACUTE) study who had AF for >48 hours and planned to undergo transesophageal echocardiography before direct-current cardioversion were enrolled. Each patient had a CHADS(2) score calculated. Of the patients with CHADS(2) scores of 0, 14 (10%) were found to have left atrial appendage thrombi on transesophageal echocardiography. After 6 months of follow up, patients with CHADS(2) scores of 3 to 6 showed a significantly higher mortality rate in comparison with patients with lower CHADS(2) scores (4.3% vs 0.5%, p = 0.004), despite their similar prevalence of left atrial appendage thrombus and stroke (thrombus: 13.4% vs 11.6%, p = 0.60; stroke: 0% vs 0.3%, p = 0.70). In conclusion, the CHADS(2) scoring system may be useful for predicting short-term mortality risk in patients with AF receiving elective direct-current cardioversion. However, in the preprocedural risk assessment of these patients, the CHADS(2) scoring system is not reliable in predicting risk for left atrial appendage thrombus formation, especially in patients with low CHADS(2) scores.

Comprehensive Left Atrial Appendage Optimization of Thrombus Using Surface Echocardiography: The CLOTS Multicenter Pilot Trial

BACKGROUND The aim of this study was to determine the ability to identify thrombus within the left atrial appendage (LAA) in the setting of atrial fibrillation (AF) using transthoracic echocardiography (TTE). In AF, the structure and function of the LAA has historically been evaluated using transesophageal echocardiography (TEE). The role of TTE remains undefined. METHODS The Comprehensive Left Atrial Appendage Optimization of Thrombus (CLOTS) multicenter study enrolled 118 patients (85 men; mean age, 67 +/- 13 years) with AF of >2 days in duration undergoing clinically indicated TEE. On TEE, the LAA was evaluated for mild spontaneous echo contrast (SEC), severe SEC, sludge, or thrombus. Doppler Tissue imaging (DTI) peak S-wave and E-wave velocities of the LAA walls (anterior, posterior, and apical) were acquired on TTE. Transthoracic echocardiographic harmonic imaging (with and without intravenous contrast) was examined to determine its ability to identify LAA SEC, sludge, or thrombus. RESULTS Among the 118 patients, TEE identified 6 (5%) with LAA sludge and 2 (2%) with LAA thrombi. Both LAA thrombi were identified on TTE using harmonic imaging with contrast. Anterior, posterior, and apical LAA wall DTI velocities on TTE varied significantly among the 3 groups examined (no SEC, mild SEC, severe SEC, sludge or thrombus). An apical E velocity < or = 9.7 cm/s on TTE best identified the group of patients with severe SEC, sludge, or thrombus. An anterior S velocity < or = 5.2 cm/s on TTE best identified the group of patients with sludge or thrombus. CONCLUSIONS The CLOTS multicenter pilot trial determined that TTE is useful in the detection of thrombus using harmonic imaging combined with intravenous contrast (Optison; GE Healthcare, Milwaukee, WI). Additionally, LAA wall DTI velocities on TTE are useful in determining the severity of LAA SEC and detecting sludge or thrombus.

Comparison of Anticoagulant and Anti-Inflammatory Responses Using Enoxaparin Versus Unfractionated Heparin for Transesophageal Echocardiography-Guided Cardioversion of Atrial Fibrillation

The Assessment of Cardioversion Using Transesophageal Echocardiography (ACUTE) II study compared enoxaparin with unfractionated heparin (UFH) as bridging therapy in patients with atrial fibrillation >2 days in duration who underwent transesophageal echocardiography-guided cardioversion. In the present study, the anticoagulant and anti-inflammatory effects of enoxaparin and UFH were compared at prespecified time points. In a randomized substudy of 155 patients from 17 clinical sites, the anticoagulant activity of enoxaparin (n = 76) was compared with that of UFH (n = 79). Blood samples were drawn at enrollment, on day 2, and on day 4 in the 2 groups. Blood samples were evaluated for anticoagulant activity by measuring the activated partial thromboplastin time, anti-Xa, anti-IIa, and tissue factor pathway inhibitor levels. In addition, levels of coagulation activation (by thrombin antithrombin complex) and inflammation (by highly sensitive C-reactive protein) were measured. The results of this substudy showed that the anti-Xa levels in the 2 groups increased on day 2. Similar increases in anti-Xa were observed on day 4. The anti-Xa levels and tissue factor pathway inhibitor levels were higher in the enoxaparin group compared with the UFH group on days 2 and 4. However, as expected, the anti-IIa levels in the UFH group were higher. In addition, markers of coagulation activation and inflammation were increased in patients with atrial fibrillation. Treatment with enoxaparin significantly decreased thrombin antithrombin complex levels compared with treatment with UFH. Highly sensitive C-reactive protein levels were also decreased after treatment in the 2 groups. In conclusion, the ACUTE II study showed that the use of enoxaparin for bridging therapy in patients with atrial fibrillation who underwent transesophageal echocardiography-guided cardioversion resulted in a more predictable and stronger anticoagulant response than that observed with UFH. Markers of inflammation were also decreased in the 2 groups.

Predictive value of exercise myocardial perfusion imaging in the Medicare population: the impact of the ability to exercise

BACKGROUND Although the prognostic value of quantitative single photon emission computed tomography myocardial perfusion imaging (MPI) with exercise and pharmacologic stress is well established, the prognostic and management value in the Medicare age population is less clear. METHODS The prospectively populated Cleveland Clinic nuclear cardiology database was used to identify 5,994 consecutive pateints, age >65 years [1,664 (28%) exercise MPI, mean age 72.4±5.1, 74% male], who underwent MPI between January 2004 and January 2008. Clinical baseline variables, post test 90 days revascularization and MPI variables were analyzed. Overall and stratified nonparametric survival estimates were obtained by Kaplan-Meier method. Median follow-up time was 2.4 years. Parametric hazard modeling with bootstrap bagging methods was used to determine prognostic variables predicting mortality. RESULTS There was no difference in mortality in patients with an abnormal MPI vs. those with normal MPI. Amongst the patients who underwent exercise MPI, there were 103 (6%) deaths and 121 (8.2%) revascularizations. Only lower exercise capacity (<7 METs) and higher end systolic volume (ESV) predicted mortality. Although a larger amount of ischemia influenced down stream revascularization ischemia, revascularization of patients with an abnormal exercise MPI did not offer a survival benefit (log rank P value=0.01). CONCLUSIONS In the a Medicare age population, exercise MPI perfusion variables influenced rates of revascularization but failed to provide incremental significant risk-stratification beyond exercise capacity. Maximum METs achieved appears to be a better predictor of survival.

Health status outcomes after cardioversion for atrial fibrillation: Results from the Assessment of Cardioversion Using Transesophageal Echocardiography (ACUTE) II Trial ☆ ☆☆ ★

BACKGROUND Atrial fibrillation is the most common significant cardiac arrhythmia and substantially impacts the health status of patients. Enoxaparin has been shown to be a safe and effective alternative to unfractionated heparin for use with transesophageal echocardiography (TEE)-guided cardioversion, but the implications on health status remain unknown. The aim of the study was to compare the health status outcomes of patients who undergo TEE-guided cardioversion with enoxaparin or unfractionated heparin as anticoagulation bridging therapy. METHODS The Assessment of Cardioversion Using Transesophageal Echocardiography (ACUTE) II multicenter trial randomized 155 patients to bridging therapy with either enoxaparin or unfractionated heparin. Of these, 118 were included in the health status substudy. Health status was assessed at baseline and 5 weeks using the RAND 36-item health survey (RAND-36), the Duke Activity Status Index (DASI), and the Health Utilities Index Mark 3 (HUI-3). RESULTS There were no significant differences in the health status measures between the treatment groups. However, patients who remained in normal sinus rhythm at follow-up had absolute improvement in all measures of health status, whereas patients in atrial fibrillation at follow-up had an absolute decrease in the DASI, HUI-3, and 5 of 8 subscales of the RAND-36. These findings reached statistical significance in the HUI-3 and 3 of 8 subscales of the RAND-36. CONCLUSIONS Health status outcomes in TEE-guided cardioversion do not significantly differ between anticoagulant bridging therapy with enoxaparin or unfractionated heparin. However, maintenance of sinus rhythm at 5 weeks was associated with an improvement in health status.