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The WATCHMAN Left Atrial Appendage Closure Device for Atrial Fibrillation
Published on: February 28, 2012
Predictors of left atrium appendage clot detection despite on-target warfarin prevention for atrial fibrillation
F Zoppo1, G Brandolino, A Berton
1Dipartimento di Cardiologia, Ospedale Civile Mirano (Venezia), Mirano, Italy. francozoppo@vodafone.it
Insights
In atrial fibrillation patients on warfarin, a 2.3% prevalence of left atrial (LA) thrombus was found. Larger LA size and higher CHA2DS2-VASc scores predicted clot detection, even with therapeutic anticoagulation.
Area of Science:
- Cardiology
- Internal Medicine
- Vascular Medicine
Background:
- Antithrombotic management for atrial fibrillation (AF) relies on clinical scores like CHADS(2) and CHA(2)DS(2)VASc.
- Left atrial (LA) thrombi occur in up to 7.7% of effectively anticoagulated AF patients.
Purpose of the Study:
- To correlate left atrial/left atrial appendage (LA/LAA) thrombus detection with clinical predictors in warfarin-treated patients.
- To investigate the prevalence of LA thrombi despite therapeutic oral anticoagulant (OAC) therapy.
Main Methods:
- Trans-esophageal echocardiography was performed on 430 patients receiving OAC therapy for AF.
- Patients were undergoing pulmonary vein isolation, with a mean age of 60.3 years.
Main Results:
- A 2.3% prevalence of LA thrombus was detected despite therapeutic warfarin (mean INR 2.6).
- Patients with LAA thrombus had higher CHADS(2) scores, lower LVEF, and larger LA size (diameter and normalized volume).
- Multivariate analysis identified larger LA diameter, normalized LA volume, and higher CHA(2)DS(2)VASc score as predictors of LAA thrombus. Spontaneous echo-contrast (SEC) was found in 9.8% of patients, bringing the cumulative incidence of thrombi or SEC to 12.1%.
Conclusions:
- A 2.3% prevalence of LA thrombus was observed, rising to 12.1% when considering SEC, despite on-target warfarin therapy.
- Larger LA size and higher CHA(2)DS(2)VASc scores are strong predictors of clot detection in AF patients.
- These findings highlight the need for careful risk assessment and potentially improved anticoagulation strategies in select AF patients.
Background And Purpose:
The antithrombotic management of atrial fibrillation (AF) is currently based on clinical scores (CHADS(2) or CHA(2)DS(2)VASc). The prevalence of left atrium (LA) thrombi in effectively anticoagulated AF patients has been reported as being up to 7.7 %. We tried to correlate LA/LA appendage (LAA) thrombus detection with possible clinical predictors in warfarin-treated patients.
Methods:
We performed trans-esophageal echocardiography on 430 patients (mean age, 60.3 ± 9.8 years) receiving oral anticoagulant (OAC) therapy and undergoing pulmonary vein isolation. In 10/430 (2.3 %), an LA thrombus was found despite therapeutic OAC (mean INR 2.6 ± 0.6; range, 2.0-3.8) over the previous 4 weeks.
Results:
Two study groups were identified: 1. T-positive group = with LAA thrombus (10 patients) 2. T-negative group = without LAA thrombus (420 patients) The T-positive patients had a higher CHADS(2) score (1.5 ± 0.7 versus 0.7 ± 0.8; p = 0.004), a lower LVEF (54.7 ± 9.5 % versus 60.2 ± 7.4; p = 0.02), and a larger LA size (LA diameter, 56 ± 12.2 mm versus 46 ± 6.5 mm; p < 0.001and normalized LA volume: 140.2 ± 66 ml/m² vs. 67 ± 39 ml/m²; p < 0.05). On multivariate analysis, a larger LA diameter and normalized LA volume (OR, 1.14; 95 % C.I., 1.04-1.26; p = 0.006 and OR, 1.02; 95 % C.I., 1.01-1.03; p = 0.001, respectively) and a higher CHA(2)DS(2)VASc score (OR, 2.4; 95 % C.I., 1.4-4.2; p = 0.001) predicted left atrium appendage (LAA) thrombus. In another 42/430 (9.8 %) patients, an LA spontaneous echo-contrast (SEC) was detected. Thus, cumulatively, 52/430 (12.1 %) patients had either LAA thrombi (10 patients) or SEC (42 patients). LA diameter continued to predict the presence of either thrombi or SEC (OR, 1.14; 95 % C.I., 1.07-1.2; p < 0.05).
Conclusions:
We found a 2.3 % prevalence of LA thrombus (12.1 % when SEC was also considered). The thrombus was present despite on-target warfarin prevention. In addition to a higher CHA(2)DS(2)VASc score, a larger LA size was a strong predictor of clot detection.
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