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Background: In atrial fibrillation (AF) patients, the left atrial appendage (LAA) is the major source of thrombi causing cardiogenic thromboembolism, including stroke. We have found a new indicator of cardiogenic stroke using cardiac computed tomography (CT). This new indicator represents another aspect of the CHADS2 clinical indicator (Congestive heart failure, Hypertension, Age of 75 years or older, Diabetes mellitus, and prior Stroke or transient ischemic attack). We assessed the hypothesis that a poor medium contrast enhancement in the left atrial appendage during the early phase of cardiac CT predicts a high risk of thrombus formation, leading to cardiogenic stroke.
Methods: We studied 147 patients with chronic AF (and without renal dysfunction) who were scheduled to undergo cardiac surgery or catheter ablation at one of two institutions. All the patients underwent cardiac CT of the LAA and were screened for a history of stroke. Three different patterns of medium contrast enhancement in the LAA were used to categorize the LAA risk: high risk, defined as an existing clear and linear border between high and low CT values during the early phase; low risk, defined as an equal enhancement during the early and late phase; and intermediate risk, defines as all other patterns not fitting the low- or high-risk patterns.
Results: The CT scans of 147 patients were analyzed (age, 69.1 ± 8.8 years; 82% men; 63% with a CHADS2 score ≥ 2). Seventy-two patients (49%) had a high-risk LAA enhancement pattern, 33 (22%) had an intermediate-risk pattern, and 42 (29%) had a low-risk pattern. Of the 147 patients, 58 (39%) had a history of ischemic stroke or TIA. The prevalence of a stroke history associated with each pattern was 58%, 27%, and 16%, respectively (P < 0.0001). After controlling for the CHADS2 score, sex, and the ejection fraction using a multivariable logistic model, the high-risk pattern was found to be significantly more likely to be associated with a stroke history (odds ratio, 4.73; 95% confidence interval, 2.2-10.1; P < 0.0001).
Conclusions: The LAA enhancement pattern observed using cardiac CT predicts the risk of stroke. This result could have a relevant impact on the anticoagulation management of patients with AF.
Poster Hall, Hall C
Sunday, March 19, 2017, 9:45 a.m.-10:30 a.m.
Session Title: Non Invasive Imaging: New Technologies
Abstract Category: 27. Non Invasive Imaging: CT/Multimodality, Angiography, and Non-CT Angiography
Presentation Number: 1292-242
- 2017 American College of Cardiology Foundation