Atrial fibrillation: relation between clinical risk factors and transoesophageal echocardiographic risk factors for thromboembolism

Abstract

Objective: To correlate clinical risk factors for thromboembolism with transoesophageal echocardiography (TOE) markers of a thrombogenic milieu. Design: Clinical risk factors for thromboembolism and TOE markers of a thrombogenic milieu were assessed in consecutive patients with non-rheumatic atrial fibrillation. The following TOE parameters were assessed: presence of spontaneous echo contrast, thrombi, and left atrial appendage blood flow velocities. A history of hypertension, diabetes mellitus, or thromboembolic events, patient age > 65 years, and chronic heart failure were considered to be clinical risk factors for thromboembolism. Setting: Tertiary cardiac care centre. Patients: 301 consecutive patients with non-rheumatic atrial fibrillation scheduled for TOE. Results: 255 patients presented with clinical risk factors. 158 patients had reduced left atrial blood flow velocities, dense spontaneous echo contrast, or both. Logistic regression analysis showed that a reduced left ventricular ejection fraction and age > 65 years were the only independent predictors of a thrombogenic milieu (both p < 0.0001). The probability of having a thrombogenic milieu increased with the number of clinical risk factors present (p < 0.0001). 17.4% of the patients without clinical risk factors had a thrombogenic milieu whereas 41.2% of the patients presenting one or more clinical risk factors had none. Conclusion: There is a close relation between clinical risk factors and TOE markers of a thrombogenic milieu. In addition, TOE examination allows for the identification of patients with a thrombogenic milieu without clinical risk factors. N on-rheumatic atrial fibrillation (AF) is a common arrhythmia with a high prevalence in the elderly population.1 2 It is well known that AF is associated with an increased risk of ischaemic stroke. Previous studies reported event rates between 2-18% per year depending on the investigated patient population.3 Some studies have shown that the presence of clinical risk factors-arterial hypertension, diabetes mellitus, increased age, and depressed left ventricular ejection fraction (LVEF)-allows for the assessment of the thromboembolic risk in patients with AF. [4][5][6][7] Moreover, it has been shown that chronic oral anticoagulation decreases the risk of embolism in the latter patient groups. 8-11Nevertheless, thromboembolism may occur in patients without clinical risk factors. Furthermore, the individual risk of embolism may vary with different settings of clinical risk factors.4 5 The SPAF III (stroke prevention in atrial fibrillation) study showed that women older than 75 years, all patients older than 75 with a history of arterial hypertension, and patients with a blood pressure > 160 mm Hg at the time of admission, have a particularly high risk for cerebral embolism. 4 Similarly, the Atrial Fibrillation Investigators (AFI) found that patients older than 75 years and the presence of clinical risk factors indicate a substantially increased thromboembolic risk. 5 More recent studies have shown that...

Relation of left atrial blood stasis to clinical risk factors in atrial fibrillation

“…Based on TEE findings, it appears that left ventricular dysfunction correlates with dense LASEC and low LAA flow velocity [10]. In the present study, however, LVEF was preserved in patients with both chronic and paroxysmal AF.…”

“…Previous reports have shown that dense LASEC, reduced LAA flow velocity, and complex aortic plaque on TEE are independent risk factors for subsequent thromboembolic events [4,[7][8][9], and are seen frequently in NVAF patients with clinical thromboembolic risk factors [8,10]. Although an accumulation of risk factors quantified by the CHADS 2 score (an acronym for Congestive heart failure (CHF), Hypertension, Age ≥ 75, Diabetes mellitus, and prior Stroke or transient ischemic attack) has been shown to be associated with an increase in thromboembolic events [2,11], it remains unknown whether an accumulation of risk factors would be related to TEE findings.…”

Age alone is not a risk factor for left atrial thrombus in atrial fibrillation

“…This was true in both anticoagulated and non-anticoagulated patients. Our results are apparently at odds with those of Illien et al ,12 who correlated clinical and transoesophageal risk factors for thromboembolism in patients with nonvalvular AF. However, their population was on average younger and age was found to correlate not with actual thrombus presence but rather with a composite index of “thrombogenic milieu”, which included spontaneous echo contrast and LAA velocities as well, so a critical comparison between the two studies is difficult.…”

Correlation of Left Atrial Appendage Ejection Velocities with the CHADS2 and CHA2DS2‐VASc Scores

“…Previous studies have reported associations between the CHADS2/CHA2DS2‐VASc scores and TEE risk factors for thromboembolism and have evaluated the CHA2DS2‐VASc score and its association with thromboembolic events in populations . Results from those studies pointed to the assumption that LAA abnormalities could be reasonable surrogates of thromboembolic events in patients with AF.…”