The average CHADS2 score (a commonly used indicator of stroke risk) was also significantly higher among cases (mean = 2.8) than among controls (mean = 1.6). The incidence of LAA thrombi was not related to age, gender or the presence of hypertension. Thus, while age above 75 years is considered a risk factor in the CHADS2 score, there was no indication that advanced age is associated with an increased risk of LAA thrombi. Based on their findings, the Mayo researchers propose a new algorithm for predicting the presence of LAA thrombi and commensurate risk of cardioembolic stroke or TIA.
A prior stroke or TIA, permanent AF, diabetes, and AF duration longer than 48 hours would each be allocated 1 point, while the presence of SEC, congestive heart failure, and AF duration longer than one year would be allocated 2 points each. Therefore, LAA thrombi risk would be graded from 0 to 10 by this new system which has yet to receive a catchy acronym. A separate analysis showed the presence of SEC and congestive heart failure to be, by far, the most predictive of LAA thrombi (odds ratios of 9.68 and 5.12 respectively). The Mayo researchers point out that prior research has shown that if TEE detects no thrombi in the LAA the risk of a cardioembolic stroke is pretty close to zero.
Wysokinski, WE, et al. Predicting left atrial thrombi in atrial fibrillation. American Heart Journal, Vol. 159, April 2010, pp. 665-71