Novel echocardiographic indicator for potential cardioembolic stroke

Cardiac imaging after ischemic stroke : Echocardiography, CT, or MRI?

About 20–25% of all ischemic strokes are of cardioembolic etiology, with atrial fibrillation and heart failure as the most common underlying pathologies. Diagnostic work-up by noninvasive cardiac imaging is essential since it may lead to changes in therapy, e.g., in—but not exclusively—secondary stroke prevention. Echocardiography remains the cornerstone of cardiac imaging after ischemic stroke, with the combination of transthoracic and transesophageal echocardiography as gold standard thanks to their high sensitivity for many common pathologies. Transesophageal echocardiography should be considered as the initial diagnostic tool when a cardioembolic source of stroke is suspected. However, to date, there is no proven benefit of transesophageal echocardiography-related therapy changes on the main outcomes after ischemic stroke. Based on the currently available data, cardiac computed tomography and magnetic resonance imaging should be regarded as complementary methods to echocardiography, providing additional information in specific situations; however, they cannot be recommended as first-line modalities.

Trimethylamine N-oxide as a risk marker for ischemic stroke in patients with atrial fibrillation

Trimethylamine N-oxide (TMAO) is an independent risk factor of cardiovascular disease. Our objective was to explore the relation between TMAO and ischemic stroke (IS) in patients with atrial fibrillation (AF). A total of 68 patients with AF with IS and 111 ones without IS were enrolled. The plasma levels of TMAO remarkably increased in IS-AF patients (8.25 ± 1.58 µM) compared with patients with AF (2.22 ± 0.09 µM, P < 0.01). The receiver operating characteristic analysis revealed that the best cutoff value of TMAO to predict IS in patients with AF was 3.53 µM with 75.0% sensitivity and 92.8% specificity (area under the curve: 0.917, 95% confidence intervals: 0.877-0.957). Univariate and multivariate logistic regression analysis showed that TMAO was an independent predictor in IS. The level of TMAO was correlated with the CHA2DS2-VASc score. In conclusion, TMAO was an independent predictor of IS, which could potentially refine stroke stratification in patients with AF.

Association of serum uric acid and cardioembolic stroke in patients with acute ischemic stroke

BACKGROUND

Although high uric acid levels have been reported to be a risk factor for cardiovascular disease and stroke, the relationship between serum uric acid (SUA) levels and cardioembolic stroke (CES) has not been fully elucidated. In this study, we sought to investigate the relationship between the risk of CES and SUA levels. We hypothesized that SUA concentrations are associated with CES.

METHODS

We retrospectively analyzed 2350 patients with acute ischemic stroke who were admitted to the Seoul National University Hospital between 2002 and 2010. The participants were stratified into five groups according to SUA levels obtained within 24h after stroke onset. The association between SUA levels and CES was evaluated using multivariable logistic regression models.

RESULTS

Of the 2350 patients, 412 (27.7%) were classified with CES, and 1077 (72.3%) were classified with non-CES, including LAA (large artery atherosclerosis) and SVO (small vessel occlusion). Among the acute stroke patients, SUA levels were higher in those with atrial fibrillation and other cardiovascular risk factors. Compared with the non-CES patients, the CES patients were more likely to fall in the highest quintile of SUA level. Multivariate analysis revealed that the patients with SUA concentrations in the highest quintile were associated with CES (OR=2.59, 95% CI: 1.35-4.97), test for trend P<0.001. Similar results were obtained for gender-based subgroups by (in men, OR=2.34, 95% CI: 1.06-5.15 and in women OR=3.41, 95% CI: 1.15-10.07), test for trend P<0.01 and P<0.001, respectively.

CONCLUSION

SUA level is associated with the risk of CES in acute ischemic stroke patients of both sexes. Further prospective clinical trials of lowering SUA to prevent CES may be worth considering.