Elevated fibrinogen and lowered homocysteine-vitamin determinants and their association with left atrial thrombus in patients with rheumatic mitral stenosis

Risk factors for left atrial thrombus or spontaneous echo contrast in non-valvular atrial fibrillation patients with low CHA2DS2-VASc score

OBJECTIVE

Risk factors of left atrial thrombus (LAT) or spontaneous echo contrast (LASEC) in non-valvular atrial fibrillation (NVAF) had been reported. However, information in the subgroup of NVAF patients with low CHA₂DS₂-VASc scores was limited. Here, we evaluated the risk factors of LAT/LASEC in NVAF patients with low CHA₂DS₂-VASc scores.

METHODS

Transesophageal echocardiography (TEE) file of NVAF patients with low CHA₂DS₂-VASc scores was reviewed (between June 2009 and Feb 2019) in this retrospective observational study. Binary logistic regression analysis was performed to identify risk factors other than the CHA₂DS₂-VASc score. Propensity score matching (PSM) was used to further evaluate independent risk markers for LAT/LASEC. The newly discovered factors were added to the CHA₂DS₂-VASc score, and receiver operating characteristic analysis was used to evaluate the ability of the model to predict LAT/LASEC.

RESULTS

TEE files of 3056 NVAF patients with low CHA₂DS₂-VASc scores were reviewed. Regression analysis revealed elevated fibrinogen and enlarged left atrium (LA) were risk factors for LAT/LASEC. Further PSM analysis confirmed that elevated fibrinogen and enlarged LA were independent risk factors for LAT/LASEC. After including fibrinogen and left atrial diameter (LAD), the CHA₂DS₂-VASc score was more accurate for LAT/LASEC prediction in NVAF patients with low CHA₂DS₂-VASc scores (area under the curve difference is 0.241, 95% confidence interval (CI) 0.188-0.294, Z = 8.890, P < 0.0001).

CONCLUSIONS

Elevated fibrinogen and enlarged LA were independent risk factors for LAT/LASEC in NVAF patients with low CHA₂DS₂-VASc scores. Taking fibrinogen and LAD into consideration may help improve LAT/LASEC risk evaluation, which warrants further validation studies.

[Independent risk factors of atrial thrombosis in patients with nonvalvular atrial fibrillation and low CHA2DS2-VASc scores]

OBJECTIVE

To explore the risk factors of atrial thrombosis in patients with nonvalvular atrial fibrillation(NVAF)with low CHA₂DS₂-VASc scores at admission (≤1 for male and ≤2 for female patients).

METHODS

We retrospectively analyzed the clinical data of 10 382 patients with NVAF undergoing transesophageal echocardiography in our hospital from 2009 to 2019, and enrolled 48 NVAF patients with thrombosis as the observation group and another 240 NVAF patients without thrombosis as the control group.The baseline characteristics, biochemical indicators, and echocardiographic findings of the patients were analyzed using univariate analysis, multivariate logistic regression analysis and Pearson correlation analysis.

RESULTS

The baseline data did not differ significantly between the two groups (P > 0.05).Compared with those in the control group, the patients with atrial thrombosis had an increased left atrial diameter (LAD; P < 0.001), a greater likelihood of hypertrophic cardiomyopathy (HCM; P < 0.001), significantly higher levels of C-reactive protein (CRP; P < 0.05) and uric acid (P < 0.001), and greater standard deviation of red blood cell distribution width(RDW-SD; P < 0.001).LAD(P < 0.001), HCM(P < 0.05)and CRP(P < 0.05) were identified as the independent factors affecting the occurrence of atrial thrombosis in patients with low CHA₂DS₂-VASc scores.

CONCLUSIONS

LAD enlargement, HCM, and an elevated CRP level are independent risk factors for atrial thrombosis in NVAF patients with low CHA₂DS₂-VASc scores.Active anticoagulation therapy should be administered for these patients once these risk factors are detected to prevent the occurrence of stroke.

Exchange protein directly activated by cAMP plays a critical role in regulation of vascular fibrinolysis

Plasmin-mediated fibrinolysis at the surface of vascular endothelial cells (SVEC) plays a key role in maintaining vascular hemostasis, in which the cAMP pathway participates. After externalization to the SVEC, annexin A2 (ANXA2) serves as a platform for conversion of plasminogen to plasmin. Here we describe a regulatory role of the exchange protein directly activated by cAMP (EPAC) in ANXA2 externalization and vascular fibrinolysis. Knockout of EPAC1 in mice results in a decreased ANXA2 expression on the SVEC associated with increased fibrin deposition and fibrinolytic dysfunction. Reduced levels of EPAC1 are also found in endocardial tissues beneath atrial mural thrombi in patients. Notably, administration of recombinant ANXA2 ameliorates fibrinolytic dysfunction in the EPAC1-null mice. Mechanistically, EPAC1 regulates the SVEC plasminogen conversion depended on ANXA2. EPAC1 promotes tyrosine-23 phosphorylation of ANXA2, a prerequisite for its recruitment to the SVEC. Our data thus reveal a novel regulatory role for EPAC1 in vascular fibrinolysis.