Relationship of warfarin versus DOACs with thrombogenic milieu in the left atrium among patients with nonvalvular atrial fibrillation.

BACKGROUND: Thrombogenic milieu (TM) within the left atrium plays a pivotal role in the pathogenesis of thromboembolic events, for which anticoagulation treatment is indicated typically on the mandatory basis. Little is known, however, about which regimen of anticoagulation, warfarin or direct oral anticoagulants (DOACs), is more likely associated with TM. We evaluated relative relationship of the two treatment options with concurrently-observed TM in patients with nonvalvular atrial fibrillation (AF) who underwent transesophageal echocardiography. METHODS: TM was defined as the presence of either left atrial spontaneous echo contrast (SEC) or thrombus, or both. To determine which regimen was more likely related to TM, we firstly compared the prevalence of TM in 208 patients taking warfarin (Warfarin group) versus 486 patients taking DOACs (DOAC group); and secondly, did the same analysis after propensity score matching. RESULTS: Warfarin group was more likely associated with TM compared with DOAC group (46% vs 29%, p < 0.001). Similar findings were observed for dense SEC (18% vs 7%, p < 0.001) and thrombus (4% vs 1%, p = 0.057). The propensity score matching (198 patients for each group), where several baseline parameters were matched including age, gender, chronicity of AF, estimated glomerular filtration rate and B-type natriuretic peptide as well as the left ventricular ejection fraction, resulted in similar findings to the original groups (TM, 47% vs 32%, p = 0.002; dense SEC, 18% vs 7%, p = 0.001; thrombus, 4% vs 1%, p = 0.047). CONCLUSIONS: This study may strengthen the data on randomized trials that DOACs are superior to warfarin in preventing thromboembolic events in nonvalvular AF patients. Further studies are required to elucidate the details behind this difference.

Pioglitazone prevents the endothelial dysfunction induced by ischemia and reperfusion in healthy subjects.

BACKGROUND: No study has investigated whether pioglitazone (an agonist of peroxisome proliferator-activated receptor gamma) protects against ischemia and reperfusion (IR)-induced endothelial dysfunction in humans. METHODS AND RESULTS: In the first crossover study, 20 volunteers were randomized to 1 week of pioglitazone (30 mg/d, postoperatively) or control (no treatment). In the second single-arm study, 15 volunteers received pioglitazone and the cyclooxygenase-2 inhibitor meloxicam for 1 week. On day 7, endothelium-dependent flow-mediated dilation (FMD) of the distal brachial artery was measured before and after IR (15 minutes of ischemia followed by 15 minutes of reperfusion in the proximal upper arm). Pre-IR brachial-artery diameter and FMD were similar across the 2 sessions (control, pioglitazone) in protocol 1 and between the 2 protocols. IR significantly blunted FMD after no treatment (pre-IR FMD: 10.2% ± 2.6%; post-IR FMD: 3.5% ± 1.9%, P < 0.01) but not after pioglitazone administration (pre-IR FMD: 9.7% ± 2.5%; post-IR FMD: 8.8% ± 2.9%, P = 0.11). This protective effect was accompanied by an increase in serum levels of the antioxidant enzyme extracellular superoxide dismutase and was not affected by concomitant administration of the cyclooxygenase-2 inhibitor meloxicam (P = 0.10). CONCLUSIONS: In humans, pioglitazone provides potent protection against IR-induced endothelial dysfunction.

Left Atrial Remodeling Related to Disproportionately Low B-Type Natriuretic Peptide in Acute Heart Failure Patients with Atrial Fibrillation.

The diagnostic performance of B-type natriuretic peptide (BNP) for acute heart failure (HF) is impaired in patients with atrial fibrillation (AF). Increased AF burden in HF is associated with left atrial (LA) remodeling. Recent studies have revealed that LA remodeling may affect LV filling. We hypothesized that LA remodeling affects BNP secretion in acute HF conditions. The study investigated the clinical impact of LA remodeling on admission BNP levels in acute HF patients with and without AF. Consecutive acute HF hospitalized patients (n = 899) were divided into groups with (n = 382) or without AF (n = 507) and subdivided into disproportionately low BNP (LB) (≤200 pg/ml), medium BNP (200 to 600 pg/ml) and high BNP (≥600 pg/ml) subgroups. The AF group had a higher proportion of patients with LB than the non-AF group (23.6% vs 16.6%, p = 0.009). BNP levels in both groups were positively correlated with LV end-diastolic volume and negatively correlated with LV ejection fraction in both groups. In contrast, BNP was positively correlated with LA volume index in the non-AF group, but negatively correlated in the AF group. The survival rates were significantly higher in the LB group than in the other groups in non-AF. Conversely, there were no significant differences across all groups in AF patients. In conclusion, in patients with acute HF and AF, disproportionately low BNP levels are associated with LA structural remodeling and poor prognosis.

Left Atrial Appendage Ostial Stenosis: A Case Report and Literature Review.

BACKGROUND Left atrial appendage (LAA) ostial stenosis is a rare cardiac condition usually identified by transesophageal echocardiography (TEE). LAA ostial stenosis can be classified into 2 types: one is idiopathic and the other is a complication after incomplete surgical LAA ligation. The former one is even rarer and only 12 cases have previously been reported. CASE REPORT An asymptomatic young woman was found at a medical checkup to have an abnormal jet signal in the left atrium on transthoracic echocardiography. TEE revealed that the abnormal signal originated from a narrowed orifice of the LAA. There were no other cardiac abnormalities in this woman. Unlike the previously reported cases, our case had LAA ostial stenosis detected by transthoracic echocardiography but not by TEE. CONCLUSIONS We describe a case of anatomic narrowing of the LAA orifice in a young woman. This was a first-ever case of idiopathic LAA ostial stenosis that was detected by transthoracic echocardiography. Because of the very small number of such cases reported, it remains unknown whether anticoagulation is required to prevent intra-atrial thrombus formation.