Dabigatran exhibits low intensity of left atrial spontaneous echo contrast in patients with nonvalvular atrial fibrillation as compared with warfarin

Severe Spontaneous Echocardiographic Contrast in a Patient With Normal Heart and Chronic Lymphocytic Lymphoma

•SEC can occur in a structurally and functionally normal heart. •SEC formation has a stoichiometric relationship between hematocrit and fibrinogen levels. •SEC may be underappreciated in hematologic malignancies after chemotherapy initiation.

Prognostic Implications of Left Atrial Spontaneous Echo Contrast with Catheter Ablation of Nonvalvular Atrial Fibrillation Patients with Left Atrial Dilation

Background: Left atrial spontaneous echo contrast (LASEC) can be detected by transesophageal echocardiography (TEE) before the catheter ablation of atrial fibrillation (AF), especially in patients with left atrial (LA) dilation. Whether LASEC has prognostic value in predicting the procedure outcomes in patients with an enlarged atrium is unknown. The prognostic implications of LASEC with the catheter ablation of AF patients with LA dilation will be evaluated in this study. Methods: AF patients scheduled to undergo catheter ablation in Ruijin Hospital, Shanghai, China, between January 2018 and June 2020 were screened for this prospective study. All patients underwent TEE before the procedure. Patients with a left atrial diameter (LAD; 45 mm ≤ LAD < 50 mm) and left atrial volume (LAV ≥ 120 mL) were enrolled in this study. The endpoint was AF/atrial tachycardia (AT) recurrence-free survival following a 3-month blanking period after the catheter ablation. All patients were followed up for 18 months. Results: This study included 123 AF patients, who were divided into the LASEC (n = 73) and no LASEC (n = 50) groups. Baseline patient characteristics were similar in the two groups. At the end of 18 months of follow-up, AF/AT recurrence-free survival was achieved in 33 (45.2%) and 34 (68.0%) patients in the LASEC and no LASEC groups, respectively (p = 0.013). In survival analysis, the LASEC group was also associated with a poor outcome of catheter ablation (log-rank test, p = 0.011; Cox regression, p = 0.015, HR = 2.058, 95%CI = 1.151−3.679). Meanwhile, during the follow-up AF/AT recurrence was observed in 30 (57.7%) and 15 (71.4%) cases in the mild and severe SEC groups, respectively. Ischemic stroke occurred in two patients in the LASEC group. Conclusions: LASEC could be a predictor of the recurrence of AF/AT after catheter ablation in AF patients with LA dilation. The higher the degree of LASEC, the worse the prognosis.

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.

Differences in D-dimer blood concentration in atrial fibrillation patients with left atrial thrombus or severe left atrial spontaneous echo contrast

PURPOSE

Severe left atrial spontaneous echo contrast (SLASEC) is considered the prior stage to thrombosis and a high-risk factor for thrombotic events. Studies have suggested an effect of D-dimer blood concentration on exclusion of left atrial thrombus (LAT), but it remains unclear whether D-dimer concentrations differ between atrial fibrillation (AF) patients with SLASEC or LAT.

METHODS

Nonvalvular AF patients scheduled to undergo catheter ablation or cardioversion in Shanghai Ruijin Hospital between January 2017 and July 2020 were screened for this prospective study. All patients underwent transesophageal echocardiography (TEE) to detect SLASEC or LAT. D-dimer concentrations were measured at the time of TEE. Clinical data including CHA₂DS₂-VASc score were evaluated. Major complications with thromboembolism in the SLASEC group were followed up at least 6 months after therapy.

RESULTS

Among 920 consecutively enrolled nonvalvular AF patients, 30 patients with SEC grade 0, 35 patients with SLASEC, and 22 patients with LAT were included. D-dimer concentration and CHA₂DS₂-VASc score were significantly lower in the SLASEC group compared with the LAT group (D-dimer, 0.26±0.13 vs. 0.86±0.9 mg/L, P<0.05; CHA₂DS₂-VASc score, 2.3±0.9 vs. 3.1±1.5, P=0.02). The cut-off value for D-dimer concentration (0.285 mg/L) had sensitivity of 77.3% and specificity of 80.0% for prediction of LAT. D-dimer concentration showed a decreasing trend with a significant difference (0.42±0.22 vs. 0.33±0.18 mg/L, P=0.03) for 9 patients in the LAT group after complete thrombus resolution by anticoagulation treatment. No major or fatal bleeding, ischemic stroke, or systemic thromboembolism events occurred in the SLASEC group during the 6-month follow-up.

CONCLUSIONS

This study demonstrated a significantly lower D-dimer concentration and CHA₂DS₂-VASc score in AF patients with SLASEC than in those with LAT. The D-dimer cut-off value (0.285 mg/L) can be used as an effective reference index to distinguish the pre-thrombotic state of LAT from LAT. D-dimer blood concentration may be a predictor of LAT thrombolysis.

Protracted impairment of left atrial compliance after cryoballoon ablation in recurrence-free patients with paroxysmal atrial fibrillation

The relationship between alterations in left ventricular (LV) diastolic function and the incidence of recurrence, as well as the associated factors after cryoballoon (CB) and radiofrequency (RF) catheter ablation in patients with paroxysmal atrial fibrillation (Paf), require clarification. We enrolled 138 patients with Paf (RF/CB 69/69) who underwent the first catheter ablation and follow-up for 12 months. Transthoracic echocardiography was performed before and after ablation. An afterload-integrated index of LV diastolic function was calculated as diastolic elastance (Ed)/arterial elastance (Ea), Ed/Ea. No significant increases were observed in Ed/Ea 3 days after RF ablation in patients with (n=12) and without (n=57) recurrence. However, a significant increase was observed in recurrence-free patients with CB ablation (n=59; P<0.05), although this level was restored after 6 months. Ed/Ea 3 days after CB ablation was correlated with left atrial pressure immediately after (r=0.630, P<0.001), but not before (r=0.290, P=0.159), ablation. The increment of creatine kinase- myocardial band release was positively associated with that of Ed/Ea (r=0.388, P<0.05) after CB ablation. Thus, the transient manifestation of LV diastolic dysfunction after CB ablation, evaluated by a new echocardiographic index, was observed only in recurrence-free patients with Paf. Protracted impairment of left atrial compliance due to ablation-induced myocardial injury may be related to the lack of recurrence in patients after CB ablation.

Outcome of non-vitamin K oral anticoagulants in the treatment of left atrial/left atrial appendage thrombus in patients with nonvalvular atrial fibrillation

BACKGROUND

Data comparing dabigatran with rivaroxaban regarding the resolution of left atrial/left atrial appendage (LA/LAA) thrombus in patients with nonvalvular atrial fibrillation (AF) are scarce. This study aimed to compare the efficacy and safety of dabigatran vs rivaroxaban regarding the resolution of LA/LAA thrombus in patients with nonvalvular AF.

METHODS

This retrospective study enrolled nonvalvular AF patients scheduled to undergo catheter ablation or cardioversion in Shanghai Ruijin Hospital between January 2014 and January 2019. Altogether, 34 patients with LA/LAA thrombus detected by transesophageal echocardiography (TEE) were enrolled. Among them, 12 patients were treated with dabigatran 150 mg bid and the other 22 with rivaroxaban 20 mg qd. Follow-up TEE was performed within greater than or equal to 3 weeks to less than 6 months of the initial TEE to evaluate the resolution of the LA/LAA thrombus.

RESULTS

Baseline patient characteristics were similar in the two groups. Overall, 18 patients (81.8%) in the rivaroxaban group had complete thrombus resolution after 70.3 ± 22.1 treatment days, and 10 patients (83.3%) in the dabigatran group had complete thrombus resolution after 69.3 ± 47.9 treatment days. There was no significant difference between the groups (P = .6). TEE showed that the average length, width, and area of thrombus significantly decreased in both groups after treatment, although there was no significant difference in the amount of change in these parameters between the two groups after treatment (P = .6). Undissolved thrombus in two patients in the rivaroxaban group did dissolve after switching to dabigatran.

CONCLUSIONS

The results suggest that both dabigatran and rivaroxaban are potential options for treating LA/LAA thrombus in patients with nonvalvular AF. Dabigatran could be an alternative option for the resolution of LA/LAA thrombus resistant to rivaroxaban.

Transient manifestation of left ventricular diastolic dysfunction following ablation in patients with paroxysmal atrial fibrillation

BACKGROUND

In patients with atrial fibrillation, ablation decreases left atrial (LA) compliance, which may lead to left ventricular (LV) diastolic dysfunction. We aimed to examine serial changes in LV diastolic function after 2 ablation procedures and their related factors in patients with paroxysmal atrial fibrillation (PAF).

HYPOTHESIS

LV diastolic function is different after 2 ablation procedures.

METHODS

We enrolled 132 patients with PAF (76 males, mean age 67 years; cryoballoon [CB] ablation/radiofrequency [RF] ablation 60/72) who underwent a single ablation procedure. The transthoracic echocardiographic parameters were obtained before, 3 days after, and 6 months after ablation.

RESULTS

The afterload-related index of LV diastolic function, Ed/Ea = E/e' / (0.9 × systolic blood pressure), increased significantly at 3 days after ablation, especially after CB ablation (P <0.05), although no differences were observed in age, sex, LA size, LV size, and E/e' before ablation between CB ablation and RF ablation. Creatine kinase release after ablation was significantly higher in CB ablation than in RF ablation (P <0.001). The increment of Ed/Ea after CB ablation was positively correlated with LV ejection fraction (LVEF) before ablation (r =0.416; P <0.05). The elderly (age ≥ 75 years), females, and patients with hypertension were more likely to show impaired LV diastolic function transiently after 3 days of ablation, but the diastolic index was restored to baseline level after 6 months.

CONCLUSIONS

The increased Ed/Ea after CB ablation represented transient manifestation of underlying LV diastolic dysfunction in PAF patients with preserved LVEF with older age, female sex, and a history of hypertension.

Dabigatran Therapy Resulting in the Resolution of Rivaroxaban-resistant Left Atrial Appendage Thrombi in Patients with Atrial Fibrillation

Patients with persistent atrial fibrillation (AF) and a large left atrium are at a high risk for thromboembolisms. Recently, direct oral anticoagulants (DOACs) have mainly been used for the prevention of cardiac embolisms caused by AF. Transesophageal echocardiography (TEE) is performed in order to exclude any left atrial appendage (LAA) thrombi. We herein report two cases of persistent AF, both of which were treated with rivaroxaban for more than two years. Since TEE identified mobile LAA thrombi with this treatment, we switched from rivaroxaban to the direct thrombin inhibitor dabigatran. Dabigatran resolved the LAA thrombi that had been refractory to rivaroxaban.