Left atrial appendage size in patients with atrial fibrillation in Japan and the United States

Prognostic impact of increase in left atrial volume following left atrial appendage closure: Insights from the OCEAN-LAAC registry

Background

Percutaneous left atrial appendage closure (LAAC) is an effective therapy to prevent thromboembolic events among patients with atrial fibrillation (AF). However, since the left atrial appendage (LAA) contributes to left atrial volume and serves as a buffer for increasing left atrial pressure, this procedure may impair left atrium (LA) compliance, enlarge LA, and deteriorate diastolic function. In this study, we sought to investigate the change in left atrial volume index (LAVI) following LAAC and its effect on prognosis.

Methods and Results

We analyzed 225 patients from the OCEAN-LAAC registry, an ongoing, multicenter Japanese study. Comparing LAVI measurements at baseline and 6 months after LAAC, no significant increase was observed (55.0 [44.0, 70.0] ml/m2 vs. 55.0 [42.0, 75.6] ml/m2; P = 0.31). However, some patients underwent LAVI increase. Particularly, a smaller LAVI (odds ratio [OR]: 0.98 [95 % confidence interval (CI): 0.97-0.996]) and elevated tricuspid regurgitation pressure (TRPG) at baseline (OR: 1.04 [95 % CI: 1.00 - 1.08]) were significantly related to the increase in LAVI at 6-month follow-up. In addition, a 5 ml/m2 increase in LAVI was significantly associated with subsequent heart failure hospitalization (HFH) (hazard ratio: 3.37 [95 % CI: 1.18-9.65]). This association, however, was not observed in patients with lower baseline LAVI (≤55 ml/m2) but was only seen in those with a baseline LAVI over 55 ml/m2.

Conclusion

Our study demonstrated an increase in LAVI after LAAC was related to smaller LAVI or elevated TRPG at baseline. The LAVI increase was significantly associated with subsequent HFH.

Transition from WATCHMAN generation-2.5 device to WATCHMAN FLX device for percutaneous left atrial appendage closure: Incidence and predictors of device-related thrombosis and short- to mid-term outcomes

BACKGROUND

Patients with nonvalvular atrial fibrillation (AF) not suitable for long-term anticoagulant therapy undergo percutaneous left atrial appendage closure (LAAC) using the WATCHMAN device. The safety and efficacy of WATCHMAN-FLX (WM-FLX) compared with WATCHMAN-2.5 (WM-2.5), particularly in Asian populations, is unknown.

METHODS

We evaluated the background, procedure, and clinical outcomes of 199 patients who underwent LAAC between September 2019 and December 2022 and compared WM-2.5 (72 patients) with WM-FLX (127 patients).

RESULTS

The mean age was 76 years, with 128 men, and 100 had nonparoxysmal AF (non-PAF). The mean CHA2DS2-VASc, and HAS-BLED were 5.1, and 3.2 points, respectively. WM-FLX group demonstrated a shorter procedure time than WM-2.5 group (50 vs. 42 min, p = 0.001). The WM-FLX group demonstrated no procedural-related acute cardiac tamponade, which was significantly low (5.6% vs. 0%, p = 0.02), and a significantly higher rate of complete seal at 45-day (63% vs. 80%, p = 0.04). WM-FLX group had a significantly higher cumulative 1-year incidence of device-related thrombosis (DRT) than WM-2.5 group (3.4% vs. 7.0%, Log-rank p = 0.01). Univariate analysis identified two DRT risk factors in the WM-FLX group: non-PAF (odds ratio [OR] 7.72; 95% confidence interval [CI] 1.20-48.7; p = 0.04), and 35-mm device (OR 5.13; 95% CI 1.31-19.8; p = 0.02).

CONCLUSIONS

WM-FLX significantly improved the procedural quality and safety of LAAC. However, DRT remains an important issue even in the novel LAAC device, being a hazard for patients with high DRT risk, such as having non-PAF and using 35-mm devices.

Left Atrial Thrombus-Are All Atria and Appendages Equal?

Although the left atrial appendage (LAA) seems useless, it has several critical functions that are not fully known yet, such as the causes for being the main origin of cardioembolic stroke. Difficulties arise due to the extreme range of LAA morphologic variability, making the definition of normality challenging and hampering the stratification of thrombotic risk. Furthermore, obtaining quantitative metrics of its anatomy and function from patient data is not straightforward. A multimodality imaging approach, using advanced computational tools for their analysis, allows a complete characterization of the LAA to individualize medical decisions related to left atrial thrombosis patients.

Initial Japanese Multicenter Experience and Age-Related Outcomes Following Left Atrial Appendage Closure: The OCEAN-LAAC Registry

Background

Limited data are available describing left atrial appendage closure (LAAC) and age-related outcomes in Asians.

Objectives

This study summarizes the initial experience with LAAC in Japan and determines age-related clinical outcomes in patients with nonvalvular atrial fibrillation undergoing percutaneous LAAC.

Methods

In an ongoing, prospective, investigator-initiated, multicenter, observational registry of patients undergoing LAAC in Japan, we analyzed short-term clinical outcomes in patients with nonvalvular atrial fibrillation who underwent LAAC. Patients were classified into younger, middle-aged, and elderly groups (≤70, 70 to 80, and >80 years of age, respectively) to determine age-related outcomes.

Results

Patients (n = 548; mean age, 76.4 ± 8.1 years; male, 70.3%) who underwent LAAC at 19 Japanese centers between September 2019 and June 2021 were enrolled in the study, including 104, 271, and 173 patients in the younger, middle-aged, and elderly groups, respectively. Participants had a high-risk of bleeding and thromboembolism with a mean CHADS2 score of 3.1 ± 1.3, a mean CHA2DS2-VASc score of 4.7 ± 1.5, and a mean HAS-BLED score of 3.2 ± 1.0. Device success rates were 96.5% and anticoagulants discontinuation at the 45-day follow-up was achieved in 89.9%. In-hospital outcomes were not significantly different, but major bleeding events during the 45-day follow-up were significantly higher in the elderly group compared to the other groups (younger vs middle-aged vs elderly, 1.0% vs 3.7% vs 6.9%, respectively; P = 0.047) despite the same postoperative drug regimens.

Conclusions

The initial Japanese experience with LAAC demonstrated safety and efficacy; however, perioperative bleeding events were more common in the elderly and postoperative drug regimens must be tailored (OCEAN-LAAC [Optimized Catheter Valvular Intervention-Left Atrial Appendage Closure] registry; UMIN000038498).

Left atrial appendage filling defects restricted to the early phase of cardiac computed tomography is significantly associated with ischemic stroke

PURPOSE

To investigate the relationship between filling defects in the left atrial appendage restricted to the early phase of cardiac computed tomography (CCT), and ischemic stroke in patients with atrial fibrillation (AF).

MATERIALS AND METHODS

A total of 152 patients with non-valvular AF were retrospectively enrolled and divided into two groups according to the stroke history, as confirmed by brain computed tomography (CT) or magnetic resonance imaging (MRI), as the non-stroke group (n = 89) and stroke group (n = 63), respectively. The numbers of patients with filling defects in the early phase of CCT images without thrombi were recorded. Morphological parameters of the LAA were measured for all participants. All patients with early-phase filling defects (n = 44) were assigned to two groups according to ischemic stroke history: the filling defects with stroke group (n = 28) and the filling defects without stroke group (n = 16). The clinical characteristics and LAA morphological parameters were compared.

RESULTS

Univariate analysis showed that compared with the non-stroke group，LAA volume index and age were higher in the stroke group, and the ratio of early phase filling defect in LAA, hypertension and diabetes were also higher, in the meanwhile the LVEF and BMI were lower (P < 0.05).After adjusting confounding factors by the multivariate logistic regression analysis, filling defect was significantly related with stroke [odds ratio (OR): 4.339, 95% confidence interval (CI): 1.951-9.653, P = 0.000]. LAA morphological parameters were not significantly different between the filling defects with stroke group and the group without stroke.

CONCLUSION

AF patients with LAA non-thrombotic filling defects in the early-phase of CCT had an increased risk of ischemic stroke compared to those without filling defects. This finding may help to optimize stroke risk stratification in patients with AF.

Left atrial appendage closure for stroke prevention in nonvalvular atrial fibrillation: A current overview

Atrial fibrillation (AF) is the most common arrhythmia encountered in clinical practice and its prevalence increases with age. AF causes palpitations, heart failure, and cardiogenic embolism. Of them, the most critical and fatal complication is a cardio-embolic event. Oral anticoagulation plays a central role in reducing stroke risk in AF patients. Recently, when oral anticoagulation is considered in patients with non-valvular AF who are eligible for direct oral coagulations, they are preferred to vitamin K antagonist based on accumulating evidence. Although many patients can tolerate oral anticoagulation, there is a subset of patients who cannot tolerate long-term oral anticoagulation. Such a subset has a higher bleeding risk as indicated by the HAS-BLED score under oral anticoagulation. This subset of patients requires effective and safe non-pharmacological alternative therapies for stroke prevention. One of the promising non-pharmacological therapies is left atrial appendage closure. Three randomized controlled trials demonstrated non-inferiority of percutaneous left atrial appendage closure using WATCHMAN family to oral anticoagulation (Boston Scientific, Marlborough, MA, USA). WATCHMAN FLX, which was innovated following WATCHMAN 2.5, was associated with fewer safety events and a higher success rate of effective appendage closure. Nevertheless, several unsolved issues remain, including device-related thrombosis, post-treatment antithrombotic therapy, and peri-device leakage. Left atrial appendage closure for patients with non-valvular AF may be an alternative therapy to avoid cardiac embolism for high bleeding risk patients with contraindications to long-term oral anticoagulation therapy.

Clinical Characteristics of Non-Valvular Atrial Fibrillation Patients With a Large Left Atrial Appendage Ostium-Limiting Percutaneous Closure

BACKGROUND

The left atrial appendage (LAA) is a therapeutic target for preventing cardioembolic stroke in patients with non-valvular atrial fibrillation (NVAF). A large LAA ostium limits percutaneous LAA closure. This study investigated the characteristics and factors associated with a large LAA ostium in Japanese patients with NVAF.

METHODS AND RESULTS

In 1,102 NVAF patients, the maximum LAA diameter was measured using transesophageal echocardiography (TEE). A large LAA ostium was defined by a maximum diameter of >30 mm. Forty-four participants underwent repeated TEEs, and changes in LAA size under lasting AF were assessed. A large LAA ostium was observed in 3.1% of all participants and 8.9% of patients with long-standing persistent AF (LSAF). The large LAA group had greater CHA2DS2-VASc (P=0.024) and HAS-BLED scores (P=0.046) and a higher prevalence of LAA thrombus (P=0.004) than did the normal LAA group. LSAF, moderate or severe mitral regurgitation, left atrial volume ≥42 mL/m2, E/E' ratio ≥9.5, and left ventricular mass ≥85 mg/m2were independently associated with a large LAA ostium (P<0.001, P<0.001, P=0.009, P=0.009, and P=0.032, respectively). In 44 patients with lasting AF, the LAA ostial diameter increased over time (P<0.001).

CONCLUSIONS

NVAF patients with a large LAA ostium may have a higher risk of stroke and bleeding. LSAF and factors leading to LA overload may be closely associated with LAA ostial dilatation and can promote it.

Left Atrial Thrombus-Are All Atria and Appendages Equal?

Although the left atrial appendage (LAA) seems useless, it has several critical functions that are not fully known yet, such as the causes for being the main origin of cardioembolic stroke. Difficulties arise due to the extreme range of LAA morphologic variability, making the definition of normality challenging and hampering the stratification of thrombotic risk. Furthermore, obtaining quantitative metrics of its anatomy and function from patient data is not straightforward. A multimodality imaging approach, using advanced computational tools for their analysis, allows a complete characterization of the LAA to individualize medical decisions related to left atrial thrombosis patients.

Computed tomography findings associated with the reduction in left atrial appendage flow velocity in patients with atrial fibrillation

The reduction in flow velocity within the left atrial appendage (LAAFV) is associated with a high risk of thromboembolic events. There has been few reports using sufficient sample size about the relationship between LAAFV reduction and LAA features on cardiac computed tomography (CT), including LAA volume and filling defects, in patients with atrial fibrillation (AF). We evaluated the predictors of reduced flow velocity within the LAA using the findings of cardiac CT in patients with AF. We retrospectively analysed the cardiac CT findings of the LAA of 440 patients who underwent transoesophageal echocardiography prior to pulmonary vein isolation between 12 February, 2013 and 16 December, 2019 at our institution. We investigated the potential predictors of reduced LAAFV and the difference in LAAFV between the different morphological types of the LAA. The reduced flow velocity within the LAA was significantly correlated with higher CHADS₂ scores [P = 0.001; odds ratio (OR), 1.52; 95% confidence interval (CI), 1.18-1.95], early filling defect in the LAA (P = 0.001; OR, 3.36; 95% CI 1.63-6.93), and increased indexed LAA volume (P = 0.036; OR, 1.09; 95% CI 1.01-1.19). The LAA morphological type and AF type were not significant predictors of the LAAFV reduction. Increased LAA volume, early filling defects in the LAA, and higher CHADS₂ scores were independent predictors of LAAFV reduction in patients with AF. Our findings suggest that cardiac CT findings might allow non-invasive estimation of reduced LAAFV. These CT-derived parameters may provide additional information for the risk stratification and management of thromboembolic events in patients with AF.