Left Atrial Appendage Parameters Assessed by Real-Time Three-Dimensional Transesophageal Echocardiography Predict Thromboembolic Risk in Patients With Nonvalvular Atrial Fibrillation

Efficiency of optimal fluoroscopic projection angle defined by computed tomography angiography for left atrial appendage closure

BACKGROUND

Left atrial appendage (LAA) closure (LAAC) procedures are conventionally performed using empirical fluoroscopic viewing angles. However, because the LAA is a highly variable anatomical structure, these angles cannot depict the LAA in the optimal position. The present study aimed to assess the efficiency of using a novel optimal fluoroscopic projection angle (OPA) for LAAC and to validate its feasibility.

METHODS

The OPAs of the derivation cohort were acquired using cardiac computed tomography angiography (CCTA) to assess its superiority for depicting LAA depth versus traditional working angles (TAs) of RAO 30°, CAU 20°. The practicability of OPA-guided LAAC was demonstrated by comparison between clinical data from the validation cohort and those from a propensity-score matched (PSM) control group, as well as randomized controlled studies investigating LAAC.

RESULTS

Of 705 patients in the derivation cohort, the median OPA was RAO 46°, CAU 31°. Compared with TA, the OPA depicted a longer mean (±SD) LAA depth (5.1 ± 4.4) mm and a larger orifice diameter (1.1 ± 1.1 mm), (P < 0.0001 for both). All 38 OPA-guided LAACs were successful, with a shorter mean procedure duration (42.9 ± 12.3 min versus [vs.] 107.2 ± 41.5 min; P < 0.0001) and reduced device consumption (1.08 vs. 1.5 per case), compared with the PSM control group. At the 3-month follow-up, the incidence of peri-device leak was 52.6% (20/38) detected by CCTA, with a mean leakage of 1.6 ± 0.8 mm.

CONCLUSION

By unfolding the LAA depth and orifice diameter for a better view, OPA demonstrated the potential to optimize LAAC procedural efficiency, although further larger-scale studies are required to confirm this.

Finding low CHA2DS2-VASc scores unreliable? Why not give morphological and hemodynamic methods a try?

Patients with atrial fibrillation (AF) suffer from a high risk of thrombosis. Currently, the CHA2DS2-VASc score is the most widely used tool for risk stratification in patients with AF, but it has disappointing accuracy and limited predictive value, especially in those with low scores. Thrombi in patients with AF mostly grow in their left atrial appendages (LAA), which is directly related to the abnormal morphology of the LAA or the left atrium and the unusual hemodynamic state around LAA, which may sensitively evaluate the risk of thrombosis complications in patients with AF and bring bases to clinical plans of medication and operation. Therefore, we investigated the research progress of hemodynamic and morphological studies about the predictive value of thrombosis risk in patients with AF, intending to discuss the prediction potential of morphological and hemodynamic indexes when compared with the presently used CHA2DS2-VASc system and how to build a more precise thromboembolic event prediction model for patients with AF.

Stroke risk evaluation for patients with atrial fibrillation: Insights from left atrial appendage

Left atrial appendage (LAA) is believed to be a common site of thrombus formation in patients with atrial fibrillation (AF). However, the commonly-applied stroke risk stratification model (such as. CHA2DS2-VASc score) does not include any structural or hemodynamic features of LAA. Recent studies have suggested that it is important to incorporate LAA geometrical and hemodynamic features to evaluate the risk of thrombus formation in LAA, which may better delineate the AF patients for anticoagulant administration and prevent strokes. This review focuses on the LAA-related factors that may be associated with thrombus formation and cardioembolic events.

ACR Appropriateness Criteria® Dyspnea-Suspected Cardiac Origin (Ischemia Already Excluded): 2021 Update

Dyspnea is the symptom of perceived breathing discomfort and is commonly encountered in a variety of clinical settings. Cardiac etiologies of dyspnea are an important consideration; among these, valvular heart disease (Variant 1), arrhythmia (Variant 2), and pericardial disease (Variant 3) are reviewed in this document. Imaging plays an important role in the clinical assessment of these suspected abnormalities, with usually appropriate procedures including resting transthoracic echocardiography in all three variants, radiography for Variants 1 and 3, MRI heart function and morphology in Variants 2 and 3, and CT heart function and morphology with intravenous contrast for Variant 3. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Left Atrial Appendage Function Assessment by Tissue Doppler Transesophageal Echocardiography in Acute Ischemic Stroke Patients

Background: Strokes due to Cardioembolic causes are the most severe in ischemic stroke subtypes. LAA flow patterns and function could be assessed accurately by TEE. The study aimed to present the importance of Transesophageal echocardiography in the assessment of LAA function and its relation to cardioembolic stroke. Methods: 120 patients were enrolled in the study and were subdivided into 3 subgroups, each group included 40 patients. Group A; patients had a stroke with normal sinus rhythm, Group B; patients had a stroke with atrial fibrillation, and Group C; normal control subjects. The study participants were evaluated by medical history, physical examination, standard 12-leads electrocardiogram, a transesophageal echocardiographic detailed evaluation of the LAA, and brain CT and/or MRI for patients with stroke. Results: both stroke patients with AF and sinus rhythm had significantly higher LAA mean orifice diameter and higher LAA length than control patients, significantly lower mean LAA medial wall tissue Doppler upward and downward motion velocities than control patients and that patients with stroke and AF had significantly lower mean LAA pulsed wave emptying and filling velocities than both patients with stroke and sinus rhythm and control patients. Presence of LAA thrombi, spontaneous echo contrast, and stroke recurrence were higher in stroked AF patients than stroke patients with sinus rhythm. Conclusion: increased LAA orifice diameter, LAA length, and reduced filling and emptying velocities and upward and downward motion velocities of the medial wall of LAA as detected by TEE are associated with stroke and cardio embolization.  

Evaluating the novel parameters for assessing the LAA function and thrombus formation with nonvalvular atrial fibrillation

The dysfunction of left atrial appendage (LAA) is prone to form thrombus when atrial fibrillation (AF) sustained more than 48 h. Traditional 2D-TEE (transesophageal echocardiography) can not accurate evaluate the function of LAA. The purpose of this study is to analyze the relationship of LAA function parameters and thrombus formation in patients with non-valvular atrial fibrillation (NVAF) by real-time three-dimensional transesophageal echocardiography (RT-3D-TEE). High risk patients can be identified according to the characteristics of ultrasonic index in patients with left atrial appendage thrombosis, which has important clinical value and significance in the risk assessment, guiding treatment and judging prognosis. We examined the relationship between the echocardiographic parameters of LAA function and the incidence of thrombus in 102 NVAF patients. They underwent RT-3D-TEE and left atrial appendage thrombus (LAAT)/severe spontaneous echocardiographic contrast (SSEC) was found in 67 patients (thrombus group) but absent in the remaining 35 patients (non-thrombus group). After measured by QLAB software, the LAA functional parameters were significantly associated with LAAT/SEC formation. Univariate analysis indicated that AF time, LAD, LVEF, LAA-OAmax, LAAVmax, LAAVI and LAAEF demonstrated a positive association (P < 0.05). However, logistic regression analysis identified that AF time (OR:1.73, P < 0.05)、LAAEF (OR:4.09, P < 0.01)and LAAVI (OR:3.28, P < 0.01) were independent predictors of LAAT/SSEC. In patients with nonvalvular atrial fibrillation, echocardiographic parameters of LAA function are significantly associated with LAAT/SSEC.

Mechanical atrial recovery after cardioversion in persistent atrial fibrillation evaluated by bidimensional speckle tracking echocardiography

BACKGROUND

Atrial fibrillation induces reversible electrical and mechanical modifications (atrial remodeling). Atrial stunning is a mechanical dysfunction with preserved bioelectrical function, occurring after successful atrial fibrillation electrical cardioversion (ECV). Two-dimensional speckle tracking echocardiography is a new technology for evaluating atrial mechanical function. We assessed atrial mechanical function after ECV with serial two-dimensional speckle tracking echocardiography evaluations. The investigated outcome was left atrium mechanical recovery within 3 months.

METHODS

A total of 36 patients [mean age 73 (7.9) years, 23 males] with persistent atrial fibrillation underwent conventional transthoracic and transesophageal echocardiography before ECV. Positive global atrial strain (GSA+) was assessed at 3 h, 1, 2, 3, 4 weeks and 3 months after ECV. Mechanical recovery was defined as the achievement of a GSA+ value of 21%.

RESULTS

Independent predictors of GSA+ immediately after ECV (basal GSA+) were E/e' ratio and left atrial appendage anterograde flow velocity. During the follow-up, 25% of patients suffered atrial fibrillation recurrence. In 12/36 patients (33%) left atrium mechanical recovery was detected (mechanical recovery group), while in 15/36 (42%) recovery did not occur (no atrial mechanical recovery group). At univariate analysis, the variables associated with recovery, were basal GSA+ (P = 0.015) and maximal velocity left atrial appendage (P = 0.022). Female sex (P = 0.038), N-terminal pro-B type natriuretic peptide (P = 0.013), E/e' (P = 0.042) and the indexed left atrium volume (P = 0.019) were associated with the lack of left atrium mechanical recovery.

CONCLUSION

In almost half of the patients, the left atrium did not resume mechanical activity within the 3 months after ECV, despite sinus rhythm recovery. The left atrium of these patients was larger, stiffer and their E/E' was higher, suggesting a higher endocavitary pressure compared with mechanical recovery patients. These findings might suggest an increased thromboembolic risk.

Prevalence and Resolution of Left Atrial Thrombus in Patients With Nonvalvular Atrial Fibrillation and Flutter With Oral Anticoagulation

Left atrial appendage (LAA) thrombus in nonvalvular atrial fibrillation or flutter (AF) is a major cause of stroke and presents a therapeutic dilemma in a rhythm-control strategy. The prevalence and resolution of LAA thrombus has not been studied well in the era of non-vitamin K antagonist oral anticoagulant use. This study sought to establish (1) the prevalence of LAA thrombus (2) the prevalence of LAA thrombus despite antithrombotic therapy, (3) the rate of persistence of LAA thrombus despite appropriate anticoagulant prescriptions, and (4) determinants of LAA thrombus persistence. Consecutive transesophageal echocardiograms (TEE) performed in patients with AF were reviewed to estimate the overall prevalence of LAA thrombus and the resolution rate in those with repeat studies. Multivariable logistic regression was used to identify clinical and echocardiographic predictors of thrombus resolution. Of 1,485 patients with AF, 117 (8%) had LAA thrombus. Of those, 62 had repeat TEE within 1 year and 58 (94%) were prescribed adequate anticoagulation in TEE studies (mean interval 96 ± 72 days). Thirty-seven patients (60%) had LAA thrombus resolution. Thrombus resolution rate was only 79% in patients considered on appropriate anticoagulation. Patients with persistent LAA thrombus were more likely to have diabetes; no other clinical or echocardiographic variable was independently associated with thrombus resolution. There was no significant difference in LAA thrombus resolution between non-vitamin K antagonist oral anticoagulants and warfarin. LAA thrombus persistence despite adequate anticoagulation is relatively common and difficult to predict clinically; TEE before electrical cardioversion should be considered regardless of anticoagulation status.

Multimodality imaging for thromboembolic risk assessment in atrial fibrillation

: Atrial fibrillation is the most widely represented sustained arrhythmia in the world. Thromboembolic risk assessment represents the main clinical challenge associated with this condition, requiring enormous medical, social and economical efforts. Several pieces of evidence in literature highlight how clinical risk factors are not enough for a correct thromboembolic risk stratification of patients with atrial fibrillation, since thromboembolic events have been proven to occur even in patients with low clinical risk scores. A comprehensive multimodality imaging approach, with special regard to echocardiography and new technologies seems to be the best method for this purpose. The aim of this review is to propose a hybrid thromboembolic risk stratification system that combinines clinical evaluation with instrumental clues on left atrial remodeling, fibrosis and deformation which, could be useful especially for patients classified at low thromboembolic risk according to clinical scores.

Does Left Atrial Appendage Amputation During Routine Cardiac Surgery Reduce Future Atrial Fibrillation and Stroke?

Purpose of Review

Stroke is the most feared complication of atrial fibrillation. To prevent stroke, left atrial appendage exclusion has been targeted, as it is the prevalent site for formation of heart thrombi during atrial fibrillation.

We review the historic development of methods for exclusion of the left atrial appendage and the evidence to support its amputation during routine cardiac surgery.

Recent Findings

Evidence is not yet sufficient to routinely recommend left atrial exclusion during heart surgery, despite a high prevalence of postoperative atrial fibrillation. Observational studies indicate that electrical isolation of scarring from clip or suture techniques reduces the arrhythmogenic substrate.

Summary

Randomized studies comparing different methods of closure of the left atrial appendage before amputation do not exist. Such studies are therefore warranted, as well as studies that can elucidate whether amputation is superior to leaving the left atrial appendage stump. Potentially, thrombogenic remaining pouch after closure should be addressed.