Cardiac Computed Tomography Versus Transesophageal Echocardiography for the Detection of Left Atrial Appendage Thrombus: A Systemic Review and Meta-Analysis

Review of the Etiology, Diagnosis, and Therapy of Left Atrial Thrombus

Thrombi in the left atrial appendage (LAA) are an important cause of systemic thromboembolism in patients with atrial fibrillation. The gold standard for the diagnosis of LAA thrombi is a transesophageal echocardiogram, although cardiac multidetector computed tomography, intracardiac echocardiogram, and cardiac magnetic resonance imaging are alternative diagnostic imaging modalities. When an LAA thrombus is diagnosed, effective anticoagulation is recommended for at least 3 weeks or until thrombus resolution is confirmed on repeat transesophageal echocardiogram. Recent prospective research shows the efficacy of nonvitamin K oral anticoagulants in the treatment of LAA thrombus, which offers a promising alternative to vitamin K antagonists. As an alternative approach, left atrial aspiration thrombectomy has been described in case reports, though there is limited evidence comparing its efficacy to anticoagulation alone.

Cardiac CT in Large Vessel Occlusion Stroke for the Evaluation of Non-Thrombotic and Non-Atrial-Fibrillation-Related Embolic Causes

Background: The purpose of this study is the evaluation of imaging findings of acute-phase cardiac CT (cCT) in stroke patients with large vessel occlusion (LVO) to identify potential cardioembolic sources (CES) in patients without intracardiac thrombi and atrial fibrillation (AF). Material and Methods: This retrospective study included 315 patients with LVO who underwent cCT imaging in the acute stroke setting. The images were analysed for 15 imaging findings following the established minor and major cardioembolic risk factors. The final stroke aetiology was determined using the TOAST classification through interdisciplinary consensus following a thorough clinical evaluation. Multivariate regression analysis was performed to identify imaging findings associated with CES. Results: A cardioembolic aetiology was identified on cardiac CT in 211 cases (70%). After adjustment for AF and intracardiac thrombi, the multivariate regression analysis revealed significant associations with left ventricular dilation (adjusted odds-ratio (AOR) 32.4; 95% CI 3.0-349; p = 0.004), visible interatrial right-to-left shunt (AOR 30.8; 95% CI 2.7-341.3; p = 0.006), valve implants (AOR 24.5; 95% CI 2.2-270.9; p = 0.009), aortic arch atheroma grade > II (AOR 6.9; 95% CI 1.5-32.8; p = 0.015) and post-ischaemic myocardial scars (AOR 6.3, 95% CI 1.2-34.1; p = 0.032) as independent risk factors for a cardioembolic aetiology. The combined model achieved an area under the ROC curve of 0.83. Conclusions: In patients with LVO without AF and intracardiac thrombi as a cause, the presence of left ventricular dilatation, interatrial right-to-left shunts, valve implants, post-ischaemic myocardial scarring and advanced aortic arch atheroma (grade > 2) in particular is significantly associated with a cardioembolic cause of stroke and should be add-on evaluated in acute-phase cCT. Further investigations are warranted to confirm these associations.

High-Risk Embolic Sources on Cardiac Computed Tomography in Patients With Acute Ischemic Stroke: A Case-Control Study

BACKGROUND

Cardiac computed tomography (CT) is increasingly used to search for cardioembolic sources of acute ischemic stroke (AIS). We assessed the association between high-risk cardioembolic sources on cardiac CT and AIS.

METHODS

We performed a case-control study using data from a prospective cohort including consecutive adult patients with suspected stroke who underwent cardiac CT acquired during the initial stroke imaging protocol between 2018 and 2020. Cases were patients with a final diagnosis of AIS. Controls were patients with a stroke mimic (SMi). We excluded patients with a transient ischemic attack. Diagnoses were established by an adjudication committee. Cardiac radiologists assessed the presence of structural high-risk sources of cardioembolism according to predefined criteria. We used the Firth penalized likelihood method to perform a logistic regression, adjusted for age, sex, and history of myocardial infarction to determine the association between high-risk embolic sources and AIS. For the primary analysis, we excluded patients with a history of atrial fibrillation. In a secondary analysis, patients with known atrial fibrillation were included.

RESULTS

Of 774 patients, we excluded 167 patients due to no written informed consent or the diagnosis of transient ischemic attack. Of 607 patients, 107 patients had known atrial fibrillation and were excluded from the primary analysis. Of 500 included patients, 375 had AIS (75%, median age 70, 61% male) and 125 SMi (25%, median age 69, 42% male). A high-risk cardioembolic source was found on CT in 32/375 (8.5%) patients with AIS and 0/125 (0%) patients with SMi (adjusted odds ratio, 23.8 [95% CI, 3.3-3032.5]). Cardiac thrombi were the most commonly observed abnormality, present in 23 (6.1%) patients with AIS and 0 (0%) patients with SMi.

CONCLUSIONS

A high-risk source of cardioembolism was detected on cardiac CT more frequently in patients with AIS than in patients with SMi. These data substantiate the clinical relevance of cardioembolic sources detected on acute cardiac CT in patients with ischemic stroke.

Identifying left atrium and left atrial appendage prone to thrombus formation in patients with atrial fibrillation using statistical shape modeling

BACKGROUND

The morphology of the left atrium (LA) and left atrial appendage (LAA) is associated with LAA thrombus formation (LAAT) in patients with atrial fibrillation (AF). Statistical shape modeling (SSM) could be a comprehensive and objective method for evaluating LA/LAA shape, thereby improving LAAT risk assessment.

METHODS AND RESULTS

In this individual-matched case-control study, 110 pairs of AF patients with or without LAAT were compared. Using SSM of cardiac computed tomography angiography images, we developed a LA/LAA shape deformation score (LADS). LADS was significantly higher in the LAAT group (4.0 ± 5.0 vs. -4.0 ± 6.5, P < 0.01) and independently associated with LAAT (odds ratio for each point increase in LADS: 1.31, 95 % confidence interval: 1.21-1.42, P < 0.01). LAAT risk assessment was significantly improved by the addition of LADS to clinical characteristics plus traditional structural parameters, evaluated by the area under the receiver-operating characteristic curve (0.879 vs 0.788, P < 0.01), net reclassification improvement (30.9 %, 95 % CI: 23.6-38.1 %, P < 0.05) and integrated discrimination improvement (18.5 %, 95 %CI: 16.8-20.3 %, P < 0.05). The predictive role of LADS in LAAT was confirmed by an unmatched external validation study including 406 patients with AF (19 cases with LAAT). Computational fluid dynamics analysis of 20 patients showed a significant association between LADS and endothelial cell activation potential, time-averaged wall shear stress, relative residence time, and blood velocity in the LAA.

CONCLUSION

SSM-derived LADS was significantly associated with LAAT and improved LAAT risk assessment. The relationship between LAAT and LADS may be attributed to mechanisms involving endothelial dysfunction and blood stasis.

Heart Failure and the Non-Resolution of Atrial Thrombus Detected in Anticoagulated Patients with Non-Valvular Atrial Fibrillation

BackgroundTo investigate the relationship between heart failure (HF) and the non-resolution of atrial thrombus detected in anticoagulated patients with non-valvular atrial fibrillation (NVAF).MethodsThis was a single-center, observational, retrospective, and prospective study. Anticoagulated patients with NVAF and atrial thrombus identified by transesophageal echocardiography or cardiac computed tomography angiography were consecutively enrolled. All patients received follow-up imaging within 6 months to assess the resolution of atrial thrombus. The primary endpoint was the resolution of atrial thrombus and the secondary endpoint was the occurrence of ischemic stroke, major bleeding, and all-cause death during the follow-up period.ResultsAmong 8987 patients with NVAF scheduled for catheter ablation or cardioversion, 70 anticoagulated patients with atrial thrombus were final analyzed. The average age was 61.8±10.6 years, 62.9% of them were men, and 32 (45.7%) patients presented with HF. Within the 6-month follow-up period, atrial thrombus resolution was observed in 47 (67.1%) patients. The rate of atrial thrombus resolution was lower in patients with baseline HF (50.0% vs 81.6%). In the adjusted logistic regression analysis model, HF was independently associated with the non-resolution of atrial thrombus (adjusted OR: 5.38, 95% CI: 1.19-24.27). During the median follow-up period of 4.5 years, four ischemic stroke events occurred in four patients. None of the patients in this study experienced major bleeding events or death during follow-up.ConclusionsHF was associated with the non-resolution of atrial thrombus detected in anticoagulated patients with NVAF. Further research is needed to identify optimal therapeutic approaches for this high-risk population.

2024 European Heart Rhythm Association/Heart Rhythm Society/Asia Pacific Heart Rhythm Society/Latin American Heart Rhythm Society expert consensus statement on catheter and surgical ablation of atrial fibrillation

In the last three decades, ablation of atrial fibrillation (AF) has become an evidence-based safe and efficacious treatment for managing the most common cardiac arrhythmia. In 2007, the first joint expert consensus document was issued, guiding healthcare professionals involved in catheter or surgical AF ablation. Mounting research evidence and technological advances have resulted in a rapidly changing landscape in the field of catheter and surgical AF ablation, thus stressing the need for regularly updated versions of this partnership which were issued in 2012 and 2017. Seven years after the last consensus, an updated document was considered necessary to define a contemporary framework for selection and management of patients considered for or undergoing catheter or surgical AF ablation. This consensus is a joint effort from collaborating cardiac electrophysiology societies, namely the European Heart Rhythm Association, the Heart Rhythm Society, the Asia Pacific Heart Rhythm Society, and the Latin American Heart Rhythm Society.

Cardiac CT vs Echocardiography for Intracardiac Thrombus Detection in Ischemic Stroke: A Systematic Review and Meta-Analysis of 43 Studies

BACKGROUND AND OBJECTIVES

Ischemic stroke, a leading cause of mortality, necessitates understanding its mechanism for effective prevention. Echocardiography, especially transesophageal echocardiography (TEE), is the gold standard for detection of cardiac sources of stroke including left atrial thrombus, although its invasiveness, operator skill dependence, and limited availability in some centers prompt exploration of alternatives, such as cardiac CT (CCT). We conducted a systematic review and meta-analysis assessing the ability of CCT in the detection of intracardiac thrombus compared with echocardiography.

METHODS

We searched 4 databases up through September 8, 2023. Major search terms included a combination of the terms "echocardiograph," "CT," "TEE," "imaging," "stroke," "undetermined," and "cryptogenic." The current systematic literature review of the English language literature was reported in adherence to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses reporting guidelines. We assessed risk of bias using the QUADAS-2 tool and used random-effects meta-analysis to calculate different diagnostic metrics.

RESULTS

The meta-analysis investigating CCT vs echocardiography for intracardiac thrombus detection yielded a total of 43 studies of 9,552 patients. Risk-of-bias assessment revealed a predominantly low risk of bias in the flow and timing, index test, and patient selection domains and a predominantly unclear risk of bias in the reference standard domain. The analysis revealed an overall sensitivity of 98.38% (95% CI 89.2-99.78) and specificity of 96.0% (95% CI 92.55-97.88). Subgroup analyses demonstrated that delayed-phase, electrocardiogram-gated CCT had the highest sensitivity (100%; 95% CI 0-100) while early-phase, nongated CCT exhibited a sensitivity of 94.31% (95% CI 28.58-99.85). The diagnostic odds ratio was 98.59 (95% CI 44.05-220.69). Heterogeneity was observed, particularly in specificity and diagnostic odds ratio estimates.

DISCUSSION

CCT demonstrates high sensitivity, specificity, and diagnostic odds ratios in detecting intracardiac thrombus compared with traditional echocardiography. Limitations include the lack of randomized controlled studies, and other cardioembolic sources of stroke such as valvular disease, cardiac function, and aortic arch disease were not examined in our analysis. Large-scale studies are warranted to further evaluate CCT as a promising alternative for identifying intracardiac thrombus and other sources of cardioembolic stroke.

Left atrial appendage thrombus is associated with a higher fractal dimension in patients with atrial fibrillation

PURPOSE

To assess the anatomical complexity of the left atrial appendage (LAA) using fractal dimension (FD) based on cardiac computed tomography angiography (CTA) and the association between LAA FD and LAA thrombosis.

MATERIALS AND METHODS

Patients with atrial fibrillation (AF) who underwent both cardiac CTA and transesophageal echocardiography (TEE) between December 2018 and December 2022 were retrospectively analyzed. Patients were categorized into normal (n = 925), circulatory stasis (n = 82), and thrombus groups (n = 76) based on TEE results and propensity score matching (PSM) was performed for subsequent analysis. FD was calculated to quantify the morphological heterogeneity of LAA. Independent risk factors for thrombus were screened using logistic regression. The diagnostic performance of FD and CHA2DS2-VaSc score for predicting thrombus was evaluated using the area under the receiver operating characteristics curve (AUC).

RESULTS

LAA FD was higher in the thrombus group (1.61 [1.49, 1.70], P < 0.001) than in the circulatory stasis (1.33 [1.18, 1.47]) and normal groups (1.30 [1.18, 1.42]) both before and after PSM. LAA FD was also an independent risk factor in the thrombus (OR [odds ratio] = 570,861.15 compared to normal, 41,122.87 compared to circulatory stasis; all P < 0.001) and circulatory stasis group (OR = 98.87, P = 0.001) after PSM. The diagnostic performance of LAA FD was significantly better than the CHA2DS2-VaSc score in identifying thrombus.

CONCLUSIONS

Patients with high LAA FD are more likely to develop LAA thrombus, and the use of FD provides an effective method for assessing the risk of thrombosis in AF patients, thereby guiding individualized clinical treatment.

Cardiac thrombus detected by cardiac computed tomography angiography in patients with acute ischemic stroke: a meta-analysis

Background

Detecting cardiac thrombus in patients with acute ischemic stroke is crucial in determine stroke etiology and predict prognosis. However, the prevalence of cardiac thrombus in patients with acute ischemic stroke is unclear.

Object

This study aimed to evaluate the prevalence of cardiac thrombus detected by cardiac computed tomography angiography (CCTA) in patients with acute ischemic stroke through a meta-analysis.

Methods

Embase, Web of Science, MEDLINE, and CENTRAL were searched from January 1, 2000, to May 1, 2024. We included observational studies enrolling patients who underwent CCTA within 1 month following acute ischemic stroke, and reporting the incidence of cardiac thrombi on CCTA. Meta-analysis was performed using random effects models.

Results

Twenty-six studies involving 4,516 patients were identified. The pooled prevalence of cardiac thrombus detected on CCTA in patients with acute ischemic stroke was 0.08 (95% confidence interval [CI]: 0.06-0.11). Inter-study heterogeneity was high (I2 = 88%). Among stroke type, the prevalence of atrial fibrillation, timing of CCTA and CCTA technology, the prevalence of atrial fibrillation was the only factor associated with cardiac thrombi prevalence detected by CCTA. However, atrial fibrillation was not documented in 41.5% of the patients with cardiac thrombi.

Conclusion

CCTA is a useful non-invasive imaging approach for detecting cardiac thrombus in patients with acute ischemic stroke, which might be helpful to determine the stroke etiology.

Left Atrial Appendage Opacification on Cardiac Computed Tomography in Acute Ischemic Stroke: The Clinical Implications of Slow-Flow

BACKGROUND

Left atrial appendage (LAA) slow-flow may increase the risk of ischemic stroke. We studied LAA attenuation on cardiac computed tomography in patients with acute ischemic stroke.

METHODS AND RESULTS

We used data from a prospective cohort of patients with acute ischemic stroke undergoing cardiac computed tomography during the acute stroke imaging protocol. We compared characteristics, functional outcome (modified Rankin scale: higher scores indicating worse outcome), stroke recurrence and major adverse cardiovascular events after 2-year follow-up between patients with LAA thrombus (filling defect<100 Hounsfield Unit (HU)), slow-flow (filling defect ≥100 HU) and normal filling. Of 421 patients, 31 (7%) had LAA thrombus, 69 (16%) slow-flow, and 321 (76%) normal filling. Patients with thrombus or slow-flow more often had known atrial fibrillation compared with normal filling (45%, 39%, and 9%, P<0.001). Patients with thrombus had higher National Institutes of Health Stroke Scale-scores compared with slow-flow and normal filling (18 [interquartile range, 9-22], 6 [interquartile range, 3-17], and 5 [interquartile range, 2-11], P<0.001). Compared with normal filling, there was no difference with slow-flow in functional outcome (median modified Rankin scale, 3 versus 2; acOR 0.8 [95% CI, 0.5-1.4]), stroke recurrence (adjusted hazard ratio, 0.8 [95% CI, 0.3-1.9]) or major adverse cardiovascular events (adjusted hazard ratio, 1.2 [95% CI, 0.7-2.1]), while patients with thrombus had worse functional outcome (median modified Rankin scale, 6, acOR, 3.3 [95% CI, 1.5-7.4]). In cryptogenic stroke patients (n=156) slow-flow was associated with stroke recurrence (27% versus 6%, aHR, 4.1 [95% CI, 1.1-15.7]).

CONCLUSIONS

Patients with slow-flow had similar characteristics to patients with thrombus, but had less severe strokes. Slow-flow was not significantly associated with functional outcome or major adverse cardiovascular events, but was associated with recurrent stroke in patients with cryptogenic stroke.

2024 European Heart Rhythm Association/Heart Rhythm Society/Asia Pacific Heart Rhythm Society/Latin American Heart Rhythm Society expert consensus statement on catheter and surgical ablation of atrial fibrillation

In the last three decades, ablation of atrial fibrillation (AF) has become an evidence-based safe and efficacious treatment for managing the most common cardiac arrhythmia. In 2007, the first joint expert consensus document was issued, guiding healthcare professionals involved in catheter or surgical AF ablation. Mounting research evidence and technological advances have resulted in a rapidly changing landscape in the field of catheter and surgical AF ablation, thus stressing the need for regularly updated versions of this partnership which were issued in 2012 and 2017. Seven years after the last consensus, an updated document was considered necessary to define a contemporary framework for selection and management of patients considered for or undergoing catheter or surgical AF ablation. This consensus is a joint effort from collaborating cardiac electrophysiology societies, namely the European Heart Rhythm Association, the Heart Rhythm Society, the Asia Pacific Heart Rhythm Society, and the Latin American Heart Rhythm Society.

Higher-Than-Usual Target International Normalized Ratio (INR) Range Required With On-X Aortic Valve Secondary to Recurrent Thromboembolic Strokes: A Case Report

Although the On-X aortic valve (AO) is considered less thrombogenic compared to its counterparts, we present a case where recurrent thromboembolic ischemic stroke occurred, first with a slightly sub-therapeutic, then even with an elevated International Normalized Ratio (INR).  A 36-year-old male, the background of On-X AO replacement but no other risk factors, developed thromboembolic stroke twice while on Warfarin, first with INR 1.4, second with INR 2.4. Despite extensive investigation, other than elevated levels of low-density lipoproteins, no other treatable cause was found with the latter episode. The INR range was increased to 2.5-3.5, and aspirin and statin were added. The occurrence of thromboembolic stroke with an On-X AO despite maintaining an INR of 2.4, presents a dilemma for future prevention. The American Heart Association (AHA) and the American College of Cardiology (ACC) guidelines for thromboembolism prevention in case of an On-X AO recommend an INR range of 1.5-2 as being effective when warfarin is used along with aspirin. The take-home message is that the recommendation of an INR range of 1.5-2 with an On-X AO should be approached with caution; aspirin should be strongly considered regardless of the presence of thromboembolic risk factors. Patients developing thromboembolism have a high risk of recurrence. Therefore, a higher INR, along with the addition of aspirin and statin should be considered. Studies are needed to establish guidelines for a reliable INR range in these scenarios.

2024 European Heart Rhythm Association/Heart Rhythm Society/Asia Pacific Heart Rhythm Society/Latin American Heart Rhythm Society expert consensus statement on catheter and surgical ablation of atrial fibrillation

In the last three decades, ablation of atrial fibrillation (AF) has become an evidence-based safe and efficacious treatment for managing the most common cardiac arrhythmia. In 2007, the first joint expert consensus document was issued, guiding healthcare professionals involved in catheter or surgical AF ablation. Mounting research evidence and technological advances have resulted in a rapidly changing landscape in the field of catheter and surgical AF ablation, thus stressing the need for regularly updated versions of this partnership which were issued in 2012 and 2017. Seven years after the last consensus, an updated document was considered necessary to define a contemporary framework for selection and management of patients considered for or undergoing catheter or surgical AF ablation. This consensus is a joint effort from collaborating cardiac electrophysiology societies, namely the European Heart Rhythm Association, the Heart Rhythm Society (HRS), the Asia Pacific HRS, and the Latin American HRS.

Role of Computed Tomography in Cardiac Electrophysiology

With the increasing prevalence of arrhythmias, the use of electrophysiology (EP) procedures has increased. Recent advancements in computed tomography (CT) technology have expanded its use in pre-assessments and post-assessments of EP procedures. CT provides high-resolution images, is noninvasive, and is widely available. This article highlights the strengths and weaknesses of cardiac CT in EP.

2024 European Heart Rhythm Association/Heart Rhythm Society/Asia Pacific Heart Rhythm Society/Latin American Heart Rhythm Society expert consensus statement on catheter and surgical ablation of atrial fibrillation

In the last three decades, ablation of atrial fibrillation (AF) has become an evidence-based safe and efficacious treatment for managing the most common cardiac arrhythmia. In 2007, the first joint expert consensus document was issued, guiding healthcare professionals involved in catheter or surgical AF ablation. Mounting research evidence and technological advances have resulted in a rapidly changing landscape in the field of catheter and surgical AF ablation, thus stressing the need for regularly updated versions of this partnership which were issued in 2012 and 2017. Seven years after the last consensus, an updated document was considered necessary to define a contemporary framework for selection and management of patients considered for or undergoing catheter or surgical AF ablation. This consensus is a joint effort from collaborating cardiac electrophysiology societies, namely the European Heart Rhythm Association, the Heart Rhythm Society, the Asia Pacific Heart Rhythm Society, and the Latin American Heart Rhythm Society .

Computed Tomography to Exclude Cardiac Thrombus in Atrial Fibrillation-An 11-Year Experience from an Academic Emergency Department

BACKGROUND

Computed tomography (CT) could be a suitable method for acute exclusion of left atrial appendage thrombus (LAAT) prior to cardioversion of atrial fibrillation (AF) and atrial flutter (AFL) at the emergency department. Our aim was to present our experiences with this modality in recent years.

METHODS

This registry-based observational study was performed at the Department of Emergency Medicine at the Medical University of Vienna, Austria. We studied all consecutive patients with AF and AFL who underwent CT between January 2012 and January 2023 to rule out LAAT before cardioversion to sinus rhythm was attempted. Follow-ups were conducted by telephone and electronic medical records. The main variables of interest were the rate of LAAT and ischemic stroke at follow-up.

RESULTS

A total of 234 patients (143 [61%] men; median age 68 years [IQR 57-76], median CHA2DS2-VASc 2 [IQR 1-4]) were analyzed. Follow-up was completed in 216 (92%) patients after a median of 506 (IQR 159-1391) days. LAAT was detected in eight patients (3%). A total of 163 patients (72%) in whom LAAT was excluded by CT were eventually successfully cardioverted to sinus rhythm. No adverse events occurred during their ED stay. All patients received anticoagulation according to the CHA2DS2-VASc risk stratification, and no patient had suffered an ischemic stroke at follow-up, resulting in an incidence risk of ischemic strokes of 0% (95% CI 0.0-1.2%).

CONCLUSION

LAAT was rare in patients admitted to the ED with AF and AFL who underwent cardiac CT prior to attempted cardioversion. At follow-up, no patient had suffered an ischemic stroke. Prospective studies need to show whether this strategy is suitable for the acute treatment of symptomatic AF in the emergency setting.

A comparison of conventional and advanced 3D imaging techniques for percutaneous left atrial appendage closure

Background

Understanding complex cardiac anatomy is essential for percutaneous left atrial appendage (LAA) closure. Conventional multi-slice computed tomography (MSCT) and transesophageal echocardiography (TEE) are now supported by advanced 3D printing and virtual reality (VR) techniques for three-dimensional visualization of volumetric data sets. This study aimed to investigate their added value for LAA closure procedures.

Methods

Ten patients scheduled for interventional LAA closure were evaluated with MSCT and TEE. Patient-specific 3D printings and VR models were fabricated based on MSCT data. Ten cardiologists then comparatively assessed LAA anatomy and its procedure relevant surrounding structures with all four imaging modalities and rated their procedural utility on a 5-point Likert scale questionnaire (from 1 = strongly agree to 5 = strongly disagree).

Results

Device sizing was rated highest in MSCT (MSCT: 1.9 ± 0.8; TEE: 2.6 ± 0.9; 3D printing: 2.5 ± 1.0; VR: 2.5 ± 1.1; p < 0.01); TEE, VR, and 3D printing were superior in the visualization of the Fossa ovalis compared to MSCT (MSCT: 3.3 ± 1.4; TEE: 2.2 ± 1.3; 3D printing: 2.2 ± 1.4; VR: 1.9 ± 1.3; all p < 0.01). The major strength of VR and 3D printing techniques was a superior depth perception (VR: 1.6 ± 0.5; 3D printing: 1.8 ± 0.4; TEE: 2.9 ± 0.7; MSCT: 2.6 ± 0.8; p < 0.01). The visualization of extracardiac structures was rated less accurate in TEE than MSCT (TEE: 2.6 ± 0.9; MSCT: 1.9 ± 0.8, p < 0.01). However, 3D printing and VR insufficiently visualized extracardiac structures in the present study.

Conclusion

A true 3D visualization in VR or 3D printing provides an additional value in the evaluation of the LAA for the planning of percutaneous closure. In particular, the superior perception of depth was seen as a strength of a 3D visualization. This may contribute to a better overall understanding of the anatomy. Clinical studies are needed to evaluate whether a more comprehensive understanding through advanced multimodal imaging of patient-specific anatomy using VR may translate into improved procedural outcomes.

Presence of Residual Cardiac Thrombus Predicts Poor Outcome in Cardioembolic Stroke After Reperfusion Therapy

BACKGROUND

In patients with acute cardiogenic cerebral embolism, a residual thrombus may still be present in the cardiac cavity even after reperfusion therapy. We aimed to investigate the occurrence of a residual cardiac thrombus in cardioembolic stroke after reperfusion therapy and analyze its impact on clinical outcome.

METHODS AND RESULTS

We enrolled patients with cardioembolic stroke from our prospectively collected database who underwent 2-phase cardiac computed tomography within 7 days after reperfusion therapy. Residual cardiac thrombus was defined as a filling defect on both early- and late-phase images, whereas circulatory stasis was defined as a filling defect only on the early-phase images in the left atrial appendage. The primary outcome was a poor clinical outcome (modified Rankin Scale score, 3-6) at 90 days. The secondary outcome was a composite end point event (cardiovascular death, nonfatal myocardial infarction, nonfatal stroke) at 90 days. A total of 303 patients were included, of whom 94 (31.0%) had a residual cardiac thrombus. Binary logistic regression analysis showed that the presence of a residual cardiac thrombus was associated with a poor clinical outcome (odds ratio, 1.951 [95% CI, 1.027-3.707]; P=0.041) but not circulatory stasis in the left atrial appendage (odds ratio, 1.096 [95% CI, 0.542-2.217]; P=0.798). Furthermore, there was no correlation between a residual cardiac thrombus and the composite end point event (30.0% versus 31.1%; P=1.000).

CONCLUSIONS

Residual cardiac thrombus occurs in approximately one-third of patients with cardioembolic stroke after reperfusion therapy and is often indicative of a poor clinical outcome.

Non-ECG-gated cardiac CT angiography in acute stroke is feasible and detects sources of embolism

BACKGROUND

A significant portion of cryptogenic stroke is hypothesized to be secondary to cardiac embolism. However, transthoracic echocardiogram is usually delayed after stroke, and more detailed cardiac imaging is not routinely done.

AIMS

This study aimed to determine whether non-ECG-gated cardiac CT angiography (cCTA) during hyperacute stroke would provide diagnostic quality images and act as an adjunct modality of cardiac imaging to detect sources of emboli.

METHODS

In this single-center prospective cohort study, modified Code Stroke imaging was implemented with a 64-slice CT scanner, where the longitudinal axis of CT angiography was extended from the carina to the diaphragm. The primary outcomes of image quality, recruitment feasibility, impact on hyperacute time metrics, and additional radiation dose were assessed. Secondary outcomes consisted of detection of high-risk cardiac sources of embolism, mediastinal or lung pathology, and impact on etiologic classification.

RESULTS

One hundred and twenty eligible patients were enrolled, of which 105 (87.5%) had good/moderate quality images for motion artifact and 119 (99.2%) for contrast opacification. Total CT time, door-to-needle time, and door-to-groin puncture time were unchanged with the addition of cCTA. Eighty-nine patients received a final diagnosis of ischemic stroke, of which 12/89 (13.5%) had high-risk cardioembolic findings on cCTA. Incidental findings, such as pulmonary embolism (PE) (7/89, 7.9%) and malignancy (6/89, 6.7%), were observed. cCTA led to changes in management for 19/120 (15.8%) of all patients, and reclassification of stroke etiology for 8/89 (9%) of patients.

CONCLUSIONS

Non-ECG-gated cCTA can be feasibly incorporated into Code Stroke and provide diagnostic quality images without delays in hyperacute time metrics. It can detect high-risk cardiac sources, and other findings impacting patient care. This may help reclassify a subset of cryptogenic stroke cases and improve secondary prevention.

Impact of left atrial appendage thrombus location on diagnostic accuracy of cardiac CT: a single-centre case-control study

OBJECTIVE

Cardiac CT (CCT) is an emerging non-invasive modality for assessing left atrial appendage (LAA) thrombus, but the results were conflicting. Our study aims to evaluate the accuracy of CCT for detecting LAA thrombus in patients undergoing catheter ablation of atrial fibrillation, using trans-oesophageal echocardiography (TEE) as the reference standard.

DESIGN

Case-control study.

SETTING

Patient data were collected from a tertiary hospital in China between 2017 and 2022.

PARTICIPANTS

The study enrolled 726 patients (male: 60.2%, age: 61±11 years) who had both TEE and CCT before catheter ablation of atrial fibrillation.

MEASURES

The CCT protocol consisted of one angiographic phase and one delayed scan 30 s later. LAA thrombi were defined as solid masses on TEE or persistent defects on CCT. The thrombus dimension and location, the LAA filling and emptying flow velocity were assessed by TEE.

RESULTS

Of the 57 (7.9%) patients with LAA thrombi identified by TEE, 29 (50.9%) were located at the LAA ostium, and 28 (49.1%) were in the LAA. The former showed higher motility following blood flow and heartbeats than the latter. The CCT detected 14 (48.3%) of the LAA-ostium thrombi but 25 (89.3%) of those in the LAA (p=0.001). The LAA-ostium thrombi with the LAA mean flow velocity >0.35 m/s and maximum diameters <10 mm were more prone to have CCT false-negative results.

CONCLUSION

For patients undergoing catheter ablation for atrial fibrillation, CCT with a 30 s delay scan is less sensitive to LAA thrombi than TEE, especially for LAA-ostium thrombi with smaller sizes and higher LAA flow velocity.

The role of CT in arrhythmia management-treatment planning and post-procedural imaging surveillance

Several interventional treatment options exist in patients with atrial and ventricular arrhythmia. Cardiac CT is routinely performed prior to occlusion of the left atrial appendage, pulmonary vein isolation, and cardiac device implantation. Besides the evaluation of coronary artery disease, cardiac CT provides isotropic, high-resolution CT images of the cardiac anatomy with the possibility of multiplanar reformations and three-dimensional reconstructions which are helpful to guide interventional treatment. In addition, cardiac CT is increasingly used to rapidly evaluate periprocedural complications and for the routine post-procedural imaging surveillance in patients after interventions. This review article will discuss current applications of pre- and post-interventional CT imaging in patients with arrhythmia.

Left atrial appendage thrombus in an elderly patient with atrial fibrillation during non-cardiac surgery- a case report

BACKGROUND

Perioperative newly developed left atrial appendage (LAA) thrombus is a rare but extremely challenging event for anesthesia management. It's important to identify and diagnose thrombosis in high-risk populations promptly.

CASE PRESENTATION

In the case of an elderly patient with atrial fibrillation undergoing non-cardiac surgery, we recorded the findings before and after thrombosis during the operation using transesophageal echocardiography (TEE). Through timely detection of the thrombus and proactive management, a satisfactory therapeutic effect was ultimately achieved.

CONCLUSIONS

Clinicians should be aware of the potential risk of LAA clot formation during surgery, even if it was not detected preoperatively. And TEE is valuable for monitoring newly developed perioperative thrombosis.

Right-to-Left Shunt Evaluation in Cardiac Patent Foramen Ovale Using Bubble Contrast Transcranial Color-Coded Doppler: A Cryptogenic Stroke Case

Traditional diagnosis of patent foramen ovale (PFO) in the heart has involved the use of transcranial Doppler (TCD). However, TCD is essentially a blind test that cannot directly visualize the location of blood vessels. Since TCD relies on qualitative assessments by examiners, there is room for errors, such as misalignment of the ultrasound's angle of incidence with the actual blood vessels. This limitation affects the reproducibility and consistency of the examination. In this study, we presented an alternative approach for assessing right-to-left shunt (RLS) associated with PFO using contrast transcranial color-coded Doppler (C-TCCD) with bubble contrast. The patient under consideration had been diagnosed with an ischemic stroke through imaging, but the subsequent cardiac work-up failed to determine the cause. Employing C-TCCD for RLS screening revealed a confirmed RLS of Spencer's three grades. Subsequently, transesophageal echocardiography (TEE) was conducted to evaluate PFO risk factors, confirming an 8 mm PFO size, a 21 mm tunnel length, a hypermobile interatrial septum, and persistent RLS. The calculated high-risk PFO score was 4 points, categorizing it as a very high risk PFO. This case underscores the importance of C-TCCD screening in detecting RLS associated with PFO, especially in cryptogenic stroke patients, when identifying the underlying cause of ischemic stroke becomes challenging.

Multimodality Cardiac Imaging in COVID

Infection with SARS-CoV-2, the virus that causes COVID, is associated with numerous potential secondary complications. Global efforts have been dedicated to understanding the myriad potential cardiovascular sequelae which may occur during acute infection, convalescence, or recovery. Because patients often present with nonspecific symptoms and laboratory findings, cardiac imaging has emerged as an important tool for the discrimination of pulmonary and cardiovascular complications of this disease. The clinician investigating a potential COVID-related complication must account not only for the relative utility of various cardiac imaging modalities but also for the risk of infectious exposure to staff and other patients. Extraordinary clinical and scholarly efforts have brought the international medical community closer to a consensus on the appropriate indications for diagnostic cardiac imaging during this protracted pandemic. In this review, we summarize the existing literature and reference major societal guidelines to provide an overview of the indications and utility of echocardiography, nuclear imaging, cardiac computed tomography, and cardiac magnetic resonance imaging for the diagnosis of cardiovascular complications of COVID.

Contrast defect of left atrial appendage on computed tomography is associated with higher risk of recurrence after catheter ablation in patients with paroxysmal atrial fibrillation

The previous study has shown that the contrast defect of the left atrial appendage (LAA) on contrast-enhanced cardiac computed tomography (CT) is associated with a higher rate of stroke in patients with atrial fibrillation (AF). This study aimed to investigate the association between LAA CT contrast defect and the risk of arrhythmia recurrence after catheter ablation (CA) in patients with paroxysmal AF. A total of 283 paroxysmal AF patients [age: 67 ± 10 years, 185 (65%) males] who underwent cardiac CT before CA were retrospectively analyzed. The presence or absence of LAA CT contrast defect was visually assessed using early phase CT images. Recurrence was an episode of atrial arrhythmia beyond the first 90 days post-ablation. LAA flow velocity was measured using transesophageal echocardiography in 246 paroxysmal AF patients. Sixty-eight (24%) patients had an LAA CT contrast defect. LAA flow velocity was significantly reduced in patients with LAA CT defect compared to those without (56.8 ± 28.7 cm/s vs. 41.1 ± 19.1 cm/s, p < 0.001). During a median follow-up period of 858 days, arrhythmia recurrence was identified in 85 (30%) patients. On a Kaplan Meier curve, patients with LAA CT contrast defect had significantly higher recurrence rates than those without (p = 0.043). On a multivariable Cox regression analysis, LAA CT contrast defect was a significant and independent predictor after adjustment of age, sex and left atrial volume index (hazard ratio: 1.79, 95% confidence interval: 1.03-3.07, p = 0.036). LAA CT contrast defect was associated with decreased LAA flow velocity and a higher rate of arrhythmia recurrence after CA, suggesting its usefulness as a non-invasive predictor for high-risk AF patients resistant to CA therapy.

Predictors of thrombosis of left atrium and its appendage before catheter ablation or cardioversion in patients with non-valvular atrial fibrillation or atrial flutter

Aim. To determine the incidence of left atrial (LA) and/or LA appendage (LAA) thrombosis in patients with non-valvular atrial fibrillation (AF) (NAF) or atrial flutter (AFL) on transesophageal echocardiography (TEE) before elective catheter ablation (CA) or cardioversion (CV) and characterize the predictors of LA/LAA thrombosis among the indicators available in the routine practice of cardiologists and general practitioners.

Material and methods. In this retrospective, single-center, casecontrol study, the medical records of 1994 patients with NAF or AFL for the period 2014-2019, who underwent TEE before CA or elective CV, were analyzed. A thrombus in the LA/LAA was detected in 33 (1,6%) of them. For the comparison group, 167 patients were randomly selected without LA/LAA thrombosis. Demographic, anamnestic and clinical parameters, transthoracic echocardiography data, and laboratory results were analyzed as potential predictors of LA/LAA thrombosis.

Results. Patients with LA/LAA thrombosis were older (mean age, 64,8±1,6 vs 59,4±10,8 (p=0,01), more often had persistent or longstanding persistent AF, hypertension, heart failure, enlarged LA, lower left ventricular ejection fraction (LVEF) and estimated glomerular filtration rate, as well as more severe symptoms according to the modified European Heart Rhythm Association (EHRA) score and a higher CHA2DS2-VASc score (median, 4,0 vs 2,0; p=0,0001). Oral anticoagulants were taken by 88% of patients; there were no significant differences in the presence and composition of anticoagulant therapy between the groups. Functional class (FC) according to the modified EHRA score (odds ratio (OR), 5,4; 95% confidence interval (CI): 1,9814,96; p=0,001) and LVEF were independent predictors of LA/LAA thrombosis (OR, 0,87; 95% CI: 0,80-0,95; p=0,002). For EHRA class 3-4, the OR was 5,1; 95% CI: 2,3-11,4 (p<0,0001), for LVEF <48% — 7,4; 95% CI: 1,2-46,7 (p=0,03). For EHRA class 3-4, the sensitivity for LA/LAA thrombosis was 93,7%, specificity — 71,9%, positive predictive value — 50,0%, negative predictive value — 87,6%; for LVEF <48% — 66,7, 32,3, 31,9 and 91,6%, respectively.

Conclusion. In the studied group of patients with NAF or AFL, without severe structural heart disease and severe concomitant diseases, most of whom received oral anticoagulants, LA/LAA thrombosis at TEE before elective CA or CV was detected in 1,6% of cases. Among the indicators available in routine medical practice, the severity of arrhythmia symptoms, assessed by the modified EHRA score, and lower LVEF were independent predictors of LA/LAA thrombosis.

Study on the correlation between false-positive filling defect in LAA CT and LAA structure in patients with atrial fibrillation based on TEE

OBJECTIVE

This study aims to explore the actual meaning of "false positive filling defect" in left atrial appendage (LAA) computed tomography (CT) in patients with atrial fibrillation (AF), with transesophageal echocardiography (TEE) as the gold standard.

METHODS

Patients with AF undergoing cardiac CT angiography and TEE examinations for proposed radiofrequency catheter ablation between October 2020 and October 2021 were selected as the study subjects. Transesophageal echocardiography was taken as the "gold standard," and spontaneous echocardiographic contrast (SEC) and thrombus events were defined as positive events. The CT manifestations were classified into three groups (true positive, false positive, and true negative) to evaluate the differences in left atrium (LA) anterior-posterior diameter (LAAP), LA anterior wall thickness, and LAA orifice long diameter and short diameter, area, and depth between the three groups.

RESULTS

(1) There was no statistical difference in LA anterior wall thickness between the three groups (p > .05); there was a statistical difference in LAAP (only) between the true-positive group and the true-negative group (p < .05). (2) There was a statistical difference in LAA orifice long diameter, short diameter, and area between the true-positive group and the true-negative group as well as between the false-positive group and the true-negative group (p < .05). (3) There was a statistical difference in LAA depth between the true-positive group and the false-positive group as well as between the true-positive group and the true-negative group (p < .05). (4) The area under the receiver operator characteristic curve (AUC) of LAA depth affecting the LAA thrombus and SEC was 0.863 (confidence interval = 0.718-1.000), the sensitivity was 77.8%, and the specificity was 90.6% for predicting the occurrence of LAA thrombus and SEC in patients with nonvalvular AF (NVAF) and an LAA depth of ≥50.84 mm.

CONCLUSIONS

There was a difference in LAA diameter between the TEE-based CT false-positive group and the other groups. A "CT false positive" is an objectively existing state, and CT might be able to identify the LAA hemodynamic disorder earlier than TEE. Furthermore, a CT + TEE combined application could more accurately evaluate LAA hemodynamics in patients with AF.

The Chinese Experience of Imaging in Cardiac Intervention: A Bird's Eye Review

Recent scientific and technological advances have greatly contributed to the development of medical imaging that could enable specific functions. It has become the primary focus of cardiac intervention in preoperative assessment, intraoperative guidance, and postoperative follow-up. This review provides a contemporary overview of the Chinese experience of imaging in cardiac intervention in recent years.

Preprocedural Multimodality Imaging in Atrial Fibrillation

Atrial fibrillation (AF) is the most common arrhythmia worldwide and is associated with increased risk of heart failure, stroke, and death. In current medical practice, multimodality imaging is routinely used in the management of AF. Twenty-one years ago, the ACUTE trial (Assessment of Cardioversion Using Transesophageal Echocardiography) results were published, and the management of AF changed forever by incorporating transesophageal echocardiography guided cardioversion of patients in AF for the first time. Current applications of multimodality imaging in AF in 2022 include the use of transesophageal echocardiography and computed tomography before cardioversion to exclude left atrial thrombus and in left atrial appendage occlusion device implantation. Transesophageal echocardiography, cardiac computed tomography, and cardiac magnetic resonance are clinically used for AF ablation planning. The decision to use a particular imaging modality in AF is based on patient's characteristics, guideline recommendation, institutional preferences, expertise, and cost. In this first of 2-part review series, we discuss the preprocedural role of echocardiography, computed tomography, and cardiac magnetic resonance in the AF, with regard to their clinical applications, relevant outcomes data and unmet needs, and highlights future directions in this rapidly evolving field.

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.

Atrial cardiomyopathy: from cell to bedside

Atrial cardiomyopathy refers to structural and electrical remodelling of the atria, which can lead to impaired mechanical function. While historical studies have implicated atrial fibrillation as the leading cause of cardioembolic stroke, atrial cardiomyopathy may be an important, underestimated contributor. To date, the relationship between atrial cardiomyopathy, atrial fibrillation, and cardioembolic stroke remains obscure. This review summarizes the pathogenesis of atrial cardiomyopathy, with a special focus on neurohormonal and inflammatory mechanisms, as well as the role of adipose tissue, especially epicardial fat in atrial remodelling. It reviews the current evidence implicating atrial cardiomyopathy as a cause of embolic stroke, with atrial fibrillation as a lagging marker of an increased thrombogenic atrial substrate. Finally, it discusses the potential of antithrombotic therapy in embolic stroke with undetermined source and appraises the available diagnostic techniques for atrial cardiomyopathy, including imaging techniques such as echocardiography, computed tomography, and magnetic resonance imaging as well as electroanatomic mapping, electrocardiogram, biomarkers, and genetic testing. More prospective studies are needed to define the relationship between atrial cardiomyopathy, atrial fibrillation, and embolic stroke and to establish a prompt diagnosis and specific treatment strategies in these patients with atrial cardiomyopathy for the secondary and even primary prevention of embolic stroke.

Incidence and Predictors of Left Atrial Appendage Thrombus before Catheter Ablation of Thrombogenic Arrhythmias

Introduction: Transesophageal echocardiography (TEE) is routinely performed before catheter ablation of atrial tachyarrhythmias to rule out the presence of left atrial thrombi. However, data to support this practice are inconsistent. Methods: We analyzed consecutive pre-procedural TEE in a high-volume electrophysiology center for the presence of left atrial thrombi and a relevant flow reduction in the left atrial appendage (LAA) defined as LAA sludge or LAA emptying velocity (LAAEV) < 20 cm/s. The possible predictors of reduced flow were recorded and compared in a multivariate logistic regression analysis. Results: 1676 TEE were included (1122 before pulmonary vein isolation, 436 before atrial flutter ablation, 166 before other ablations). 543 patients (32%) were female and 991 (59%) were on DOAC. Nine patients (0.5%) had an LAA thrombus on pre-procedural TEE. Ninety-five further patients (5.7%) had a relevant reduction in LAA flow. The underlying rhythm showed a significant association with the presence of LAA thrombus or reduced LAA flow (p = 0.003). Patients in sinus rhythm and cavotricuspid isthmus-dependent atrial flutter exhibited the lowest risk. Additionally, reduced kidney function was associated with a reduction in LAA flow velocities (p = 0.04). Of note, two LAA thrombi occurred in patients in sinus rhythm and six out of nine patients with an LAA thrombus were on vitamin-K antagonists. Conclusions: LAA thrombus is a rare occurrence before an elective catheter ablation. The underlying rhythm and kidney function may serve as markers of a higher likelihood of significantly reduced LAAEV and LAA thrombus.