Impact of routine transoesophageal echocardiography on safety, outcomes, and cost of pulmonary vein ablation: inferences drawn from a decision analysis model

Artificial intelligence in detecting left atrial appendage thrombus by transthoracic echocardiography and clinical features: the Left Atrial Thrombus on Transoesophageal Echocardiography (LATTEE) registry

AIMS

Transoesophageal echocardiography (TOE) is often performed before catheter ablation or cardioversion to rule out the presence of left atrial appendage thrombus (LAT) in patients on chronic oral anticoagulation (OAC), despite associated discomfort. A machine learning model [LAT-artificial intelligence (AI)] was developed to predict the presence of LAT based on clinical and transthoracic echocardiography (TTE) features.

METHODS AND RESULTS

Data from a 13-site prospective registry of patients who underwent TOE before cardioversion or catheter ablation were used. LAT-AI was trained to predict LAT using data from 12 sites (n = 2827) and tested externally in patients on chronic OAC from two sites (n = 1284). Areas under the receiver operating characteristic curve (AUC) of LAT-AI were compared with that of left ventricular ejection fraction (LVEF) and CHA2DS2-VASc score. A decision threshold allowing for a 99% negative predictive value was defined in the development cohort. A protocol where TOE in patients on chronic OAC is performed depending on the LAT-AI score was validated in the external cohort. In the external testing cohort, LAT was found in 5.5% of patients. LAT-AI achieved an AUC of 0.85 [95% confidence interval (CI): 0.82-0.89], outperforming LVEF (0.81, 95% CI 0.76-0.86, P < .0001) and CHA2DS2-VASc score (0.69, 95% CI: 0.63-0.7, P < .0001) in the entire external cohort. Based on the proposed protocol, 40% of patients on chronic OAC from the external cohort would safely avoid TOE.

CONCLUSION

LAT-AI allows accurate prediction of LAT. A LAT-AI-based protocol could be used to guide the decision to perform TOE despite chronic OAC.

Imaging of left heart intracardiac thrombus: clinical needs, current imaging, and emerging cardiac magnetic resonance techniques

Intracardiac thrombus in the left atrium and atrial appendage (LA/LAA) and left ventricle (LV) increases the risk of systemic thromboembolism and causes potentially devastating diseases such as ischemic stroke and acute ischemia in abdominal organs and lower extremities. Detecting the presence and monitoring the resolution of left heart intracardiac thrombus are of vital importance for stratifying patients and guiding treatment decisions. Currently, echocardiography is the most frequently used method for the above clinical needs, followed by computed tomography. An increasing number of studies have been performed to investigate the value of cardiac magnetic resonance (CMR) as an alternative imaging modality given its several unique strengths. This article provides an overview of the clinical relevance of the LA/LAA and LV thrombus as well as the diagnostic performance of the current imaging modalities and emerging CMR techniques.

Atrial thrombus detection on transoesophageal echocardiography in patients with atrial fibrillation undergoing cardioversion or catheter ablation: A pooled analysis of rates and predictors

OBJECTIVE

To summarize data on the rates and predictors of left atrial thrombus/left atrial appendage thrombus (LAT/LAAT) detection by transoesophageal echocardiography (TEE) before electrical cardioversion (ECV) or catheter ablation (CA) for atrial fibrillation (AF).

METHODS

EMBASE, MEDLINE, and Web of Science Core Collection were searched to identify all studies providing relevant data and published by October 7, 2020. A random-effects meta-analysis method was used to pool effect size estimates.

RESULTS

A total of 85 studies were included, reporting data from 56 660 patients with AF. In patients undergoing CA and ECV, the pooled prevalence of LAT/LAAT was 1.8% and 7.5% in those not on oral anticoagulation (OAC), 1.8% and 5.5% in those taking OAC, and 1.3% and 4.9% in case of adequate OAC, respectively. According to the type of OAC, the prevalence was 2.0% and 7.6% for vitamin K antagonist, 1.3% and 3.5% for direct oral anticoagulant. Predictors of LAT/LAAT detection were nonparoxysmal AF (odds ratio [OR]: 3.6, 95% confidence interval: 2.4-5.2), hypertension (OR: 2.9, 1.2-7.0), previous stroke (OR: 3.0, 1.6-5.63), heart failure (OR: 4.3, 2.7-6.8), and CHADS₂ score ≥2 (OR: 3.3, 1.9-5.8) for patients undergoing CA; and heart failure (OR: 2.8, 1.3-6.2) and the CHA₂ DS₂ -VASc score (OR: 2.55, 1.5-4.5) for those undergoing ECV.

CONCLUSION

The prevalence of LAT/LAAT in AF patients undergoing ECV or CA varies widely, mainly due to differences in patient risk profiles and OAC types. Further research should determine whether the predictors of LAT/LAAT detection identified by this study could be used to select patients who require preprocedural TEE.

Safety of catheter ablation of atrial fibrillation without pre- or peri-procedural imaging for the detection of left atrial thrombus in the era of uninterrupted anticoagulation

BACKGROUND

The need for pre- or peri-procedural imaging to rule out the presence of left atrial thrombus in patients undergoing catheter ablation of atrial fibrillation (AF) is unclear in the era of uninterrupted direct oral anticoagulant (DOAC) regimen. We sought to examine the safety of catheter ablation in appropriately selected patients with paroxysmal AF without performing screening for left atrial thrombus.

PATIENTS AND METHODS

Consecutive patients planned for radiofrequency AF catheter ablation between January 2016 and June 2020 were enrolled, and prospectively studied. All subjects were receiving uninterrupted anticoagulation with DOACs for at least 4 weeks before the procedure. All subjects were in sinus rhythm the day of the procedure. The primary outcome of the study was ischemic stroke or transient ischemic attack (TIA) during at 30 days.

RESULTS

A total of 451 patients (age 59.7 ± 10.2 years, 289 males) with paroxysmal AF were included in the study. The mean CHA2DS2-VASc score was 1.4 ± 1.2. The mean left ventricular ejection fraction and left atrial diameter were 60 ± 5% and 39.3 ± 4 mm, respectively. Regarding the anticoagulation regimen, apixaban was used in 197 (43.6%) patients, rivaroxaban in 148 (32.8%) patients, and dabigatran in 106 (23.5%) patients. None of the patients developed clinical ischemic stroke or TIA during the 30-day post-discharged period.

CONCLUSIONS

Catheter ablation can be safely performed in low-risk patients with paroxysmal AF without imaging for the detection of left atrial thrombus in the era of uninterrupted DOAC anticoagulation.

Is transesophageal echocardiography necessary in patients undergoing ablation of atrial fibrillation on an uninterrupted direct oral anticoagulant regimen? Results from a prospective multicenter registry

BACKGROUND

Thromboembolic stroke is a rare but devastating consequence of atrial fibrillation (AF) ablation. Transesophageal echocardiography (TEE) is recommended to rule out left atrial appendage thrombus; however, its use is variable.

OBJECTIVE

The purpose of this study was to assess whether TEE is mandatory in patients undergoing AF ablation on uninterrupted direct oral anticoagulants (DOACs).

METHODS

Data from our prospective multicenter registry of patients with AF undergoing radiofrequency catheter ablation on uninterrupted DOACs were analyzed. All the included patients were on anticoagulation for at least 4 weeks before ablation. All AF ablation procedures were performed under intracardiac echocardiography guidance. Before transseptal puncture, heparin bolus was administered, followed by continuous infusion, with a target activated clotting time of >300 seconds.

RESULTS

A total of 6186 patients (3180 on apixaban [51.4%], 2528 on rivaroxaban [40.9%], 404 on dabigatran [6.5%], and 74 on edoxaban [1.2%]) were analyzed. The mean age of the study population was 69.4 ± 10.3 years; 4194 patients (67.8%) were male, and 5120 patients (82.8%) had persistent and long-standing persistent AF. The mean CHA₂DS₂-VASc score was 2.86 ± 1.58; the mean CHADS₂ score was 1.65 ± 1.14. Intracardiac echocardiography ruled out left atrial appendage and left atrial thrombi in all patients and revealed "smoke" in 1672 patients (27.03%). Transient ischemic attack was noted in 1 patient with long-standing persistent AF in the setting of a missed dose of rivaroxaban before ablation.

CONCLUSION

Our study showed that performing AF ablation in patients on uninterrupted DOACs without TEE is safe and feasible in high stroke risk patients. Elimination of routine preablation TEE would have significant economic and clinical implications.

Prevalence and clinical characteristics associated with left atrial thrombus detection: Apixaban

BACKGROUND

The prevalence of left atrial appendage (LAA) thrombus detection by transesophageal echocardiogram (TEE) in patients with non-valvular atrial fibrillation (AF) anticoagulated with apixaban is not well defined and identification of additional risk factors may help guide the selection process for pre-procedural TEE. The purpose of our study was to retrospectively analyze the prevalence of LAA thrombus detection by TEE in patients continuously anticoagulated with apixaban for ≥ 4 wk and evaluate for any cardiac risk factors or echocardiographic characteristics which may serve as predictors of thrombus formation.

AIM

To retrospectively analyze the prevalence of LAA thrombus detection by TEE in patients continuously anticoagulated with apixaban.

METHODS

Clinical and echocardiographic data for 820 consecutive patients with AF undergoing TEE at Augusta University Medical Center over a four-year period were retrospectively analyzed. All patients (apixaban: 226) with non-valvular AF and documented compliance with apixaban for ≥ 4 wk prior to index TEE were included.

RESULTS

Following ≥ 4 wk of continuous anticoagulation with apixaban, the prevalence of LAA thrombus and LAA thrombus/dense spontaneous echocardiographic contrast was 3.1% and 6.6%, respectively. Persistent AF, left ventricular ejection fraction < 30%, severe LA dilation, and reduced LAA velocity were associated with thrombus formation. Following multivariate logistic regression, persistent AF (OR: 7.427; 95%CI: 1.02 to 53.92; P = 0.0474), and reduced LAA velocity (OR: 1.086; 95%CI: 1.010 to 1.187; P = 0.0489) were identified as independent predictors of LAA thrombus. No Thrombi were detected in patients with a CHA₂DS₂-VASc score ≤ 1.

CONCLUSION

Among patients with non-valvular AF and ≥ 4 wk of anticoagulation with apixaban, the prevalence of LAA thrombus detected by TEE was 3.1%. This suggests that continuous therapy with apixaban does not completely eliminate the risk of LAA thrombus and that TEE prior to cardioversion or catheter ablation may be of benefit in patients with multiple risk factors.

The ability of left ventricular end-diastolic volume variations measured by TEE to monitor fluid responsiveness in high-risk surgical patients during craniotomy: a prospective cohort study

BACKGROUND

This study was aimed to evaluate the ability of left ventricular end-diastolic volume variations (LVEDVV) measured by transesophageal echocardiography (TEE) compared with stroke volume variation (SVV) obtained by the FloTrac/Vigileo monitor to predict fluid responsiveness, in patients undergoing craniotomy with goal direct therapy.

METHODS

We used SVV obtained by the FloTrac/Vigileo monitor to manage intraoperative hypotension in adult patients undergoing craniotomy (ASA III - IV) after obtaining IRB approval and informed consent. The LVEDVV were measured by TEE through the changes of left ventricular short diameter of axle simultaneously. When cardiac index (CI) ≤ 2.5 and SVV ≥ 15%, comparisons were made between the two devices before and after volume expansion.

RESULTS

We enrolled twenty-six patients referred for craniotomy in this study and 145 pairs of data were obtained. Mean Vigileo-SVV and TEE-LVEDVV were 17.8 ± 2.78% and 22.1 ± 7.25% before volume expansion respectively, and were 10.95 ± 2.8% and 13.58 ± 3.78% after volume expansion respectively (P < 0.001). The relationship between Vigileo-SVV and TEE-LVEDVV was significant (r2 = 0.55; p < 0.001). Agreement between Vigileo-SVV and TEE-LVEDVV was 3.3% ± 3.9% (mean bias ± SD, Bland-Altman).

CONCLUSIONS

For fluid responsiveness of patients during craniotomy in ASA III-IV, LVEDVV measured by left ventricular short diameter of axle using M type echocaidiographic measurement seems an acceptable monitoring indicator. This accessible method has promising clinical applications in situations where volume and cardiac function monitoring is of great importance during surgery.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, ChiCTR-TRC-13003583 , August 20, 2013.

Incidence and Predictors of Left Atrial Appendage Thrombus in Patients Treated With Nonvitamin K Oral Anticoagulants Versus Warfarin Before Catheter Ablation for Atrial Fibrillation

The utility of routine transesophageal echocardiography (TEE) to exclude left atrial appendage (LAA) thrombus before atrial fibrillation (AF) ablation in patients treated with nonvitamin K oral anticoagulant (NOAC) therapy is unclear. This single-center retrospective study sought to investigate the incidence of LAA thrombus in patients undergoing routine TEE before AF ablation treated with warfarin or NOAC therapy. We included 937 routine pre-AF ablation TEE procedures performed in patients treated with warfarin (n = 517) or NOAC (n = 420). Patients were anticoagulated without interruption for at least 4 consecutive weeks before the TEE. Patients treated with warfarin had lower LAA velocity and underwent TEE earlier in the study period than those treated with NOAC (p <0.05). The incidence of LAA thrombus was higher in patients treated with warfarin (1.55%, 8 of 517) compared with patients treated with NOAC (0.24%, 1 of 420, p = 0.0473 for difference). No LAA thrombus was identified in NOAC-treated patients with a CHA₂DS₂-VASC score <5 and in warfarin-treated patients with a CHA₂DS₂-VASC score <2. TEE-related complications occurred in 3 of 937 procedures (0.3%). In conclusion, LAA thrombus is detected rarely during pre-AF ablation TEE. Treatment with an NOAC is associated with a lower incidence of pre-AF ablation LAA thrombus compared with warfarin.

Cost analysis of periprocedural imaging in patients undergoing catheter ablation for atrial fibrillation

Cardiovascular imaging is an important part of procedural planning and safety for catheter ablation of atrial fibrillation (AF). However, the costs of imaging surrounding catheter ablation of AF have not been described. Medicare fee-for-service data were used to evaluate Medicare expenditures before, during, and after catheter ablation for AF from July 2007 to December 2009. Among 11,525 patients who underwent catheter ablation for AF, the mean overall expenditure on the day of the procedure was $14,455 (SD $7,441). The mean imaging expenditure in the periprocedural period, which included the 30 days before the catheter ablation and the day of the ablation itself, was $884 (SD $455). Periprocedural imaging expenditures varied by the imaging strategy used, ranging from a mean of $557 (SD $269) for patients with electroanatomic mapping only to $1,234 (SD $461) for patients with electroanatomic mapping, transesophageal echocardiogram, and computed tomography or magnetic resonance imaging. Mean patient-level imaging expenditures varied by provider (mean $872, SD $249). Periprocedural imaging expenditures also varied by patient risk, with mean expenditures of $862 (SD $444) for patients with a CHADS2 score of ≥2 compared with $907 (SD $466) for CHADS2 score<2 (p<0.001). In conclusion, periprocedural imaging accounts for approximately 6% of mean Medicare expenditures for catheter ablation of AF. The expenditures for periprocedural imaging vary both at the patient and at the provider level and they are inversely related to stroke risk by CHADS2 score.

Cost-effectiveness of the convergent procedure and catheter ablation for non-paroxysmal atrial fibrillation

OBJECTIVE

Patients with persistent or longstanding atrial fibrillation have modest success achieving sinus rhythm with catheter ablation or rhythm control medications. Their high risk of stroke, bleed, and heart failure leads to significant morbidity and health care costs. The convergent procedure has been shown to be successful in this population, with 80% of patients in sinus rhythm after 1 year. This study evaluated the cost-effectiveness of the convergent procedure, catheter ablation, and medical management for non-paroxysmal AF patients.

METHODS

A Markov micro-simulation model was used to estimate costs and effectiveness from a payer perspective. Parameter estimates were from the literature. Three patient cohorts were simulated, representing lower, medium, and higher risks of stroke, bleed, heart failure, and hospitalization. Effects were estimated by quality-adjusted life-years (QALYs). Single-variable sensitivity analysis was performed.

RESULTS

After 5 years, convergent procedure patients averaged 1.10 procedures, with 75% of survivors in sinus rhythm; catheter ablation patients had 1.65 procedures, with 49% in sinus rhythm. Compared to medical management, catheter ablation and the convergent procedure were cost-effective for the lower risk (ICER <$35,000) and medium risk (ICER <$15,000) cohorts. The procedures dominated medical management for the higher risk cohort (lower cost and higher QALYs). The convergent procedure dominated catheter ablation for all risk cohorts. RESULTS were subject to simplifying assumptions and limited by uncertain factors such as long-term maintenance of sinus rhythm after successful procedure and incremental AF-associated event rates for AF patients relative to patients in sinus rhythm. In the absence of clinical trial data, convergent procedure efficacy was estimated with observational evidence. Limitations were addressed with sensitivity analyses and a moderate 5 year time horizon.

CONCLUSION

The convergent procedure results in superior maintenance of post-ablation sinus rhythm with fewer repeat ablation procedures compared to catheter ablation, leading to lower cost and higher QALYs after 5 years.

Use of number needed to treat in cost-effectiveness analyses

OBJECTIVE

To review the use of number needed to treat (NNT) and/or number needed to harm (NNH) values to determine their relevance in helping clinicians evaluate cost-effectiveness analyses (CEAs).

DATA SOURCES

PubMed and EconLit were searched from 1966 to September 2012.

STUDY SELECTION AND DATA EXTRACTION

Reviews, editorials, non-English-language articles, and articles that did not report NNT/NNH or cost-effectiveness ratios were excluded. CEA studies reporting cost per life-year gained, per quality-adjusted life-year (QALY), or other cost per effectiveness measure were included. Full texts of all included articles were reviewed for study information, including type of journal, impact factor of the journal, focus of study, data source, publication year, how NNT/NNH values were reported, and outcome measures.

DATA SYNTHESIS

A total of 188 studies were initially identified, with 69 meeting our inclusion criteria. Most were published in clinician-practice-focused journals (78.3%) while 5.8% were in policy-focused journals, and 15.9% in health-economics-focused journals. The majority (72.4%) of the articles were published in high-impact journals (impact factor >3.0). Many articles focused on either disease treatment (40.5%) or disease prevention (40.5%). Forty-eight percent reported NNT as a part of the CEA ratio per event. Most (53.6%) articles used data from literature reviews, while 24.6% used data from randomized clinical trials, and 20.3% used data from observational studies. In addition, 10% of the studies implemented modeling to perform CEA.

CONCLUSIONS

CEA studies sometimes include NNT ratios. Although it has several limitations, clinicians often use NNT for decision-making, so including NNT information alongside CEA findings may help clinicians better understand and apply CEA results. Further research is needed to assess how NNT/NNH might meaningfully be incorporated into CEA publications.

Usefulness of transoesophageal echocardiography before circumferential pulmonary vein ablation in patients with atrial fibrillation: is it really mandatory?

AIMS

Transoesophageal echocardiography (TEE) is recommended prior to circumferential pulmonary vein ablation (CPVA) in patients with atrial fibrillation (AF) to identify left atrial (LA) or left atrial appendage (LAA) wall thrombi. It is not clear whether all patients undergoing CPVA should receive pre-procedural TEE. We wanted to assess the incidence of LA thrombus in these patients and to identify factors associated with its presence.

METHODS AND RESULTS

Consecutive patients referred for CPVA from 2004 to 2009 underwent TEE within 48 h prior to the procedure. Of 408 patients included in the study, 6 patients (1.47%) had LA thrombi, persistent AF, and LA dilation. Compared with patients without thrombus, these six patients had larger LA diameter (P = 0.0001) and more frequently were women (P = 0.002), had persistent AF (P = 0.04), and had underlying structural cardiac disease (P = 0.014). The likelihood of presenting LA thrombus increased with the number of these four risk factors present (P < 0.001). None of the patients with paroxysmal AF and without LA dilation had LA thrombus. A cut-off value of 48.5 mm LA diameter yielded 83% sensitivity, 92% specificity, and a 10.1 likelihood ratio to predict LA thrombus appearance.

CONCLUSION

The incidence of LA thrombus prior to CPVA is low. Persistent AF, female sex, structural cardiopathy, and LA dilation were associated with the presence of LA thrombus. Our data suggest that the use of TEE prior to CPVA to detect LA thrombi might not be needed in patients with paroxysmal AF and no LA dilation or structural cardiopathy.