Exclusion Of Thrombus Research Articles

Effectiveness of integrating delayed computed tomography angiography imaging for left atrial appendage thrombus exclusion into the care of patients undergoing ablation of atrial fibrillation

Computed tomography angiography (CTA) can identify and rule out left atrial appendage (LAA) thrombus when delayed imaging is also performed. In patients referred for CTA to evaluate pulmonary vein anatomy before the ablation of atrial fibrillation (AF) or left atrial flutter (LAFL), we sought to determine the effectiveness of a novel clinical protocol for integrating results of CTA delayed LAA imaging into preprocedure care. After making delayed imaging of the LAA part of our routine preablation CTA protocol, we integrated early reporting of preablation CTA LAA imaging results into clinical practice as part of a formal protocol in June 2013. We then analyzed the effectiveness of this protocol by evaluating 320 AF/LAFL ablation patients with CTA imaging during the time period 2012-2014. In CTA patients with delayed LAA imaging, the sensitivity and negative predictive values for LAA thrombus using intracardiac echocardiography or transesophageal echocardiography (TEE) as the reference standard were both 100%. Intracardiac echocardiography during ablation confirmed the absence of thrombus in patients with negative CTA or negative TEE results. No patients with either negative CTA results or equivocal CTA results combined with negative TEE results had strokes or transient ischemic attacks. Overall, the need for TEE procedures decreased from 57.5% to 24.0% during the 3-year period because of the CTA protocol. Clinical integration of CTA delayed LAA imaging into the care of patients having catheter ablation of AF or LAFL is feasible, safe, and effective. Such a protocol could be used broadly to improve patient care.

Comparison of Transesophageal Echocardiography Versus Computed Tomography for Detection of Left Atrial Appendage Filling Defect (Thrombus)

Patients with atrial fibrillation, who are referred for radiofrequency pulmonary vein antral isolation, frequently undergo transesophageal echocardiography (TEE) to detect and/or exclude left atrial or left atrial appendage (LAA) thrombus and cardiac computed tomographic angiography (CCTA) to define and/or evaluate left atrial and pulmonary venous anatomy. Previous studies have reported CCTA to have high sensitivity and negative predictive value (NPV) for detecting thrombus in the LAA. Previous studies determining an optimal LAA/ascending aorta (AA) Hounsfield unit (HU) density ratio for detection of LAA thrombus have been small, with limited numbers of thrombi. We thus sought to determine both the optimal cutoff for LAA HU density and LAA/AA HU density ratio in detecting LAA thrombus compared with TEE in a multicenter population. We included 84 patients who had undergone CCTA and TEE. LAA was evaluated by 64-row CCTA qualitatively (visual filling defect) and quantitatively (measurement of LAA HU density and LAA/AA HU density ratio), using a 1-cm area of interest in the same axial plane. Results were compared with TEE visualization of thrombus or spontaneous echo contrast. Qualitative identification of thrombus in LAA by CCTA compared with TEE detection of thrombus had a sensitivity of 100%, a specificity of 77.9%, a positive predictive value (PPV) of 51.6%, an NPV of 100%, and a total accuracy of 82.1%. The optimal LAA HU density cutoff for thrombus detection was 119 with a sensitivity of 88%, a specificity of 86%, PPV 56%, and an area under the curve of 0.923 (p = 0.0004). The optimal LAA/aorta HU ratio was 0.242 with a sensitivity of 87%, a specificity of 88%, a PPV of 64%, and an area under the curve of 0.921 (p = 0.0011). There is no significant difference (p = 0.72) between both areas under the curve, and both measurements improved the specificity and PPV compared with qualitative measures. Multidetector computed tomography is an imaging technique that can exclude LAA thrombus with very high NPV. Quantitative measurement of LAA HU density (cutoff 119) or LAA/aorta HU density ratio (cutoff 0.242) improves accuracy of positively detecting LAA thrombus. This technique is especially useful when delayed scanning is not performed and LAA is found incidentally after the patient scanning is complete.

Contrast enhanced transesophageal echocardiography in patients with atrial fibrillation referred to electrical cardioversion improves atrial thrombus detection and may reduce associated thromboembolic events

AimsTransesophageal echocardiography (TEE) is the gold standard for the detection of thrombi in patients with atrial fibrillation (AF) before undergoing early electrical cardioversion (CV). However, TEE generates inconclusive results in a considerable number of patients. This study investigated the influence of contrast enhancement on interpretability of TEE for the detection of left atrial (LA) thrombi compared to conventional TEE and assessed, whether there are differences in the rate of thromboembolic events after electrical cardioversion.MethodsOf 180 patients with AF (51 females, 65.2±13 years) who were referred to CV, 90 were examined with native imaging and contrast enhancement within the same examination (group 1), and 90 were examined with native TEE alone and served as control (group 2). Cineloops of the multiplane examination of the LA and LA appendage (LAA) were stored digitally before and, in group 1, after intravenous bolus application of a transpulmonary contrast agent. Images of group 1 were assessed offline and the diagnosis of LA thrombi was made semi-quantitatively: 1= thrombus present; 2=inconclusive result; 3=no thrombus. The presence of spontaneous echocontrast (SEC) was registered and flow velocity in the LA appendage (LAA-flow) was measured. All patients in whom CV was performed were followed up for 1 year or until relapse of AF. CV related adverse events were defined as any thromboembolic event within 1 week after CV.ResultsNo serious adverse events occurred during TEE and contrast enhanced imaging. In group 1 atrial thrombi were diagnosed in 14 (15.6%) during native and in 10 (11.1%) patients during contrast enhanced imaging (p<0.001). Of the 10 patients with thrombi in the contrast TEE group, 7 revealed a decreased LAA-flow (≤0,3m/s) and 8 showed moderate or marked SEC. Uncertain results were significantly more common during native imaging than with contrast enhanced TEE (16 vs. 5 patients, p<0.01). Thrombi could definitely be excluded in 60 (66.7%) during conventional and in 75 patients (83.3%) during contrast enhanced TEE (p<0.01). CV was performed subsequently after exclusion of thrombi and at the discretion of the investigator. In group 1, 74 patients (82.2%) were cardioverted and no patient suffered a CV related complication (p=0.084). In group 2, 76 patients (84.4%) underwent CV, of whom 3 suffered a thromboembolic complication after CV (2 strokes, 1 peripheral embolism).ConclusionIn patients with AF planned for CV contrast enhancement renders TEE images more interpretable, facilitates the exclusion of atrial thrombi and may reduce the rate of embolic adverse events.

A dedicated cardioversion unit for the treatment of atrial fibrillation

Atrial fibrillation (AF) is the most frequent arrhythmia seen in man. Many patients are admitted to the hospital to undergo transesophageal echocardiography (TEE) for thrombus exclusion and subsequent electrical cardioversion (ECV) under deep sedation to restore sinus rhythm. The present study investigated prospectively how workflow optimization can contribute to reducing time and costs in AF patients scheduled for ECV in an outpatient setting. A cardioversion unit (CU) was established and equipped to perform all ECV-associated procedures. Between November2007 and January2009, ECV was performed in 115patients in an outpatient setting. Three different settings were tested for ECV: (1) usual care (n = 19): preparation/follow-up in the outpatient clinic, blood testing in the central hospital laboratory (CHL), TEE in the echocardiography laboratory, and ECV in the intensive care unit; (2) optimized process1 (n = 41): preparation/follow-up, TEE + ECV during one sedation in the CU, blood testing in the CHL; (3) optimized process2 (n = 55): preparation/follow-up, TEE + ECV and point of care (POC) blood testing in the CU. All procedure-related costs were listed and classified according to material, human resources, and infrastructure. From setting1 to 3, there was a significant decrease in procedural time from 480 ± 105min to 205 ± 85min (p < 0.001). Likewise, ECV-associated costs could be reduced from 683 ± 104<euro> to 299 ± 63<euro> (p < 0.001). Establishing a CU for AF enables a more than 50% reduction in procedural time and costs. A combination of TEE and ECV in one sedation and POC testing in the CU were the major contributors to this time and cost reduction.

TEE time? ICETEE time! IntraCardiac Echocardiography probe used for TransoEsophageal Echocardiography

Transoesophageal echocardiography (TEE) is performed to exclude thrombi, both in the left atrium (LA) and the left atrial appendage (LAA) before radiofrequency ablation (RFA) for atrial fibrillation (AF). Some patients experience discomfort during TEE. Intracardiac echocardiography (ICE) is used for the exclusion of thrombi and guiding transseptal puncture (TSP). We describe the first cases using an expired and then re-sterilised ICE probe (AcuNav™) for TEE. A 70-year-old male patient was admitted for ablation of a 10-year lasting permanent AF ( Figure 1A ). Because of gastrointestinal bleeding he temporarily discontinued Warfarin and suffered a transient ischaemic attack 9 months prior to RFA. The gastroscopic procedure was …

Endovascular Therapy for Symptomatic Mobile Thrombus of Infrarenal Abdominal Aorta

Mobile thrombus is a rare cause of distal arterial embolization. We report 2 cases of mobile thrombus of the abdominal aorta leading to distal embolization. Both patients were successfully treated with endovascular exclusion of the thrombus and distal embolectomy. Endovascular exclusion of a mobile thrombus of the abdominal aorta is a significantly less invasive alternative to open abdominal aorta thrombectomy.

A novel approach to the diagnosis of left atrial appendage thrombus using contrast echocardiography and power Doppler imaging

Transesophageal echocardiography is performed routinely among patients with atrial fibrillation (AF) in order to exclude left atrial appendage (LAA) thrombus prior to cardioversion. Because assessment for LAA thrombus is dependent upon the experience of the operator and is therefore subjective, there remains a subset of patients in whom the diagnosis may not be definitive. The purpose of this report is to present a novel technique which may aid in the confirmation and/or exclusion of LAA thrombus using contrast echocardiography (CE) and power Doppler (PD) imaging. TEE imaging of the LAA appendage was performed in 3 patients. By visual inspection, the presence of the thrombus was absent (patient one), equivocal (patient two) and definite (patient three). Contrast echocardiography with Definity and power Doppler imaging was performed to aid in the confirmation and/or exclusion of thrombus in these 3 patients. CE alone was useful in confirming the absence and presence of LA thrombus determined by visual inspection in patients one and three, respectively. CE in conjunction with PD imaging was useful in identifying the presence of LAA thrombus (by showing a filling defect and the absence of flow in the tip) in the patient with equivocal results by visual inspection Contrast echocardiography alone may be useful in confirming and/or excluding the presence of LAA thrombus among patients with AF. CE with PD imaging provides incremental information in aiding in the diagnosis when the conventional images are equivocal.

Single-step atrial thrombus exclusion and transesophageal cardioversion in atrial fibrillation

Atrial fibrillation (AF), the most common arrhythmia, has a major impact on both patient morbidity and healthcare economics. Hospital admissions due to AF have risen by two-thirds in the last 20 years. This is due mainly to an aging population and an increasing prevalence of chronic heart disease. Strategies for the management of AF include prevention of thromboembolism, rate control and correction of the arrhythmia. Electrical cardioversion as one component of the treatment of AF requires the absence of atrial thrombi. Transesophageal echocardiography is used routinely for exclusion of atrial thrombi prior to cardioversion in many hospitals. This review presents preliminary data on the clinical use of devices for simultaneous transesophageal echocardiography and transesophageal cardioversion.

Simultaneous transesophageal cardioversion and echocardiography: Feasibility and safety

Transesophageal echocardiography (TEE) is routinely used to exclude atrial thrombus prior to cardioversion of atrial fibrillation (AF). Because the TEE probe lies adjacent to the atria, cardioversion using an electrode attached to the TEE probe should allow for immediate low-energy transesophageal cardioversion. The purpose of this study was to evaluate a cardioversion electrode sheath that can be affixed to conventional TEE probes for simultaneous thrombus exclusion and cardioversion of AF. A thin electrode was integrated into a latex or polyurethane sheath covering a conventional TEE probe. TEE thrombus exclusion and biphasic transesophageal cardioversion using a step-up protocol were performed during deep sedation. Esophagoscopy was performed immediately after cardioversion and after 1 week. TEE was performed in 27 patients. One patient showed left atrial thrombi. Transesophageal cardioversion was successful in 25 of the remaining 26 patients. Mean atrial cardioversion threshold was 63 +/- 48 J. Transesophageal cardioversion restored sinus rhythm in two patients with unsuccessful transthoracic cardioversion. Transesophageal cardioversion in deep sedation was well tolerated. Esophagoscopy revealed slight mucosal damage in three patients at the site of shock application; two of these patients showed signs of gastroesophageal reflux disease. Mucosal damage unrelated to the site of shock delivery was noted in three patients. Atrial thrombus exclusion and transesophageal cardioversion of AF via a disposable cardioversion sheath offers the opportunity to perform transesophageal cardioversion and TEE thrombus exclusion during one sedation. It may not be suitable for use in patients with gastroesophageal reflux disease. Transesophageal cardioversion may establish sinus rhythm in selected patients refractory to transthoracic cardioversion.

Prevalence of left atrial chamber and appendage thrombi in patients with atrial flutter and its clinical significance

OBJECTIVESThe study was done to assess the prevalence of left atrial (LA) chamber and appendage thrombi in patients with atrial flutter (AFl) scheduled for electrophysiologic study (EPS), to evaluate the prevalence of thromboembolic complications after transesophageal echocardiographic (TEE)-guided restoration of sinus rhythm and to evaluate clinical risk factors for a thrombogenic milieu.BACKGROUNDRecent studies showed controversial results on the prevalence of atrial thrombi and the risk of thromboembolism after restoring sinus rhythm in patients with AFl.METHODSBetween 1995 and 1999, patients with AFl who were scheduled for EPS were included in the study. After transesophageal assessment of the left atrial appendage and exclusion of thrombi, an effective anticoagulation was initiated and patients underwent EPS within 24 h.RESULTSWe performed 202 EPSs (radiofrequency catheter ablation, n = 122; overdrive stimulation, n = 64; electrical cardioversion, n = 16) in 139 consecutive patients with AFl. Fifteen patients with a thrombogenic milieu were identified. All of them had paroxysmal atrial fibrillation (AF). Transesophageal echocardiography revealed LA thrombi in two cases (1%). After EPS no thromboembolic complications were observed. Diabetes mellitus, arterial hypertension and a decreased left ventricular ejection fraction were found to be independent risk factors associated with a thrombogenic milieu.CONCLUSIONSThe findings of a low prevalence of LA appendage thrombi (1%) in patients with AFl and a close correlation between a history of previous embolism and paroxysmal AF support the current guidelines that patients with pure AFl do not require anticoagulation therapy, whereas patients with AFl and paroxysmal AF should receive anticoagulation therapy. In addition, the presence of clinical risk factors should alert the physician to an increased likelihood for a thrombogenic milieu.

Transesophageal echocardiography for early cardioversion of atrial fibrillation

Exclusion of thrombi in the setting of atrial fibrillation (AF) has important implications for early cardioversion. Cardioversion guided by transesophageal echocardiography (TEE) is a safe and relatively cost-effective technique with a high accuracy for detecting left-atrial thrombi. Nowadays, TEE-guided cardioversion may help to select patients suitable for early cardioversion. However, the long-term effect of early TEE-guided cardioversion on the maintenance of sinus rhythm needs to be determined.

Role of echocardiography in patients undergoing elective cardioversion of atrial fibrillation.

Echocardiography has emerged as a fundamental tool in the evaluation of patients with atrial fibrillation (AF). Transthoracic echocardiography remains a primary tool for the evaluation and management of many patients presenting with their first episode of AF, but it is not adequate for exclusion of atrial thrombi. TEE offers excellent visualization of the atria and accurate identification or exclusion of thrombi. In concert with therapeutic anticoagulation, a TEE-guided approach to early cardioversion appears to have a safety profile similar to that of conventional therapy (1 month of precardioversion warfarin). The TEE-guided approach offers the advantages of simplified anticoagulation management and shorter duration of sustained AF, thereby allowing for a more rapid recovery of atrial mechanical function. Warfarin should be continued for 1 month after cardioversion to allow for more complete recovery of atrial function and for prophylaxis should the patient revert to AF. Cost-effectiveness models demonstrate that TEE-guided cardioversion represents a cost-effective strategy, but only if the transthoracic echocardiogram is omitted. For patients with a thrombus on the initial TEE, follow-up TEE (to document thrombus resolution) is recommended before cardioversion.

Transoesophageal echocardiography in critically ill patients. A comprehensive approach

Transoesophageal echocardiography in critically ill patients. A comprehensive approach

Effect of intracoronary ultrasound imaging on clinical decision making

The aim of this study was to determine the effect of intravascular ultrasound (IVUS) imaging on decision making in the performance of coronary interventions. One hundred lesions were assessed in 87 patients undergoing balloon or laser angioplasty, atherectomy, stent placement, and additional diagnostic examination. Angiographically acceptable results were deemed inadequate by IVUS in 29% of angioplasties and 30% of stent deployments, and planned procedures subsequently were altered. Abnormalities commonly identified by IVUS and not by angiography were 13 coronary dissections after the procedure and 14 significant stenoses in apparently normal angiograms and significant stenoses were excluded in 7 patients with ambiguous angiograms. The apparent contribution of coronary IVUS imaging led to its significantly increased use over a 1-year period, as coronary interventional decisions on the basis of IVUS findings increased from 4 (17%) of 19 to 60 (74%) of 81. These data suggest that IVUS is a useful adjunct to angiography in selected patients for (1) identification or exclusion of dissection, (2) assessment of the adequacy of balloon angioplasty, (3) identification or exclusion of thrombus, (4) measurement of the depth of tissue removal, (5) determination of stent size and the result of stent deployment, and (6) assessment of the severity of stenoses, especially at ostial sites.

Left ventricular thrombi: evaluation with spin-echo and gradient-echo MR imaging.

Gradient-echo (GRE) and spin-echo (SE) magnetic resonance (MR) imaging was performed in 31 patients with chronic left ventricular (LV) thrombi. Thrombi were confirmed or excluded at surgery or by means of other corroborative diagnostic techniques. MR images were evaluated by three reviewers without knowledge of results of corroborative studies. Diagnoses were graded unequivocal if agreed on by three observers and probable if agreed on by two observers. With SE imaging, 12 of 18 confirmed thrombi were detected unequivocally, five were considered probable, and one was not detected. With GRE imaging, 16 of the 18 thrombi were visualized unequivocally; two were considered probable. With SE technique, thrombus was unequivocally excluded in nine of 13 cases and exclusion was considered probable in four. One finding was false-negative. Exclusion of thrombus with GRE imaging was unequivocal in 10 of 13 cases and probable in two, and one finding of thrombus was false-positive. GRE imaging resulted in improved differentiation of thrombi from the surrounding blood pool and myocardium and thus was diagnostically superior to SE imaging in detection of LV thrombi.