Transthoracic echocardiography versus transesophageal echocardiography in detecting cardiac sources of embolism

Multimodal Cardiac Imaging in the Assessment of Patients Who Have Suffered a Cardioembolic Stroke: A Review

Cardioembolic strokes account for 20-25% of all ischaemic strokes, with their incidence increasing with age. Cardiac imaging plays a crucial role in identifying cardioembolic causes of stroke, with early and accurate identification affecting treatment, preventing recurrence, and reducing stroke incidence. Echocardiography serves as the mainstay of cardiac evaluation. Transthoracic echocardiography (TTE) is the first line in the basic evaluation of structural heart disorders, valvular disease, vegetations, and intraventricular thrombus. It can be used to measure chamber size and systolic/diastolic function. Trans-oesophageal echocardiography (TOE) yields better results in identifying potential cardioembolic sources of stroke and should be strongly considered, especially if TTE does not yield adequate results. Cardiac computed tomography and cardiac magnetic resonance imaging provide better soft tissue characterisation, high-grade anatomical information, spatial and temporal visualisation, and image reconstruction in multiple planes, especially with contrast. These techniques are useful in cases of inconclusive echocardiograms and can be used to detect and characterise valvular lesions, thrombi, fibrosis, cardiomyopathies, and aortic plaques. Nuclear imaging is not routinely used, but it can be used to assess left-ventricular perfusion, function, and dimensions and may be useful in cases of infective endocarditis. Its use should be considered on a case-by-case basis. The accuracy of each imaging modality depends on the likely source of cardioembolism, and the choice of imaging approach should be tailored to individual patients.

Clinical Utility of the Transthoracic Echocardiogram for Isolated Lacunar Infarcts: A Single-Center Experience

BACKGROUND

Stroke is a prominent and financially burdensome disease. Lacunar strokes are traditionally attributed to small vessel disease rather than cardioemboli, which typically occlude larger arteries. Thus, the benefit of screening for potential sources of cardioemboli in lacunar stroke patients is unclear. We evaluated the clinical utility of the transthoracic echocardiogram performed in patients with lacunar strokes.

METHODS

A single-center retrospective analysis of ischemic stroke patients from January 2013 through December 2017 was performed. Brain magnetic resonance imaging was used to select patients with a single lacunar infarct. Patients presenting with acute symptoms of cardiac disease or an abnormal electrocardiogram were excluded. Transthoracic echocardiogram results were reviewed, and their utility in decision-making was evaluated.

RESULTS

Of the 442 patients at our institution diagnosed with ischemic stroke during the inclusion period, 89 met inclusion criteria. Transthoracic echocardiogram detected a patent foramen ovale in 5.6% of patients, mitral annular calcification in 9.0% of patients, and abnormal wall motion in 4.5% of patients. For all patients, there were no findings that prompted anticoagulation, antibiotic, or surgical intervention. The cost of an inpatient transthoracic echocardiogram is $4100, resulting in $364,900 in unnecessary health care spending.

CONCLUSIONS

Transthoracic echocardiogram appears to have minimal therapeutic value in most patients with lacunar strokes. In stroke patients with no acute symptoms of cardiac disease and a normal electrocardiogram, it may be reasonable to forgo the transthoracic echocardiogram if the brain magnetic resonance imaging shows an isolated lacunar infarct.

Screening in cryptogenic brain abscess: Do not forget pulmonary arteriovenous malformations

Background:

Brain abscess usually occurs secondary to trauma, through contiguous spread (e.g.; dental infections, [paranasal] sinusitis, otitis, and mastoiditis), after intracranial neurosurgical procedures, or through hematogenous spread in case of an arteriovenous (AV) shunt, for example; atrial septum defect. Although uncommon, another possible cause of AV shunt which can facilitate brain abscess is a pulmonary arteriovenous malformation (PAVM). We report a case of brain abscess secondary to a solitary PAVM and review the literature.

Case Description:

A 74-year-old male patient presented with headaches, fatigue, low-grade fever, and homonymous hemianopsia. He was diagnosed with a brain abscess in the left occipital lobe. A chest computed tomography (CT) with intravenous (IV) contrast was performed because of fever and respiratory insufficiency in a period where screening for COVID-19 in suspected patients was important. A solitary PAVM of the left lung was diagnosed. Initial stereotactic burr hole drainage of the abscess was insufficient and resection of the abscess was deemed necessary. Routine workup did not reveal any additional pathology apart from the PAVM. After treatment of the cerebral abscess, the PAVM was treated with embolization using an endovascular plug.

Conclusion:

It is recommended to screen for PAVM by chest CT with IV contrast in patients with brain abscess when no obvious source of infection can be identified.

Effect of abnormal right heart structures on the diagnosis of pulmonary hypertension

The diagnosis of pulmonary hypertension (PH) requires a right heart catheterization (RHC) that reveals a mean pulmonary artery pressure ≥ 25 mmHg. The pulmonary artery catheter traverse the right atrium and ventricle on its way to the pulmonary artery. The presence of abnormal right heart structures, i.e. thrombus, vegetation, benign or malignant cardiac lesions, can lead to complications during this procedure. On the other hand, avoidance of RHC delays the diagnosis and treatment of PH, an approach that might be associated with worse outcomes. This paper discusses the impact of right heart lesions on the diagnosis of PH and suggests an approach on how to manage this association.

Peripheral Arterial Embolism: Prevalence, Outcome, and the Role of Echocardiography in Management

The aims of this study were to review the prevalence and outcome of all surgically treated upper and lower limb emboli presenting to one vascular unit in the last 3 years and to compare transthoracic with transesophageal echocardiography for defining the source of the embolus. All patients who underwent surgical embolectomy for acute limb ischemia from January 2001 to June 2004 were reviewed. Transthoracic and transesophageal echocardiography were carried out on a subset of consecutive unselected patients. Forty-two patients, with a mean age of 80 years, underwent surgical embolectomy from January 2001 to June 2004 (M/F 1:1.8): 27 for lower limb ischemia and 15 for upper limb ischemia. Two thirds of these patients were found to be in atrial fibrillation at presentation (n=28), of whom less than a third were receiving anticoagulants or antiplatelet agents (n=8). The mean hospital stay was 15 days with 36 patients (86%) being fully anticoagulated before discharge from hospital. The 30-day mortality rate was 11% (n=3/27) with 5 patients requiring fasciotomies (12%) and 3 patients requiring an amputation of the lower limb (11%). Postoperatively, 34 patients (81%) had transthoracic echocardiography (TTE), which demonstrated a source or potential source for thrombus in 19 (56%). Fifteen patients (36%) had transesophageal echocardiography (TEE), which changed the subsequent management in 3 patients. All patients in whom TEE altered clinical management would have required this investigation if standard clinical guidelines were followed. TEE did not identify any additional patients with cardiac embolic sources that were not detected by TTE. Arterial limb emboli are still prevalent, but limb salvage and mortality rates appear to be improving. Despite clear guidelines on anticoagulation for patients in atrial fibrillation, many are not receiving appropriate treatment. Transthoracic echocardiography is a good screening tool for detecting a potential cardiac source for peripheral embolism, with transesophageal echocardiography being reserved for specific indications.

Current incidence of peripheral arterial embolism and role of echocardiography

We reviewed the incidence and outcome of all cases of upper and lower limb embolism surgically treated in our vascular unit, from January 2001 to June 2006, to assess the role of transthoracic and transesophageal echocardiography in defining the source of the embolus. Transthoracic echocardiography was carried out postoperatively, and patients in whom the embolic source was not found underwent transesophageal echocardiography. There were 85 patients (mean age, 69 years) who underwent embolectomy: 58 for lower and 27 for upper limb ischemia. The source or potential source of thrombus was demonstrated in 17 (20%) patients after transthoracic echocardiography. Fifty-three patients had transesophageal echocardiography, the source of embolism was found in 85%, and the subsequent management was changed in 47% of them. Arterial limb emboli are still prevalent in developing countries. Transthoracic echocardiography is a good screening tool for detecting a potential cardiac source of peripheral embolism, with transesophageal echocardiography being reserved for specific indications.

[Clinical and therapeutic characteristics of limb emboli]

INTRODUCTION

To treat an extremity embolus seems to be a simple and safe procedure. However, it is not exempt from potentially serious complications. We review our experience of treating acute peripheral arterial occlusion due to emboli.

PATIENTS AND METHOD

We retrospectively analyzed the data of 127 embolectomies performed during the last five years, in 120 extremities in 116 patients. The mean age of the patients was 80 years and 66% were female. All cases were presented as acute threatened limb ischemia grades IIA or IIB, and the mean evolution time was 27 hours. The patency, limb salvage and morbidity-mortality rates in the postoperative period and the salvage and survival rates in the follow-up were analyzed.

RESULTS

Of the embolectomies, 55% were femoral and 30% brachial. Although 90% of the cases improved, only 75% of them recovered distal pulses. In the postoperative period the patency, limb salvage, morbidity and mortality rates were 90%, 96%, 13% and 6.4%, respectively. The mean follow-up was 24 months. Up until this time, the patency and survival rates are 91% and 61%, respectively. The only factor related with an increase in the amputation rate was a clinical presentation, such as a threatened immediate ischemia. The factors related with an increase in survival rate were appropriate cardiological treatment and control, and long-term anticoagulation treatment.

CONCLUSIONS

Suffering an embolus of the extremities and its treatment causes considerable morbidity-mortality and limb amputation rates. The extremity salvage is associated with the clinical presentation at the time of the treatment. Long-term anticoagulation treatment and appropriate cardiological control increase the survival of these patients.

Clinical, imaging, and pathological characteristics of left ventricular thrombus: a comparison of contrast-enhanced magnetic resonance imaging, transthoracic echocardiography, and transesophageal echocardiography with surgical or pathological validation

BACKGROUND

Left ventricular (LV) thrombus is a frequent and potentially dangerous complication of ischemic heart disease (IHD). We evaluated the clinical, imaging, and pathology characteristics of confirmed LV thrombus and compared the diagnostic value of contrast-enhanced magnetic resonance imaging (MRI) with transthoracic (TTE) and transesophageal echocardiography (TEE) for the diagnosis of LV thrombi.

METHODS

Between November 1997 and December 2003, 361 patients with IHD had surgical and/or pathological confirmation of presence or absence of LV thrombus. Clinical information and preoperative imaging study reports were retrospectively reviewed regarding detection of thrombus. Comparisons were made between clinical and imaging characteristics of patients with and without confirmed thrombus.

RESULTS

Left ventricular thrombus was present in 106 (29%) of 361 patients in this study. Patients with thrombus had a higher incidence of recent embolic events (6.1% vs 0.8%, P < .005). In 160 patients with all 3 imaging modalities performed within 30 days of surgical or pathological confirmation, contrast-enhanced MRI showed the highest sensitivity and specificity (88% +/- 9% and 99% +/- 2%, respectively) compared with TTE (23% +/- 12% and 96% +/- 3.6%, respectively) and TEE (40% +/- 14% and 96% +/- 3.6%, respectively) for thrombus detection.

CONCLUSIONS

Left ventricular thrombus occurs frequently in patients with IHD and is associated with risk of systemic embolization. Contrast-enhanced MRI provided the highest sensitivity and specificity for LV thrombus when compared to TTE and TEE, and should be considered in the care of patients at high risk of LV thrombus formation.

Treatable Potential Cardiac Sources of Embolism in Patients with Cerebral Ischemic Events: A Selective Transesophageal Echocardiographic Study

OBJECTIVES

To characterize cardiac sources of emboli detected by transesophageal echocardiography (TEE) in patients without recognizable cause of transient ischemic attack (TIA) and/or ischemic stroke and TIA.

METHODS

We examined a prospective registry that included all patients with TIA and/or stroke evaluated by TEE between July 2000 and August 2001 at our medical center. Ischemic events were classified according to clinical and neuroimaging findings as cortical, lacunar, or vertebrobasilar circulation. Demographic, clinical, neuroimaging, and echocardiographic characteristics were studied.

RESULTS

TEE was performed in 237 patients without recognized cause of TIA and/or stroke, of which 105 (44%) events were cortical, 35 (15%) were lacunar, 32 (14%) were vertebrobasilar, and 65 (27%) were in multiple distributions. Mean age of patients was 59 +/- 14 years (range, 21 to 93 years); 119 (51%) were men. Potential treatable cardioembolic sources were detected in 146 (61%) patients: patent foramen ovale with right-to-left shunt (n = 59), left atrial clot (n = 6), left atrial appendage clot (n = 8), and severe thoracic aortic atherosclerotic plaque disease (plaque thickness >4 mm) (n = 79 patients [33%], 56 had an ulcerated plaque and 4 had mobile plaque). Patient age and topography of the ischemic event did not correlate with TEE-defined cardioembolic sources.

CONCLUSIONS

TEE identified high frequencies of potential treatable cardioembolic sources in patients with ischemic events. TEE should be considered in all patients who do not have identified cause of TIA and/or stroke for early treatment and prevention of recurrent events.

Evaluation and management of acute ischemic stroke

Stroke continues to be a major cause of adult mortality and disability. After numerous clinical trials and hundreds of millions of dollars spent on research, only two drugs are effective in treating patients with acute stroke. Recombinant tissue-plasminogen activator improves the chance of an excellent outcome in treated patients by 30%. Danaparoid sodium improves the chance of a very favorable outcome in treated patients with stroke due to large artery atherosclerosis. Although acute treatments are limited, our understanding of stroke pathogenesis and the importance of preventing poststroke complications has improved patient outcome significantly.

Role of echocardiography in systemic arterial embolism. A review with recommendations

The ability of echocardiography to diagnose sources of embolism and the role of the examination in the prediction of thromboembolism are reviewed. In addition, the yield of transthoracic (TTE) and transoesophageal echocardiography (TEE) is analysed in patients with suspected embolism and guidelines are proposed for performing echocardiography in this setting. In general, echocardiography is reliable for diagnosing sources of embolism and this applies in particular to TEE in the case of atrial, valvular, and aortic abnormalities. However, the method is useful for predicting embolism in a few cases only. There is a substantial risk in the event of mobile or protruding thrombi, but screening for these and other markers of thromboembolism seems to be unproductive in most groups of risk patients. Yet, in the presence of atrial fibrillation, echocardiography may be helpful in defining patients with an otherwise normal heart and low risk of embolism--and in defining the relatively rare patient with a clinically low-risk profile but moderate-to-severe left ventricular systolic dysfunction and a high risk of embolism. TEE-guided conversion of atrial fibrillation without weeks of preceding anticoagulation may prove useful, after further investigation. The risk of embolism in relation to the size and mobility of valvular vegetations has remained controversial. In patients with suspected recent embolism, TTE results in less than 5% new therapeutic consequences. In those with a normal TTE, the yield of TEE seems to be equally low. We therefore recommend a selective strategy: TTE and TEE can be omitted when a cardiac source of embolism appears from the clinical setting and in most patients with an obvious predisposition to cerebrovascular disease. However, in the latter cases TTE should be performed if indicated by the clinical situation, e.g. in the presence of fever and murmur. TTE is also recommended when there are no obvious markers of primary vascular disease. To preclude very rare sources of embolism (e.g. atrial thrombi despite sinus rhythm), supplementary TEE is recommended in younger patients in whom primary vascular disease is very unlikely. The diagnosis by TEE of common conditions such as atrial septal aneurysms and patent foramen ovale cannot, however, be taken as proof of the mechanism of a systemic arterial occlusive event; thus it is difficult to change therapy on the basis of such diagnoses.

Role of transesophageal echocardiography in the management of thromboembolic stroke

Cardiac causes of stroke account for approximately 20% of strokes occurring in the United States. Transthoracic echocardiography (TTE) remains the cornerstone of non-invasive cardiac imaging, but transesophageal echocardiography (TEE) is superior for identifying potential cardiac sources of emboli, including left atrial thrombi, valvular vegetations, thoracic aortic plaque, patent foramen ovale, and spontaneous left atrial echocardiographic contrast. The diagnostic yield of TEE for potential cardiac causes of thromboembolism exceeds 50%. The impact of TEE on the clinical management of this group, however, remains undefined for most TEE-specific diagnoses. Thus, routine use of TEE in these patients has been questioned. The diagnostic yield is highest if the clinical history/physical examination suggests a cardiac source. However, the clinical scenario often dictates patient management, and TEE data are used to "validate" the clinical impression. Data from large, prospective, randomized (aspirin/warfarin) studies, in which TEE data are obtained from patients with suspected cardiac thromboembolism, are needed. If specific TEE diagnoses can be identified in which defined therapies are beneficial, "source of embolism" will continue to be the most common indication for TEE referral. In this paradigm, TEE (without initial TTE) will probably become a more direct diagnostic pathway. However, if these studies demonstrate that all patients with suspected cardiac source benefit from one (or no) therapy, independent of TEE data, referrals for TEE will decline. Results of ongoing randomized trials to evaluate the efficacy of TEE in patients with cryptogenic stroke or transient ischemic attack are awaited.

Detection of prosthetic valve strands by transesophageal echocardiography: clinical significance in patients with suspected cardiac source of embolism

OBJECTIVES

The purpose of this study was to determine how frequently prosthetic valve strands are associated with prosthetic mitral and aortic valves, as detected by transesophageal echocardiography, and to assess their significance in relation to clinical cardioembolic events.

BACKGROUND

Strands attached to prosthetic mitral valves are a recently described finding of uncertain clinical significance. There are no reports of strands attached to aortic valve prostheses, and data are limited concerning the relation of valvular strands to cardioembolic events.

METHODS

We identified all transesophageal echocardiographic studies performed during a 5-year period at our institution for evaluation of valve dysfunction or a suspected cardioembolic event in patients with a valve prosthesis. All studies were reviewed. The presence of strands was noted and the prevalence compared between patients evaluated for a suspected cardioembolic event and those evaluated for valve dysfunction. In patients with no strands detected, the presence of other potential cardiac sources of embolism was noted.

RESULTS

Strands were detected in 56 (26%) of 214 studies. There was a significant difference (p = 0.0001) in the prevalence of strands between studies performed for a suspected cardioembolic event (34 [53%] of 64) versus those performed for suspected valve dysfunction (22 [15%] of 150). Strands were more prevalent on mitral than on aortic valves (32% vs. 13%, p = 0.0004) and were more frequently detected on mechanical than on bioprosthetic valves (27% vs. 8%, p = 0.003). Among patients with a suspected cardioembolic event and normal valves, other potential cardiac sources of embolism were detected in 67%.

CONCLUSIONS

Prosthetic valve strands are frequently detected by transesophageal echocardiography. They are more commonly detected in patients being evaluated for a suspected cardioembolic event and thus represent a potential cardiac source of embolism. In patients with apparently normal valves, other potential sources of embolism are frequently detected. Thus, transesophageal echo-cardiography may have a significant impact on the management of these patients.

Transesophageal echocardiography

Preview Echocardiography is invaluable in assessing patients with known or suspected cardiac disorders. However, there are often impediments to adequate imaging using the standard transthoracic route (eg, mechanical ventilation, bandages). Transesophageal imaging overcomes many of these technical limitations and, as one researcher notes, provides a "new window to the heart." Drs Peterson and Orsinelli review common clinical applications of the procedure and adjunctive uses.

Tumor invasion of the pulmonary veins: a unique source of systemic embolism detected by transesophageal echocardiography

Two patients with a malignancy involving the lungs and spontaneous systemic embolization in whom transesophageal echocardiography detected masses consistent with tumor invading the pulmonary veins are reported. In the first patient, tumor embolization resulted in acute aortic obstruction. Transesophageal echocardiography revealed tumor present in the pulmonary veins that extended into the left atrium. This was confirmed by magnetic resonance imaging. The second patient had a stroke. Transesophageal echocardiography demonstrated a mass in the right pulmonary vein in this patient as well. In patients with pulmonary malignancy who have a systemic embolic event, tumor emboli from the pulmonary vein should be included in the differential diagnosis of possible causes of the event. Transesophageal echocardiography is a valuable tool for diagnosis of tumor involvement of the pulmonary veins in such patients.