To Transesophageal Echocardiography Research Articles

Intracardiac Transvenous Echocardiography Is Superior to Both Precordial Doppler and Transesophageal Echocardiography Techniques for Detecting Venous Air Embolism and Catheter-Guided Air Aspiration

Venous air embolism (VAE) is a potentially fatal complication during surgical procedures with patients in the sitting position. Since methods for detection of persistent low-volume VAE and targeted air aspiration are limited, we tested the hypotheses that transvenous intracardiac echocardiography (ICE) 1) improves detection of small air emboli in comparison to transesophageal echocardiography (TEE) and precordial Doppler monitoring (PCD) techniques, and that 2) image-guided multiorifice central venous catheter manipulation improves air recovery in moderate and large VAE, when compared with aspiration with the multiorifice central venous catheter in a static position. Adult swine (73 +/- 4.6 kg, n = 7) were premedicated, anesthetized with propofol and fentanyl, endotracheally intubated, mechanically ventilated, and placed in a 45 degrees head-up position. First, nine different small volumes of air emboli (0.05-1 mL) were randomly injected via an ear vein, and VAE detection methods were applied in random order. For 378 small volume air injections, ICE had a much higher sensitivity (82.5%, P < 0.0001) on the analysis of VAE detection than TEE (52.8%) or PCD (46.8%), with no difference (P = 0.571) between TEE and PCD. An injected air volume as small as 0.15 mL was detected by ICE in 90% of injections performed, whereas PCD and TEE detected only half of the boluses of 0.25-0.30 mL of air, and required boluses of 0.4-1.0 mL to achieve 100% detection. Air recovery was assessed in a second series of moderate VAE (2, 5, 10 mL); image-guided aspiration-catheter manipulation recovered significantly more (34.1% vs 17.2%, P < 0.0001) intracardiac air than without catheter manipulation. In a third series of injections of large air volumes (25, 50, and 100 mL), air recovery was not significantly different with ultrasound-guided aspiration (41.3% vs 31.8%, P = 0.11). Small air emboli are detected by ICE with much greater sensitivity compared with both PCD and TEE techniques. Furthermore, recovery of embolized air is enhanced by image-guided manipulation of a multiorifice central venous catheter. Clinical studies are required to assess this technique during surgery with patients in the sitting position.

Gastric Perforation after Transesophageal Echocardiography for Cardiac Surgery: Was There an Indication for the Transesophageal Echocardiogram?

I read with great interest the recent report by Soong et al.1 detailing the delayed presentation of a gastric perforation (lesser curve) most likely due to transesophageal echocardiography (TEE) during coronary revascularization with cardiopulmonary bypass. The patient required surgical repair with an omental patch during laparotomy. Unfortunately, the patient died in the intensive care unit from overwhelming sepsis after 27 days in the hospital. To my knowledge, this is the first reported case of full-thickness gastric perforation on the lesser curve.2The question that this case raises is whether there was an indication for TEE in this case. Let us examine the arguments for and against this invasive procedure whose exceedingly rare complication proved fatal in this index case.The argument against TEE begins with the preoperative echocardiogram that showed no significant valvular disease, and adequate ventricular function with an estimated ejection fraction of 40%. Thus, there was no category I indication (supported by the strongest evidence or expert opinion) as defined by published perioperative TEE guidelines.3 In fact, at our institution, this patient would most likely not qualify for TEE, based on the aforementioned considerations and our conservative approach.However, the argument for TEE begins with the fact that this patient has category II indications (supported by weaker evidence and expert consensus) for TEE, namely a higher risk of perioperative hemodynamic disturbance and ventricular dysfunction. Nationally, there are many centers where TEE is performed in every cardiac surgical case, regardless of level of clinical necessity. Proponents of this approach cite the impact of TEE on therapy in coronary artery surgery, which is at least 10%, many orders of magnitude greater than the risk of upper gastrointestinal injury such as gastric perforation.2,4How do we balance this risk–benefit profile of perioperative TEE in cardiac surgery? Would it help to identify clinical risk factors besides obvious pathology in the upper gastrointestinal tract? Would a case registry allow further analysis of these rare but devastating complications?2There are no easy answers to these questions. Perhaps, the way forward is a case registry, as in the example of perioperative visual loss. It would allow for a more focused examination and analysis of the rare but clinically serious upper gastrointestinal injuries associated with perioperative TEE.

Diagnostic value of harmonic transthoracic echocardiography in native valve infective endocarditis: comparison with transesophageal echocardiography

BackgroundAlthough echocardiography has been incorporated into the diagnostic algorithm of patients with suspected infective endocarditis (IE), systematic usage in clinical practice remains ill defined. To determine the diagnostic accuracy of detecting vegetations using harmonic transthoracic echocardiography (hTTE) as compared to transesophageal echocardiography (TEE) in patients with an intermediate likelihood of native valve IE.MethodsBetween 2004 and 2005, 36 consecutive inpatients with an intermediate likelihood of disease were prospectively evaluated by hTTE and TEE.ResultsOf 36 patients (21 males with a mean age of 57 ± 15 years, range 32 to 86 years), 19 patients had definite IE by TEE. The sensitivity for the detection of vegetations by hTTE was 84%, specificity of 88%, positive predictive value (PPV) of 89% and negative predictive value (NPV) of 82%. The association between hTTE and TTE interpretation for the presence and absence of vegetations were high (kappa = 0.90 and 0.85 respectively).ConclusionIn patients with an intermediate likelihood of native valve IE, TTE with harmonic imaging provides diagnostic quality images in the majority of cases, has excellent concordance with TEE and should be recommended as the first line test.

Stroke Patients With Cardiac Atrial Septal Abnormalities: Differential Infarct Patterns on DWI

Stroke mechanism in patent foramen ovale (PFO) and/or atrioseptal aneurysm (ASA) remains unclear. We aimed to study the stroke pattern on diffusion weighted imaging (DWI), in cryptogenetic stroke according to septal abnormalities. We prospectively evaluated 314 cryptogenetic strokes. Patients were categorized according to transesophageal echocardiography (TEE) findings: PFO with ASA, PFO alone, and no abnormalities. The study group consisted of 126 patients with acute DWI lesions within the first 7 days after the stroke onset. We considered the presence of scattered lesions or a cortico-subcortical territorial lesion as highly suggestive of an embolic pattern. PFO was identified in 77 patients (61%) and no alterations in 49 patients (39%). TEE revealed ASA in 42 patients (54.5% of PFO patients). An "embolic" pattern was depicted in 84 (66.7%) and subcortical in 42 (33.3%). An "embolic" pattern was significantly (P= .01) more frequently seen in PFO with ASA patients (n= 37;44%) as compared to PFO without ASA (n= 22; 26.2%) or no abnormalities (n= 25; 29.8%) on TEE. Univariate analysis revealed that age (P= .06), hyperlipidemia (P= .04), degree of shunt on TEE (P= .002), and the presence of an ASA (P= .008) were associated with an embolic pattern. After adjusting for sex, age, and vascular risk factors, only the presence of PFO, with ASA (OR 7.27; 95% CI 1.5-35.22 P= .014) was independently associated with an embolic pattern. In patients with cryptogenetic stroke, the presence of PFO with ASA, but not isolated PFO, is associated with an embolic pattern on DWI. These findings provide insights into the patho-mechanism of stroke in patients with PFO.

Methemoglobinemia Following Transesophageal Echocardiography: A Case Report and Review

Benzocaine (ethyl aminobenzoate) is a topical anesthetic widely used for oropharyngeal anesthesia prior to transesophageal echocardiography (TEE). Topical anesthetics have been reported to cause methemoglobinemia, but this adverse event is extremely rare and has not been listed as one of the possible complications of TEE. However, recently the number of published case reports of TEE-associated methemoglobinemia has increased. Since its first description in 1950, 65 cases of methemoglobinemia have been reported including a recent report of five cases from a single center. Physicians who are not familiar with the association of TEE with benzocaine-induced methemoglobinemia may not recognize the idiosyncratic and often nonspecific characteristic of this condition. Recognition is critical, however, since left untreated methemoglobinemia can lead to cardiopulmonary compromise, neurological sequelae, and even death. The current report documents an additional case of TEE-associated methemoglobinemia from a high-volume (8000 cases /year including 400-450 TEE/year) echo lab. A review of the literature suggests that this complication may be more prevalent, than generally appreciated. This case report emphasizes the importance of appropriate dose, recognition, and the treatment of this entity to cardiologists performing TEE.

Defeitos de septo atrial como fator de risco para migrânea: um estudo de caso controle

To determine the magnitude of the association between atrial septal defect (ASD) and migraine. We evaluated 101 subjects submitted to transesophageal echocardiography (TEE). They have been asked about headache. Migraine diagnosis was established according the criteria of the International Headache Society (IHS). The subjects were match in cases (ASD carrier) and controls (without ASD). We analyzed the occurrence of migraine, of aura and the frequency of crises in the last month by chi-square test. We matched 34 cases and controls: 82.4% female, the mean age, in years was 38.7 (+/-11.24) and 38.9 (+/-11.17)). Migraine occurred in 79.4% of the cases and in 55.9% of the controls (OR = 4.3) CI = 95% (1.04-8.8), (p = 0.038). Aura occurred in 65.1% (cases) and 40% (controls). It was observed more than three migraine crises in the last month in 76.7% of the cases and 60% of the controls (OR = 1.56) (p = 0.2) (95% CI, 0.6 to 7.6). ASD is a risk factor to migraine with aura in the sample studied. ASD apparently increase the frequency of migraine crises.

Planimetry of Aortic Valve Area in Aortic Stenosis by Magnetic Resonance Imaging

The aim of the study was to determine whether noninvasive planimetry of aortic valve area (AVA) by magnetic resonance imaging (MRI) is feasible and reliable in patients with valvular aortic stenosis in comparison to transesophageal echocardiography (TEE) and catheterization. Planimetry of AVA by MRI (MRI-AVA) was performed on a clinical magnetic resonance system (1.5-T Sonata, Siemens Medical Solutions) in 33 patients and compared with AVA calculated invasively by the Gorlin-formula at catheterization (CATH-AVA, n = 33) as well as to AVA planimetry by multiplane TEE (TEE-AVA, n = 27). Determination of MRI-AVA was possible with an adequate image quality in 82% (27/33), whereas image quality of TEE-AVA was adequate only in 56% (15/27) of patients because of calcification artifacts (P = 0.05). The correlation between MRI-AVA and CATH-AVA was 0.80 (P < 0.0001) and the correlation of MRI-AVA and TEE-AVA was 0.86 (P < 0.0001). MRI-AVA overestimated TEE-AVA by 15% (0.98 +/- 0.31 cm2 vs. 0.85 +/- 0.3 cm2, P < 0.001) and CATH-AVA by 27% (0.94 +/- 0.29 cm2 vs. 0.74 +/- 0.24 cm2, P < 0.0001). Nevertheless, a MRI-AVA below 1,3 cm2 indicated severe aortic stenosis (CATH-AVA < 1 cm2) with a sensitivity of 96% and a specificity of 100% (ROC area 0.98). Planimetry of aortic valve area by MRI can be performed with better image quality as compared with TEE. In the clinical management of patients with aortic stenosis, it has to be considered that MRI slightly overestimates aortic valve area as compared with catheterization despite an excellent correlation.

Intracardiac echocardiography: an ideal guiding tool for device closure of interatrial communications

This study sought to evaluate safety and radiation exposure when using intracardiac echocardiography (ICE) in comparison to transesophageal echocardiography (TEE) in order to guide transcatheter closure of interatrial communications. Eighty patients (44 males, 36 females, mean age 46, SD 13 years) undergoing device closure of atrial septal defect (n=12) or patent foramen ovale (n=68) had the procedure guided by ICE (n=50, group 1) or TEE (n=30, group 2). In group 1, all procedural stages were completely guided by ICE, including imaging of the interatrial communication during balloon sizing, device unfolding and release, and during the final check for adequate positioning. In group 2, exclusive implantation of devices was guided by use of TEE. Especially, the spatial relationship between device and cardiac structures (e.g. the ascending aorta, the interatrial septum and the superior vena cava) was accurately demonstrated in group 1. Image resolution provided by ICE was superior to that of TEE. No severe complications, including any related to ICE, were seen. Fluoroscopy time (FT) and procedure time (PT) were shorter in group 1 than in group 2 (FT: 5.5+/-1.5 min vs. 9.3+/-1.6 min, P<0.0001; PT: 31.9+/-4.6 min vs. 38.8+/-5.8 min, P<0.01). Neither sedation nor anesthesia was required in group 1. ICE is a safe tool to guide device closure of interatrial communications. For the patient, procedural stress and radiation exposure are negligible. ICE can be considered the guiding tool of choice for device closure, particularly when long or repeated echocardiographic viewing is required.

Case 5—2004: Transesophageal echocardiography-guided insertion of a pulmonary artery catheter

Pulmonary artery (PA) catheterization is commonly used during cardiac surgery and is successfully inserted without much difficulty in most patients. The authors describe a patient with severe aortic stenosis (congenital bicuspid valve) in whom conventional techniques for PA catheter insertion failed leading to transesophageal echocardiography (TEE)-guided placement. The TEE not only helped in the correct placement of the PA catheter but also helped to diagnose another congenital cardiac anomaly, which had not been previously documented.

Central-nervous side effects of midazolam during transesophageal echocardiography

Background: Midazolam is a broadly used drug that can enhance tolerance to transesophageal echocardiography (TEE) in patients with cardiac conditions. Adverse reactions to midazolam have been described previously. We describe central-nervous side effects in 6 of 104 consecutive patients. Methods: One hundred four patients undergoing TEE-diagnostic procedure were investigated. TEE was performed using a SSA 360 Power Vision ultrasound unit (Toshiba, Tokyo, Japan) and a 5- to 6-MHz probe. Indication for TEE was evaluation of cardiac valves (6), search for cardiac embolism (23), patent foramen ovale or atrial septum defect (20), left ventricular dysfunction (11), aortic dissection (7), and other (37). Midazolam and, if necessary, the benzodiazepine antagonist flumazenil (0.25-0.5 mg) were administered intravenously. Results: The mean cumulative dose of midazolam administered in small fractions was 4.8 ± 2 mg. In 6 of 104 patients (5.7%) clinically significant adverse effects to midazolam occurred. The reactions were aggressiveness, euphoria, depression, and intense hiccups (singultus) despite low doses of midazolam. The severest forms of these adverse effects to midazolam could be successfully treated with intravenous infusion of flumazenil (0.25-0.5 mg intravenously). Conclusion: Adverse effects including aggressive, euphoric, or depressive behavior can occur in a significant proportion (6%) of patients with cardiac conditions undergoing TEE after intravenous administration of midazolam. The administration of the benzodiazepine antagonist flumazenil can reverse the adverse effects to midazolam successfully. (J Am Soc Echocardiogr 2002;15:1297-1300.)

A comprehensive strategy to avoid transesophageal echocardiography probe damage

To describe the factors predisposing to transesophageal echocardiography (TEE) probe damage and to propose a strategy aimed at preventing damage to the TEE probe. Description of equipment and procedures: Damage to the TEE probe can occur anywhere and anytime during use in the operating room (OR) or when the probe is not in use in the OR, such as in the cleaning room, during storage or during transport of the probe. The components of the strategy used in our institution to avoid probe damage are: 1) storage of the probe in a dedicated holder in the OR when it is not in use, 2) use of a lexan box in the OR to protect the probe connector, 3) use of a custom-made holder when the probe is inserted in the patient, 4) use of a dedicated holder for soiled TEE probe storage in the cleaning room and for subsequent probe storage. We describe a comprehensive strategy designed to decrease TEE probe damage and the associated expenses. Further studies will be required to determine the effectiveness of the proposed measures.

Introduction to Transesophageal Echocardiography (TEE) with A Historical Perspective

Since its introduction in the early 1980s, TEE has become an important standard clinical tool with greatly expanded applications. The technique continues to develop. We can expect the future to bring reliable imaging of myocardial perfusion and user-friendly three-dimensional applications.

Détection de shunt droit-gauche par échocardiographie transœsophagienne et Doppler transcrânien

Objective: Comparison between the diagnostic: accuracy of transcranial Doppler (TCD) relative to transesophageal echocardiography (TEE) In the detection of right-to-left shunt. Design: Detection of right-to-left shunt by TEE with contrast study at rest and during Valsalva maneuver or coughing, and during TCD of the middle cerebral artery using the same contrast test. Detection by TEE was considered positive when air micro-bubbles were detected in the left atrium, and by TCD when a characteristic acoustic signal and typical spike-like interruptions of the Doppler signal detecting the bubbles appeared during the first twelve seconds after the injection. Results: Both examinations were performed in a Medical Intensive Care Unit and in a Nuclear Medicine and Ultrasound Unit in 124 patients (108 with strokes, two with arterial embolisms of upper limbs, two with arterial embolisms associated with pulmonary embolism, eight with chronic respiratory failure, four with ARDS). A right-to-left shunt was detected in 56 patients (45.2%) by TEE and in 64 patients (51.6%) by TCD, TCD sensitivity was 90.9%, specificity 72.2%, positive predictive value 75% and negative prédictive value 89.7%. Concordance was found in 82.3% examinations (κ = 0.65). Conclusion: TEE is a semi-invasive examination. TCD is a simple and sensitive method for the detection of a right-to-left shunt. This latter can be performed when it is impossible to perform TEE, and when the examination is limited to search a right-to-left shunt. The main limitation of TCD is that this examination is unable to detect the exact location of the right-to-left shunt. But de l’étude: Analyse de l’intérêt diagnostique du Doppler transcrânien (DTC) dans la détection de shunt droit-gauche comparé à l’échocardlo-graphie transœsophagienne (ETO). Méthode: Recherche de shunt droit-gauche effectuée par ETO avec épreuve de contraste sensibilisée par la toux ou une manœuvre de Valsalva, puis DTC de l’artère cérébrale moyenne avec le même protocole d’injection. La recherche en ETO était considérée comme positive s’il existait un passage.de microbulles dans l’oreillette gauche et en DTC s’il apparaissait un signal acoustique caractéristique détectant les microbulles dans les 12 secondes suivant l’injection. Résultats: Les deux examens ont été effectués dans les services de réanimation médicale et de médecine nucléaire in vivo et ultrasons chez 124 patients (108 accidents vasculaires cérébraux, deux embolies artérielles des membres supérieurs, deux embolies systémiques associées à une embolie pulmonaire, huit insuffisances respiratoires chroniques, quatre syndromes de détresse respiratoire aiguë). La recherche de shunt droit-gauche était positive avec mise en évidence d’un foramen ovale perméable chez 56 patients (45,2%) par ETO et chez 64 patients (51,6%) par DTC. Le DTC avait une sensibilité de 90,9%, une spécificité de 72,2%, une valeur prédictive positive de 75% et une valeur prédictive négative de 89,7 %, Les, deux examens étaient concordants dans 82,3% des cas (κ=0,65). Conclusion: L’ETO est un examen semi-invasif, qui est parfois contre-indiqué. Le DTC est une méthode simple et sensible de dépistage de shunt droit-gauche. II peut permettre d’éviter une ETO lorsque l’exploration se résume à la recherche d’un shunt droit-gauche. La principale limite est qu’il s’agit d’un examen «aveugle», ne visualisant pas directement le siège du shunt.

Transesophageal echocardiography in patients less than 60 years of age without obvious cardiac source of embolism

Minor potential cardioembolic sources of stroke such as atrial septal aneurysms (ASA) or patent foramen ovale (PFO) are important risk factors for cryptogenic stroke. We aim to determine the prevalence of these abnormalities through an exhaustive etiological workup including transesophageal echocardiography and cervical arteries assessment in stroke patients younger than 60 years of age who had no evidence of a significant source of embolism. We classified 118 stroke patients into four groups according to transesophageal echocardiography (TEE) and cervical arteries assessment findings. Group A, consisted of 30 (25.4%) patients who had an arteriopathy likely related to stroke without any cardiac abnormality; Group B, 49 (41%) patients who had only a potential cardiac source; Group C, 9 (7.6%) patients who had an obvious arterial source of stroke and incidental cardiac abnormalities, and Group D, 30 (25.4%) patients who had neither cardiac nor arterial source. Data were analysed with X2 test for the comparison of risk factors between groups. Variance analysis was used to compare age between groups. Significance was assessed as p < 0.05. ASA represented 56.8% of the cardiac abnormalities and was diagnosed in 35.4% of the 79 patients who had an unexplained stroke (B and D). A PFO was found in 34.1% of the patients who had a cryptogenic stroke (B and D). According to Fisher's exact test, ASA was significantly associated to PFO (p << 0.001). According to this selection one fourth of the patients might have a truly cryptogenic stroke as the etiological workup failed to demonstrate any source of stroke. Comparison between groups showed that the patients in whom an arterial source was detected also had a potential cardioembolic source in 23% of the cases (C), versus 62% in patients who had no arterial source (B and D) (p = 0.0007). Our study confirmed the strong association between ASA, PFO and stroke. Although there was a lower incidence of minor potential cardioembolic sources in patients who had a cervical artery disease, we suggest a systematic TEE screening in all patients with stroke without major cardiac source, in order to ensure a better prevention.

Left Atrial Thrombus and Spontaneous Echo-Contrast in Nonanticoagulated Mitral Stenosis: A Transesophageal Echocardiographic Study

The aim of the study was to investigate if evidence at transthoracic echocardiography (TTE) of left atrial (LA) thrombus and LA spontaneous echo-contrast (LA SEC), which are potential precursors of embolization, can be predicted by clinical and TTE variables in nonanticoagulated mitral valve stenosis (MS). Clinical (age, NYHA class, rhythm, previous embolization) and TTE variables were related to transesophageal echocardiography (TEE) evidence of LA thrombus and/or LA SEC. Nonanticoagulated MS was the setting. Fifty-nine patients had MS, and they were not receiving anticoagulant or antiplatelet therapy (24 in sinus rhythm and 35 in atrial fibrillation). Previous arterial embolization had occurred in 12 patients (20.3 percent). The following TTE variables were analyzed: mitral orifice area (pressure half-time method), mitral gradient (Bernouilli's equation), LA end-systolic area, and mitral regurgitation (color Doppler grading). LA thrombus and LA SEC were analyzed by monoplane TEE. LA thrombus was found by TEE in 12 patients (20.3 percent). Of these 12, 11 (91.6 percent) were in atrial fibrillation. LA SEC was found by TTE in 2 patients (3.5 percent) and by TEE in 40 (67.8 percent) (p < 0.001). Previous embolization had occurred only in patients with LA SEC, of whom 5 had and 7 did not have LA thrombus. Patients with LA SEC, compared with those without LA SEC, were characterized by more frequent advanced NYHA class, atrial fibrillation, smaller mitral valve area, and larger LA size. By multivariate regression analysis, atrial fibrillation and LA end-systolic area were factors related to both LA thrombus and LA SEC, whereas mitral area was related only to LA SEC. However, whereas LA SEC was accurately predicted by the presence of atrial fibrillation (sensitivity: 87.5 percent; specificity: 100 percent) and a LA area > or = 30 cm2 (sensitivity: 72.5 percent; specificity: 89.5 percent), among patients with LA SEC no clinical or TTE variable accurately identified those with actual LA thrombus. TEE is not necessary in many patients with MS in order to recognize LA SEC. However, when actual LA thrombus detection is necessary for clinical decision making, TEE should be performed.