Single, Biplane, Multiplane, and Three-Dimensional Transesophageal Echocardiography

Characterization of the infarct pattern caused by vulnerable aortic arch atheroma: DWI and multidetector row CT study

BACKGROUND

Aortic arch atheroma (AAA) has been accepted as a possible embolic source in patients with ischemic stroke, especially cryptogenic stroke. However, despite its well-known role as a risk factor for stroke, research focused on the mechanism or characteristics of stroke caused by AAA is insufficient. In this study, we aimed to evaluate clinical and radiological characteristics including lesion pattern on DWI in acute stroke patients associated with vulnerable AAA detected by multidetector row computed tomography (MDCT).

METHODS

From September 2008 through May 2011, patients who presented with acute ischemic stroke and underwent MDCT were found in a prospective stroke registry. Patients without evident stroke etiology were included and classified by presence of vulnerable AAA. Vulnerable AAA was defined as (i) at least 6 mm thick adjacent to the aortic wall; (ii) ulcerated plaque, or (iii) soft plaque. Soft plaque was defined as the presence of clearly visualized area of hypoattenuation (<80 Hounsfield units) suggestive of thrombus. The patients without vulnerable AAA were classified as no/simple AAA group. The characteristics of diffusion-weighted MRI (DWI) lesions were analyzed in terms of the number and size of the lesions, and the involved vascular territories.

RESULTS

A total of 63 cryptogenic stroke patients were included in this study. Vulnerable AAA was observed in 15 (23.8%) patients. The patients with vulnerable AAA were older than those with no/simple AAA (p = 0.026). DWI analysis revealed that the vulnerable AAA group had a greater chance of having multiple and small lesions in multiple vascular territories that were mainly located in cortical and border-zone regions than the no/simple AAA group. Multiple logistic regression analysis showed that age (odds ratio 1.17; 95% confidence interval 1.02-1.34) and multiple small lesions in multiple vascular territories (odds ratio 33.18; 95% confidence interval 4.26-258.45) were independently associated with vulnerable AAA.

CONCLUSION

Vulnerable AAA is independently associated with a DWI pattern characterized by multiple small scattered lesions in multiple vascular territories in conjunction with age. It may help determine stroke mechanism quickly and easily, and provide more information about the pathomechanism of vulnerable AAA-related stroke.

Site-specific detection of bleeder using transesophageal echocardiography

Transesophageal echocardiography continues to be an indispensable postoperative diagnostic tool for cardiac surgical patients. Transesophageal echocardiography was carried out postoperatively in 30 consecutive hypotensive patients with low cardiac output who had undergone coronary bypass surgery. In 19 of these patients, a cause of low cardiac output requiring surgical intervention was excluded, and they were managed conservatively. In 11 patients, a surgical cause of low cardiac output was indicated: diffuse bleeding from no particular site in 5, and from a specific site in 6. They underwent urgent re-operation, and the echocardiography findings were confirmed on the operating table. Not only is transesophageal echocardiography important in diagnosis, but it is also highly specific in locating the site of bleeding.

Blunt chest trauma victims: role of intravascular ultrasound and transesophageal echocardiography in cases of abnormal thoracic aortogram

PURPOSE

The objective of our study was to use transesophageal echocardiography (TEE) and intravascular ultrasonography (IVUS) to evaluate their role in interrogating abnormal or equivocal findings seen on thoracic aortography performed on blunt chest trauma patients.

METHODS

A prospective, nonblinded, observational, institutional review board-approved study of IVUS and TEE was conducted in acute blunt chest trauma victims with abnormal findings on thoracic aortograms. IVUS was performed with a 20-MHz catheter and TEE was performed with an omniplane probe.

RESULTS

Abnormal aortographic findings were present in 10 men and 4 women (mean age, 40.5 years). All 14 patients were evaluated with IVUS and 13 with TEE. TEE was not performed on one patient because of time constraints. By IVUS, there were 11 true-positives, 2 true-negatives, and 1 equivocal (considered as false-negative), resulting in 91.7% sensitivity and 100% specificity. In the equivocal case, an intimal flap was missed by IVUS and by TEE, but was present at surgery. By TEE, there were six true-positives, two true-negatives, one false-positive, and four false-negatives, resulting in 60% sensitivity and 66.7% specificity. In the false-positive case, an avulsed intercostal artery without an intimal flap was found at surgery. The remaining three false-negative cases were a missed intimal flap, a missed intramural hematoma, and a missed intimal flap obscured by a mural hematoma. In our study, both IVUS and TEE were found to be diagnostic in the four equivocal aortograms. Three of the equivocal results were cases read as a prominent ductus diverticulum versus a pseudoaneurysm. Two were confirmed to be false lumen/pseudoaneurysm by both IVUS and TEE, whereas the other was confirmed to be a prominent ductus diverticulum by both of these modalities. In the fourth equivocal case, thoracic aortography showed an abnormal contour but no intimal flap located along the lesser curvature of the aorta at the junction of the arch and isthmus. No abnormalities were found by IVUS or TEE. This patient was followed clinically. A follow-up thoracic aortogram obtained 1 year later showed no aortic injury.

CONCLUSION

When thoracic aortography yields an abnormal and especially equivocal findings, both IVUS and TEE are helpful in further sorting this out rather than subjecting the patient to a potentially unnecessary thoracotomy. In cases of aortic injury suspected at the lesser curvature of the arch-isthmic junction, TEE allowed better delineation because of multiplane imaging capability.

Transesophageal echocardiography in hypotensive post-coronary bypass patients

The utility of transesophageal echocardiography in the evaluation of hypotension in the postoperative period after coronary artery bypass was assessed in 126 patients in the intensive care unit. There were 86 men and 40 women, with a mean age of 58.3 years. The indication for transesophageal echocardiography was hypotension refractory to conventional treatment. Valuable diagnostic information was obtained in 103 patients (82%). Based on the echocardiographic findings, 24 patients (19%) underwent urgent surgical intervention. The mean time required to obtain a diagnosis was 9.6 +/- 2.8 min. No significant complications were noted. Our experience suggests that transesophageal echocardiography is highly specific in diagnosing the cause of postoperative hypotension, thus preventing unnecessary surgical intervention and facilitating decision making in cardiac surgical emergencies.

The assessment of the proximal left pulmonary artery by transesophageal echocardiography and computed tomography in neonates and infants: a case series

IMPLICATIONS

Transesophageal echocardiography (TEE) is often used during surgical repair of congenital heart disease. In our case series of 256 newborns and infants, we found that a left paracarinal view of TEE could visualize the proximal left pulmonary artery, a frequent blind spot for TEE, in most patients, except in a few cases with anatomic variations of the esophagus in the right lateral to the vertebra.

Three-dimensional morphometry in ultrasound

The clinical use of three-dimensional (3D) ultrasound has rapidly spread to many specialities over the last ten years. The reason is easy to see, namely that single two-dimensional (2D) scans are often difficult to interpret and the mental correlation of multiple 2D scans to form a 3D image of anatomical morphology is taxing and uncertain. The rapid development of techniques for the realtime tracking of the spatial position and orientation of ultrasound probes and the development of computer graphics techniques for the presentation of anatomical images have made 3D ultrasound a realistic diagnostic tool. The authors describe the range of methods of data acquisition and display and provide illustrations of some current clinical applications.

Relation between the number of image planes and the accuracy of three-dimensional echocardiography for measuring left ventricular volumes and ejection fraction

The relation between accuracy of 3-dimensional echocardiography (3DE) in determining left ventricular end-diastolic volume, end-systolic volume, and ejection fraction (compared with magnetic resonance imaging) and the number of component planes used for 3DE ventricular reconstruction was evaluated in 41 adult subjects with normal (n = 24) and abnormal (n = 17) left ventricles. Accuracy and confidence of 3DE gradually increased with use of additional component planes, so that > or = 10 planes from both parasternal and apical windows provided 3DE reconstructions that accurately predict magnetic resonance imaging-measured left ventricular volumes and ejection fraction with confidence.

Multiplane transesophageal echocardiographic identification of the involved scallop in patients with flail mitral valve leaflet: intraoperative correlation

Although the role of multiplane transesophageal echocardiography in the diagnosis of flail mitral valve leaflet is well described, the accuracy of this modality in localizing the involved posterior leaflet scallop (medial, middle, or lateral) has never been validated. For 54 patients undergoing intraoperative transesophageal echocardiography for severe mitral regurgitation due to flail mitral valve leaflet, we assessed the accuracy of a systematic approach to localization of the flail mitral valve leaflet. Surgical confirmation was performed for all patients. At blinded review, a sensitivity of 78%, specificity of 92%, and overall diagnostic accuracy of 88% were achieved for correct localization of the flail posterior leaflet scallop. The middle scallop was most commonly affected in this series. The medial scallop was affected least often, and diagnosis of lesions in that area was least accurate. This diagnostic approach appears to be accurate and feasible and may assist in planning specific surgical therapy for this disorder.

Torn ascending aorta missed by transesophageal echocardiography

Transesophageal echocardiography has become a commonly used screening tool for traumatic tears of the descending aorta. The role of transesophageal echocardiography for ascending aortic tears is not yet well-defined. We report an ascending aortic tear imaged by aortography but missed on transesophageal echocardiography.

Evaluation of Ventricular dP/dt Before and After Open Heart Surgery Using Transesophageal Echocardiography

The mean dP/dt during isovolumetric contraction (mean dP/dt(ic)) is a new echocardiographic index of ventricular function that has been shown to approximate and closely correlate with invasively measured peak dP/dt. It is amenable to rapid measurement via transesophageal echocardiography (TEE) and is theoretically independent of variations in ventricular anatomy and wall motion. It is therefore well suited for the assessment of ventricular function during surgery. The purpose of this study was to assess the clinical value of TEE determinations of mean dP/dt(ic) before and after cardiopulmonary bypass (CPB). The mean dP/dt(ic) of 50 patients undergoing open heart surgery for a variety of congenital and acquired heart defects was measured before and 15-30 minutes after CPB. Mean dP/dt(ic) averaged 1147 +/- 492 before and 1428 +/- 702 mmHg/sec after CPB (P < 0.01). Mean dP/dt(ic) was unchanged or increased in 45 patients and fell in only 5 patients. It increased significantly even among patients who did not receive supplemental inotropic agents. Mean dP/dt(ic) correlated well with the shortening fraction, especially among patients without segmental left ventricular wall-motion abnormalities. The general patterns observed for mean dP/dt(ic) were also seen when the data was corrected for variations in heart rate. A preoperative mean dP/dt(ic) < 765 mmHg/sec or a heart rate corrected mean dP/dt(ic) < 620 mmHg/sec indicated a high likelihood that inotropic support would be needed to facilitate weaning from CPB. Mean dP/dt(ic) may be a clinically useful, quantitative TEE index of perioperative changes in ventricular contractility.

Pulsed wave Doppler measurement of cardiac output from the right ventricular outflow tract

Doppler ultrasound can be used to measure cardiac output (CO). Intraoperative Doppler cardiac output (DCO) by transesophageal echocardiography (TEE) has been studied using blood flow velocity from the left ventricular outflow tract (LVOT), the mitral valve (MV), and the main pulmonary artery (MPA). The purpose of this study was to compare DCO, measured from a relatively new TEE view of the right ventricular outflow tract (RVOT), with thermodilution cardiac output (TDCO). We also compared changes in DCO from the RVOT to changes in TDCO. A 5.0/3.7 MHz multiplane TEE probe was placed in 45 adult cardiac surgical patients undergoing general anesthesia. Patients were excluded if there was greater than mild tricuspid valve insufficiency. From the transgastric view, at approximately 110-140 degrees, the RVOT was imaged. DCO was calculated from 1) the time-velocity integral (TVI) using pulse wave (PW) Doppler, 2) the area of the RVOT (measured in early systole using the diameter (pi(D/2)2) of the RVOT at the level of the PW Doppler sample volume), and 3) the heart rate. Simultaneous TDCO was performed by a separate examiner. The RVOT was imaged satisfactorily in 84% of patients (38/45). The mean bias between DCO and TDCO was -0.01 L/min (2 SD +/- 0.45 L/min; n = 38). There was good correlation between DCO and TDCO (R2 = 0.97). Changes in TDCO and changes in DCO were compared in 15 patients. The mean bias between changes in DCO and changes in TDCO was 0.04 L/min (2 SD +/- 0.66 L/min). Analysis of the changes in DCO and TDCO showed good correlation (R2 = 0.96). We conclude that there is a good correlation between DCO measured from the RVOT and TDCO. This technique permits cardiac output measurement without the necessity of placing a pulmonary artery catheter, and it also provides a method of evaluating RVOT blood flow.

Transesophageal echocardiographic image of double-chambered right ventricle

Double-chambered right ventricle is a rare congenital heart disease. Anomalous muscle bundles in the right ventricle divide the right ventricle into two portions and cause intracavitary obstruction of the right ventricle. Transesophageal echocardiography of the double-chambered right ventricle has never been reported. We present a 32-year-old man with double-chambered right ventricle associated with perimembranous-type ventricular septal defect and left superior vena cava. Multiplane transesophageal echocardiography provides excellent views of an anomalous muscle bundle in the right ventricle, which differed from a moderator band by its insertion site on the right ventricle.

Intraoperative multiplane vs biplane transesophageal echocardiography for the assessment of cardiac surgery

This study was undertaken to test whether multiplane transesophageal echocardiography (TEE) offers advantages in comparison with biplane TEE in the intraoperative monitoring during cardiac surgery. A diagnostic multiplane TEE was performed in 400 patients in the immediate preoperative and postoperative periods. We systematically acquired cardiac images from the gastric fundus, lower esophagus, and upper esophagus; complete views of the descending aorta were also recorded. Usefulness of the different views in providing essential additional clinical information compared with exclusive transverse (0 to 20 degrees) and longitudinal (70 to 110 degrees) planes of the biplane TTE was assessed assuming that with manipulation of a biplane probe, a 20 degrees are could be added to the conventional horizontal and vertical planes. A high success rate of each view was demonstrated; anatomy and pathologic condition were best visualized in oblique planes. The method proved to be particularly useful in the preoperative and postoperative phases of aortic dissection (27 cases), aortic (65 cases) and mitral (35 cases) valve replacement, mitral valve repair (38 cases), left ventricular aneurysmectomy (25 cases), bleeding from proximal suture of an aortic heterograft (2 cases), and positioning of left ventricular hemopump (2 cases). Additional regional wall motion abnormalities of the right (four cases) and left ventricle (six cases) not appreciated in 0 to 20 degrees or 70 to 110 degrees planes were detected. Multiplane TEE is a useful clinical tool during intraoperative monitoring of cardiac surgery. Most structures of the heart and great vessels lie on oblique planes, while other views are optimized with the aid of slight angle corrections. This method improves the evaluation of anatomy and pathologic condition of the heart and great vessels, of native and prosthetic valves, and of left and right ventricular function.

Left ventricular fibromuscular band is not a specific substrate for idiopathic left ventricular tachycardia

BACKGROUND

A fibromuscular band has been detected in patients with idiopathic left ventricular tachycardia, and this band has been suggested to be the anatomic substrate for the arrhythmia. Whether the fibromuscular band is a specific substrate for the tachycardia was systematically evaluated in a large group of consecutive patients with and without idiopathic left ventricular tachycardia.

METHODS AND RESULTS

Conventional transthoracic two-dimensional echocardiography and multiplane transesophageal echocardiography were performed in 18 patients with idiopathic left ventricular tachycardia that was responsive to calcium blockers (group 1, tachycardia patients) and 40 patients with paroxysmal supraventricular tachycardia (group 2, control patients). There were 17 men and 1 woman, with a mean age of 29 +/- 11 years, in group 1 patients, and 21 men and 19 women, with a mean age of 42 +/- 12 years, in group 2 patients. The QRS morphology during tachycardia in group 1 patients displayed a pattern of right bundle-branch block with superior axis in 15 patients, indeterminate axis in 2 patients, and inferior axis in 1 patient. Radiofrequency ablation successfully eliminated the tachycardia in all 18 patients; the successful ablation site was located at the inferior apical septum in 11 patients, at the midseptum in 6 patients, and at the anterior lateral wall in 1 patient. Transthoracic echocardiography detected the fibromuscular band in 11 of the 18 patients, whereas multiplane transesophageal echocardiography detected the band in 17 of 18 patients. The fibromuscular band extended from the interventricular septum to the apex of the left ventricle. In group 2 patients, transthoracic echocardiography detected the fibromuscular band in 22 and multiplane transesophageal echocardiography detected the band in 35 of the 40 patients. The presence of a fibromuscular band in these two groups of patients was not statistically different.

CONCLUSIONS

The presence of a left ventricular fibromuscular band is not a specific anatomic substrate for idiopathic left ventricular tachycardia.

Dynamic three-dimensional transesophageal echocardiography using a computed tomographic imaging probe--clinical potential and limitation

Dynamic three-dimensional echocardiography is a new diagnostic tool for spatial visualisation of cardiac anatomy and volumetric assessment. A computer-controlled probe acquires parallel tomographic slices, from which dynamic three-dimensional images of the heart can be reconstructed. Thirty adult patients with valvular heart diseases, congenital heart diseases, intracardiac masses, heart failure and other cardiac lesions, underwent conventional two-dimensional (n = 30), three-dimensional echocardiography (n = 30) and thermodilution (n = 17). The feasibility, usefulness and possibility of simulating a surgical view of intracardiac anatomy and exact volumetry were determined. The two different morphologic images were compared qualitatively. For quantitative analysis volumetry was performed using standard thermodilution technique and dynamic three-dimensional echocardiography. In more than 80% of the patients additional morphologic information was gained and a strong correlation (r = 0.75-0.95) between two volumetry assessments was found. Based on this findings, dynamic three-dimensional echocardiography is an additional and valuable approach in the perioperative and intensive care management in this group of patients.

Multiplane transesophageal echocardiography in the diagnosis of congenital coronary artery fistula

The purpose of this study was to examine the advantages of multiplane transesophageal echocardiography in the diagnosis of congenital coronary artery fistula, specifically in depicting the origin, the course, and the drainage site. Seven consecutive patients ranging in age from 20 to 72 years with a suspected coronary artery fistula underwent conventional transthoracic and multiplane transesophageal echocardiographic studies between March 1993 and July 1994. When a coronary artery fistula was noted, the origin, the course, and the drainage site were carefully searched for. All patients then underwent a cardiac catheterization with the performance of coronary angiography. A large right coronary artery fistula was detected in three patients; one of them had a drainage to the posterior left ventricle, one to the lateral right ventricle, and the other to the medial aspect of the right ventricle just below the insertion of the septal leaflet of the tricuspid valve. A small coronary artery fistula arising from the left coronary artery was noted in four patients, two from the left anterior descending artery and the other two from the left circumflex artery. Three of these four patients had a drainage to the main pulmonary artery and one to the left ventricle. The drainage site was clearly depicted in all seven patients, whereas the origin and the course were precisely defined in five patients by using multiplane transesophageal echocardiographic examination. The multiplane transesophageal echocardiography provides a panoramic view of the coronary artery and the fistulous vessel with a precise definition of the origin, the course, and the drainage site of the fistula. Therefore it is the noninvasive diagnostic mode of choice.

Transesophageal echocardiography in cardiac surgical emergencies

The value and utility of transesophageal echocardiography (TEE) in unstable cardiac surgical patients have been assessed; 119 TEE studies were performed and evaluated in the emergency setting. The studies were performed in the cardiac surgical intensive care unit (n = 62) and in the operating room (n = 57). There were 81 men and 38 women with a mean age of 58.2 years. The indications for TEE were as follows: hypotension refractory to conventional treatment (n = 83); prosthetic or native valve dysfunction (n = 25); and suspected aortic dissection (n = 10). TEE provided valuable diagnostic information in 107 patients and was completely normal in 12 patients. Based on these results 22 patients had urgent surgical intervention without further studies. The average time to diagnosis was 11.2 minutes. No significant complications were noted. Our results suggest that TEE is highly diagnostic for most of the abnormalities responsible for hemodynamic instability in the perioperative period and facilitates decision making in cardiac surgical emergencies.