Experience with use of multiplane transesophageal echocardiography to guide closure of atrial septal defects using the amplatzer device.

By providing unlimited imaging planes, multiplane transesophageal echocardiography (MTEE) should improve real-time guidance of interventional procedures. The potential advantages of MTEE in this scenario have not been systematically evaluated. We retrospectively reviewed our experience with MTEE-guided Amplatzer device closure of atrial septal defects (ASDs) MTEE angles used to obtain images for guiding all measurements and maneuvers were recorded. These angles were compared to the range of MTEE angles that are postulated to be available from biplane TEE. Images obtained using MTEE angles from 21 degrees to 70 degrees and from 111 degrees to l59 degrees were defined as only obtainable by MTEE. The MTEE probe was successfully introduced in all (89) patients. Thirteen patients (15%) had multiple defects. Ninety-five devices (5-32 mm in diameter) were deployed. In 66% of patients, balloon sizing and device deployment necessitated imaging planes that are only obtainable by MTEE. All devices were well positioned, with no impingement on inflows or outflows. At follow-up, 79 of 89 (88.7%) patients had no residual ASDs. Each of the remaining 10 patients (11.3%) had a small (<3 mm) residual defect. MTEE played an important role in guiding device closure of ASD, particularly during the phases of balloon sizing and device deployment.

Estimation of right ventricular free-wall mass using two-dimensional echocardiography.

Echocardiographic methods based on geometric models have long been in use for estimating left ventricular mass, but there is currently no similar method for estimating right ventricular (RV) free-wall mass. We hypothesized that a one-quarter prolate ellipsoid model could be used with two-dimensional echocardiography to approximate RV mass. Over a 2-year period 39 patients who had both a complete cardiac magnetic resonance imaging (MRI) scan and an echocardiogram within 2 weeks of each other were retrospectively analyzed. MRI-derived RV mass was used as the standard for comparison. Echocardiographic RV mass was estimated using three equations based on the geometric model. Linear regression analysis was performed to determine the correction factors used in the final formulae. The formula with the lowest standard error of the estimate was then prospectively analyzed for accuracy using a separate group of 88 subjects. The most accurate echocardiographic equation derived was RV mass = 5.84 (apical four-chamber RV cavity planar area) (RV free-wall thickness) + 1. Compared to MRI-RV mass the correlation coefficient was 0.97 and the standard error of the estimate was 16.8%. The positive and negative predictive values for diagnosing RV hypertrophy were 95% and 88%, respectively. We conclude that RV free-wall mass can be estimated by two-dimensional echocardiography using a one-quarter prolate ellipsoid shell model.

Reliability of intraoperative transesophageal echocardiography during Tetralogy of Fallot repair.

UNLABELLED: There is limited information available concerning the accuracy of intraoperative transesophageal echocardiography (TEE) in predicting the extent of residual abnormalities after recovery from surgical repair of tetralogy of Fallot. Therefore, we investigated differences between the results of final postbypass TEE and those of postrecovery (mean, 6 days after surgery) transthoracic echocardiography in a total of 28 consecutive pediatric patients who underwent repair of tetralogy of Fallot with biplane or multiplane TEE. Both postbypass and postrecovery echocardiographic examinations included measurements of the right ventricle (RV)-main pulmonary artery (PA) and the main PA-branch PA peak instantaneous gradients, the degree of pulmonary valvar insufficiency, and color Doppler interrogation of the ventricular septum for residual defects. The RV-main PA gradient did not change significantly: 15 +/- 13 vs 18 +/- 14 mmHg (postbypass versus postrecovery, mean +/- SD). None of the patients had a decrease of > or = 10 mmHg; and only one patient had an increase of > or = 15 mmHg. There also was no change in the degree of pulmonary insufficiency (3.0 +/- 1.2 versus 3.1 +/- 1.1, using a scale of 0 to 4). Only one of the seven very small (< or = 2 mm) residual ventricular septal defects was not discovered during postbypass TEE. However, postrecovery transthoracic echocardiography detected significant branch PA stenosis (peak gradient, > or = 15 mmHg) in five patients (18%) that was not detected during postbypass TEE (P < 0.03). Of the branch PA stenoses that were not detected during TEE, four were left and one was right. CONCLUSIONS: Postbypass TEE after tetralogy of Fallot repair reliably predicts residual postrecovery hemodynamic abnormalities, except for branch PA stenosis.

Computational methods for wide-field reconstruction of transoesophageal echocardiographic images.

Transoesophageal echocardiography imaging is limited by the proximity of the transducer to many cardiovascular structures. The location of the transducer causes these structures to appear near the apex of the backscatter image, and since the angle of the scan cannot exceed 90 degrees, much of the image information appears in a constricted area. We describe a computer-based, wide-field reconstruction technique which pieces together the picture fields from adjacent sector scans to form composite images. This description includes information regarding lessons learned, as well as technical details of the algorithms, in sufficient depth to permit reproduction of the system by interested parties. Significant aspects of wide-field image reconstruction, including computational complexity, image-pair alignment processes, requirements of alignment resolution, and image acquisition techniques, are addressed in depth. We believe that wide-field presentation of echocardiographic backscatter data enhances the utility of the transoesophageal approach, particularly when dealing with posteriorly located cardiovascular lesions.

Echocardiographic and anatomic correlation of ventricular septal defect morphology in newborn Yucatan pigs.

With the use of a Yucatan micropig strain with a high incidence of ventricular septal defects (VSDs), results of two-dimensional and color-flow Doppler echocardiography of VSD morphology in newborn piglets were correlated with autopsy findings. A spectrum of perimembranous, muscular outlet, and doubly committed subarterial VSDs was found. Echocardiography was performed in 29 piglets weighing 1.2 to 4.4 (mean 2.8) kg, studied at age 4 to 18 (mean 8) days. VSD was diagnosed by means of echocardiography in 16 of 29 subjects; morphologic findings included perimembranous defects in 12, muscular outlet in two, and doubly committed subarterial defect in two. At autopsy the presence and location of defects were confirmed in all pigs. No additional defects were found. VSD diameters were 1.0 to 5.0 (mean 3.94) mm on echocardiography and 1.0 to 6.0 (mean 2.84) mm at autopsy. After aortic valve diameter was used as an internal control for tissue shrinkage during fixation, echocardiography/color Doppler imaging tended to overestimate VSD diameter by 21% (0.6 mm). In conclusion, echocardiography/Doppler imaging accurately identified the presence, morphology, and size of even the smallest VSDs in newborn Yucatan micropigs. Echocardiographic classification of VSD morphology in vivo will facilitate future research on specific types of VSDs in this animal model.

Transesophageal echocardiography detects thrombus formation not identified by transthoracic echocardiography after the Fontan operation.

Transesophageal echocardiography demonstrated six instances of venous thrombus formation in the inferior vena cava, right atrium and caval-pulmonary anastomosis region in four children after a modified Fontan operation. Transthoracic surface echocardiography failed to identify these thrombi in five of the six cases because of the posterior location of the thrombus or imaging interference from surgical hardware. These thrombotic episodes occurred 2 days to 5 years after the Fontan operation in children 25 to 168 months of age. Clinical features of compromised cardiac performance with cyanosis or inadequate perfusion were present during four of the six episodes. In two patients, thrombi occurred around transvenous permanent atrial pacing leads. Therapy to eliminate thrombus included surgery (two cases), anticoagulation with warfarin (three cases) and streptokinase thrombolysis (one case). Disappearance of the thrombus was confirmed by transesophageal study in three of the four cases with follow-up echocardiography. Transesophageal echocardiographic demonstration of atrial and pulmonary thrombi that could not be seen by transthoracic imaging suggests that these thrombi occur with greater frequency in patients who have undergone the Fontan operation than was previously suspected.

Comparison of intraoperative transesophageal echocardiography to epicardial imaging in children undergoing ventricular septal defect repair.

Intraoperative transesophageal echocardiography was compared with epicardial echocardiography after ventricular septal defect repair. This comparison was made in 18 children aged 7 to 137 months (median, 32 months), weighing 6.3 to 49.1 kg (median, 10.8 kg) from November 1989 to January 1991. Ventricular septal defect types were perimembranous (six), malalignment (seven), supracristal (three), midmuscular (one), and inlet (one). Eight children had isolated ventricular septal defects, four had tetralogy of Fallot, three had double outlet right ventricle, two had double chambered right ventricle, and one had pulmonary stenosis. Patch interrogation was complete in 17 of 18 transesophageal echocardiography and 16 of 18 epicardial echocardiography studies. Inability to fully interrogate the ventricular septal defect patch by epicardial echocardiography occurred in two children as a result of anterior ventricular septal defect location, limited epicardial exposure, and surgical hardware interference. Incomplete transesophageal echocardiography patch interrogation occurred in the child with the midmuscular ventricular septal defect. Seven residual ventricular septal defects were documented by color flow Doppler in six patients. Five of seven residual defects were demonstrated by both real-time transesophageal echocardiography and epicardial echocardiography imaging. Transesophageal echocardiography and epicardial echocardiography missed 1 and 7 defects, respectively. The missed defects were different with each technique and were confirmed by postoperative surface echocardiography. No residual defects of sufficient size to require reoperation were found as determined by combination color flow jet analysis and intraoperative oximetry (no pulmonary to systemic flow ratio was greater than 1.50). Patches caused two-dimensional and Doppler signal masking, but this was not limiting because all residual defects were found at the margins of the ventricular septal defect patch.(ABSTRACT TRUNCATED AT 250 WORDS)

The utility of transesophageal echocardiography during and after Fontan operations in small children.

Transesophageal echocardiography with Doppler examination was performed intraoperatively in 19 children undergoing modified Fontan operations and in 10 patients postoperatively. Comparisons were made with results of intraoperative epicardial imaging (9 patients) and with postoperative transthoracic imaging (10 patients). Transesophageal echocardiography optimally visualized atriopulmonary and cavopulmonary anastomoses. Epicardial echocardiography was successful in only three of nine patients. Intraoperative transesophageal echocardiography showed residua in 8 of 19 studies and led directly to surgical revision or medical therapy. These residua included stenosis of the cavopulmonary anastomosis (1 patient), unsatisfactory atrial fenestration (2 patients), patent ductus arteriosus (1 patient), residual cavoatrial shunting (1 patient), atrial thrombi (1 patient), and poor ventricular function (2 patients). Results of examination in the postoperative intensive care unit showed significant abnormalities in 4 of 10 patients. This study demonstrates that transesophageal echocardiography provides unique anatomic and physiologic information during and after modified Fontan operations in small children and therefore may have significant impact on patient management.

Transesophageal echocardiography for congenital heart disease.

Surface echocardiographic imaging of small children is routinely successful in defining anatomical details and Doppler flow patterns with even the most complex congenital cardiac malformations. However, in larger children or adults, imaging is frequently limited. A recent expansion of the role of echocardiography is intraoperative epicardial imaging. Epicardial and postoperative imaging, however, have significant limitations. To avoid some of these limitations, transesophageal echocardiography has increasingly been used in the arena of congenital heart disease. The more recent development of small sized gastroscopic probes has allowed transesophageal echocardiographic assessment of congenital heart disease in children down to newborn size. As detailed studies of individual lesions are reported, it has become clear that the mere presence of a congenital heart defect is not an indication for transesophageal echocardiography in most children if imaging can be accomplished by surface examination. However, transesophageal echocardiography may be indicated for the intraoperative or postoperative assessment of that defect, particularly when repair has been difficult or is known to be associated with significant residual abnormalities. Cardiac structures encountered with horizontal and vertical imaging plane transducers have been described and should be completely familiar to the examining echocardiographer.