Two-dimensional echocardiography in discrete subaortic stenosis

Two-dimensional and M-mode echocardiographic predictors of disease severity in dogs with congenital subaortic stenosis

Echocardiographic studies from 50 dogs with congenital subaortic stenosis were examined. The degree of concentric, left-ventricular hypertrophy as assessed by M-mode measurement demonstrated a positive relationship (P<0.05) to disease severity. However, the clinical utility of these measures is hindered by a large amount of individual variation (r2=0.243 to 0.473). Two-dimensional ultrasound was used to compare the cross-sectional area of the left-ventricular outflow tract to the cross-sectional area of the aortic root. The ratio of these two areas demonstrated a strong inverse relationship (P=0.001; r2=0.778) with disease severity. This ratio provides a method of estimating severity of disease by two-dimensional echocardiography.

Use of three-dimensional echocardiography for analysis of outflow obstruction in congenital heart disease

To evaluate the feasibility and accuracy of 3-dimensional (3D) echocardiography in analysis of left and right ventricular outflow tract (LVOT and RVOT) obstruction, 3D echocardiography was performed in 28 patients (age 4 months to 36 years) with outflow tract pathology. Type of lesion and relation to valves were assessed. Length and degree of obstruction were measured. Three-D data sets were adequate for reconstruction in 25 of 28 patients; 47 reconstructions were made. In 13 patients with LVOT obstruction, 3D echocardiography was used to study subvalvular details in 8, valvular in 13, and supravalvular in 1. Four of these 13 patients had complex subaortic obstruction. In 12 patients with RVOT lesions, 3D echocardiography was used to study subvalvular details in 11, valvular in 12, and supravalvular in 2. Three-dimensional reconstructions were suitable for analysis in 100% of subvalvular LVOT, 77% valvular LVOT, 100% supravalvular LVOT, 100% subvalvular RVOT, 50% valvular RVOT, and 50% supravalvular RVOT. Twenty patients underwent operation, and surgical findings served as morphologic control for thirty-four 3D reconstructions (LVOT 17, RVOT 17). Operative findings revealed an accuracy at subvalvular LVOT of 100%, valvular LVOT 90%, supravalvular LVOT 100%, subvalvular RVOT 100%, valvular RVOT 100%, and supravalvular RVOT 100%. Quantitative measurements could adequately be performed. Three-D echocardiography is feasible and accurate for analyzing both outflow tracts of the heart. Particularly, generation of nonconventional horizontal cross sections allows a good definition of extension and severity of lesions.

Transesophageal Echocardiographic Imaging for Congenital Lesions of the Left Ventricular Outflow Tract and the Aorta

A comprehensive transthoracic echocardiographic imaging is possible for most pediatric patients. However, for patients in whom accurate anatomical and physiological assessment is not possible, transesophageal echocardiography (TEE) provides a supplemental diagnostic modality. Imaging the left ventricular outflow tract and the aorta involves a complicated technique of rotation, flexion, and changes in the depth of the transesophageal probe because the areas of interrogation involve multiple planes within the thoracic cavity. Furthermore, the relationship between the esophagus and the cardiovascular structures changes at various levels of the thorax. Transesophageal probes having characteristics of frequency agility, all forms of Doppler capability, and a higher number of crystal elements are now available. Abnormalities of the subaortic area, the aortic valve, coronary arteries, and the entire thoracic aorta can be clearly demonstrated. TEE also has played a complementary role in diagnostic and interventional catheterization. It has become vital in the operating room for the preoperative definition of certain aspects of the anatomy and for immediate postoperative evaluation of the result of surgery. (ECHOCARDIOGRAPHY, Volume 13, July 1996)

Transoesophageal echocardiographic assessment of fixed subaortic obstruction in children

OBJECTIVE

To evaluate the clinical usefulness of transoesophageal echocardiography in the assessment of children with fixed left ventricular outflow tract stenosis.

PATIENTS AND METHODS

Eight consecutive children, aged over 5 years, with fixed subaortic stenosis and one child with fixed subpulmonary left ventricular outflow tract stenosis were prospectively assessed by precordial and transoesophageal echocardiography.

RESULTS

Transoesophageal images of the left ventricular outflow tract were much clearer than precordial images in all patients except one with a prosthetic mitral valve. Improved visualisation provided further information on the nature of the lesion (additional chordal attachment of the mitral valve in one, accessory atrioventricular valve tissue with aneurysm formation in one), on the extent of the lesion (circumferential in three), and on the very close relation of a ridge to the aortic valve leaflets in one. Transoesophageal Doppler did not provide any additional information on aortic regurgitation and was unreliable for gradient estimation across the left ventricular outflow tract.

CONCLUSIONS

Transoesophageal imaging provides an excellent means of visualising lesions in the left ventricular outflow tract and can be useful in a few children and adolescents in whom precordial echocardiography does not provide adequate information. The technique can also be used intraoperatively to define the full extent of the obstructive lesion and to assess residual lesions after surgery.

Subaortic obstruction: intraoperative echocardiography as an adjunct to operation

Fourteen patients undergoing operation for subaortic obstruction (membranous obstruction in 11 patients, tunnel obstruction in 2 patients, obstruction due to reduplicated mitral valve tissue in 1 patient) were evaluated by intraoperative epicardial echocardiography. In all 9 patients with "discrete" obstruction who underwent prebypass epicardial echocardiography, the septal and lateral attachments of the lesion were correctly demonstrated. The precise extent of tunnel stenosis was seen in both patients. The lateral attachment of the membrane in 4 patients and multiple extensions in another 2 were identified by the epicardial study (having been missed on precordial echocardiography). The discrete membrane was enucleated in 10 of the 11 patients and was partially resected in 1. One tunnel obstruction was completely relieved; the other was partially relieved. Reduplicated mitral valve tissue in the remaining patient was completely resected. Epicardial imaging after bypass showed remnants of the membrane in 2 patients. Intraoperative Doppler echocardiography and color flow imaging confirmed the absence of clinically significant residual gradients (less than 20 mm Hg) in all but 1 patient with tunnel obstruction. Epicardial imaging provided excellent morphological information about obstructive lesions of the left ventricular outflow tract and enabled immediate assessment of surgical repair.

Obstruction of the left ventricular outflow tract in childhood--improved diagnosis by transoesophageal echocardiography

We used transoesophageal echocardiography in 4 children with either documented or suspected obstruction of the left ventricular outflow tract to determine whether this technique may provide additional morphologic information when compared to praecordial ultrasound. Transoesophageal studies defined unsuspected mitral valvar abnormalities in two patients and involvement of the subvalvar mitral apparatus in one. In one patient, the study documented a suspected fibrous ridge associated with malalignment of the outlet septum. Transoesophageal echocardiography would appear to be a new technique with definite advantages in defining the spectrum of lesions which cause obstruction to the left ventricular outflow tract in children.

Discrete subaortic stenosis. Surgery in children based on two-dimensional and Doppler echocardiography

Twenty pediatric patients underwent surgical resection of a "discrete" subaortic membrane. The diagnosis and the surgical indication were based on two-dimensional and Doppler echocardiography without cardiac catheterization and angiography. In all patients the echocardiographic diagnosis was confirmed at surgery in terms of presence, dimension and location of the membrane and in ten patients in terms of pressure gradients. Two-dimensional and Doppler echocardiography has proved to be a very reliable tool for the diagnosis and surgical indication in pediatric patients with a DSAS. Our criteria for the selection of surgical patients are the following: (1) isolated form of discrete subaortic stenosis with a short base of attachment to the ventricular septum; (2) pressure gradients higher than 25 mm Hg; (3) presence of significant aortic insufficiency. All of this information can be consistently obtained with two-dimensional and Doppler echocardiography.

Fixed subaortic stenosis: the value of cross-sectional echocardiography in evaluating different anatomical patterns

We present a study using cross-sectional echocardiography in 39 patients (29 male and 10 female) with discrete subaortic stenosis. Five parameters were evaluated in the study: the morphology of the obstruction, the distance of the stenosis from the aortic valve, the type of insertion, the base of implantation, and any associated anomalies. The lesion could be divided into groups with either fibrous or fibromuscular shelves. In the group of 14 patients with fibrous shelves, the distances from the stenotic lesion to the aortic valve was less than 15% of the length of the left ventricle. The obstructive fibrous tissue was inserted on the septum and extended onto the aortic leaflet of the mitral valve (circumferential lesion) in 12 cases. The base of implantation was narrow in all 14 of them. In the 25 patients having fibromuscular lesions, the distance between obstruction and valve was greater than 18.4% of the length of the left ventricle. The insertion of the obstructive lesion was circumferential in 18 cases and its base of implantation was wide in 20 of the patients. Nineteen patients, 16 of whom had fibromuscular lesions, showed associated anomalies. Statistical analysis showed a good correlation between the type of stenosis and the base of implantation of the stenotic lesion (P less than 0.001) or associated anomalies (less than 0.01), but there was no distinction between the groups with regard to the type of insertion (less than 0.38). Twenty-five patients underwent surgical correction which was carried out between the ages of 4-14 years. Prosthetic valves (3 aortic and 1 mitral) were inserted in 4 patients.(ABSTRACT TRUNCATED AT 400 WORDS)

Subaortic fibrous ridge and ventricular septal defect: role of septal malalignment

The purpose of this study was to test the hypothesis that the presence of a subaortic ridge associated with a ventricular septal defect (VSD) is related to a malaligned ventricular septum caused by anterior or posterior deviation of the infundibular septum with or without obstructive lesions of the aortic arch. Thirty-two of 295 patients in whom a diagnosis of VSD was made by two-dimensional echocardiography and who were studied from June 1983 to April 1985 presented with a subaortic shelf. Every patient (p less than .00001) had a malalignment type of defect; the defect was produced by anterior deviation of the outlet septum (without compromise of the right ventricular outflow tract) in 28 and by posterior deviation of the infundibular septum in four. The prevalence of a subaortic shelf in the malalignment VSD group was 82% (32/39). Among the 28 patients with a subaortic ridge and anterior deviation of the outlet septum only three had aortic coarctation, but all four patients with subaortic stenosis and posterior infundibular malalignment had obstructive lesions of the aortic arch--coarctation in three and interruption of the aortic arch in one (p less than .001). We conclude that a malalignment type of VSD may be a consistent feature in patients with VSD and associated discrete subaortic stenosis. We also noted a high prevalence of subaortic ridge in the presence of a malalignment VSD and therefore speculate that there may be a common morphogenesis for malalignment VSD, subaortic shelf, and obstructive lesions of the aortic arch.