Indication for systemic-pulmonary artery shunts guided by two-dimensional and Doppler echocardiography: criteria for patient selection

Accordion-like prosthesis for modified Blalock-Taussig shunt

From March 1996 to July 2002, 26 consecutive patients, with a mean age of 17.9 months and a mean body weight of 6.6 kg, underwent the modified Blalock-Taussig shunt with a tubular accordion-like prosthesis. In a mean follow-up period (defined as the interval between the shunt procedure and repair or last evaluation) of 10.9 months (range, 1 to 32 months), there were 1 death due to excessive pulmonary blood flow in a neonate with hypoplastic left heart syndrome and 3 reoperations to correct shunt-related problems, 2 of them early and 1 late (to regulate pulmonary blood flow after left ventricular retraining for transposition of the great arteries). There was no occurrence of shunt obstruction or kinking. Other shunt-related early complications, such as bleeding, infection, or serous fluid leakage, did not occur, and no patient needed pulmonary artery reconstruction during surgical repair. Shunt patency was confirmed by Doppler echocardiography in all patients and also by angiography in 73% of the patients. This prospective study confirmed our preliminary results with this prosthesis. The use of this prosthesis is justified for reducing early and late complications potentially associated with the modified Blalock-Taussig shunt, particularly distortion of the pulmonary arteries.

Echocardiographic diagnosis alone for the complete repair of major congenital heart defects

OBJECTIVES

The study was done to determine the diagnostic accuracy of echocardiography alone in the preoperative diagnosis of children with major congenital heart defects undergoing primary complete repair.

BACKGROUND

Although echocardiography is well established as the first-line imaging technique for the diagnosis of all forms of congenital heart disease, most institutions continue to perform cardiac catheterization prior to complete repair of more complex defects.

METHODS

To determine the diagnostic accuracy of echocardiography alone and echocardiography plus catheterization, we reviewed the records of 503 children with major congenital heart defects who underwent primary complete repair at our institution between July 1992 and June 1997. We included children with transposition of the great arteries, tetralogy of Fallot, double-chamber right ventricle, interrupted aortic arch, aortic coarctation, atrioventricular septal defect, truncus arteriosus, aortopulmonary septal defect, and totally anomalous pulmonary venous return. We excluded children with less complex defects such as isolated shunt lesions, as well as those with the most complex defects that would require surgical palliation (e.g., functional univentricular heart). We defined major errors as those that increased the surgical risk and minor errors as those that did not. Errors in diagnosis were determined at surgery.

RESULTS

Eighty-two percent of children (412 of 503) underwent surgery after preoperative diagnosis by echocardiography alone. There were 9 major (2%) and 10 minor errors in the echocardiography alone group and 7 major and 5 minor errors in the echocardiography plus catheterization group. The most common type of error was misidentification of coronary artery anatomy in patients with transposition of the great arteries. No error in either group resulted in surgical morbidity or mortality.

CONCLUSIONS

This study suggests that echocardiography alone is an accurate tool for the preoperative diagnosis of major congenital heart defects in most children undergoing primary complete repair, and may obviate the need for routine diagnostic catheterization.

Echocardiographically guided repair of tetralogy of Fallot

Although 2-dimensional, Doppler, color flow echocardiography is accepted as a safe diagnostic method to guide the surgical treatment of certain heart defects, cardiac catheterization remains mandatory for patients with tetralogy of Fallot. Based on the excellent diagnostic correlation between echocardiography and angiocardiography, a policy of echo-guided primary repair of uncomplicated, selected cases of tetralogy of Fallot was introduced at Ospedale Bambino Gesù. In the last 5 years, of 139 patients who had surgery for tetralogy of Fallot, 105 underwent primary repair. In 56 patients (53.3%), surgery was guided only by echocardiography (group I). In the remaining 49 patients (46.7%) (group II), unclear imaging of cardiovascular anatomy (n = 23), or echo-suspected associated malformations (n = 26) prompted cardiac catheterization. The 2 groups did not differ in age and weight at surgery. Intraoperative examination did not show diagnostic errors in patients of group I; cardiac catheterization and surgery confirmed the suspected associated anomalies in 16 of 26 patients of group II (38.4% false-positive). Echocardiography showed an overall sensitivity of 100% and specificity of 85% for detection of associated malformations. In conclusion, echocardiography proved to be adequate for selection of patients with uncomplicated forms of tetralogy of Fallot for primary repair.

Ductus arteriosus in pulmonary atresia with and without ventricular septal defect. Anatomic and functional differences

The pulmonary circulation is dependent on the ductus arteriosus in all patients with pulmonary atresia and intact ventricular septum and in some with pulmonary atresia and ventricular septal defect (tetralogy of Fallot type). To assess the time of ductal closure in these two patient categories, we compared the ages at first operation in 58 patients with pulmonary atresia and intact ventricular septum and 32 with pulmonary atresia and septal defect. The age distribution differed significantly between the groups. Whereas 90% of the children with intact ventricular septum required surgery in the first week of life, 50% of those with ventricular septal defect underwent surgery after the first month and 25% after the third month. The previously described and now confirmed anatomic differences of ductus arteriosus or different levels of endogenous prostaglandins may explain persistent patency of the ductus in pulmonary atresia with ventricular septal defect. The phenomenon may have important clinical implications regarding the timing and choice of surgical procedure.

Pulmonary atresia with ventricular septal defect. Selection of patients for systemic-to-pulmonary artery shunt based on echocardiography

From January 1987 to December 1988, in 22 infants with PAVSD, the diagnostic results obtained with echocardiography (two-dimensional, Doppler, and color) were prospectively compared to the angiocardiographic findings. We classified into group 1 patients with confluent and good-sized pulmonary (greater than or equal to 3 mm) arteries, single ductus arteriosus, and normal pulmonary venous connections ("favorable pattern"). The other patients with PAVSD were classified into group 2 ("unfavorable pattern"). The intracardiac anatomy, the morphology of the pulmonary arteries, and the pattern of pulmonary blood supply and pulmonary venous connection were correctly identified with echocardiography in all but one patient, who was erroneously considered to be in group 2. No false-positive of the "favorable pattern" (group 1) was detected. Echocardiography is an effective tool in infants with PAVSD, in order to discriminate cases with "favorable" and "unfavorable" patterns of pulmonary arteries, pulmonary blood supply, and pulmonary veins. The first group with the "favorable pattern" may be considered for systemic-to-pulmonary shunt surgery without angiocardiography. Based on this experience from January to December 1989, four patients with this "favorable pattern" underwent a successful systemic-to-pulmonary artery shunt with an echocardiographic diagnosis alone.

Pediatric cardiac surgery guided by echocardiography. Established indications and new trends

Cardiac surgery in 602 children was not preceded by cardiac catheterization, the diagnosis being based on clinical findings and two-dimensional and Doppler echocardiography. In the 355 operations without cardiopulmonary bypass there were nine major and seven minor diagnostic errors (2.5% and 2%). Among the 247 cases with open-heart surgery there were no major and eight (3.2%) minor errors. The malformations most suitable for nonbypass surgery without catheterization seem to be those with reduced pulmonary blood flow requiring systemic-pulmonary artery shunt, aortic coarctation and patent ductus arteriosus. For open-heart surgery without invasive investigation, atrial septal defect, partial atrioventricular canal, aortic and pulmonary stenosis, cardiac tumor and isolated valve disorder are 'classic' candidates. Recent experience indicated that selected cases of complete atrioventricular canal, tetralogy of Fallot, truncus arteriosus, total anomalous pulmonary venous connection and transposition of the great arteries may safely undergo primary repair without cardiac catheterization. Because of its diagnostic potentialities, pediatric cardiac surgeons must become familiar with echocardiography.

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.