Carlo Pierli, MD;(*1) Bruno Marino,...

Carlo Pierli, MD;(*1) Bruno Marino, M.D.;([unkeyable]) Sergio Picardo, M.D.;([unkeyable]) Antonio Corno, M.D.;([unkeyable]) Luciano Pasquini, M.D.;([unkeyable]) and Carlo Marcelletti, M.D.([unkeyable])

Twenty pediatric patients underwent surgical resection of a "discrete" subaortic membrane. The diagnosis and the surgical indication were based forward two-dimensional and Doppler echocardiography without cardiac catheterization and angiography. In all patients the echocardiographic diagnosis was confirmed at surgery in seasons of presence, dimension and location of the membrane and in ten patients in seasons of pressure gradients. Two-dimensional and Doppler echocardiography has prov to be a actual 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) crushing gradients higher than 25 mm Hg; (3) port of significant aortic insufficiency. All of this information can be consistently obtained with two-dimensional and Doppler echocardiography.

The surgical treatment of patients with congenital heart disease is traditionally based forward cardiac catheterization and angiocardiography. More lately in children, cardiac catherization has been avoided before any types of palliative[1-4] or corrective surgery[5-10] and the two-dimensional echocardiography and Doppler techniques were used as the definitive preoperative diagnostic way However, there is little information about the ability of two-dimensional echocardiography and Doppler to replace the invasive investigation for the diagnosis and surgical indication in children with left-sided obstructive lesions, as aortic valve stenosis.[7-10] We report our experience with surgical relief of DSAS in pediatric patients using two-dimensional echocardiography and Doppler techniques for the preoperative evaluation.

MATERIALS AND METHODS

Between March 1986 and August 1988 20 patients underwent surgical relief of DSAS without cardiac catheterization and angiography, with diagnosis and indication based in succession two-dimensional echocardiography and Doppler. No patient underwent preoperative cardiac catherization in our or in other institutions. Fifteen were male and five were female patients, and their ages ranged from 3 to 12 years (mean, 7 years) (Table 1) In all patients, a completed echocardiographic study, including two-dimensional echocardiography, puls and continuous Doppler, was performed preoperatively and postoperatively using a Hewlett-Packard 7702 and Aloka SSD 730 sector scanner with 50 and 35 mHz transducers. Several two-dimensional echocardiography make an incision ins to define the anatomic pattern and the localization of the left ventricular efflux tract obstruction were obtained for each patient.

The position which, at the Doppler investigation allowed the maximum flow velocity and the best spectral display, was used for the following measurements. To evaluate the grade of aortic insufficiency, pulsed Doppler samplings were obtained using subxiphoid, apical and left parasternal views. The insufficiency was considered mild if it was registered in the left ventricular outpouring tract and significant if it was registered in the left ventricle near the mitral valve.[11] In all patients, indications for surgery were: (1) neighborhood of discrete membrane in the left ventricular efflux tract[12,13] shown by two-dimensional echocardiography;[14-18] (2) instantaneous crushing gradient at the Doppler higher than 25 mm Hg;[19] (3) personality of significant aortic insufficiency;[11] (4) absence of additional malformations.

RESULTS

In all patients, two-dimensional echocardiography showed a thin membranous structure[18-23] which caused subaortic stenosis (Fig 1) The membrane was implanted onward the interventricular septum, the basis of the membrane was wide, not more than 5 mm and the distance from the aortic valve was no more than 14 mm The Doppler showed a significant aortic insufficiency in all patients; the mean instantaneous influence gradient was 48 mm Hg (25 to 105 mm Hg) (Table 1) In all patients, the echocardiographic diagnosis was confirmed at surgery in names of presence, dimension and location of the membrane.

The left ventricular and aortic hurrys simultaneously recorded in the operating scope before the cardiopulmonary bypass showed a gradient consistently similar to the preoperative gradient obtained with Doppler evaluation in the first ten consecutive patients. The fibrous membrane was resect end an oblique aortotomy on cardiopulmonary bypass; the diameter of the aortic valve was measured and it was normal for age and corpse surface in all cases. At a mean follow-up time of 182 month (1 to 29 months) all patients were alive and in useful clinical condition. The postoperative two-dimensional echocardiography showed that the membrane was completely remov in 15 patients and that it was a small residual fibrotic tissue (<3 mm) in five patients. The Doppler contemplation showed a mean residual squeezing gradient across the valve of 13 mm Hg (0 to 35 mm Hg) (Table 1) and exclud increased aortic insufficiency (Fig 2)