[Quantitative evaluation of complete endocardial cushion defect using two-dimensional echocardiography].

To avoid postoperative mitral valve dysfunction, the common atrioventricular valves of 21 preoperative patients with complete common atrioventricular canal were quantitatively evaluated using two-dimensional echocardiography. The criteria for diagnosing hypoplasia of the left lateral leaflet, which often made complete repair difficult, were also investigated. The patients were 10 boys and 11 girls, who ranged in age from one month to three years and three months. The subcostal short-axis view was used to evaluate the common atrioventricular valves. The sizes of the leaflets and diameters of the ventricles were measured by two-dimensional echocardiography and at surgery. The measurements by both methods were nearly identical, and the correlation coefficient was 0.95. Thus, two-dimensional echocardiography correctly evaluated common atrioventricular valve size. The length of the left lateral leaflet varied from 5 mm to 22 mm. In four patients, it was less than 10 mm, and was under the 99% confidence limit. In all four patients, two papillary muscles were noted in the left ventricle. Two of these patients underwent corrective surgery and died of postoperative mitral valve stenosis. This new technique can prevent postoperative mitral valve dysfunction by estimating preoperatively the appropriate suturing length of the anterior and posterior components of the anterior mitral valve. It is concluded that two-dimensional echocardiography can correctly evaluate the size of common atrioventricular valves, which is often difficult by angiocardiography. Hypoplasia of the left lateral leaflet could be diagnosed when its length was less than 10 mm measured by two-dimensional echocardiography. This technique is more accurate compared to the method which demonstrates the presence of a single papillary muscle in the left ventricle. Corrective surgery for the patients with a hypoplastic left lateral leaflet involves great risks, resulting in postoperative mitral valve stenosis. Preoperative evaluation of a common atrioventricular valve is useful to avoid postoperative mitral valve dysfunction.