Author + information
- Received January 20, 1993
- Revision received May 7, 1993
- Accepted May 12, 1993
- Published online November 1, 1993.
- Sabine Kleinert, MD and
- Tal Geva, MD∗
- ↵∗Address for correspondence: Dr. Tal Geva, Division of Pediatric Cardiology, Texas Children's Hospital, 6621 Fannin, Houston, Texas 77030.
Objectives. This study was designed to identify, by echocardiography, morphometric abnormalities of the left ventricular out-flow tract in children with fixed subaortic stenosis and to determine whether these abnormalities precede the development of subaortic obstruction.
Background. Fixed subaortic stenosis typically develops and progresses after the 1st year of life and is therefore often regarded as an acquired lesion. Although it has been speculated that there may be an underlying anatomic substrate, there are no data to support this hypothesis.
Methods. The size of the aortic annulus, mitral-aortic valve separation, aorto-left ventricular septal angle and degree of aortic override were determined in two groups of children. Group 1 comprised 35 patients with isolated subaortic stenosis noted on initial echocardiogram who were compared with an age- and weight-matched normal control group (Group 1A). Group 2 comprised 23 patients with ventricular septel defect or coarctation of the aorta, or both, who had no subaortic stenosis on initial echocardiogram but who developed it subsequently. This group was compared with an age-, weight- and lesion-matched control group (Group 2A).
Results. Compared with control subjects, patients with isolated subaortic stenosis hed a significantly wider mitral-aortic separation ([mean ± SD] 5.1 ± 1.3 vs. 3.4 ± 0.9 mm, p < 0.001), a steeper aortoseptal angle (131 ± 6 ° vs. 144 ± 5 °, p < 0.001) and an exaggerated aortic override (p < 0.05). Similar differences were found on initial echocardiogram in Group 2 patients before development of subaortic stenosis: wider mitral-aortic separation (4.2 ± 1.2 vs. 2.5 ± 0.7 mm, p < 0.001), a steeper aortoseptal angle (132 ± 7 ° vs. 145 ± 7 °, p < 0.001) and an exaggerated aortic override (p < 0.05).
Conclusions. A left ventricular outflow tract malformation characterized by a wider mitral-aortic separation, an exaggerated aortic override and a steeper aortoseptal angle are present in children with ventricular septal defect or coarctation of the aorta or both, who subsequently develop subaortic stenosis. These morphometric features can be used to identify by echocardiography patients who are at risk for developing fixed subaortic stenosis.
- Received January 20, 1993.
- Revision received May 7, 1993.
- Accepted May 12, 1993.