[Stable fibrous subaortic stenosis]

The authors studied 37 patients belonging to the Pediatric Cardiology Service of the Institute National of Cardiology who were carriers of fixed fibrinous subaortic stenosis. The diagnosis was established by surgery or autopsy. Isolated subvalvular obstruction was found in 24 patients (63%), which represents the most important number of cases in the literature. The analysis of the 24 cases permitted important conclusions: 1. All the patients had systolic thrills in the suprasternal hollow and carotidinous pathways. 2. No case had protosystolic click. In all, the murmur's epicenter was in the 3rd and 4th IIS in the parasternal line, a fact which can lead to a mistaken diagnosis of interventricular septal defect. 66.6% of the patients had a diastolic murmur heard in the aortic focus, a secondary accompaniement to secondary valvular aortic insufficiency. The intensity of the second aortic sound held an inverse relationship to the magnitude of the gradient. The presence of paradoxic splitting of the second heart sound as well as prolongation of the expulsion period in the carotidogram are indexes for the severity of the obstruction. 3. A relationship between the severity of the lesion and the dilatation of the left atrium was found. The cardiomegaly had no relationship to the severity of the obstruction with the increase in ventricular telediastolic pressure or to the evolution time. 4. An adequate hemodynamic study permits evaluating and locating the site of the obstruction. Likewise, precise ventriculography appraises the nature of the narrowing. 5. Aortic regurgitation is located at the valvular level. Aortography permits its affirmation. Probably the stream coming from subvalvular stenosis produces fibrosis or asynchronism in the closing of the aortic valves. 6. Surgical treatment offers excelent perspectives in mortality as well as reducing the gradient. None of our patients operated on had hospital or later death. 7. Postoperatory evaluation was performed on six patients, and by means of measuring the gradient between the left ventricle and the aorta, the good surgical results could be demonstrated. 8. The natural evolution of patients with fixed fibrous subaortic stenosis is similar to that of other forms of congenital aortic stenosis. Taking into consideration this concept, and before the low risk (0%) in this type of surgery, this is the treatment of choice.