318 Factors determining the nature of progression of discrete fixed subaortic stenosis

IntroductionIn discrete fixed subaortic stenosis, surgery is indicated when the systolic gradient (Gmax) between the left ventricle (LV) and the aorta exceed 50mmHg or in the presence of significant aortic regurgitation (AR).The aim of this study is to determine the factors that influence the progression of the obstruction and the appearance of AR.Methodsretrospective serial echocardiographic review of 19 patients, mean age 16 years (2 years-38 years), with fixed discrete subaortic stenosis that don’t require surgery (initial Gmax at inclusion <50mmHg and without any symptom). The mean follow up was 5,42 years. The progression of gradient is defined by the formula (Gmax at follow up – initial Gmax)Resultsthe mean velocity of increasing of Gmax was 2mmHg/year. This progression was correlated to the patient's age (cut off=15 years, r=−0,5; p=0,02), and the initial value of the Gmax (cut off=40mmHg, r=0,43; p=0,04).The appearance or the aggravation of aortic regurgitation was determined by: the initial grade of AR (r=0,64; p=0,003), initial Gmax (r=0,65; p=0,002), progression's velocity of G max (r=0,47; p=0,04), and distance between the membrane and the aortic cusps (cut off=5mm, r=0,49; p=0,03). LV hypertrophy was influenced by the velocity of progression of obstruction (>2mmHg/year)Conclusionthe identification of factors determining the evolution of discrete subaortic stenosis (age <15 years, initial Gmax >40mmHg, distance membrane-cusps >5mm) allows an adequate screening of patients that will require early operation