Clinical and echocardiographic aspects in fixed subaortic stenosis.

Aims - Fixed subaortic stenosis (SAS) can be classifi ed into a complex form when it is associated with other defects involving the left ventricular (LV) infl ow and outfl ow tract and a simple form when this is not the case. Previous studies have suggested that these two forms have different outcomes and might represent different pathologies altogether. Our purpose was to study the characteristics and outcomes of operated and unoperated complex SAS and simple SAS patients in a single tertiary centre of general cardiology. Methods - A total of 93 consecutive patients were retrospectively identifi ed between 2003 and 2016. Propensity score matching was used to obtain comparable subgroups of complex SAS (n=24) and simple SAS (n=20) in terms of age (mean 26 years), gender (52% female), functional class (class III 9%, class II 75%) and LV ejection fraction (mean 61%) at diagnosis. Results - LV diastolic diameter (51 vs. 47 mm, p=0.08) and interventricular septum thickness (12 vs. 10 mm, p=0.08) seemed to have higher values in the complex SAS group, despite a similar mean aortic gradient in the two subgroups (40 vs. 45 mmHg, p=0.23). There was no signifi cant difference regarding LV ejection fraction (60% vs. 61%, p=0.4). There were more patients with moderate to severe mitral regurgitation in the complex SAS group (25% vs. 10%), whereas moderate to severe aortic regurgitation was equally noticed in both groups (54% vs. 55%). There were more patients who received surgical treatment (54% vs. 25%, p=0.05), with a higher usage of aortic valve replacement in the complex SAS group (38% vs. 0%, p=0.15). Mortality seemed higher in the complex SAS group when compared to simple SAS group (16% vs. 10%, p=0.4), both in operated (15% vs. 0%, p=0.5) and unoperated patients (18% vs. 13%, p=0.6), without reaching the statistical signifi cance due to small sample size. Mean subaortic gradient correlated signifi cantly with left ventricular end-diastolic diameter (negative correlation, R2=0.22, p=0.04), interventricular thickness (positive correlation, R2=0.22, p=0.03) and posterior wall thickness (positive correlation, R2=0.25, p=0.02) in the complex SAS group, with no signifi cant correlations in the simple SAS group. Conclusion - Complex form of subaortic stenosis is associated with a more important left ventricular remodelling probably due to the role played by associated cardiac defects and seems to have a less favourable outcome, both in surgically managed and conservatively treated patients, independent of NYHA functional class and left ventricular ejection fraction at initial diagnosis, with the limitation of the small dimension of the studied group. Further larger and prospective studies are needed in order to confi rm these aspects. [ABSTRACT FROM AUTHOR]