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Natural history and risk stratification of discrete subaortic stenosis in children: an echocardiographic study
Mao-Sheng Hwang1, Jaw-Ji Chu, Wen-Jen Su
1Department of Pediatric Cardiology, Chang Gung Children's Hospital, Taoyuan, Taiwan.
Insights
Discrete subaortic stenosis (DSS) can have two distinct clinical courses. Shorter DSS-AV distance and anterior mitral valve leaflet involvement predict rapid progression, aiding risk assessment for this acquired cardiac defect.
Area of Science:
- Pediatric Cardiology
- Cardiac Surgery
- Echocardiography
Background:
- Discrete subaortic stenosis (DSS) is an acquired cardiac defect with an unclear natural history and pathogenesis.
- Understanding the anatomical factors contributing to DSS development is crucial for effective management.
Purpose of the Study:
- To investigate the natural history of discrete subaortic stenosis (DSS) using echocardiography.
- To identify potential anatomical abnormalities associated with the development and progression of DSS.
Main Methods:
- Retrospective review of 12 children diagnosed with DSS between 1988 and 2002.
- Serial echocardiographic analysis of left ventricular outflow tract obstruction (LVOTO) and aortic regurgitation (AR).
- Comparison of anatomical measurements (indexed MV-AV distance, ASA, indexed DSS-AV distance, anterior MV leaflet involvement) between DSS subgroups and controls.
Main Results:
- Two distinct clinical courses of DSS were observed: slower progression (n=9) and rapid progression (n=3).
- Severe DSS was associated with shorter indexed DSS-AV distance and anterior mitral valve leaflet involvement.
- Patients with DSS had a longer indexed MV-AV distance and steeper aortoseptal angle (ASA) compared to controls.
Conclusions:
- DSS exhibits two distinct clinical trajectories.
- Shorter indexed DSS-AV distance and anterior mitral valve leaflet involvement may predict more rapid DSS progression.
- Longer indexed MV-AV distance and steeper ASA could help identify individuals at risk for developing DSS.
Background And Purpose:
Discrete subaortic stenosis (DSS) is considered an acquired cardiac defect. However, its clinical course and pathogenesis have not been well defined. This study used echocardiography to investigate the natural history of DSS and identify the possible anatomic abnormalities leading to its development.
Methods:
We reviewed the medical records of 12 children with a diagnosis of DSS between 1988 and 2002. Data on the age at initial diagnosis of DSS was collected and the sequential changes of left ventricular outflow tract obstruction (LVOTO) and aortic regurgitation (AR) were analyzed by serial echocardiographic studies. Patients were divided into 2 subgroups according to the latest or presurgical (in patients with operations for DSS) Doppler-derived peak instantaneous left ventricular outflow tract gradient (deltaP; cut-off point: deltaP 50 mm Hg, our institutional criterion of operation for DSS). The indexed mitral valve (MV)-aortic valve (AV) distance, aortoseptal angle (ASA), indexed DSS-AV distance, and whether the anterior MV leaflet was involved were also determined. The DSS patients were compared with an age- and lesion-matched control group (12 patients).
Results:
The mean age at initial diagnosis of DSS was 4.9 +/- 3.7 years. Nine children had disease characterized by milder LVOTO (latest deltaP < 50 mm Hg) and slower progression of LVOTO (mean increase of deltaP, 7.1 +/- 4.4 mm Hg/year) and AR ( 50 mm Hg) and more rapid progression of LVOTO (mean increase of deltaP, 27.8 +/- 8.4 mm Hg/year) and AR (>/= grade II). Compared with the control group, the study group had a significantly longer indexed MV-AV distance and a steeper ASA. Compared with the patients with milder disease, patients with more severe disease had a significantly shorter indexed DSS-AV distance and more frequent involvement of the anterior MV leaflet.
Conclusions:
These data indicate that DSS may present with 2 distinct clinical courses. A shorter indexed DSS-AV distance and the involvement of the anterior MV leaflet might be predictive of more rapidly progressive DSS. Longer indexed MV-AV distance and steeper ASA might be useful to evaluate primary cardiac defects and thus to identify patients who are at risk for developing DSS.
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