Development and Validation of an Echocardiographic Model for Predicting Progression of Discrete Subaortic Stenosis in Children

doi:10.1016/S0002-9149(97)00911-9

The American Journal of Cardiology

Volume 81, Issue 3, 1 February 1998, Pages 314-320

https://doi.org/10.1016/S0002-9149(97)00911-9 Get rights and content

Abstract

The clinical course of discrete subaortic stenosis (DSS) varies considerably between patients. This study was performed to identify echocardiographic characteristics of DSS that distinguish progressive from nonprogressive disease. The study included 100 patients from 2 institutions and was performed in 2 stages. In phase I, a prediction model was developed based on multivariate analysis of morphometric and Doppler variables obtained from the initial echocardiogram in 52 children with DSS from Texas Children’s Hospital. In phase II, the performance characteristics of the prediction model were tested in 48 patients with DSS followed at Children’s Hospital in Boston. Patients were divided into 3 outcome groups: nonprogressive, progressive, and intermediate progression. In phase I, multivariate analysis identified 3 independent predictors of progressive disease: indexed aortic valve to subaortic membrane distance, anterior mitral leaflet involvement, and initial Doppler gradient. The logistic regression equation—Probability = [1 + e^{−(−3.22+0.334X}₁^+4.06X₂^−0.708X₃⁾]⁻¹, where X = initial gradient in mm Hg; X₂ = absence (0) or presence (1) of mitral leaflet involvement; and X₃ = indexed distance between aortic valve and subaortic membrane in mm/body surface area^0.5 were used to predict progression. When the prediction model was applied to phase II study patients, none of the patients with nonprogressive DSS had a prediction value >0.29 and none of the patients with progressive DSS had a prediction value <0.58. Thus, a prediction value >0.55 yielded a 100% sensitivity and 100% specificity for distinguishing progressive from nonprogressive DSS. Patients with intermediate progression were indistinguishable from progressive DSS but were clearly separable from nonprogressing patients. We conclude that progressive subaortic obstruction in children with DSS can be predicted from morphologic, morphometric, and Doppler echocardiographic analysis of left ventricular outflow.

Section snippets

Study Design:

The study included 100 patients from 2 institutions and was performed in 2 stages. In phase I, a multiple logistic regression prediction model was developed based on multiple clinical and echocardiographic variables of 52 patients with DSS from Texas Children’s Hospital. In phase II, the prediction model was applied to 48 patients with DSS from Children’s Hospital in Boston to examine its diagnostic accuracy in an independent study sample.

Phase I Study:

All patients diagnosed by echocardiography as having DSS

Patients:

One hundred patients with DSS who met inclusion criteria were included in the study: 52 patients from Texas Children’s Hospital participated in phase I and 48 patients from Children’s Hospital, Boston, were included in phase II. Based on the defined criteria, 33 patients were classified as having nonprogressive DSS, 50 as having progressive stenosis, and the remaining 17 patients formed the intermediate progression group. The demographic and clinical characteristics of the groups are summarized

Discussion

This study identified 3 echocardiographic features that were independently predictive of progressive DSS in children: (1) the distance of subaortic obstruction from the aortic valve, (2) involvement of the anterior mitral leaflet by the subaortic membrane, and (3) initial Doppler gradient. These 3 variables can be applied using a prediction equation to discriminate between nonprogressive and progressive subaortic stenosis.

Early studies based largely on cardiac catheterization data from patients

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Subaortic stenosis (SAS) is a rare entity in adults with an unclear aetiology and variable clinical presentations and outcomes. SAS typically tends to occur in the first decade of life either as an isolated lesion or in association with other congenital heart diseases. The clinical presentation of SAS can closely mimic hypertrophic cardiomyopathy (HCM) with obstructive physiology.
We present two cases of SAS in adults that were initially presumed to be HCM. The patients were in their late forties and were referred to HCM clinic for further evaluation. Careful review of the transthoracic echocardiogram was indicative for the presence of possible subaortic membrane. These patients underwent subsequent imaging studies that completed the diagnosis for SAS and thereafter had successful surgical resection of the subaortic membrane.
Subaortic stenosis remains a rare and clinically challenging diagnosis in the adult population. Often a combination of imaging modalities is needed to distinguish SAS from HCM with obstruction. It is critical to make the appropriate diagnosis as the treatment options are vastly different from the SAS and HCM with obstruction as well as the implications of a diagnosis of HCM with regards to risk of sudden death and family screening.
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Discrete subaortic membranes in adults-a clinicopathological analysis
2009, Cardiovascular Pathology
A discrete subaortic membrane (DSM) is one of the causes of subaortic stenosis in children. The incidence, characteristics, and the therapeutic options for such membranes in adults have not been well documented. This report documents the clinical and pathological features of DSM in adults.
DSMs, surgically excised over a 10-year period in a large adult tertiary care center, were reviewed with regard to the age and gender of the patients, clinical findings, and the morphological features.
Among the 19 adults, there were six males and 13 females, with age ranging from 26 to 75 years. The patients most often presented with dyspnea, fatigability, and palpitation for 3 months to 2 years. Four patients (21%) had other congenital heart disease in association with the DSM; in the rest, the membranes were isolated occurrences (79%). A cardiac murmur or the presence of membranes had been noted in childhood in four patients. Tissue growths over the ventricular surface of the anterior mitral leaflet were seen in 18 cases. Irrespective of the gross appearance, the stenosing lesions exhibited five tissue layers, beginning from the luminal aspect, endothelium, acid mucopolysaccharide-rich subendothelial layer, collagen-rich fibrous layer, fibroelastotic layer, and a smooth muscle layer. Twelve patients (63%) had aortic regurgitation, which necessitated repair or replacement in seven. Septal myectomy resulted in conduction abnormalities in nine.
The study describes the occurrence of DSM in adults. It is important to remember that it can occur following a repair of underlying congenital heart disease.
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Risk Factors for Reoperation After Repair of Discrete Subaortic Stenosis in Children
2007, Journal of the American College of Cardiology
This study aimed to identify independent predictors of reoperation after successful resection of discrete subaortic stenosis (DSS).
Recurrence of DSS has been reported to range from 0% to 55% of patients. Factors associated with recurrence have not been adequately defined.
Patients were included if they had a diagnosis of DSS, normal segmental cardiac anatomy, previous resection of DSS, and at least 36 months’ follow-up. Demographic, surgical, and echocardiographic data were analyzed. Primary outcome was repeat resection of DSS in patients after successful primary resection.
Of 111 subjects who had successful surgical resection of DSS, 16 patients (14%) required reoperation. Median follow-up time was 8.2 years. Form of DSS and gender did not differ significantly between those with reoperation and those without. In multivariate analysis, independent predictors of reoperation that would be available before first surgery were <6 mm distance between the aortic valve (AoV) and the obstruction (hazard ratio [HR] 5.1; p = 0.013) and peak gradient by Doppler ≥60 mm Hg (HR 4.2; p = 0.016). If intraoperative variables are also considered, peeling of the membrane from the AoV or mitral valve at first surgery, <6 mm distance between the DSS and AoV, and peak gradient by Doppler ≥60 mm Hg were independent predictors of reoperation.
Proximity of the obstructive lesion to the AoV and severe obstruction determined by preoperative echocardiography, as well as involvement of valve leaflets requiring surgical peeling, predict recurrent DSS requiring reoperation.

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Congenital Heart DiseaseDevelopment and Validation of an Echocardiographic Model for Predicting Progression of Discrete Subaortic Stenosis in Children

Abstract

Section snippets

Study Design:

Phase I Study:

Patients:

Discussion

Am J Cardiol

J Am Coll Cardiol

Am Heart J

Am J Cardiol

Am Heart J

Am J Cardiol

Am J Cardiol

Int J Cardiol

J Am Coll Cardiol

J Thorac Cardiovasc Surg

Am J Cardiol

J Am Coll Cardiol

Int J Cardiol

J Am Coll Cardiol

J Am Coll Cardiol

Congenital Heart Disease
Development and Validation of an Echocardiographic Model for Predicting Progression of Discrete Subaortic Stenosis in Children