Long-term follow-up of subvalvular aortic stenosis in children: a single-centre experience

Incidence of Reoperation After Surgical Procedure for Left Ventricular Outflow Tract Obstruction in Children and Young Adults

BACKGROUND

The common causes of subaortic left ventricular outflow tract obstruction (LVOTO) are hypertrophic cardiomyopathy (HCM) and membranous/tunnel subaortic stenosis (SAS). Reoperation after corrective surgery may be due to recurrent disease, associated congenital defects, or complications of the initial procedure. This study compares the late outcomes of young patients with HCM and SAS.

METHODS

We studied clinical, echocardiographic, and operative data of patients ≤21 years of age at the time of surgery for LVOTO between August 1963 and August 2018. We stratified patients into HCM (n = 152) and congenital SAS (n = 63) groups and compared survival and cumulative incidence of reoperation.

RESULTS

At initial repair, patients with HCM were older than patients with SAS (median [interquartile range] age, 15 [10-19] years vs 8 [5-13] years; P < .001), and patients with HCM were more symptomatic with dyspnea (P < .001), chest pain (P = .002), and presyncope/syncope (P = .005). Thirty-day mortality was 1.3% vs 0% for HCM and SAS groups. During a median follow-up of 13.1 years, survival was similar through the first 10 years; but during the second decade, patients with HCM had poorer survival (survival at 20 years, 80% vs 91% for patients with SAS; P = .007). Ten years after repair, reoperation for recurrent LVOTO was performed in 5% of patients with HCM vs 31% in those with SAS (P < .001).

CONCLUSIONS

In this surgical cohort, patients with HCM were more symptomatic preoperatively than those with SAS. Late survival of patients with SAS was superior to that of patients with HCM despite a greater need for reoperation.

Adult Presentation of Subaortic Stenosis with Subaortic Membrane Treated with Surgical Removal

Subaortic stenosis (SAS) is a rare heart disease in adults with an unclear etiology and variable clinical presentation. In some cases, SAS appears as hypertrophic cardiomyopathy with obstruction due to the accompanying systolic anterior motion of the mitral valve. A 46-year-old male with dizziness for several months presented in the outpatient department. Two-dimensional transthoracic echocardiography demonstrated a slightly hypertrophic left ventricle with normal systolic function without wall-motion abnormalities. Just below the aortic valve, a linear structure protruding from the septum side and the left-ventricular outflow tract (LVOT) side of the mitral valve was confirmed, which was causing a significant pressure gradient (mean and maximum of 91 mmHg and 138 mmHg, respectively). A diagnosis of SAS with subaortic membrane was made, and surgical myomectomy and subaortic membrane removal surgery were performed. Postoperative transthoracic echocardiography did not show flow acceleration through the LVOT, nor a significant pressure gradient across the aortic valve. This case report highlights the clinical significance of SAS with subaortic membrane, which can be confused with aortic stenosis of other etiology.

Adult Presentation of Subaortic Stenosis with Subaortic Membrane Treated with Surgical Removal

Subaortic stenosis (SAS) is a rare heart disease in adults with an unclear etiology and variable clinical presentation. In some cases, SAS appears as hypertrophic cardiomyopathy with obstruction due to the accompanying systolic anterior motion of the mitral valve. A 46-year-old male with dizziness for several months presented in the outpatient department. Two-dimensional transthoracic echocardiography demonstrated a slightly hypertrophic left ventricle with normal systolic function without wall-motion abnormalities. Just below the aortic valve, a linear structure protruding from the septum side and the left-ventricular outflow tract (LVOT) side of the mitral valve was confirmed, which was causing a significant pressure gradient (mean and maximum of 91 mmHg and 138 mmHg, respectively). A diagnosis of SAS with subaortic membrane was made, and surgical myomectomy and subaortic membrane removal surgery were performed. Postoperative transthoracic echocardiography did not show flow acceleration through the LVOT, nor a significant pressure gradient across the aortic valve. This case report highlights the clinical significance of SAS with subaortic membrane, which can be confused with aortic stenosis of other etiology.