Long-Term Aortic Valve Function in Patients With or Without Surgical Treatment for Discrete Subaortic Stenosis.

The purpose of this study was to evaluate the long-term function of the aortic valve in patients with discrete subaortic stenosis (DSS), and its prognostic implications. 34 patients with the diagnosis of isolated DSS were treated at our pediatric heart center between 1992 and 2019. Demographic, echocardiographic and surgical data were analyzed. 26 patients had surgery to remove the subaortic membrane. The primary endpoint of this study was a change in the aortic valve function, secondary outcomes included functional class, aortic valve replacement, and reoperation due to recurrence of DSS. The mean post-operative follow-up time was 7.07 years (1-22.5). At the time of the most recent follow up, in the surgical group 11 patients (46%) had echocardiographic evidence of deterioration in their aortic valve insufficiency (AI) (p < 0.002). The deterioration was associated with a pre-operative left ventricular outflow tract (LVOT) gradient greater than 49 mmHg (p < 0.022). 8 patients with DSS were followed for a mean of 12.9 years (6.8-21.3), without meeting the criteria for surgical intervention, none showed any change in the aortic valve function during follow-up time. DSS resection may not prevent worsening of aortic valve insufficiency over time. Patients with stable AI and low LVOT gradient may not require surgery. Given these findings, it may be appropriate to carefully follow patients with new onset AI and low LVOT gradient, delaying surgical intervention.

Membranous subaortic stenosis coexisting with hypertrophic cardiomyopathy: A case report.

Subaortic stenosis (SAS) is a congenital heart disease, and its association with hypertrophic cardiomyopathy is very rare and clinically underappreciated. We report here a case of a 45-year-old female who was admitted to our hospital with chest tightness and shortness of breath. Both transthoracic and transesophageal echocardiography revealed asymmetric left ventricular hypertrophy and a membrane-like echo below the level of the aortic valve. This patient was diagnosed with membranous SAS with hypertrophic cardiomyopathy. Screening of her immediate family members revealed that her son also had hypertrophic cardiomyopathy. The patient chose conservative treatments and has been closely followed-up after discharge.

Resection of subaortic membrane for discrete subaortic stenosis.

BACKGROUND: We reviewed the long-term results of surgery for discrete subaortic membrane (SubAM) from a single institute. METHODS: A retrospective review of medical records of all patients (n = 146) who underwent resection of a SubAM for discrete subaortic stenosis between 1990 and 2015 at the All India Institute of Medical Sciences, New Delhi, India was undertaken. RESULTS: Median age at surgery was 9.0 years (9 months-47 years). There was one early death. Preoperative peak left ventricular outflow tract (LVOT) Doppler gradient was 83.4 ± 26.2 mmHg (range: 34-169 mmHg). On preoperative echocardiography, aortic regurgitation (AR) was absent in 69 (47.3%), mild in 35 (24%), moderate in 30 (20.5%), and severe in 12 (8.2%). After surgery, the LVOT gradient was reduced to 15.1 ± 6.2 mmHg (P < 0.001). Fourteen patients (9.6%) who had residual/recurrent significant gradients are currently being followed-up or awaiting surgery. There was improvement in AR for operated patients with freedom from AR of 92.6 ± 0.03% at 15 years. Kaplan-Meier survival at 25 years was 93.0 ± 3.9% (95% confidence interval: 79.6, 97.7). Freedom from re-operation at 25 years was 96.9 ± 1.8%. CONCLUSIONS: Long-term results of surgery for discrete SubAM are good. Resection of the membrane along with septal myectomy decreases the risk of recurrence.

Subaortic stenosis surgical correction after previous substernum coloesophagoplasty.

Alternate approaches for aortic valve procedures are rare but occasionally used in cardiac surgery because of previous mediastinum radiotherapy or other procedures that preclude median sternotomy. We present one case of right lateral thoracotomy for membrane subaortic stenosis resection in a child with a restrosternal gastric tube.

Illustration of the echocardiographic diagnosis of subaortic membrane stenosis in adults: surgical and live three-dimensional transoesophageal findings.

We report here two cases of patients admitted in our institution for heart failure. The first had been previously diagnosed with severe aortic valve stenosis and was referred for aortic valve replacement. The myocardial and valvular anatomy combined with the Doppler profiles allowed, however, to suggest the diagnosis of a discrete subaortic membrane that was confirmed by surgical findings. In the second case, the use of real-time three-dimensional transoesophageal echocardiography (3D TEE) provided superb 3D visualization quality of the subaortic membrane and allowed assessing the stenosis area using the multiplanar review mode. Hence, the use of live real-time 3D TEE is likely to be key in the spatial assessment of this complex lesion.

The role of shear stress in the pathogenesis of discrete subaortic stenosis: implications for surgical treatment.

Discrete subaortic stenosis (DSS) is characterized by the presence of an obstructing membrane in the left ventricular outflow tract (LVOT). Evidence suggests that the formation of DSS represents a fibroproliferative reaction of the endocardium occurring in response to alterations in shear stress caused by geometric abnormalities within the LVOT. The aim of this review is to discuss the role of altered LVOT shear stress in the pathogenesis of DSS, and its implications in surgical decision making.

Noninvasive evaluation of membranous subaortic stenosis: complimentary roles of echocardiography and computed tomographic angiography.

A 29-year-old Ethiopian woman that was referred to the Wisconsin Heart Hospital for treatment of subaortic stenosis, diagnosed 4 years earlier, in Ethiopia, using transthoracic echocardiography. Preoperative evaluation included transesophageal echocardiography, which showed severe membranous subaortic stenosis with a mean outflow gradient of 70 mmHg. Cardiac computed tomographic angiography also demonstrated a subaortic membrane, and additionally showed normal epicardial coronary arteries. The patient underwent uneventful surgical resection of the subaortic membrane without undergoing cardiac catheterization.

Takedown of Yasui procedure due to closed ventricular septal defect.

A two and a half year old girl who had undergone the Yasui procedure as a neonate for ventricular septal defect, subaortic stenosis, and interrupted aortic arch underwent follow-up catheterization 2 years postoperatively. It showed that the neo-left ventricular tract reconstructed by Damus-Kaye-Stansel anastomosis had occluded due to closure of the ventricular septal defect and residual subaortic stenosis at the original left ventricular outflow tract. The patient therefore underwent takedown of the Yasui procedure.

Left Ventricle to Right Atrial Shunt Associated With Ventricular-Atrial Malalignment, Double Outlet Right Atrium, and Subaortic Membrane.

We describe an asymptomatic 7-year-old boy who was taken to the operating room for repair of a subaortic membrane and possible Gerbode's defect. He was found to have a double outlet right atrium associated with an accessory atrioventricular valve in addition to a small atrial septal defect and subaortic membrane. Regurgitant flow through this accessory valve led to the left ventricle to right atrial shunt that was seen on preoperative ECHO. The atrial septal defect was repaired and a baffle was used to isolate blood flow across the accessory valve from the left atrium to the left ventricle. The patient was discharged on postoperative day 4 and has been doing well 2 years postoperatively.