Long-Term Functional Results of Patients Operated for Isolated Discrete Subaortic Stenosis.

BACKGROUND: This study aimed to examine the long-term functional results of patients with isolated discrete subaortic stenosis who underwent subaortic membrane resection and myectomy, using transthoracic M-mode echocardiography and 2D speckle-tracking echocardiography. METHODS: Twenty patients operated for isolated discrete subaortic stenosis and 31 controls were included in the study. Patients underwent subaortic membrane resection and myectomy. During the long-term follow up, patients were evaluated with transthoracic M-mode echocardiography and 2D speckle-tracking echocardiography for functional assessment. RESULTS: The mean age at operation and mean duration of follow up was 8.1±5.6 years and 7.2±3.3 years, respectively. Interventricular septal thickness at diastole (0.9±0.1 vs. 0.8±0.1 cm, P = 0.001), ejection time (285.7±26.2 vs. 261.2±24.3 msec, P = 0.001), and aortic strain (15.6±3.7 vs. 10.5±4.0, P < 0.001) were significantly higher in patients. On the other hand, ejection fraction (64.9±6.1 vs. 75.1±5.4 %, P < 0.001), fractional shortening (35.0±5.1 vs. 43.7±5.1, P < 0.001), and corrected velocity circumferential fiber shortening (0.12±0.02 vs. 0.17±0.03, P < 0.001) were significantly lower, when compared with the controls. Longitudinal strain value significantly differed among the groups, with patients having significantly lower strain (18.8±1.8 vs. 20.1±2.1, P = 0.021). CONCLUSION: In patients operated for isolated discrete subaortic stenosis, aortic gradient seems to continue in the long-term, with the persistence of low longitudinal strain.

Subaortic Membranes in Patients With Hereditary Hemorrhagic Telangiectasia and Liver Vascular Malformations.

Background Patients with hereditary hemorrhagic telangiectasia have liver vascular malformations that can cause high-output cardiac failure (HOCF). Known sequelae include pulmonary hypertension, tricuspid regurgitation, and atrial fibrillation. Methods and Results The objectives of this study were to describe the clinical, echocardiographic, and hemodynamic characteristics and prognosis of hereditary hemorrhagic telangiectasia patients with HOCF who were found to have a subaortic membrane (SAoM). A retrospective observational analysis comparing patients with and without SAoM was performed. Among a cohort of patients with HOCF, 9 were found to have a SAoM in the left ventricular outflow tract by echocardiography (all female, mean age 64.8±4.0 years). The SAoM was discrete and located in the left ventricular outflow tract 1.1±0.1 cm below the aortic annular plane. It caused turbulent flow, mild obstruction (peak velocity 2.8±0.2 m/s, peak gradient 32±4 mm Hg), and no more than mild aortic insufficiency. Patients with SAoM (n=9) had higher cardiac output (12.1±1.3 versus 9.3±0.7 L/min, P=0.04) and mean pulmonary artery pressures (36±3 versus 28±2 mm Hg, P=0.03) compared with those without SAoM (n=19) during right heart catheterization. Genetic analysis revealed activin receptor-like kinase 1 mutations in each of the 8 patients with SAoM who had available test results. The presence of a SAoM was associated with a trend towards higher 5-year mortality during follow-up. Conclusions SAoM with mild obstruction occurs in patients with hereditary hemorrhagic telangiectasia and HOCF. SAoM was associated with features of more advanced HOCF and poor outcomes.

Right Anterior Mini-Thoracotomy for Discrete Fibromembranous Subaortic Stenosis.

Discrete fibromembranous subaortic stenosis is a common type of subaortic stenosis causing clinically significant left ventricular outflow obstruction. Surgery for discrete subaortic stenosis is most often performed through a typical midline sternotomy. Herein, we present our experience with an adult patient who underwent a right mini-thoracotomy for subaortic membrane resection with central cannulation under direct operative vision.

Reoperation after isolated subaortic membrane resection.

BACKGROUND: The resection of a subaortic membrane remains far from a curative operation. We sought to examine factors associated with reoperation and the degree of aortic valve regurgitation as a potential long-term source for reoperation. METHODS: All patients who underwent resection of an isolated subaortic membrane between 1995 and 2018 were included. Patients who underwent other procedures were excluded. Paired categorical data were compared using McNemar's test. Univariate time-to-event analyses were performed using Kaplan-Meier methods with log-rank tests for categorical variables and univariate Cox models for continuous variables. RESULTS: A total of 84 patients (median age 6.6, 31% females) underwent resection of isolated subaortic membrane. At a median follow-up of 9.3 years (interquartile range 0.6-22.5), 12 (14%) patients required one reoperation and 1 patient required two reoperations. Median time to first reoperation was 4.6 years. The degree of aortic valve regurgitation improved post-operatively from pre-operatively (p = 0.0007); however, the degree of aortic valve regurgitation worsened over the course of follow-up (p = 0.010) to equivalence with pre-operative aortic valve regurgitation (p = 0.18). Performance of a septal myectomy was associated with longer freedom from reoperation (p = 0.004). CONCLUSIONS: In patients with isolated subaortic membranes, performance of a septal myectomy can minimise risk for reoperation. Patients should be serially monitored for degradation of the aortic valve, even if aortic regurgitation is not present post-operatively.

Percutaneous Balloon Dilation of Discrete Subaortic Stenosis: A Futile Exercise.

Discrete subaortic stenosis (DSS) is a progressive obstruction of left ventricular outflow tract (LVOT) resulting in the development of aortic regurgitation in its natural course. Hence, early intervention is recommended. Percutaneous balloon dilation of DSS has been reported and can substantially reduce LVOT pressure gradient. The response to balloon dilation of DSS is transient and may complicate with chordal or papillary muscle rupture. Hence, balloon dilation of DSS should be discouraged.

Long-term outcomes and risk factors for aortic regurgitation after discrete subvalvular aortic stenosis resection in children.

OBJECTIVES: To characterise long-term outcomes after discrete subaortic stenosis (DSS) resection and to identify risk factors for reoperation and aortic regurgitation (AR) requiring repair or replacement. METHODS: All patients who underwent DSS resection between 1984 and 2009 at our institution with at least 36 months' follow-up were included. Demographic, surgical and echocardiographic data were reviewed. Outcomes were reoperation for recurrent DSS, surgery for AR, death and morbidities, including heart transplant, endocarditis and complete heart block. RESULTS: Median length of postoperative follow-up was 10.9 years (3-27.2 years). Reoperation occurred in 32 patients (21%) and plateaued 10 years after initial resection. Survival at 10 years and 20 years was 98.6% and 86.3%, respectively. Aortic valve (AoV) repair or replacement for predominant AR occurred in 31 patients (20%) during or after DSS resection. By multivariable analysis, prior aortic stenosis (AS) intervention (HR 22.4, p<0.001) was strongly associated with AoV repair or replacement. Risk factors for reoperation by multivariable analysis included younger age at resection (HR 1.24, p=0.003), preoperative gradient ≥60 mm Hg (HR 2.23, p=0.04), peeling of membrane off AoV or mitral valve (HR 2.52, p=0.01), distance of membrane to AoV <7.0 mm (HR 4.03, p=0.03) and AS (HR 2.58, p=0.01). CONCLUSIONS: In this cohort, the incidence of reoperations after initial DSS resection plateaued after 10 years. Despite a significant rate of reoperation, overall survival was good. Concomitant congenital AS and its associated interventions significantly increased the risk of AR requiring surgical intervention.

Adult presentation of subaortic stenosis: another great hypertrophic cardiomyopathy mimic.

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.

Congenital coronary artery anomaly simulating a ventricular septal defect.

Anomalous origin of the circumflex artery of the right sinus of Valsalva is a rare finding which may be present with other cardiac malformations. A 19-year-old man presented with syncope. A transthoracic echocardiogram revealed discrete subaortic stenosis with a small defect just below the aortic valve, suggesting a ventricular septal defect. Transesophageal echocardiography showed anomalous origin of the circumflex artery from the right sinus of Valsalva. This was confirmed by coronary angiography. The patient underwent successful web resection without concomitant coronary surgery. Failure to demonstrate a coronary artery anomaly can be misleading for surgeons and perilous for patients.

Acquired discrete subaortic stenosis in solid organ transplant recipients.

DSS is a rare acquired abnormality of the LV outflow tract in children and adults. DSS can be seen with or without associated congenital heart disease, but the mechanism of its emergence has been poorly understood. Here, we report two cases of DSS that developed after solid organ transplant in childhood. One patient underwent liver and kidney transplant at three yr of age for hereditary polycystic disease, and the other had liver transplant at three months of age due to uncontrollable high-output failure secondary to a large hepatic hemangioma. Both patients developed mild dynamic LV outflow tract obstruction and systemic hypertension soon after transplant, both of which resolved by the time of discharge. Transient LV hypertrophy was observed in both cases. Corticosteroids, cyclosporine A, and tacrolimus were used as initial immunosuppressants. Both patients developed DSS long after the regression of the initial dynamic LV outflow tract obstruction. Herein, we report DSS as an atypical late cardiovascular complication after solid organ transplant and postulate that transient post-transplant hyperdynamic LV outflow tract obstruction and chronic immunosuppressive treatment may lead to subendocardial remodeling resulting in a fibromuscular membranous ridge in susceptible subjects.

Diagnosis and surgical management of subaortic stenosis and mitral valve systolic anterior motion.

The case is reported of a patient with a previously undiagnosed cause of severe congestive heart failure (CHF) caused by the presence of a discrete subaortic stenosis (SAS) from a subvalvular membrane (SVM). The clinical decision making was complicated by the concurrent presence of systolic anterior motion (SAM) of the mitral valve leaflet. Due to the limitations and eventual failure of physiologically opposing medical management strategies, the patient eventually required an open-heart surgical approach and underwent intraoperative SVM resection. A persistent intraoperative left ventricular outflow tract (LVOT) gradient of 50 mmHg due to SAM prompted mitral valve replacement, which resulted in a complete resolution of the LVOT gradient and symptoms. In this extremely rare scenario of SAS and SAM, when SVM resection is thought to be inadequate to relieve LVOT obstruction due to the concurrent presence of SAM, mitral valve replacement represents a reasonable therapeutic approach.

Isolated subpulmonic fibrous ring, mirror-image dextrocardia and situs solitus in a young lady unreported and a near miss.

Congenital diseases causing obstruction of the right ventricular outflow tract (RVOT) are common, but the isolated subpulmonary membrane/ring is extremely rare and can be difficult to diagnose precisely, especially in adults. We report a case of surgically resected isolated subpulmonic fibrous ring in a lady with mirror-image dextrocardia and abdominal situs solitus that was misdiagnosed by echocardiography as a subaortic membrane.

Discrete subaortic stenosis 37 years after repair of a ventricular septal defect.

Discrete subaortic stenosis (DSS) is uncommon in adults after surgical correction of congenital heart defects. There are only a few published reports on the occurrence of DSS in adults. We present an adult case with DSS after repair of a ventricular septal defect (VSD). The case was a 44-year old female patient who underwent VSD closure at 7 years of age. Thirty-seven years later, she presented with congestive heart failure associated with severe subaortic membranous stenosis and atrial fibrillation (AF) that required surgical repair. We report successful surgical treatment of this adult patient with DSS and AF 37 years after repair of a VSD.

Aortopulmonary window with subaortic fibrous stenosis and septal defect: surgery through a minimal right vertical infra-axillary thoracotomy.

Aortopulmonary window with subaortic stenosis and ventricular septal defect is an uncommon congenital cardiac malformation that is repaired using cardiopulmonary bypass. The authors describe a 3-year-old patient on whom we performed surgery through a minimal right vertical infra-axillary thoracotomy. This minimally invasive surgery is likely to be applicable in a few cases.