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.

Congenital, acquired, or both? The only two congenitally based, acquired heart diseases.

Discrete subaortic stenosis (DSS) is a type of left ventricular outflow tract obstruction whereas double-chambered right ventricle is a form of right ventricular outflow tract obstruction. Both of these cardiac malformations share lots of similar characteristics which classify them as acquired developmental heart diseases despite their congenital anatomical substrate. Both of them are frequently associated to ventricular septal defects. The initial stimulus in their pathogenetic process is anatomical abnormalities or variations. Subsequently, a hemodynamic process is triggered finally leading to an abnormal subaortic fibroproliferative process with regard to DSS or to hypertrophy of ectopic muscles as far as double-chambered right ventricle is concerned. In many cases, these pathologies are developed secondarily to surgical management of other congenital or acquired heart defects. Moreover, high recurrence rates after initial successful surgical therapy, particularly regarding DSS, have been described. Finally, an interesting coexistence of DSS and double-chambered aortic ventricle has also been reported in some cases.

Computational Assessment of Valvular Dysfunction in Discrete Subaortic Stenosis: A Parametric Study.

PURPOSE: Discrete subaortic stenosis (DSS) is a left-ventricular outflow tract (LVOT) obstruction caused by a membranous lesion. DSS is associated with steep aortoseptal angles (AoSAs) and is a risk factor for aortic regurgitation (AR). However, the etiology of AR secondary to DSS remains unknown. This study aimed at quantifying computationally the impact of AoSA steepening and DSS on aortic valve (AV) hemodynamics and AR. METHODS: An LV geometry reconstructed from cine-MRI data was connected to an AV geometry to generate a unified 2D LV-AV model. Six geometrical variants were considered: unobstructed (CTRL) and DSS-obstructed LVOT (DSS), each reflecting three AoSA variations (110°, 120°, 130°). Fluid-structure interaction simulations were run to compute LVOT flow, AV leaflet dynamics, and regurgitant fraction (RF). RESULTS: AoSA steepening and DSS generated vortex dynamics alterations and stenotic flow conditions. While the CTRL-110° model generated the highest degree of leaflet opening asymmetry, DSS preferentially altered superior leaflet kinematics, and caused leaflet-dependent alterations in systolic fluttering. LVOT steepening and DSS subjected the leaflets to increasing WSS overloads (up to 94% increase in temporal shear magnitude), while DSS also increased WSS bidirectionality on the inferior leaflet belly (+ 0.30-point in oscillatory shear index). Although AoSA steepening and DSS increased diastolic transvalvular backflow, regurgitant fractions (RF < 7%) remained below the threshold defining clinical mild AR. CONCLUSIONS: The mechanical interactions between AV leaflets and LVOT steepening/DSS hemodynamic derangements do not cause AR. However, the leaflet WSS abnormalities predicted in those anatomies provide new support to a mechanobiological etiology of AR secondary to DSS.

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.

Preoperative Factors That Predict Recurrence After Repair of Discrete Subaortic Stenosis.

BACKGROUND: Several factors predict reintervention for subaortic stenosis (SubAS): age, preoperative left ventricular outflow tract gradient, distance from the obstructive subaortic ridge to the aortic valve, and peeling of membrane from the aortic/mitral valves. We sought to develop a prediction rule to categorize risk of reintervention for recurrent SubAS and guide follow-up in patients with discrete SubAS. METHODS: We retrospectively reviewed patients who underwent SubAS resection between 1984 and 2016. Our primary outcome was reintervention for recurrent SubAS after discharge. Kaplan-Meier estimates were used for time-to-event analysis of any reintervention. Multivariable models were used to create a prediction rule. We excluded patients without 3 years of follow-up. RESULTS: Of 172 patients, 21 (12.2%) required reintervention. The characteristics predicting reintervention were age younger than 2 years (P < .001), preoperative left ventricular outflow tract gradient of 65 mm Hg or more (P = .011), peeling of membrane from the mitral valve (P < .001), distance from the membrane to the aortic valve of less than 5 mm (P < .001), prior complex operation (P = .035), other left-sided heart lesions (P = .008), and aortic annulus z-score of -2.5 or less (P < .001). Our final prediction rule includes age, membrane to aortic valve distance, and other left-sided heart lesions each scored as 1 point. For patients with a score of 1 or less, 4% required a reintervention compared with 34% with a score of 2 or more. CONCLUSIONS: A prediction rule that incorporates the patient's age at the index operation, membrane to aortic valve distance, and associated left-sided heart lesions can determine the likelihood of reintervention for recurrent SubAS.

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.

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.

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.

Surgical outcome in aortopulmonary window beyond the neonatal period.

OBJECTIVE: Aortopulmonary window (APW) is a rare congenital cardiac defect accounting for 0.1% to 0.2% of all congenital cardiac defects. We here present the current midterm outcome of surgical repair of APW in patients more than 3 months of age. METHODS: The retrospective study was conducted to identify all the patients more than 3 months of age at presentation who underwent surgical repair of APW between June 2010 and August 2018 at our tertiary care institute and their outcome was analyzed. RESULTS: We found 14 patients of APW operated at the age of more than 3 months over a period of 8 years. Mean age of the cohort was 2.29 ± 2.96 years ranging from 3 months to 10 years with 57.14% being males. There were 11 (78.57%) patients with isolated APW and 3 (21.43%) had associated cardiac defects including tetralogy of Fallot (n = 1), ventricular septal defect (n = 1), subaortic membrane causing subaortic stenosis (n = 1), and one had extracardiac malformations. Two patients had type I, nine had type II, and three had type III APW as per Jacobs' classification. The mean size of the defect was 14.14 ± 4.33 mm. Mean duration of mechanical ventilation was 26.91 ± 16.65 hours (range, 12.25-67 hours). There was one in-hospital mortality and no late mortality over a mean follow-up of 3.06 ± 2.19 years. None of the patients required any kind of reintervention. CONCLUSION: Good results can be obtained even on late presentation with adequate perioperative care of the patients with the reversible pulmonary hypertensive disease.

Echocardiographic predictors of reoperation for subaortic stenosis in children and adults.

OBJECTIVES: Subaortic stenosis (SAS) can present as various types of obstruction of the left ventricular outflow tract (LVOT) below the level of the aortic valve. Even though corrective surgery has been identified as the most effective treatment, SAS more frequently reoccurs requiring reoperation in a significant proportion of the patients. Previous studies have focused on predictors of recurrence in various subgroups of patients with SAS, but rarely in the overall population of patients with SAS. The aim of this study was to determine the predictors of recurrence of SAS after initial corrective surgery. METHODS: Patients from the database of the Congenital Cardiology Department of the University Hospital of Southampton with significant SAS requiring corrective surgery were included in the study. Data retrieved were obtained and used to determine the predictors of SAS recurrence after the initial corrective surgery. RESULTS: Eighty-two patients (paediatric, n = 72 and adult, n = 10) who underwent initial successful resection were included in the analysis. Thirty patients required reoperation for recurrent SAS. These were significantly younger (median age 3.0 vs 6.7 years, P = 0.002). The recurrence of SAS was more common in patients with an interrupted aortic arch (23.3% vs 3.8%, P = 0.010) and unfavourable left ventricle geometry (43.3% vs 7.6%, P < 0.001), with steeper aortoseptal angle (131.0° ± 8.7° vs 136.1° ± 8.6°, P = 0.030), shorter distance between the point of obstruction of the LVOT and the aortic valve annulus in systole and diastole (median 4.30 vs 5.90 mm, P = 0.003 and 3.65 vs 4.95 mm, P = 0.006, respectively) and in those who had higher residual peak and mean LVOT gradients postoperatively (29.3 ± 16.0 vs 19.8 ± 10.7 mmHg, P = 0.006 and 15.9 ± 8.3 vs 10.1 ± 5.8 mmHg, P = 0.002, respectively). Overall, the presence of an interrupted aortic arch [odds ratio (OR) 10.34, 95% confidence interval (CI) 1.46-73.25; P < 0.019] and unfavourable left ventricle geometry (OR 10.42, 95% CI 1.86-58.39; P < 0.008) could independently predict reoperation for SAS after initial successful resection. CONCLUSIONS: Patients who have initial corrective surgery for SAS at a younger age, unfavourable left ventricle geometry, an interrupted aortic arch and higher early postoperative LVOT gradients are more likely to have recurrent SAS requiring reoperation.

Correction of left ventricular outflow tract obstruction caused by anomalous papillary muscle and subaortic membrane

Abstract This paper presents a case study of a 30-year-old male patient with dyspnea on exertion had echocardiographic diagnosis of aortic subvalvar stenosis. Discrete mitral regurgitation and aortic valve dysplasia with mild to moderate insufficiency and hypertrophic cardiomyopathy were also noted. During surgery, a rare condition was identified: presence of papillary muscle anomaly associated with the subaortic membrane as a cause of obstruction of the left ventricular outflow tract. With the resection of these structures and a mitral valve annuloplasty, the patient evolved with a significant improvement of clinical condition and heart failure, with no residual mitral insufficiency.

Routine Septal Myectomy During Subaortic Stenosis Membrane Resection: Effect on Recurrence Rates.

Recurrence of subaortic stenosis (SubAS) is up to ~ 19% following resection. Historically, treatment has consisted of membrane resection alone. This study investigated the effect of routine septal myectomy in addition to membrane resection. A single-center retrospective review was performed in all patients < 18 years of age undergoing membrane resection with septal myectomy for SubAS from 2003 to 2013. Demographic, perioperative, and follow-up data were collected. Freedom from reoperation and risk factors for reoperation were determined. 107 patients (median age 4.8 years) were included. There was one in-hospital death, five patients (5%) requiring pacemaker, and no iatrogenic ventricular septal defects. Follow-up was 80% complete and median follow-up was 4.9 years (range 0.5-12 years). Fourteen (16%) subjects required reoperation. Freedom from reoperation was 98% at 1 year, 86% at 5 years, and 69% at 10 years (Fig. 1). There was no difference in decrease of peak gradient between subjects who did and did not require reoperation (- 47 vs. - 40 mmHg; p = 0.59). In univariate analysis, chromosomal anomaly (hazard ratio [HR] 5.0, p = 0.02), smaller body surface area (HR 0.1, p = 0.03), and younger age at surgery (HR 0.7, p = 0.01) were significantly associated with reoperation. The routine use of myectomy with membrane excision did not result in a lower rate of reoperation or higher rates of complications compared to historical controls. Younger age, smaller size, and chromosomal anomaly were associated with increased risk for reoperation. Patients with these risk factors may benefit from more intensive long-term follow-up.