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.

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.

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.

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.

Surgical Relief of Left Ventricular Outflow Tract Obstruction in Adults With Congenital Aortic Stenosis and Associated Aortic Annulus Hypoplasia and/or Subaortic Obstruction.

BACKGROUND: In children and adolescents, a Ross/Konno operation is commonly done to both enlarge the aortic root and provide a competent aortic valve with relief of left ventricular outflow tract obstruction (LVOTO). Optimum management is not so straightforward in adults. METHODS: Between 1995 and 2014, 16 patients of mean age 39.4 years (18-57 years) with hypoplastic aortic annulus (AA) measuring 20mm and less, and mean aortic valve/LVOT gradient of 61mmHg (30-70mmHg) presented for surgery. RESULTS: Eight patients with mean LVOT/AA diameter 19.6mm (18-20mm) underwent an "inclusion-cylinder" type Ross procedure (RP). Eight patients with more severe LVOT/AA obstruction, with mean diameter of 17.4mm (16-19mm) underwent mechanical aortic valve replacement (AVR) with standard Konno-type aortoventriculoplasty. There was zero early and late mortality; with mean follow-up of 11.6 years (3-21 years) in the Ross group and 6 years (2-10 years) in the Konno-AVR group. One patient in the Konno-AVR group had reoperation after 2 years for RVOT obstruction. The postoperative echocardiograms of these patients at last follow-up show residual mean gradient across LVOT/AA of 4.4mmHg (2-6mmHg) after RP, and 11.9mmHg (8-17mmHg) after Konno-AVR. CONCLUSIONS: In adults, the "inclusion-cylinder" Ross-procedure is a good alternative for mild to moderate aortic root hypoplasia. However, for cases with severe LVOT obstruction, a Ross-Konno is not possible with the same method of autologous support used in a non-Konno RP, and this could be expected to have an impact on late durability and the need for further intervention, in a group that has already undergone multiple procedures in childhood. Both methods of RP and Konno-AVR lead to excellent early and late results.

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.

Outcomes of Subaortic Obstruction Resection in Children.

BACKGROUND: Studies of long-term outcomes of discrete subaortic stenosis are rare. Therefore, we reviewed the long-term outcomes of fibromuscular resection in children with subaortic stenosis over 26 years from a single institution. METHODS: We conducted a retrospective review of all children (n=72) who underwent resection of subaortic obstruction for discrete subaortic stenosis between 1989 and 2015. RESULTS: Median age at surgery was 5.0 years (2.7-7.6 years). There were no operative deaths but three late deaths (4.2%, 3/72). Overall Kaplan-Meier survival at 10 years was 93.0 ± 3.9% (95% CI: 79.6, 97.7). Peak instantaneous left ventricular outflow tract Doppler gradient decreased from 74.2±36.7mmHg (16.0-242.0mmHg) preoperatively to 12.8±7.4mmHg (2.6-36.0mmHg) postoperatively (p<0.001). Mean left ventricular outflow tract Doppler gradient decreased from 42.4±17.2mmHg (12.0-98.0) preoperatively to 7.5±2.7mmHg (1.4-19.3mmHg) postoperatively (p<0.001). However, over the mean follow-up period of 7.8±6.1 years (0.1-25.2 years), 29.0% (20/69) of patients had recurrence and 18.8% (13/69) required reoperation at median time of 4.8 years (3.1-9.1 years) after the initial repair. Freedom from reoperation at 10 years was 71.1±7.1% (95% CI: 54.6, 82.3). Risk factors for reoperation were age less than five years at initial repair (p=0.036) and extension of the membrane to the aortic valve (p=0.001). Aortic insufficiency was present in 54.2% (39/72) of patients preoperatively. Progression of aortic insufficiency occurred in 38.9% (28/72). Involvement of the aortic valve at initial repair was associated with need for subsequent aortic valve repair or replacement (p=0.01). CONCLUSIONS: Resection of subaortic obstruction is associated with low mortality and morbidity. Recurrence and reoperation rates are high and progression of aortic insufficiency following subaortic resection is common. Therefore, these patients warrant close follow-up into adult life.

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.

[Discrete Subaortic Stenosis in an Adult; Report of a Case].

Discrete subaortic stenosis (DSS) is a well-described cause of isolated left ventricular outflow tract obstruction( LVOTO) in children. But prevalence, rate of progression and postoperative data in adults are limited. We report a case of a 30-year-old woman, who was referred to our institution because of chest pain and loss of consciousness. Echocardiography revealed DSS with LVOTO (peak gradient 81 mmHg) and mild aortic regurgitation. Increased age at the time of diagnosis, female sex and preoperative left ventricular outflow tract(LVOT) gradient ≥80 mmHg were thought to be predictors for reoperation, therefore the obstructing membrane was circumferentially excised and concomitant localized myectomy of the ventricular septum was performed to achieve complete relief of the LVOT obstruction. Her postoperative course was uneventful, and she was discharged on the 5th postoperative day.

Surgical outcome of discrete subaortic stenosis in adults: a multicenter study.

BACKGROUND: Discrete subaortic stenosis is notable for its unpredictable hemodynamic progression in childhood and high reoperation rate; however, data about adulthood are scarce. METHODS AND RESULTS: Adult patients who previously underwent surgery for discrete subaortic stenosis were included in this retrospective multicenter cohort study. Mixed-effects and joint models were used to assess the postoperative progression of discrete subaortic stenosis and aortic regurgitation, as well as reoperation. A total of 313 patients at 4 centers were included (age at baseline, 20.2 years [25th-75th percentile, 18.4-31.0 years]; 52% male). Median follow-up duration was 12.9 years (25th-75th percentile, 6.2-20.1 years), yielding 5617 patient-years. The peak instantaneous left ventricular outflow tract gradient decreased from 75.7±28.0 mm Hg preoperatively to 15.1±14.1 mm Hg postoperatively (P<0.001) and thereafter increased over time at a rate of 1.31±0.16 mm Hg/y (P=0.001). Mild aortic regurgitation was present in 68% but generally did not progress over time (P=0.76). A preoperative left ventricular outflow tract gradient ≥80 mm Hg was a predictor for progression to moderate aortic regurgitation postoperatively. Eighty patients required at least 1 reoperation (1.8% per patient-year). Predictors for reoperation included female sex (hazard ratio, 1.53; 95% confidence interval, 1.02-2.30) and left ventricular outflow tract gradient progression (hazard ratio, 1.45; 95% confidence interval, 1.31-1.62). Additional myectomy did not reduce the risk for reoperation (P=0.92) but significantly increased the risk of a complete heart block requiring pacemaker implantation (8.1% versus 1.7%; P=0.005). CONCLUSIONS: Survival is excellent after surgery for discrete subaortic stenosis; however, reoperation for recurrent discrete subaortic stenosis is not uncommon. Over time, the left ventricular outflow tract gradient slowly increases and mild aortic regurgitation is common, although generally nonprogressive over time. Myectomy does not show additional advantages, and because it is associated with an increased risk of complete heart block, it should not be performed routinely.

Natural history of discrete subaortic stenosisin adults: a multicentre study.

AIMS: Discrete subaortic stenosis (DSS) is often diagnosed early in life and known for its sometimes rapid haemodynamic progression in childhood and strong association with aortic regurgitation (AR). However, data about the evolution of DSS in adulthood are scarce. Therefore, we aimed to evaluate the natural history of DSS, and identify risk factors for the progression of DSS, AR, and intervention-free survival. METHODS AND RESULTS: Conservatively managed adult DSS patients were included in this retrospective multicentre cohort study. Mixed-effects and joint models were used to assess the progression of DSS and AR, and intervention-free survival. Longitudinal natural history data were available for 149 patients [age 20 (IQR: 18-34) years, 48% male]. Sixty patients (40.3%) had associated congenital heart defects (CHDs). The median follow-up duration was 6.3 (IQR: 3.0-12.4) years. The baseline peak left ventricular outflow tract (LVOT) gradient was 32.3 ± 17.0 mmHg and increased by 0.8 ± 0.1 mmHg/year. While the baseline LVOT gradient (P = 0.891) or age (P = 0.421) did not influence the progression rate, the presence of associated CHD was associated with faster progression (P = 0.005). Mild AR was common (58%), but did not significantly progress over time (P = 0.701). The median intervention-free survival was 16 years and associated with the baseline LVOT gradient [hazard ratio (HR) = 3.9 (95% CI: 2.0-7.6)], DSS progression [HR = 2.6 (95% CI: 2.0-3.5)], and AR [HR = 6.4 (95% CI 2.6-15.6)]. CONCLUSION: In contrast to children, DSS progresses slowly in adulthood. In particular, patients with associated CHD are at risk for faster progression and should be monitored cautiously. Discrete subaortic stenosis progression is not influenced by the baseline LVOT gradient or age. Mild AR is common, but non-progressive over time.

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.

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.

Damus-Kaye-Stansel procedure 5 years after Fontan operation with ligated main pulmonary artery.

We report a case of tricuspid atresia with transposed great arteries and rudimentary right ventricle owing to which the patient developed severe subaortic stenosis and restrictive bulboventricular foramen 5 years after her extracardiac Fontan operation. She underwent a successful modified Damus-Kaye-Stansel operation using her native pulmonary valve. Spiral cardiac computed tomography with three-dimensional reconstructions was instrumental in pre-operative surgical planning.

Adult patient with Shone's syndrome and patent ductus arteriosus: a case report.

Shone's syndrome is a very rare cardiac malformation composed of four obstructive congenital lesions, which include the parachute mitral valve (PMV), supravalvular ring, subaortic stenosis, and coarctation of aorta. Diagnosis requires a comprehensive examination including a carefully performed echocardiography. It is extremely unusual for a patient to remain undiagnosed during adulthood. Here we report a 26-year-old male patient with Shone's syndrome and patent ductus arteriosus (PDA). The patient reported that he had been suffering from exercise intolerance and aggravating dyspnea. Two years ago, he was operated on in another hospital based on the wrong diagnosis of mitral valve prolapse and subaortic membrane. Transthoracic echocardiography revealed the existence of a PMV, which led to severe mitral stenosis through a previously implanted mitral annular ring. Other components of Shone's syndrome, subaortic membrane and aortic coarctation, together with PDA, were also observed. Another operation was suggested, but the patient refused. During the two year follow-up period, in spite of an atrial fibrillation attack and deteriorating dyspnea, the patient still did not want another operation. Once any of the four components of the Shone's complex is detected, clinicians must look for the presence of other lesions.

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.

The dilemma of subaortic stenosis--a single center experience of 15 years with a review of the literature.

OBJECTIVE: The term "subaortic stenosis" includes a variety of obstructions of the left ventricular outflow tract (LVOT), ranging from a short (discrete) subvalvular membrane to long, tunnel-like narrowing. An association with other congenital lesions is frequent. We reviewed the reported literature and describe our results, analyzing the nomenclature of and risk factors for restenosis after surgical treatment. METHODS: From 1994 to 2009, 81 children (53 males, 28 females; median age: 57 months, range [ R]: 5-204) underwent surgical relief of a subaortic stenosis. Patients were divided, according to pathology, into short segment (group A, n = 42) and complex obstructions (group B, n = 39), with the latter including long segment stenosis and/or associated anomalies such as aortic coarctation, interrupted aortic arch or Shone's complex. RESULTS: Surgery resulted in a significant reduction of the gradient between the left ventricle and the aorta in both groups (Δ P group A: 51 ± 28 mmHg, group B: 46 ± 25 mmHg). There was no operative mortality. One patient died in the early postoperative period due to pericardial tamponade. Median follow-up was 90 months (R = 0.5-187). Twenty-five (31%) patients required reoperation because of recurrent stenosis after a median of 43 months (R = 0.5-128). Seven (16%) patients belonging to group A developed restenosis, and 18 (46%) in group B. Freedom from reoperation for all patients was 60% after 10 years. 10 (40%) of the patients of group B were ultimately treated with a Ross-Konno reconstruction of the LVOT. CONCLUSION: Despite adequate surgical resection, recurrence of subaortic stenosis within several years after initial surgical treatment is frequent, especially in patients with complex lesions. In cases requiring reoperation, the surgical therapy is often extensive, and even includes Ross-Konno reconstruction of the LVOT.

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.