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.

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.

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.

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.

Subaortic Stenosis Resection in Children: Emphasis on Recurrence and the Fate of the Aortic Valve.

BACKGROUND: Recurrence after surgical resection of discrete subvalvar aortic stenosis in children often requires repeat operation. Risk factors for recurrence are poorly understood. We sought to determine potential risk factors for recurrence and postoperative comorbidities in the long term. METHODS: Retrospective chart review was performed on all pediatric patients who underwent surgical resection of discrete subaortic stenosis at our institution. Demographics, perioperative findings, and clinical data were analyzed for predisposing factors. RESULTS: From 1991 to 2015, a total of 104 patients underwent primary surgical resection of discrete subaortic stenosis. There were no postoperative deaths. Three (2.9%) patients required pacemaker implantation. Nine (8.4%) patients required repeat resection for recurrence of subaortic membrane over a median follow-up of 8.5 years (interquartile range: 5.9-13.5 years). Actuarial freedom from repeat resection was 100%, 94%, and 82% at one, five, and ten years, respectively. Repeat resection occurred more frequently in patients with genetic disease (37.5% vs 10.7%; P = .033) and preoperative mitral regurgitation (MR; 25% vs 1.2%; P < .001). Postoperative aortic insufficiency (AI) that was moderate or worse was associated with older age at the time of first resection (relative risk [RR]: 1.54, P < .05), moderate or severe preoperative AI (RR: 1.84, P = .002), and repeat resection of subaortic stenosis (RR: 1.90, P < .001). CONCLUSION: The majority of children who undergo surgical resection of subaortic stenosis will not experience recurrence in childhood and those who do require repeat resection may have a higher incidence of genetic disease and preoperative MR. Postoperative AI is associated with repeat resection, older age at the time of surgery, and degree of preoperative AI.

56-year-old lady with transaortic gradient.

CLINICAL INTRODUCTION: A 56-year-old lady with a background of hypertension was admitted to our institution with acute pulmonary oedema. She reported gradual and increasingly severe dyspnoea on exertion over the preceding 12 months and, prior to presentation, her exercise tolerance was restricted to one flight of stairs. On transthoracic echocardiography during the index admission, left ventricular size and systolic function were normal, and peak and mean transaortic gradients were 67 mm Hg and 33 mm Hg, respectively, with a peak velocity of 3.9 m/s. No aortic incompetence or other significant valvular abnormality was noted. A transoesophageal echocardiogram was performed. Figure 1 depicts the mid-oesophageal parasternal long-axis view. What is the explanation behind the significant transaortic gradient?heartjnl;104/12/1036/F1F1F1Figure 1Transoesophageal echocardiogram, mid-oesophageal long-axis view at 135 degrees. QUESTION: What is the explanation behind the significant transaortic gradient?Ventricular septal defect Supravalvular aortic stenosisAortic valvular stenosisSubaortic membraneHypertrophic obstructive cardiomyopathy.

Surgical pathology of subaortic septal myectomy: histology skips over clinical diagnosis.

BACKGROUND: Subaortic septal myectomy is usually performed to mitigate obstruction in patients with the obstructive form of hypertrophic cardiomyopathy (HCM) or in those with congenital subaortic stenosis. Moreover, it is combined with aortic valve replacement in patients with severe aortic valve stenosis (SAS) and asymmetrical septal hypertrophy causing concomitant left ventricular outflow tract obstruction. When both conditions coexist, it is conceptually difficult to identify a cardiomyopathy beyond an adaptive myocardial hypertrophy, strictly related to pressure overload. Myectomy histopathology might be useful to enlighten the cause of the obstruction and establish the diagnosis. AIM: The aim was to describe the pathological findings of surgical septal myectomy specimens obtained from a group of patients with diverse clinical diagnosis, including HCM, severe aortic stenosis, and asymmetrical septal hypertrophy. METHODS: This was a retrospective study of 56 patients undergoing septal myectomy along a 10-year period at a tertiary cardiac surgical center. Clinical, interventional, and anatomopathological findings between patients with and without a preoperative diagnosis of HCM were analyzed and compared. RESULTS: Mean age at intervention was 67.5±20.5 years; 37 (66.1%) were female Preoperative diagnosis of sarcomeric obstructive HCM was assumed in 23 (41.1%) patients. All the other patients (58.9%) were referred for surgery with preoperative diagnosis of asymmetric septal hypertrophy, mainly in the context of severe aortic stenosis (24 patients). Twenty-seven (48.2%) patients had a greater than 30 mmHg intraventricular gradient at rest. Patients with presumed HCM were significantly younger (56.5±15.8 vs. 70.2±13.3 years, P<.001), had higher prevalence of significant intraventricular obstruction at rest [20 (87.0%) vs. 8 (34.8%), P<.001], and more frequently had moderate or severe mitral regurgitation [9 (39.1%) vs. 5(15.1%), P=.043]. All patients with aortic valve stenosis underwent both aortic valve replacement and septal myectomy. Twelve (52.1%) of the patients with obstructive HCM had isolated septal myectomy, while in the remaining 11, the procedure was combined with intervention on the mitral valve. Histopathological final diagnosis was of nonspecific reactive myocardial hypertrophy in all but 4 (92.2%) patients. In those, 2 (3.6%) had the final diagnosis of HCM and 2 (3.6%) the diagnosis of congenital subaortic membranous stenosis with reactive myocardial hypertrophy. Different grades of subendocardial fibroelastosis and myocardial fibrosis, mainly interstitial, were present [27 (48.2%) and 18 (32%) patients, respectively]. When microscopic data were compared between patients with or without a preoperative clinical diagnosis of HCM, no significant differences were found. CONCLUSION: In patients submitted to surgical septal myectomy, histology was mostly indistinctive among different clinical entities. Since different myocardial hypertrophy etiologies may share similar pathological expression, there is a need for detailed clinical assessment when trying to define the best strategy for clinical management.

Causes of an increased pressure gradient through the left ventricular outflow tract: a West Coast experience.

BACKGROUND: Left ventricular outflow tract obstruction (LVOTO) occurs from not only obstructive hypertrophic cardiomyopathy but also other conditions such as sigmoid septum or post mitral valve repair. However, the changes of the LVOT pressure gradient (LVOT PG) in LVOTO with various conditions remain unclear. METHODS: The clinical characteristics and echocardiographic parameters of 73 patients with LVOT PG ≥50 mmHg at rest on Doppler ultrasound were retrospectively investigated. RESULTS: In these patients (age 69 ± 15 years, 38% male), high prevalences of hypertension (66%) and anemia (43%) were observed. The most frequent clinical disease causing LVOTO was hypertrophic obstructive cardiomyopathy (HOCM) (74%). There were other conditions, including hypertensive left ventricular hypertrophy (9%), post-open heart surgery (7%), sigmoid septum (4%), hyperkinetic LV (3%), takotsubo cardiomyopathy (1.5%), and discrete subaortic membrane (1.5%). Significant improvement or reduction of LVOTO was observed in 93% of cases at follow-up (mean 44 months) echocardiography compared with the initial one with the use of medications and transcatheter procedures. CONCLUSIONS: The causes of LVOTO are diverse. However, the occurrence of LVOTO might depend on the coexistence of primary morphological LV characteristics and hemodynamic LV status. Specific factors causing LVOTO need to be investigated, and efforts for improvement of each individual status by the appropriate approach are required.

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.

Correction of Left Ventricular Outflow Tract Obstruction Caused by Anomalous Papillary Muscle and Subaortic Membrane.

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.

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.

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.