Evaluation of subvalvular aortic stenosis in children: a 16-year single-center experience

Perioperative and Anesthetic Considerations in Pediatric Valvar and Subvalvar Aortic Stenosis

Aortic stenosis (AS) is a common form of left ventricular outflow tract obstruction (LVOTO) in children with congenital heart disease. This review specifically considers the perioperative features of valvar (VAS) and subvalvar AS (subAS) in the pediatric patient. Although VAS and subAS share some clinical features and diagnostic approaches, they are distinct clinical entities with separate therapeutic options, which range from transcatheter intervention to surgical repair. We detail the pathophysiology of AS and highlight the range of treatment strategies with a focus on anesthetic considerations for the care of these patients before, during, and after intervention.

Mid- and long-term outcomes after surgical correction of subaortic stenosis: a 27-year experience

OBJECTIVES

We reviewed the mid- and long-term surgical outcomes of patients with subaortic stenosis (SAS).

METHODS

Patients operated for SAS from April 1990 to August 2016 were reviewed retrospectively. Patients with major associations such as aortic arch obstruction were excluded. Time to reintervention and predictors of recurrence were assessed using Kaplan-Meier analysis, log-rank test and uni/multivariable Cox regression.

RESULTS

120 patients at a median age of 4.7 years (interquartile range 2.9, 8.1) underwent primary operation (median peak preoperative left ventricular outflow tract gradient 52.5 mmHg, interquartile range 40, 70) involving fibrous tissue excision (n = 120) with septal myectomy (93%; n = 112) as the procedure of choice.At median follow-up of 13 years (interquartile range 7, 18), freedom from reintervention at 1, 3, 5 and 10 years was 99% (95% confidence interval 94%, 99%), 94% (87%, 97%), 93% (86%, 96%) and 90% (82%, 94%), respectively. Recurrence occurred in 18% (n = 20) with 15 patients undergoing reinterventions, 13 of whom required radical reoperation. Multivariable analysis revealed higher preoperative peak left ventricular outflow tract gradient (hazard risk 1.06, confidence interval 1.03, 1.09, P < 0.001), and presence of bicuspid aortic valve (hazard risk 14.13, confidence interval 3.32, 60.1, P < 0.001) as predictors for reintervention. Mild/moderate aortic regurgitation occurred in 49% (n = 55) of patients at the most recent follow-up.

CONCLUSIONS

Reintervention for recurrent SAS is common, predicted by higher preoperative peak left ventricular outflow tract gradient, and presence of bicuspid aortic valve, and frequently involves a radical procedure. Aortic regurgitation is a major consequence of SAS, but its severity usually remains low.

CLINICAL REGISTRATION NUMBER

SCHN HREC reference number 2019/ETH02729, approved on 09 July 2019.

Long-term outcomes after surgical repair of subvalvular aortic stenosis in pediatric patients

Objectives

Subvalvular aortic stenosis (SAS) can occur as discrete or tunnel-like obstruction of the left ventricular outflow tract and as progressive disease often leads to aortic valve regurgitation. We report our 30-year single-center experience after surgical repair of SAS.

Methods

A retrospective chart review of all patients aged &lt; 18 years, who underwent surgical repair of SAS from May 1985 to April 2020, was conducted. Mortality was cross-checked with the national health insurance database (93.8% complete mortality follow-up in April 2020). Survival and competing risks analysis were used to analyze the primary endpoints survival and incidence of reoperations.

Results

From May 1985 until April 2020 103 patients (median age 5.5 years) underwent surgical repair of SAS. Survival was 90.8% at 10 years and 88.7% at 20 and 30 years. Age &lt; 1 year at time of surgery, Shone’s complex, mitral stenosis and concomitant mitral valve surgery were associated with mortality. The cumulative incidence of reoperation for SAS was 21.6% at 10 years, 28.2% at 20 and 30 years. The incidence of reoperation for SAS did not differ between the myectomy, membrane resection and combined myectomy and membrane resection groups. The cumulative incidence of reoperation on the aortic valve was 13.5% at 20 years.

Conclusion

Recurrence rate of SAS is not to be neglected, though surgical repair of subaortic stenosis has good long-term results. Patients who needed a combined membrane resection and septal myectomy are not more prone to recurrence than patients who underwent solitaire myectomy or membrane resection.

Long-term follow-up of subvalvular aortic stenosis in children: a single-centre experience

OBJECTIVE

The aim of this study is to evaluate clinical and surgical outcomes of children with subaortic stenosis, to determine the risk factors for surgery and reoperation and to compare isolated subaortic stenosis and those concomitant with CHDs.

METHODS

The study involved 80 children with subaortic stenosis. The patients were first classified as isolated and CHD group, and the isolated group was further classified as membranous/fibromuscular group. The initial, pre-operative, post-operative and the most recent echocardiographic data, demographic properties and follow-up results of the groups were analysed and compared. The correlation of echocardiographic parameters with surgery and reoperation was evaluated.

RESULTS

There was a significant male predominance in all groups. The frequency of the membranous type was higher than the fibromuscular type in the whole and the CHD group. The median time to the first operation was 4.6 years. Thirty-five (43.7%) patients underwent surgery, 5 of 35 (14%) patients required reoperation. The rate of surgery was similar between groups, but reoperation was significantly higher in the isolated group. The gradient was the most important factor for surgery and reoperation in both groups. In the isolated group besides gradient, mitral-aortic separation was the only echocardiographic parameter correlated with surgery and reoperation.

CONCLUSION

Reoperation is higher in isolated subaortic stenosis but similar in membranous and fibromuscular types. Early surgery may be beneficial in preventing aortic insufficiency but does not affect the rate of reoperation. Higher initial gradients are associated with adverse outcomes, recurrence and reoperation.

Discrete Left Ventricle Outflow Tract Obstruction in Children: Incidence and Predictors of Recurrence. A Multi-Center Study

Objectives

The purpose of this study is to measure the incidence of recurrence of discrete subaortic stenosis (DSS) after primary resection in two major cardiac centers in Saudi Arabia and to identify risk factors associated with recurrence.

Methods

Data on 234 patients who were diagnosed with DSS and underwent surgical resection between 1999 and 2018 were retrospectively reviewed. Patient demographics as well as echocardiographic, surgical, and pathological data were compared between patients with recurrence and non-recurrence.

Results

The overall recurrence incidence after primary resection was 44.87% (N = 105). Most patients were male (59%). The median age at the 1^st operation was 60 months (range 3 months to 133 months). The presence of aortic stenosis at the time of diagnosis was significantly associated with recurrence (p-value = 0.002). The overall median peak gradient in which the primary resection was indicated is 60 mmHg (range 11 to 152 mmHg). The median peak gradient pre-operation and post-operation were significantly higher for the recurrence group (p-value=0.018 and p<0.001, respectively). We used univariate and multivariate analysis and controlled for the follow-up time, but there were no significant independent predictors of recurrence.

Conclusion

The recurrence rate of DSS after the primary resection is relatively high in this study. Further prospective studies are needed to draw a definite conclusion on risk factors for recurrence after primary resection.

Intraoperative transesophageal echocardiographic predictors of recurrent left ventricular outflow tract obstruction in children undergoing subaortic stenosis resection

BACKGROUND

Intraoperative transesophageal echocardiography (iTEE) is used to assess for residual left ventricular outflow tract obstruction (LVOTO) after surgical resection of subaortic membrane causing subaortic stenosis (sub-AS). We aimed to identify the iTEE features associated with recurrence of LVOTO.

METHODS

We conducted a retrospective study of children undergoing sub-AS resection from June 2006 to June 2014. Doppler assessment of the flow velocity and the anatomical features of the left ventricular outflow tract were analyzed from stored echocardiograms. Recurrent LVOTO was defined as an increase in the mean pressure gradient across the left ventricular outflow tract of > 15 mm Hg on the most recent follow-up echocardiogram from the mean pressure gradient on the predischarge echocardiogram or as doubling of the mean pressure gradient to a value ≥20 mm Hg.

RESULTS

Thirty-five patients were included, with median age at surgery was 8.1 years (range: 0.7-29 years) and median follow-up was 47 months (2-91 months). Ten patients (29%) had recurrent LVOTO, which was associated with a shorter distance between the narrowest diameter of the outflow tract and the aortic valve on iTEE [median 0.59 cm (range 0.39-0.74) vs 0.98 cm (0.75-1.5), P = .03]. No patients with more than mild residual LVOTO on iTEE regressed to mild or no LVOTO on follow-up echocardiograms.

CONCLUSIONS

LVOTO recurrence after sub-AS resection is common, and residual LVOTO remains the same or increases over time. Proximity of the LVOTO to the aortic valve is a risk factor for recurrent LVOTO. These findings may be useful in counseling patients and to guide the frequency of postoperative follow-up.

When Is It Better to Wait? Surgical Timing and Recurrence Risk for Children Undergoing Repair of Subaortic Stenosis

Recurrence of subaortic stenosis (SAS) after surgery is common in children. The effects of patient characteristics and surgical timing on disease recurrence are largely unknown. We performed a retrospective study, assessing the relative effects of patient age and left ventricular outflow tract (LVOT) gradient on the need for reoperation for recurrent SAS. We included all children <20 years of age who underwent initial surgical resection of SAS at our center, January 2003-December 2013. Stratified logistic regression was performed, considering the effects of patient demographics, clinical characteristics, echocardiographic parameters, and operative technique, and clustering standard errors by surgeon. The multivariable model was used to simulate predicted probabilities of recurrent SAS for children at varying ages and baseline LVOT gradients. Sixty-three patients (38 males) underwent initial operation for SAS. Patients were followed for a median of 3.7 years (IQR 1.2-7.1). Twenty-one percent of patients (n = 13) underwent reoperation for SAS. Twelve were male. For every 10 mmHg increase in preoperative peak gradient in boys, the odds of reoperation for SAS doubled (OR 2.01, CI 1.5-2.72, p < 0.001), and for every additional 6 months of age, the odds of reoperation decreased by 14% (OR 0.86, CI 0.84-0.88, p < 0.001). Both younger age and higher preoperative outflow tract gradient are independently associated with risk of reoperation. Clinicians should consider the age and rate of LVOT gradient change-and not just the absolute gradient-in determining initial surgical timing.

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.