First report from the European registry for anomalous aortic origin of coronary artery (EURO-AAOCA).

OBJECTIVES: Anomalous aortic origin of a coronary artery (AAOCA) is a group of rare congenital heart defects with various clinical presentations. The lifetime-risk of an individual living with AAOCA is unknown, and data from multicentre registries are urgently needed to adapt current recommendations and guide optimal patient management. The European AAOCA Registry (EURO-AAOCA) aims to assess differences with regard to AAOCA management between centres. METHODS: EURO-AAOCA is a prospective, multicentre registry including 13 European centres. Herein, we evaluated differences in clinical presentations and management, treatment decisions and surgical outcomes across centres from January 2019 to June 2023. RESULTS: A total of 262 AAOCA patients were included, with a median age of 33 years (12-53) with a bimodal distribution. One hundred thirty-nine (53.1%) were symptomatic, whereas chest pain (n = 74, 53.2%) was the most common complaint, followed by syncope (n = 21, 15.1%). Seven (5%) patients presented with a myocardial infarction, 2 (1.4%) with aborted sudden cardiac death. Right-AAOCA was most frequent (150, 57.5%), followed by left-AAOCA in 51 (19.5%), and circumflex AAOCA in 20 (7.7%). There were significant differences regarding diagnostics between age groups and across centres. Seventy-four (28.2%) patients underwent surgery with no operative deaths; minor postoperative complications occurred in 10 (3.8%) cases. CONCLUSIONS: Currently, no uniform agreement exists among European centres with regard to diagnostic protocols and clinical management for AAOCA variants. Although surgery is a safe procedure in AAOCA, future longitudinal outcome data will hopefully shed light on how to best decide towards optimal selection of patients undergoing revascularization versus conservative treatment.

Long-term follow-up of atrioventricular valve function in Fontan patients: effect of atrioventricular valve surgery.

OBJECTIVES: The aim of this study was to evaluate the relationship between atrioventricular valve and ventricular function in Fontan survivors, including the effect of atrioventricular valve surgery. METHODS: Analysis focused on transplant-free survival and the need for atrioventricular valve surgery in single ventricle patients after Fontan completion. Longitudinal echocardiographic examination of long-term valve and ventricular function was performed. RESULTS: Fontan completion was performed in 113 patients, having a right univentricular morphology in 33.6%, a left ventricle morphology in 62.8% and ambiguous in 3.6%. Perioperative mortality was 2.7% (n = 3). Within a median follow-up of 16.3 years (interquartile range 10.6-23.6), transplant-free survival was 96.1 ± 1.9% and 90.4 ± 5.8% at 10-25 years. Twenty AV valve procedures were performed in 14 (12.4%) children, respectively, pre-Fontan (n = 10), per-Fontan (n = 8) and post-Fontan (n = 2), resulting in a cumulative incidence of AV valve surgery is 5.7 ± 2.2% and 12.3 ± 3.2% at 1-5 years. Atrio-ventricular valve function deteriorated over time [hazard ratio (HR) 1.112, 95% confidence interval (CI) 1.089-1.138, P < 0.001], without difference for valve morphology (P = 0.736) or ventricular dominance (P = 0.484). AV valve dysfunction was greater in patients requiring AV valve surgery (HR 20.383, 95% CI 6.223-36.762, P < 0.001) but showed a comparable evolution since repair to those without valve surgery (HR 1.070, 95% CI 0.987-1.160, P = 0.099). Progressive time-related ventricular dysfunction was observed (HR 1.141, 95% CI 1.097-1.182, P < 0.001), significantly less in left ventricle-dominance (HR 0.927, 95% CI 0.860-0.999, P = 0.047) but more after AV valve surgery (HR 1.103, 95% CI 1.014-1.167, P = 0.022). CONCLUSIONS: In a homogeneously treated Fontan population, 25-year transplant-free survival is encouraging. Atrio-ventricular valve surgery was necessary in 12.4%, resulting mostly in a durable valve function. However, a slow time-related decline of atrioventricular valve function as of ventricular function is worrisome, evoking a role for additional heart failure therapy.

Failure of Tricuspid Annuloplasty for Functional Tricuspid Regurgitation: Impact of Patient's Body Size.

Tricuspid repair is recommended for significant functional tricuspid regurgitation (FTR) or tricuspid annulus (TA) dilation, based on TA >40 mm or >21 mm/m². The concordance between both TA dimensions related to the patient's body size has not been investigated. Patients who underwent rigid ring tricuspid annuloplasty for FTR between 2009 and 2017 were included. Assuming equality between both TA diameter criteria, patients were divided per body surface area (BSA): group 1 = BSA ≤1.9 m² and group 2 = BSA >1.9 m². The primary outcome was TR recurrence at 5 years. Tricuspid annuloplasty was performed in 186 patients (group 1: 130 patients [69.9%]; group 2: 56 patients [30.1%]). Group 1 comprised more female (70.8% to 23.2%, p <0.001) and older patients (77.1 ± 9.3 years; 74.2 ± 8.2 years, p = 0.048). Group 1 had a smaller absolute TA diameter (group 1: 45.3 ± 5.2 mm; group 2: 48.2 ± 5.6 mm, p <0.001), whereas the indexed TA size was inversely higher (group 1: 26.3 ± 3.4 mm/m²; group 2: 24.2 ± 2.7 mm/m², p <0.001). The tenting height was comparable (group 1: 7.8 ± 3.0 mm; group 2: 8.0 ± 2.7 mm, p = 0.714). The median ring size was 30 (interquartile range 28 to 32) and 32 (interquartile range 30 to 34) for groups 1 and 2, respectively (p <0.001). TR recurrence at 5 years was noticed in 20.2% and 6.5% of group 1 and 2 (p = 0.035). Indexed TA diameter (hazard ratio 1.43, 95% confidence interval 1.10 to 1.87, p = 0.008) and tenting height (hazard ratio 5.52, 95% confidence interval 1.87 to 14.57, p = 0.002) were independent predictors of TR recurrence. In conclusion, when the absolute TA diameter is used as the primary criterion, smaller patients are at a higher risk for TR recurrence by having a proportionally larger TA at the time of repair. An individualized approach guided by patient's body size might be more appropriate to indicate FTR correction to adjust for the annuloplasty sizing method.

Potential of Urine Biomarkers CHI3L1, NGAL, TIMP-2, IGFBP7, and Combinations as Complementary Diagnostic Tools for Acute Kidney Injury after Pediatric Cardiac Surgery: A Prospective Cohort Study.

Acute kidney injury (AKI) is common after pediatric cardiac surgery (CS). Several urine biomarkers have been validated to detect AKI earlier. The objective of this study was to evaluate urine CHI3L1, NGAL, TIMP-2, IGFBP7, and NephroCheck® as predictors for AKI ≥ 1 in pediatric CS after 48 h and AKI ≥ 2 after 12 h. Pediatric patients (age < 18 year; body weight ≥ 2 kg) requiring CS were prospectively included. Urine CHI3L1, NGAL, TIMP-2, IGFBP7, and NephroCheck® were measured during surgery and intensive care unit (ICU) stay and corrected for urine dilution. One hundred and one pediatric patients were included. AKI ≥ 1 within 48 h after ICU admission occurred in 62.4% and AKI ≥ 2 within 12 h in 30.7%. All damage biomarkers predicted AKI ≥ 1 within 48 h after ICU admission, when corrected for urine dilution: CHI3L1 (AUC-ROC: 0.642 (95% CI, 0.535-0.741)), NGAL (0.765 (0.664-0.848)), TIMP-2 (0.778 (0.662-0.868)), IGFBP7 (0.796 (0.682-0.883)), NephroCheck® (0.734 (0.614-0.832)). Similarly, AKI ≥ 2 within 12 h was predicted by all damage biomarkers when corrected for urine dilution: uCHI3L1 (AUC-ROC: 0.686 (95% CI, 0.580-0.780)), NGAL (0.714 (0.609-0.804)), TIMP-2 (0.830 (0.722-0.909)), IGFBP7 (0.834 (0.725-0.912)), NephroCheck® (0.774 (0.658-0.865)). After pediatric cardiac surgery, the damage biomarkers urine CHI3L1, NGAL, TIMP-2, IGFBP7, and NephroCheck® reliably predict AKI after correction for urine dilution.

Post-operative Outcomes for Vascular Rings: A Systematic Review and Meta-analysis.

OBJECTIVES: Vascular rings may cause tracheal and/or oesophageal compression. For many patients, symptoms/signs have been present for a long period before diagnosis. However, in the era of prenatal diagnosis, some units advocate universal early surgery. The risks and efficacy of surgery must be known to adequately counsel for the operation. This meta-analysis sought to define the morbidity and mortality associated with surgical correction, and persistent post-operative symptoms. METHODS: PubMed, Cochrane Library and CINAHL databases were searched for studies that described the outcome of patients undergoing surgery for a double or right aortic arch (DAA or RAA). Non-comparative and random effects model-based meta-analyses were conducted to calculate the pooled rates of mortality, surgical complications, reintervention, and persistent follow-up symptoms. RESULTS: Nineteen eligible studies were included comprising 18 studies describing outcomes for DAA surgery and 15 for RAA surgery. For DAA surgery, overall mortality rate was 0% [95% confidence interval (CI) 0.0-1.0], post-surgical complication rate 18% [95% CI: 12.0-23.0], prevalence of reintervention 3% [95% CI: 1.0-5.0] and prevalence of symptoms at last follow-up was 33% [95% CI: 17.0-52.0]. For RAA surgery, overall pooled mortality was 0% [95% CI: 0.0-0.0], prevalence of post-surgical complications was 15% [95% CI: 8.0-23.0], reintervention rate was 2% [95% CI: 0.0-4.0], prevalence of symptoms at last follow-up was 40% [95% CI: 26.0-55.0]. CONCLUSIONS: While surgery to correct a vascular ring is safe, the rate of persistent symptoms is high and further strategies must be sought to reduce this burden.

Pulmonary artery banding as adjunct therapy for ventricular recovery after anomalous left coronary artery from the pulmonary artery repair: a case report.

Anomalous left coronary artery from the pulmonary artery is a rare congenital coronary anomaly commonly associated with severe but reversible left ventricular dysfunction. We present an anomalous left coronary artery from the pulmonary artery case of persisting left ventricular failure with inability to wean off the ventilator and inotropes after successful coronary reimplantation, in whom pulmonary artery banding enhanced myocardial recovery.

Exploring the Mutational Landscape of Isolated Congenital Heart Defects: An Exome Sequencing Study Using Cardiac DNA.

Congenital heart defects (CHD) are the most common congenital anomalies in liveborn children. In contrast to syndromic CHD (SCHD), the genetic basis of isolated CHD (ICHD) is complex, and the underlying pathogenic mechanisms appear intricate and are incompletely understood. Next to rare Mendelian conditions, somatic mosaicism or a complex multifactorial genetic architecture are assumed for most ICHD. We performed exome sequencing (ES) in 73 parent-offspring ICHD trios using proband DNA extracted from cardiac tissue. We identified six germline de novo variants and 625 germline rare inherited variants with 'damaging' in silico predictions in cardiac-relevant genes expressed in the developing human heart. There were no CHD-relevant somatic variants. Transmission disequilibrium testing (TDT) and association testing (AT) yielded no statistically significant results, except for the AT of missense variants in cilia genes. Somatic mutations are not a common cause of ICHD. Rare de novo and inherited protein-damaging variants may contribute to ICHD, possibly as part of an oligogenic or polygenic disease model. TDT and AT failed to provide informative results, likely due to the lack of power, but provided a framework for future studies in larger cohorts. Overall, the diagnostic value of ES on cardiac tissue is limited in individual ICHD cases.

Impact of mean perfusion pressure and vasoactive drugs on occurrence and reversal of cardiac surgery-associate acute kidney injury: A cohort study.

PURPOSE: Low cardiac output and kidney congestion are associated with acute kidney injury after cardiac surgery (CSA-AKI). This study investigates hemodynamics on CSA-AKI development and reversal. MATERIALS AND METHODS: Adult patients undergoing cardiac surgery were retrospectively included. Hemodynamic support was quantified using a new time-weighted vaso-inotropic score (VISAUC), and hemodynamic variables expressed by mean perfusion pressure and its components. The primary outcome was AKI stage ≥2 (CSA-AKI ≥2) and secondary outcome full AKI reversal before ICU discharge. RESULTS: 3415 patients were included. CSA-AKI ≥2 occurred in 37.4%. Mean perfusion pressure (MPP) (OR 0.95,95%CI 0.94-0.96, p < 0.001); and central venous pressure (CVP) (OR 1.17, 95%CI 1.13-1.22, p < 0.001) are associated with CSA-AKI ≥2 development, while VISAUC/h was not (p = 0.104). Out of 1085 CSA-AKI ≥2 patients not requiring kidney replacement therapy, 76.3% fully recovered of AKI. Full CSA-AKI reversal was associated with MPP (OR 1.02 per mmHg (95%CI 1.01-1.03, p = 0.003), and MAP (OR = 1.01 per mmHg (95%CI 1.00-1.02), p = 0.047), but not with VISAUC/h (p = 0.461). CONCLUSION: Development and full recovery of CSA-AKI ≥2 are affected by mean perfusion pressure, independent of vaso-inotropic use. CVP had a significant effect on AKI development, while MAP on full AKI reversal.

Clipping of an Aortopulmonary Window in a Small Neonate With Bronchial Bleeding: A Simple Solution for a Complex Condition.

Although the conventional treatment of aortopulmonary (AP) window consists of reconstructive surgery with the use of cardiopulmonary bypass (CPB), some conditions like low birth weight or active respiratory tract bleeding may lead to diverting therapeutic options. We present a case of a premature 1.9 kg neonate with severe pulmonary arterial hypertension based on the association of an AP window and large patent ductus arteriosus. Because of intrabronchial hemorrhage, a conservative strategy was chosen excluding the need for heparinization and CPB. Through median sternotomy, the ductus arteriosus and AP window were clipped, effectively occluding both shunts. The postoperative course was uneventful with a rapid decrease of pulmonary artery pressure. Although classical surgical reconstruction is still advocated as primary therapy, this case illustrates the suitability of an alternative approach without the need for CPB and full heparinization in a patient with an increased risk of bleeding complications.

Mid-term clinical and haemodynamic results after aortic valve replacement with the Trifecta bioprosthesis.

OBJECTIVES: The aim of this study was to evaluate the clinical and haemodynamic results after implantation of the Trifecta bioprosthesis. METHODS: This study is a retrospective analysis of all patients undergoing Trifecta aortic valve replacement between 01 January 2012 and 31 December 2017 at the Ghent University Hospital. Univariable and multivariable analyses were performed to identify predictors of valve- and procedure-related complications and mortality. The haemodynamic performance was analysed by longitudinal Doppler echocardiography. RESULTS: The mean age of the 182 patients was 77 [standard deviation (SD): 5.5] years; 54.9% were women. The mean follow-up was 39.8 (SD: 24.3) months. Overall survival at 1 and 5 years was 86% (SD: 3%) and 68% (SD: 4%), respectively, and overall freedom from structural valve deterioration was 100% and 98% at 1 and 5 years, respectively. There was no valve thrombosis nor early endocarditis. Urgent surgery was the only risk factor for early mortality in the multivariable analysis [P = 0.009, odds ratio 0.06, 95% confidence interval (CI) 0.01-0.5]. Preoperative atrial fibrillation was the most important predictor of late mortality (P = 0.001, hazard ratio 3.68, 95% CI 1.65-8.21). The average peak gradients were stable from discharge up to 1 and 5 years postoperatively [15 (SD: 6) and 17 (SD: 8) mmHg]. CONCLUSIONS: These results confirm the excellent clinical performance of the Trifecta valve, particularly in an elderly age group. Through the 7-year follow-up period, low transvalvular gradients persisted, and only a few patients needed reoperation. Although structural valve degeneration occurred rarely, it was unrelated to valve size or age at implantation; therefore, further long-term follow-up remains mandatory.

Long-term outcomes of atrioventricular septal defect and single ventricle: A multicenter study.

OBJECTIVE: The study objective was to analyze survival and incidence of Fontan completion of patients with single-ventricle and concomitant unbalanced atrioventricular septal defect. METHODS: Data from 4 Dutch and 3 Belgian institutional databases were retrospectively collected. A total of 151 patients with single-ventricle atrioventricular septal defect were selected; 36 patients underwent an atrioventricular valve procedure (valve surgery group). End points were survival, incidence of Fontan completion, and freedom from atrioventricular valve reoperation. RESULTS: Median follow-up was 13.4 years. Cumulative survival was 71.2%, 70%, and 68.5% at 10, 15, and 20 years, respectively. An atrioventricular valve procedure was not a risk factor for mortality. Patients with moderate-severe or severe atrioventricular valve regurgitation at echocardiographic follow-up had a significantly worse 15-year survival (58.3%) compared with patients with no or mild regurgitation (89.2%) and patients with moderate regurgitation (88.6%) (P = .033). Cumulative incidence of Fontan completion was 56.5%, 71%, and 77.6% at 5, 10, and 15 years, respectively. An atrioventricular valve procedure was not associated with the incidence of Fontan completion. In the valve surgery group, freedom from atrioventricular valve reoperation was 85.7% at 1 year and 52.6% at 5 years. CONCLUSIONS: The long-term survival and incidence of Fontan completion in our study were better than previously described for patients with single-ventricle atrioventricular septal defect. A concomitant atrioventricular valve procedure did not increase the mortality rate or decrease the incidence of Fontan completion, whereas patients with moderate-severe or severe valve regurgitation at follow-up had a worse survival. Therefore, in patients with single-ventricle atrioventricular septal defect when atrioventricular valve regurgitation exceeds a moderate degree, the atrioventricular valve should be repaired.

Midterm Comparison Between Different Annuloplasty Techniques for Functional Tricuspid Regurgitation.

BACKGROUND: Several tricuspid annuloplasty (TA) techniques are used for concomitant repair of functional tricuspid regurgitation (TR). This study compared the midterm clinical and valvular outcome among 3 annuloplasty techniques. METHODS: TA was performed in 307 patients (aged 75.9 ± 10.4 years) with a rigid ring (RA) in 184, a flexible band (FA) in 80, or a suture annuloplasty (SA) in 43. Study end points were survival and recurrence of TR >grade 2 at 5 years. RESULTS: TA was performed concomitantly to mitral valve surgery in 136 patients (44.3%), aortic valve surgery in 18 (5.9%), coronary artery bypass grafting in 13 (4.2%), or a combined procedure in 140 (45.6%). Most had TR >grade 2 (78.5%), without significant differences between the TA groups (P = .878). Within a median follow-up of 3.4 years (interquartile range, 2.2-5.0 years), the 5-year survival was 80.1% ± 3.4% for RA, 83.5% ± 4.7% for FA, and 85.1% ± 6.5% for SA (P = .471). Independent risk factors for late mortality were renal impairment (hazard ratio [HR], 2.83; 95% CI, 1.16-6.89; P = .022), diabetes (HR, 2.10; 95% CI, 1.07-4.11; P = .030), and severe right ventricular dysfunction by tricuspid annulus plane systolic excursion <10 mm (HR, 11.52; 95% CI, 4.98-26.66; P < .001). Pulmonary hypertension was nearly significant (HR, 1.92; 95% CI, 0.98-3.74; P = .057). The cumulative incidence of TR recurrence at 5 years was 15.9%, 19.4%, and 21.1% for RA, FA, and SA, respectively (P = .342). Severe pulmonary hypertension (HR, 2.64; 95% CI, 1.38-5.07; P = .003), preoperative TR grade (HR, 1.82; 95% CI, 1.01-3.27; P = .046), and residual TR >grade 2 at discharge (HR, 3.38; 95% CI, 1.64-6.96; P = .001) were predictive for later TR recurrence, regardless of the annuloplasty technique. CONCLUSIONS: This study demonstrates that advanced pathophysiological right circulatory impairment, such as severe pulmonary hypertension and right ventricular dysfunction, affects the midterm survival and TR recurrence rate more than the annuloplasty technique used for concomitant repair of functional TR.

Non-invasive assessment of liver abnormalities in pediatric Fontan patients.

Liver abnormalities are well known among long-term survivors of Fontan palliation, which remains the definite surgery for complex congenital heart disease and single ventricle physiology. Pediatric data however are scarce. We assessed the prevalence and degree of liver abnormalities in pediatric Fontan patients through non-invasive investigations suitable for longitudinal follow-up. Thirty-five patients with a median age of 11.8 years (5.2-16.6) and median time since Fontan of 6 years (1.17-13.83) were studied. Each child underwent a blood test, liver Doppler ultrasound (US), and transient elastography (TE). Healthy children were used as controls for TE measurement. AST, ALT, γGT, and direct bilirubin were abnormal in respectively 12 (34%), 5 (14%), 24 (69%), and 7 (20%) patients, while platelet count was decreased in 7 (20%). Splenomegaly was present in 7 (20%) patients. Portal vein mean flow velocity was < 15 cm/s in 19 (54%) patients indicative of portal hypertension. Twenty-two patients (63%) showed inferior vena cava collapsibility index values below 17%, indicating venous congestion. Hepatic artery and superior mesenteric artery resistance index were inversely correlated with time post Fontan (p < 0.05). TE values in Fontan patients were significantly higher than controls, with a median of 12.6 versus 4.6 kPa (p < 0.001) and were already increased shortly after Fontan completion. Conclusion: Liver abnormalities are frequently observed in pediatric Fontan patients. The non-invasive investigations used were not able to confirm liver fibrosis or differentiate hepatic congestion from fibrosis. Based on our findings, we propose a prospective screening protocol with serial measurements of laboratory, (Doppler) US, and TE parameters. What is Known: • Hepatic dysfunction is a well-known consequence of the Fontan circulation. • The natural history of Fontan-associated liver disease in the pediatric age group remains unclear. What is New: • Liver abnormalities are frequently observed in pediatric Fontan patients; however, differentiating liver fibrosis and hepatic congestion with non-invasive investigations remains challenging. Sonographic Doppler measurements may improve our insight in both Fontan-associated liver disease development and the functioning of the Fontan circulation. • A prospective screening protocol is proposed to improve our ability to detect Fontan-associated liver disease early on and understand its natural history.

Study design and rationale of the pAtients pResenTing with cOngenital heaRt dIseAse Register (ARTORIA-R).

AIM: Due to improved therapy in childhood, many patients with congenital heart disease reach adulthood and are termed adults with congenital heart disease (ACHD). ACHD often develop heart failure (HF) as a consequence of initial palliative surgery or complex anatomy and subsequently require advanced HF therapy. ACHD are usually excluded from trials evaluating heart failure therapies, and in this context, more data about heart failure trajectories in ACHD are needed to guide the management of ACHD suffering from HF. METHODS AND RESULTS: The pAtients pResenTing with cOngenital heaRt dIseAse Register (ARTORIA-R) will collect data from ACHD evaluated or listed for heart or heart-combined organ transplantation from 16 countries in Europe and the Asia/Pacific region. We plan retrospective collection of data from 1989-2020 and will include patients prospectively. Additional organizations and hospitals in charge of transplantation of ACHD will be asked in the future to contribute data to the register. The primary outcome is the combined endpoint of delisting due to clinical worsening or death on the waiting list. The secondary outcome is delisting due to clinical improvement while on the waiting list. All-cause mortality following transplantation will also be assessed. The data will be entered into an electronic database with access to the investigators participating in the register. All variables of the register reflect key components important for listing of the patients or assessing current HF treatment. CONCLUSION: The ARTORIA-R will provide robust information on current management and outcomes of adults with congenital heart disease suffering from advanced heart failure.

Paediatric subaortic stenosis: long-term outcome and risk factors for reoperation.

OBJECTIVES: Surgical repair of subaortic stenosis (SAS) is associated with a substantial reoperation risk. We aimed to identify risk factors for reintervention in relation to discrete and tunnel-type SAS morphology. METHODS: Single-centre retrospective study of paediatric SAS diagnosed between 1992 and 2017. Multivariable Cox regression analysis was performed to identify reintervention risk factors. RESULTS: Eighty-five children [median age 2.5 (0.7-6.5) years at diagnosis] with a median follow-up of 10.1 (5.5-16.4) years were included. Surgery was executed in 83% (n = 71). Freedom from reoperation was 88 ± 5% at 5 years and 82 ± 6% at 10 years for discrete SAS, compared to, respectively, 33 ± 16% and 17 ± 14% for tunnel-type SAS (log-rank P < 0.001). Independent risk factors for reintervention were a postoperative gradient >20 mmHg [hazard ratio (HR) 6.56, 95% confidence interval (CI) 1.41-24.1; P = 0.005], tunnel-type SAS (HR 7.46, 95% CI 2.48-22.49; P < 0.001), aortic annulus z-score <-2 (HR 11.07, 95% CI 3.03-40.47; P < 0.001) and age at intervention <2 years (HR 3.24, 95% CI 1.09-9.86; P = 0.035). Addition of septal myectomy at initial intervention was not associated with lesser reintervention. Fourteen children with a lower left ventricular outflow tract (LVOT) gradient (P < 0.001) and older age at diagnosis (P = 0.024) were followed expectatively. CONCLUSIONS: Children with SAS remain at risk for reintervention, despite initially effective LVOT relief. Regardless of SAS morphology, age <2 years at first intervention, a postoperative gradient >20 mmHg and presence of a hypoplastic aortic annulus are independent risk factors for reintervention. More extensive LVOT surgery might be considered at an earlier stage in these children. SAS presenting in older children with a low LVOT gradient at diagnosis shows little progression, justifying an expectative approach.