Left-Ventricular Unloading With Impella During Refractory Cardiac Arrest Treated With Extracorporeal Cardiopulmonary Resuscitation: A Systematic Review and Meta-Analysis.

OBJECTIVES: Extracorporeal cardiopulmonary resuscitation (ECPR) is the implementation of venoarterial extracorporeal membrane oxygenation (VA-ECMO) during refractory cardiac arrest. The role of left-ventricular (LV) unloading with Impella in addition to VA-ECMO ("ECMELLA") remains unclear during ECPR. This is the first systematic review and meta-analysis to characterize patients with ECPR receiving LV unloading and to compare in-hospital mortality between ECMELLA and VA-ECMO during ECPR. DATA SOURCES: Medline, Cochrane Central Register of Controlled Trials, Embase, and abstract websites of the three largest cardiology societies (American Heart Association, American College of Cardiology, and European Society of Cardiology). STUDY SELECTION: Observational studies with adult patients with refractory cardiac arrest receiving ECPR with ECMELLA or VA-ECMO until July 2023 according to the Preferred Reported Items for Systematic Reviews and Meta-Analysis checklist. DATA EXTRACTION: Patient and treatment characteristics and in-hospital mortality from 13 study records at 32 hospitals with a total of 1014 ECPR patients. Odds ratios (ORs) and 95% CI were computed with the Mantel-Haenszel test using a random-effects model. DATA SYNTHESIS: Seven hundred sixty-two patients (75.1%) received VA-ECMO and 252 (24.9%) ECMELLA. Compared with VA-ECMO, the ECMELLA group was comprised of more patients with initial shockable electrocardiogram rhythms (58.6% vs. 49.3%), acute myocardial infarctions (79.7% vs. 51.5%), and percutaneous coronary interventions (79.0% vs. 47.5%). VA-ECMO alone was more frequently used in pulmonary embolism (9.5% vs. 0.7%). Age, rate of out-of-hospital cardiac arrest, and low-flow times were similar between both groups. ECMELLA support was associated with reduced odds of mortality (OR, 0.53 [95% CI, 0.30-0.91]) and higher odds of good neurologic outcome (OR, 2.22 [95% CI, 1.17-4.22]) compared with VA-ECMO support alone. ECMELLA therapy was associated with numerically increased but not significantly higher complication rates. Primary results remained robust in multiple sensitivity analyses. CONCLUSIONS: ECMELLA support was predominantly used in patients with acute myocardial infarction and VA-ECMO for pulmonary embolism. ECMELLA support during ECPR might be associated with improved survival and neurologic outcome despite higher complication rates. However, indications and frequency of ECMELLA support varied strongly between institutions. Further scientific evidence is urgently required to elaborate standardized guidelines for the use of LV unloading during ECPR.

Strategies for the Surgical Management of Highly Aggressive Williams Syndrome Aortopathy: A Three Case Report.

Severe aortopathy in Williams syndrome can sometimes present with an initial ascending aortic pathology, followed in short order by more distal multilevel obstruction and recurrence requiring reintervention. In this series, an early, comprehensive surgical approach using a combination of various access and perfusion strategies yielded excellent long-term results.

Liberal use of veno-arterial extracorporeal membrane oxygenation in combined sequential heart-liver transplantation.

Combined heart-liver transplantation (CHLT) is a rarely though increasingly performed procedure with evolving indications. Despite CHLT being performed at only a handful of centers, the use of intraoperative mechanical circulatory support to optimize hemodynamics and facilitate dual-organ transplantation varies widely. At our center, we liberally utilize veno-arterial extracorporeal membrane oxygenation (V-A ECMO) when a veno-venous shunt is anticipated to be insufficient in mitigating the hemodynamic perturbations associated with liver reperfusion. In this series, we describe our experience with V-A ECMO in sequential (heart-first) CHLT and demonstrate highly favorable outcomes with this strategy.

Relationship between indexed surgery and postcardiotomy extracorporeal life support outcomes.

OBJECTIVES: Veno-arterial extracorporeal life support (V-A ECLS) is increasingly being utilized for postcardiotomy shock (PCS), though data describing the relationship between type of indexed operation and outcomes are limited. This study compared V-A ECLS outcomes across four major cardiovascular surgical procedures. METHODS: This was a single-center retrospective study of patients who required V-A ECLS for PCS between 2015 and 2022. Patients were stratified by the type of indexed operation, which included aortic surgery (AoS), coronary artery bypass grafting (CABG), valve surgery (Valve), and combined CABG and valve surgery (CABG + Valve). Factors associated with postoperative outcomes were assessed using logistic regression. RESULTS: Among 149 PCS patients who received V-A ECLS, there were 35 AoS patients (23.5%), 29 (19.5%) CABG patients, 59 (39.6%) Valve patients, and 26 (17.4%) CABG + Valve patients. Cardiopulmonary bypass times were longest in the AoS group (p < 0.01). Regarding causes of PCS, AoS patients had a greater incidence of ventricular failure, while the CABG group had a higher incidence of ventricular arrhythmia (p = 0.04). Left ventricular venting was most frequently utilized in the Valve group (p = 0.07). In-hospital mortality was worst among CABG + Valve patients (p < 0.01), and the incidence of acute kidney injury was highest in the AoS group (p = 0.03). In multivariable logistic regression, CABG + Valve surgery (odds ratio (OR) 4.20, 95% confidence interval 1.30-13.6, p = 0.02) and lactate level at ECLS initiation (OR, 1.17; 95% CI, 1.06-1.29; p < 0.01) were independently associated with mortality. CONCLUSIONS: We demonstrate that indications, management, and outcomes of V-A ECLS for PCS vary by type of indexed cardiovascular surgery.

Bridge to simultaneous heart-kidney transplantation via extracorporeal life support: National outcomes in the new heart allocation policy era.

BACKGROUND: Since United Network for Organ Sharing (UNOS) revised their heart allocation policy in 2018, usage of veno-arterial extracorporeal life support (VA-ECLS) has dramatically increased as a bridge to transplant. This study investigated outcomes of VA-ECLS patients bridged to simultaneous heart-kidney transplant (SHK) in the new policy era. METHODS: This study included 774 adult patients from the UNOS database who received SHK between 10/18/18 and 12/31/21 and compared patients bridged to transplant on VA-ECLS (n = 50) with those not bridged (n = 724). RESULTS: At baseline, SHK recipients bridged from VA-ECLS were younger (50.5 vs 58.0 years, p = 0.007), had higher estimated glomerular filtration rate (eGFR) at time of transplant (47.6 vs 30.1, p < 0.001), and spent fewer days on the waitlist (7.0 vs 33.5 days, p < 0.001). In the perioperative period, VA-ECLS was associated with higher rates of temporary dialysis (56.0% vs 28.0%, p < 0.001) but similar 2-year cumulative incidence of chronic dialysis (7.5% vs 5.4%, p = 0.800) and renal allograft failure (12.0% vs 8.1%, p = 0.500) compared to non-ECLS cohort. However, VA-ECLS patients had decreased survival to discharge (76.0% vs 92.7%, p < 0.001) and 2-year post-transplant survival (71.7% vs 83.0%, p = 0.004), as well as greater 2-year cumulative incidence of cardiac allograft failure (10.0% vs 2.7%, p = 0.002). Multivariable analyses found VA-ECLS at time of transplant to be independently associated with 2-year post-transplant mortality (HR [95% CI]: 3.40 [1.66-6.96], p = 0.001) and cardiac allograft failure (sub-distribution hazard ratio [SHR] [95% CI]: 8.51 [2.77-26.09], p < 0.001). CONCLUSION: Under the new allocation policy, patients bridged to SHK from VA-ECLS displayed greater early mortality and cardiac allograft failure but similar renal outcomes compared to non-ECLS counterparts.

Long-term autograft dilation and durability after the Ross procedure are similar in infants, children, and adolescents with primary aortic stenosis.

BACKGROUND: Autograft durability and remodeling are thought to be superior in younger pediatric patients after the Ross operation. We sought to delineate the fate of autografts across the pediatric age spectrum in patients with primary aortic stenosis (AS). METHODS: We retrospectively reviewed patients age ≤18 years with primary AS who underwent the Ross operation between 1993 and 2020. Patients were categorized by age. The primary endpoint was autograft dimensional change, and secondary endpoints were severe neo-aortic insufficiency (AI) and autograft reintervention. RESULTS: A total of 119 patients underwent the Ross operation, including 37 (31.1%) in group I (age <18 months), 24 (20.2%) in group II (age 18 months-8 years), and 58 (48.7%) in group III (age 8-18 years). All groups exhibited similar annular growth rates within the first 5 postoperative years, followed by a collective decrease in annulus growth rates from year 5 to year 10. Group III experienced rapid sinus dilation in the first 5 years, followed by stabilization of the sinus z-score from year 5 to year 10, whereas groups I and II demonstrated stable sinus z-scores over 10 years. There were 4 early deaths (3.4%) and 2 late deaths (1.7%) at a median follow-up of 8.1 years (range, 0.01-26.3 years). At 15 years, the incidences of severe neo-AI (0.0 ± 0.0% vs 0.0 ± 0.0% vs 3.9 ± 3.9%; P = .52) and autograft reintervention (8.4 ± 6.0% vs 0.0 ± 0.0% vs 2.4 ± 2.4%; P = .47) were similar in the 3 groups. CONCLUSIONS: Age at the time of Ross operation for primary AS does not influence long-term autograft remodeling or durability. Other physiologic or technical factors are likely greater determinants of autograft fate.

Surgical management of pleural complications in lymphangioleiomyomatosis.

OBJECTIVE: Lymphangioleiomyomatosis (LAM) is a rare cystic lung disease occurring primarily in women. Pneumothorax and chylothorax are common pleural complications in LAM. We aim to explore various options in the surgical management of pleural disease in LAM. METHODS: A retrospective chart review of all patients at the Center for LAM and Rare Lung Diseases at Columbia University was performed, and date, type, and indication for surgical procedure were collected. All patients with any cystic lung disease seen between January 1, 2000, and March 1, 2023, were included in the database. RESULTS: The charts for 326 patients with possible LAM were reviewed, including 213 with confirmed LAM and 113 women with cystic lung disease consistent suspected to be LAM were reviewed. A total of 40.5% underwent surgical procedures at our institution or at referring hospitals. A total of 15.6% of patients underwent surgical lung biopsies. A total of 16.6% had a history of pneumothoraces, of whom 79.6% underwent chemical and/or mechanical pleurodesis, 14.8% required pleurectomy, and 7.4% were discharged with tunneled indwelling pleural catheters. We found that 5.6% of confirmed LAM patients have history of chylothorax, with thoracic duct ligation, thoracic duct embolization, pleurodesis, and pleurodesis with long-term tunneled indwelling pleural catheter placement all used as treatment strategies. CONCLUSIONS: Here we demonstrate the significant burden of pleural disease in patients with LAM. It is imperative that thoracic surgeons understand the high incidence of pneumothorax in this patient population. Tunneled indwelling pleural catheters are underutilized but provide long-term options for chylous management with long-term mechanical pleurodesis and a decrease in hospital length of stay.

Rare coronary artery variants are associated with increased mortality and reinterventions following the arterial switch operation.

OBJECTIVE: To determine the influence of coronary anatomy on long-term outcomes of the arterial switch operation (ASO). METHODS: We retrospectively reviewed patients with transposition of the great arteries or Taussig-Bing anomaly who underwent ASO at our institution between 1992 and 2022. The primary endpoint was freedom from a composite of death, transplantation, and coronary reintervention. RESULTS: A total of 632 patients (median age, 5.0 days; interquartile range [IQR], 4.0-7.0 days) underwent ASO. Coronary anatomy included the following categories: usual (n = 411; 65%), circumflex (Cx) from sinus 2 (n = 89; 14%), inverted (n = 55; 9%), single sinus (n = 46; 7%), and intramural (n = 31; 5%). Overall operative mortality was 3% (n = 16) and highest in patients with intramural cardiac anatomy (n = 3; 10%), although it dropped to 0% in this group in the most recent decade. The median duration of follow-up was 14.5 years (IQR, 6.0-20.3 years). Twenty-year freedom from the primary endpoint was 95 ± 1% for usual anatomy, 99 ± 1% for Cx from sinus 2, 90 ± 4% for inverted, 91 ± 4% for single sinus, and 80 ± 9% for intramural (P < .001). Intramurals had the highest 20-year incidence of coronary reintervention (11 ± 8%). Cox modeling identified intraoperative coronary revision (hazard ratio [HR], 20.1; 95% confidence interval [CI], 9.4-53.9; P < .001), Taussig-Bing anomaly (HR, 4.9; 95% CI, 2.2-10.9; P < .001), and an intramural coronary artery (HR, 2.9; 95% CI, 1.0-8.2; P = .04) to be risk factors for the composite endpoint. CONCLUSIONS: Rare coronary artery variants-particularly intramural-are associated with increased mortality and coronary reinterventions after ASO. A low threshold for unroofing intramurals is likely associated with declining mortality and improved outcomes. Additional investigations are needed to determine the long-term fate of the coronary arteries after ASO.

The Impact of a Residual Atrial Communication in Patients Undergoing Complete Repair for Tetralogy of Fallot: A Propensity Score Matched Analysis.

OBJECTIVE: Surgeons may leave a residual atrial-level communication during complete repair of Tetralogy of Fallot (TOF) in anticipation of restrictive right ventricle physiology or as routine practice. We investigated the impact of closing the interatrial communication at the time of definitive TOF repair. METHODS: We retrospectively reviewed TOF patients who underwent definitive repair at <12 months of age between June 2000 and January 2023. Propensity score matching identified 82 patients with a patent interatrial communication and 50 with no interatrial communication on postoperative echocardiography (as-treated analysis). The primary endpoint was maximum vasoactive-inotropic score (VIS) as a surrogate for low cardiac output syndrome. RESULTS: A total of 132 patients (median age: 3.5[IQR,1.8-5.8] months) were matched. There was no difference in maximum VIS (patent interatrial communication: 5.0[IQR, 4.8-9.0] vs. no interatrial communication: 6.0[IQR, 5.0-8.0], P=0.78). Additionally, duration of inotrope therapy (3.0[IQR, 2.0-4.0] vs 3.0[IQR, 1.3-4.0] days, P=0.57), peak lactate (2.2[IQR, 1.9-3.0] vs. 2.3[IQR, 1.9-3.2] mmol/L, P=0.58), time to lactate clearance (0.2[IQR, 0.0-0.3] vs. 0.1[IQR, 0.0-0.3] days, P=0.57), chest tube duration (4.0[IQR,3.0-6.0] vs 4.0[IQR, 3.0-5.0] days, P=0.23), and length of intensive care stay (5.0[IQR, 3.0-7.0] vs. 5.0[IQR, 3.0-7.0] days, P=0.71) were similar. Median follow-up was 5.5[IQR, 2.7-9.9] years. Among patients with a residual communication, patency rates were 93.6% and 53.7% at discharge and latest follow-up, respectively, with most having bidirectional shunting across the defect. CONCLUSIONS: Closure of the atrial-level communication during complete TOF repair does not significantly impact the immediate postoperative course or mid-term outcomes. Further investigation is warranted to better understand how patency influences long-term outcomes.

Medium-Term Outcomes of Concomitant Aortic Valve Repair in Patients with Continuous-Flow Left Ventricular Assist Device.

OBJECTIVE: Our objective was to analyze the development of aortic insufficiency in patients who received central aortic valve repair when undergoing continuous-flow left ventricular assist device implantation. METHODS: We conducted a retrospective review of patients who underwent HeartMate II or 3 (Abbott Lab) implantation between 2004 and 2022. Ninety-four patients were excluded from analysis for history of aortic valve procedures, a bicuspid aortic valve, baseline trace aortic insufficiency, or other concomitant aortic valve procedure. Patients who had ≥ mild aortic insufficiency had concomitant aortic valve repair. Clinical characteristics, serial echocardiograms, and outcomes were determined. RESULTS: Of the 656 patients who underwent HeartMate II or 3 implantation, 105 patients (59 HeartMate II and 46 HeartMate 3) met study criteria. Median age was 68 years [60-74 years], 91.4% [n=96] were male, 54.4% [n=56] were white, and 68.6% [n=72] received support as destination therapy. Preoperative aortic insufficiency degree was 54.3% (n=57) mild, 23.8% (n=25) mild-to-moderate, 20.0% (n=21) moderate, 1.0% (n=1) moderate-to-severe, 1.0% (n=1) severe. In hospital mortality was 5.7% [n=6]. Freedom from ≥ moderate aortic insufficiency was 96.4% (95%CI: 92.5%-100%), 93.3% (95%CI: 87.6%-99.2%), and 91.0% (95%CI: 84.1%-98.5%) at 1-year, 2-year, and 3-year post-implantation, respectively. One HeartMate II patient experienced severe aortic insufficiency and was treated with a heart transplant. Three-year survival was 63.4% [95%CI: 52.9%-75.9%]. CONCLUSIONS: Central aortic valve repair may be an effective technique to mitigate aortic insufficiency in HeartMate II and 3. A larger cohort study with longer duration of follow up is warranted to further investigate the clinical impact.

Long-term outcomes of heart transplantation in adults with congenital heart disease: The impact of single-ventricle versus biventricular physiology.

Objective: Congenital heart disease is a risk factor for mortality after orthotopic heart transplantation; however, the impact of preoperative circulation type and primary congenital heart disease diagnosis remains poorly delineated. Methods: We retrospectively reviewed patients with adult congenital heart disease aged 16 years or more who underwent orthotopic heart transplantation at our institution between 2008 and 2022. Patients were categorized as having single-ventricle or biventricular circulation. The primary end point was 5-year post-transplant survival. Results: Sixty-one patients with adult congenital heart disease (single-ventricle: n = 26 [42.6%], biventricular: n = 35 [57.4%]) underwent orthotopic heart transplantation at 33.7 [interquartile range, 19.1-48.7] years. The most common congenital heart disease diagnosis was hypoplastic left heart syndrome (n = 11, 42.3%) in the single-ventricle group and congenitally corrected transposition of the great arteries (n = 7, 20.0%) in the biventricular group. Twenty-four patients previously underwent Fontan palliation. At transplant, patients in the single-ventricle group were younger (18.5 [interquartile range, 17.6-32.3] years vs 45.0 [interquartile range, 33.0-52.2] years, P < .001) and more likely to have biopsy-proven cirrhosis (46.2% vs 14.3%, P = .01) and protein-losing enteropathy (42.3% vs 2.9%, P < .001). Patients in the single-ventricle group also had longer bypass times (223.4 ± 65.3 minutes vs 187.4 ± 59.5 minutes, P = .03) and longer durations of mechanical ventilatory support (3.5 [interquartile range, 2.0-6.0] days vs 1.0 [interquartile range, 1.0-2.0] days, P < .001). Operative mortality was comparable (11.5% vs 8.6%, P = 1). Median follow-up was 6.0 [interquartile range, 2.4-10.0] years. Five-year survival was worse in the single-ventricle group (66.0% ± 10.0% vs 91.3% ± 4.8%, P = .03), as was freedom from major rejection (58.3% ± 10.2% vs 84.0% ± 6.6%, P = .02). In univariable analysis, hypoplastic left heart syndrome and Fontan circulation were risk factors for post-transplant mortality (hypoplastic left heart syndrome: hazard ratio, 5.0, P < .001; Fontan: hazard ratio, 3.5, P = .03). Conclusions: Adult patients with congenital heart disease undergoing heart transplant with single-ventricle physiology experienced a more complicated post-transplant course, with worse long-term survival and freedom from rejection. Multicenter studies are required to guide orthotopic heart transplantation decision-making in this complex cohort.

Preoperative left ventricular diastolic dimension index is associated with outcomes after HeartMate 3 implantation.

OBJECTIVES: We investigated the association between indexed left ventricular diastolic dimension and clinical outcomes after HeartMate 3 implantation. METHODS: We retrospectively reviewed patients implanted with the HeartMate 3 at our centre between November 2014 and September 2021. Left ventricular diastolic dimension was assessed via preoperative transthoracic echocardiography and left ventricular diastolic dimension index was calculated as left ventricular diastolic dimension/body surface area. The primary outcome was a composite of death or readmission due to right heart failure or stroke. The cut-off left ventricular diastolic dimension index value most closely associated with outcomes was determined by receiver-operating characteristic curve and restricted cubic spline analyses. RESULTS: Left ventricular diastolic dimension index measurements were available for 252 of 253 (99.6%) patients. Using a left ventricular diastolic dimension index cut-off value of 33.5 mm/m2, the cohort was divided: left ventricular diastolic dimension index ≤ (n = 131) or > (n = 121) 33.5 mm/m2. While there were no significant differences in age, INTERMACS level and preoperative haemodynamics between groups, patients with smaller left ventricular diastolic dimension index were more likely to have a larger body surface area (2.1 vs 1.9 m2, P < 0.001), ischaemic cardiomyopathy [64 (49%) vs 40 (33%), P = 0.01] and smaller left atrium volume index [40.5 (32.3-54.0) ml/m2 vs 54.0 (43.0-66.8) ml/m2, P < 0.001]. Smaller left ventricular diastolic dimension index patients had significantly worse survival (74% vs 88%, log-rank P = 0.009) and freedom from adverse events (55% vs 73%, log-rank P = 0.005) at 3-year follow-up. Smaller left ventricular diastolic dimension index was independently associated with the composite outcome (Hazard ratio 2.24, P = 0.002). CONCLUSIONS: Smaller preoperative left ventricular diastolic dimension index is associated with worse outcomes in patients undergoing HeartMate 3 implantation.

Use of the Inspiris valve in the native right ventricular outflow tract is associated with early prosthetic regurgitation.

OBJECTIVE: The Inspiris Resilia prosthesis (Edwards Lifesciences) has been increasingly used in the pulmonic position with limited performance data. We sought to investigate its durability as a surgical pulmonary valve replacement (PVR). METHODS: We retrospectively reviewed patients who underwent PVR or conduit replacement with an Inspiris or non-Inspiris valve/conduit from 2018 to 2022. The primary end point was freedom from a composite of at least moderate pulmonary regurgitation, pulmonary stenosis, or valve/conduit reintervention. Secondary end points were individual components of the composite outcome. To account for baseline differences, propensity matching identified 70 patient pairs. RESULTS: A total of 227 patients (median age: 19.3 years [interquartile range, 11.8-34.4]) underwent PVR or conduit replacement (Inspiris: n = 120 [52.9%], non-Inspiris: n = 107 [47.1%]). Median follow-up was 26.6 months [interquartile range, 12.4-41.1]. Among matched patients, 2-year freedom from valve failure was lower in the Inspiris group (53.5 ± 9.3% vs 78.5 ± 5.9%, P = .03), as was freedom from at least moderate pulmonary regurgitation (54.2 ± 9.6% vs 86.4 ± 4.9%, P < .01). There was no difference in 2-year freedom from at least moderate pulmonary stenosis (P = .61) or reintervention (P = .92). Inspiris durability was poorer when implanted in the native right ventricular outflow tract compared with as a conduit, with 18-month freedom from valve failure of 59.0 ± 9.5% versus 85.9 ± 9.5% (P = .03). CONCLUSIONS: Early durability of the Inspiris valve is poor when implanted in the native right ventricular outflow tract; its unique design may be incompatible with the compliant pulmonary root. Modified implantation techniques or alternative prostheses should be considered.

Long-term outcomes of surgery for obstructive hypertrophic cardiomyopathy in a pediatric cohort.

Background: Septal reduction therapy via septal myectomy or a modified Konno procedure is the mainstay of therapy for drug-refractory obstructive hypertrophic cardiomyopathy (HCM), although outcomes data on septal myectomy in pediatric patients are limited. We evaluated long-term outcomes following surgery for obstructive HCM in a pediatric cohort. Methods: We retrospectively reviewed patients age ≤18 years with obstructive HCM who underwent a left and/or right ventricular septal myectomy at our institution between 1992 and 2022. Primary endpoints were transplantation-free survival, freedom from HCM-related death, and cumulative probability of HCM-related reintervention. We further evaluated outcomes in patients with and without Noonan syndrome or other RASopathies. Results: Thirty-seven patients (median age, 7.4 years; interquartile range [IQR], 3.4-12.9 years) underwent transaortic septal myectomy. A combined modified Konno procedure was performed in 5 patients (13.9%). Sixteen patients (43.2%) had a RASopathy. A concomitant right ventricular outflow tract resection was performed in 9 patients (24.3%). There was 1 (2.7%) in-hospital death and 4 late deaths at a median follow-up of 10.5 years (IQR, 0.1-29.3). Twenty-year transplant-free survival and freedom from HCM-related death were 80.6% (95% confidence interval [CI], 64.2%-100%) and 87.1% (95% CI, 71.8%-100%), respectively. The 20-year cumulative probability of HCM-related reintervention was 34.2% (95% CI, 12.8%-57.1%). Seven patients required a septal reintervention. There was no difference in any primary endpoints between patients with and without a RASopathy. Conclusions: Surgery for obstructive HCM, including septal myectomy with and without a modified Konno procedure, may be performed with low morbidity and good long-term outcomes in pediatric patients. Recurrent outflow tract obstruction is not uncommon.