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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.

Transapical ventriculotomy is an important technique in the surgical management of hypertrophic cardiomyopathy (HCM). It is our preferred method for addressing complex long-segment subaortic obstruction and isolated midventricular HCM, as it provides better exposure of the midcavity than alternate methods such as the transaortic or transmitral approach. The procedure can also be used to improve symptoms of diastolic heart failure caused by reduced left ventricular end-diastolic volume as may occur in patients with apical HCM. In this article, we describe our surgical method for transapical myectomy to relieve midventricular obstruction or enlarge the left ventricular cavity to improve diastolic dysfunction in cases of extensive apical hypertrophy. [ABSTRACT FROM AUTHOR]

Background Electrocardiogram-gated cardiac computed tomography (CT) imaging enables a more accurate understanding of the patient's cardiac anatomy. Preoperative planning for transaortic septal myectomy (TASM), based on cardiac CT, may be useful in patients with subaortic septal hypertrophy associated with severe aortic stenosis (AS). Case summary Two elderly patients (age >80 years) with subaortic septal hypertrophy associated with AS underwent surgical aortic valve replacement (SAVR) and concomitant TASM after preoperative planning based on cardiac CT. Both patients showed subaortic septal hypertrophy with blood flow acceleration, left ventricular (LV) hypercontractility, and a short distance from the coaptation point of the mitral valve to the septum, resulting in possible dynamic LV outflow tract (LVOT) obstruction after resolution of AS. Optimal mid-diastolic images, selected from the 70–80% phase, were used for preoperative TASM planning. Planned sizes for myectomy based on multi-planar reconstruction were 10 × 26 × 9 mm (width × length × depth) and 10 × 25 × 9 mm for patient 1 and 2, respectively, while resected tissue size was 10 × 24 × 8 mm and 9 × 24 × 8 mm in patient 1 and 2, respectively. After TASM procedure, SAVR was performed with bioprosthetic valve. Postoperative course of both patients was uneventful with no evidence of complete atrioventricular block, septal perforation, or blood flow acceleration at the LVOT. Discussion Preoperative planning based on cardiac CT images is safe and useful for guiding adequate myectomy and preventing associated complications in patients with subaortic septal hypertrophy associated with AS. [ABSTRACT FROM AUTHOR]

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., Competing Interests: The authors reported no conflicts of interest. The Journal policy requires editors and reviewers to disclose conflicts of interest and to decline handling or reviewing manuscripts for which they may have a conflict of interest. The editors and reviewers of this article have no conflicts of interest.

Transaortic extended septal myectomy is the best treatment option for patients with obstructive hypertrophic cardiomyopathy whose symptoms are refractory to medical management. In this article, we describe our operative technique of transaortic septal myectomy, which relieves subaortic left ventricular outflow tract obstruction and systolic anterior motion of the mitral valve associated with hypertrophic cardiomyopathy. In experienced centers, surgical outcomes are excellent (operative mortality <1%) and long-term symptomatic relief is achieved in the majority of patients. [ABSTRACT FROM AUTHOR]

Background: Resolution of left ventricular outflow tract (LVOT) obstruction predicts symptom relief postmyectomy. Intraoperative measurement of LVOT gradients thus is essential for surgical guidance. We hypothesized that (1) hypertrophic cardiomyopathy patients have lower LVOT gradients when measured intraoperatively with transesophageal echocardiography (TEE) compared with preoperative measurements with transthoracic echocardiography (TTE) and that (2) intraoperative provocative testing can help evaluate the adequacy of surgical resection., Methods: We compared resting LVOT gradients on preoperative TTE to intraoperative TEE. We also compared intraoperative resting and provoked gradients pre- and postresection. Either isoproterenol 10 μg/kg/min or dobutamine 20 μg/kg/min was used. Patients with provoked LVOT gradients >30 mm Hg were considered for further resection based on LVOT/mitral valve morphology and clinical comorbidities., Results: Of 315 patients identified, 293 patients were included in the analysis. There was a statistically significant difference between preoperative TTE and intraoperative TEE resting LVOT gradients (60.9 ± 39.4 mm Hg vs 42.0 ± 30.5 mm Hg, P < .0001). Out of 197 patients who had significant resting obstruction preoperatively, 82 (41.6%) demonstrated mild or no dynamic obstruction under general anesthesia. Provocative testing with both isoproterenol and dobutamine increased peak gradients (116.8 ± 33 mm Hg isoproterenol vs 107.5 ± 33 mm Hg dobutamine, P = .03). Post-cardiopulmonary bypass, seven patients (2.3%) had LVOT gradients > 30 mm Hg at rest, while 63 patients (21.5%) had residual gradients >30 mm Hg only with provocation. Elevated gradients, persistent systolic anterior motion of the mitral valve with near contact, and/or significant mitral regurgitation with provocative testing resulted in return to cardiopulmonary bypass in 41 patients (14%)., Conclusions: Resting intraoperative TEE LVOT gradients are significantly lower than preoperative TTE gradients, with systolic anterior motion of the MV and outflow obstruction often not visualized after inducing general anesthesia. Intraoperative pharmacologic provocation can identify patients who may benefit from further surgical intervention, facilitating procedural success., (Copyright © 2019 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.)