Immediate and long-term echocardiographic evaluation of cardiac structures in children with obstructive hypertrophic cardiomyopathy after transaortic extended septal

Hypertrophic cardiomyopathy (HCM) is a genetically determined myocardial disease with a characteristic relentless progression. The manifestation of this pathology in childhood is associated with a high risk of sudden cardiac death and the development of heart failure (HF) symptoms. Transaortic extended septal myectomy (TAESM) is currently recognized as the “gold standard” for the treatment of this pathology. However, data on the outcomes of such interventions in children with obstructive HCM are very limited, which does not allow for a complete assessment of its effectiveness.

Aim: To evaluate structural and systolic-diastolic changes in the characteristics of the left heart chambers in children with obstructive HCM after TAESM in the early and long-term follow-up periods, based on echocardiography (EchoCG) data.

Material and Methods. A retrospective analysis was conducted of data from children with HCM after successful TAESM in the cardiac surgery department No. 2 of the Research Institute of Cardiology, Tomsk National Research Medical Center, from 2010 to 2024. Immediate and long-term EchoCG indicators of heart structures were evaluated.

Results. The average age of patients was 5.51 ± 2.2 years. 46 (92%) patients had symptoms of HF. Biventricular myectomy was performed in 16 (32%) cases. In the preoperative period, there was a significant gradient in the left ventricular outflow tract (LVOT) of 75.0 [57.0; 127.0] mm Hg, mitral regurgitation of varying degrees, and systolic anterior motion of the mitral valve (SAM syndrome) in all patients. After successful TAESM, a significant decrease in dynamic LVOT obstruction, structural and anatomical characteristics, and systolic and diastolic function of the left ventricle (LV) was recorded. Follow-up in the long-term period showed a decrease in the median z-score of the left ventricular posterior wall thickness from 2.6 [0.9; 5.2] to 2.0 [1.1; 3.12], the left ventricular mass index from 167.6 [55.1; 370.37] to 148.66 [34.25; 3259.1] g/m², the TEI index from 0.95 [0.3; 1.64] to 0.65 [0.34; 1.15], p = 0.04; 0.012 and 0.024, respectively. The z-score of the left ventricular end-diastolic volume (EDV) also changed statistically significantly from –3.8 [–2.42; 5.99] to –0.07 [–1.99; 5.6], p = 0.034. The remaining indicators remained within the reference values.

Conclusion: TAESM is an effective procedure for reducing the gradient in the LVOT, eliminating SAM syndrome, and reducing mitral regurgitation in children with obstructive HCM, both in the early and long-term follow-up periods. These results are confirmed by EchoCG data, the “gold standard” of diagnosis. In addition, there is a significant decrease in left ventricular myocardial mass, the z-score of the LV posterior wall thickness, and the left atrial volume index, which may indirectly indicate reverse remodeling of the chambers after successful TAESM in children. A statistically significant decrease in the z-score of hypertrophic and restrictive cardiomyopathy after TRESM indicates the possibility of using these indicators to quantitatively assess the effectiveness of surgical intervention.

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