Left ventricular posterior wall hypertrophy leads to poor prognosis of hypertrophic obstructive cardiomyopathy in children - a cohort study

Objective: The modified Morrow operation for hypertrophic obstructive cardiomyopathy (HOCM) in children has a favorable outcome, but some children still have a poor prognosis after the procedure. In this study, we aimed to investigate the application of cardiac computed tomography (CCT) to construct a three-dimensional(3D) model of the left ventricle (LV) and analyze the association between hypertrophy in different parts of the LV and poor prognosis. Methods: We retrospectively analyzed 57 children with HOCM from April 2015 to October 2022, among whom 16 underwent preoperative CCT examination. All children underwent the modified Morrow surgery in our center. We defined heart failure (HF), malignant ventricular arrhythmia, and recurrent left ventricular outflow tract obstruction (LVOTO) as adverse events. We performed a retrospective Cox analysis and conducted genetic testing. A 3D model of the LV was built through the standard 17-segment method and analyzing the high-risk factors. Results: 17 (29.8%) had adverse events during follow-up. Multivariate Cox analysis revealed that genetic mutation ( HR: 5.634, 95%CI: 1.663-19.086, P =0.005), Noonan syndrome ( HR: 3.770, 95%CI: 1.245-11.419, P =0.019), preoperational systolic anterior motion (SAM)( HR: 4.596, 95%CI: 1.532-13.792, P =0.007)and mid-ventricular obstruction ( HR: 4.763, 95%CI: 1.538-14.754, P =0.007) were high-risk factors, suggesting that the degree of hypertrophy in the left ventricle is associated with poor prognosis. By analyzing the CCT with 3D model, children with poor prognosis have more hypertrophy in basal-inferior ( P =0.014), mid-inferoseptal( P =0.044), mid-inferior( P =0.017). It suggests that a more hypertrophied posterior left ventricular wall portends a worse prognosis. Conclusion: Even after modified Morrow surgery, the prognostic impact of genetic mutation remains significant. Moreover, the degree of hypertrophy of the posterior wall in the LV was also related to the postoperative prognosis through CCT combined with 3D technology. It provides surgeons guiding to evaluate the overall prognosis and the treatment plan before surgery.