小児の閉塞性肥厚性心筋症に対する経尖端開心術式心室中隔縮小術の利点

Surgical septal myectomy is the gold-standard therapeutic strategy for majority of patients with obstructive hypertrophic cardiomyopathy (oHCM). However, limited data is currently available in pediatric population, partially due to increased technical challenges in this subgroup of patients.

From December 2018 through December 2024, 63 patients with oHCM aged 5 to 18 years underwent conventional septal myectomy (CSM, n=28) or transapical beating-heart septal myectomy (TA-BSM, n=35). All patients had clinical and multimodality imaging evaluations before operation and at follow-up.

Two groups of patients had largely similar baseline clinical characteristics. The median age of patients was 14 (IQR: 11-16) years, and 18 of them (28.6%) were female. The median preoperative left ventricular outflow tract (LVOT) gradient was 58 (IQR: 32-85) mmHg. Around 55.6% of the patients had more than moderate mitral regurgitation (MR, CSM n=12, TA-BSM n=23). Both approaches demonstrated equivalent efficacy for eliminating LVOT obstruction, with a median postoperative LVOT gradient of 8 and 10 mmHg (p=0.852) in the CSM and TA-BSM groups, respectively. The degree of MR decreased to ≤ mild upon follow-up in 9 (75% of 12) in the CSM group, and 20 (87% of 23) in the TA-BSM group (p=0.223). Compared to those in the CSM group, patients in the TA-BSM group experienced shorter durations of surgery (1.0 vs 5.5 hours, p<0.001), mechanical ventilation (3.6 vs 20.5 hours, p<0.001), and ICU stay (23.2 vs 56.5 hours, p=0.001), with less 24-hour drain outputs (100 vs 250 mL, p<0.001). The median weight of resected myocardium was much greater following TA-BSM than that in the CSM group (p=0.013). Two post-CSM patients received permanent pacemaker implantation due to atrioventricular block. One patient required intraoperative thoracoscopic mitral repair due to mitral chordae tendineae fracture during TA-BSM and was discharged from hospital in normal condition. No 30-day mortality or septal perforation occurred in either group of patients.

TA-BSM is a simple, safe, and effective septal reduction treatment for pediatrics with oHCM. Compared with CSM, reduced surgical trauma in the TA-BSM group led to quicker postoperative rehabilitation and recovery. More importantly, with real-time transesophageal echocardiographic guidance and evaluation, the TA-BSM approach can help to overcome the technical difficulties posed by a narrowed transaortic exposure in CSM in pediatric patients.