Sustained improvement after combined anterior mitral valve leaflet retention plasty and septal myectomy in preventing systolic anterior motion in hypertrophic obstructive cardiomyopathy in children.

OBJECTIVE: Anatomic alterations of the mitral valve such as increased mitral leaflet area, length and laxity, and anterior displacement of the papillary muscles in hypertrophic obstructive cardiomyopathy predispose patients to residual systolic anterior motion and persistence of outflow obstruction and mitral regurgitation after septal myectomy. We investigate the long-term results of combined anterior mitral leaflet retention plasty and septal myectomy in children with hypertrophic obstructive cardiomyopathy.

METHODS AND RESULTS: Anterior mitral leaflet retention plasty and subaortic septal myectomy were performed in 12 children (mean age 10.8+/-1.7 years) with hypertrophic obstructive cardiomyopathy. Mean preoperative left ventricular outflow tract pressure gradient was 49+/-11 mmHg. After careful assessment of the mobility of the anterior leaflet and subvalvular apparatus, segments of the anterior leaflet nearest the trigones were sutured to the corresponding posterior annulus with polypropylene reinforced with untreated autologous pericardial pledgets. Intraoperative valve orifice measurement based on age-related valve diameter ensures that no mitral stenosis is produced. Mean intraoperative pre- and post-septal myectomy pressure gradient was 60+/-25 mmHg and 5+/-6 mmHg, respectively. Post-myectomy mitral insufficiency was reduced to a regurgitant fraction of 0-10%. Mean follow-up is 11.85+/-1.22 years. Mean left ventricular outflow tract pressure gradient was 6.2+/-3.95 mmHg. No mortality, no repeat myectomy or repeat mitral valve repair or replacement, no mitral stenosis and no systolic anterior motion occurred.

CONCLUSIONS: Long-term follow-up shows sustained absence of systolic anterior motion, attenuation of mitral regurgitation, sustained improvement in functional status, and reduction of outflow tract obstruction.