Severe congenital mitral stenosis in infants

Abstract

Background: Despite current medical and surgical therapy, infants with symptomatic congenital mitral stenosis (CMS) continue to have high rates of morbidity and mortality. Catheter balloon dilation has been successful in relieving symptoms in a few older children with CMS but has not been evaluated in infants. Methods and Results: We reviewed the records of 85 infants with CMS to assess severity of CMS, associated cardiac lesions, echocardiagraphic morphological appearance of the mitral valve, treatment, and outcome. There were five valve morphologies identified: 'typical' hypoplastic mitral valve with symmetric papillary muscles (SYMM, 52%), supravalvar mitral ring (SVMR, 20%), double-orifice mitral valve (DOMV, 11%), hypoplastic mitral valve with asymmetric papillary muscles (ASYMM, 8%), and parachute mitral valve (PARA, 8%). Of the 85 infants, 31 (36%) were severely symptomatic, requiring intervention within the first 2 years. Balloon dilation was performed in 18 infants (age, 8.7±5.7 months; weight, 5.9±1.9 kg) and valve surgery in 13 (age, 10.9±5.9 months; weight, 6.7 ± 2.1 kg). Balloon dilation decreased the peak transmitral gradient (LAa-LVED) >30% in 15 of 18 initial attempts, from 20.3±8.2 to 10.9±4.9 mm Hg (P