Mitral valve replacement and trans-mitral myectomy for a child with Noonan syndrome accompanied by hypertrophic obstructive cardiomyopathy

  • Takashi SasakiEmail author
  • Toshihide Asou
  • Makoto Shirakawa
  • Ken-ichiro Takahashi
  • Shinobu Kunugi
  • Takashi Nitta
Case Report


A 4-year-old boy with Noonan syndrome accompanied by hypertrophic obstructive cardiomyopathy presented with refractory heart failure owing to severe left ventricular outflow obstruction and mitral regurgitation. He underwent mitral valve replacement and trans-mitral myectomy. The pathology of the resected myocardium was consistent with hypertrophic cardiomyopathy, and the mitral valve leaflets were severely degenerated. Compared with a control patient who is a non-syndromic 4-year-old boy with hypertrophic obstructive cardiomyopathy, mitral pathology was much more severe in Noonan syndrome. Regarding trans-mitral myectomy, residual pressure gradient at the mid-ventricular level made us think about more aggressive muscle resection with various approaches.


Noonan syndrome Hypertrophic obstructive cardiomyopathy Pediatric Myectomy Mitral valve replacement Pathology 



We would like to thank Dr. Shunichi Ogawa, Dr. Ryuji Fukazawa, and Dr. Makoto Watanabe for pre and postoperative management and follow-up, Dr. Yuki Izumi for review of the echocardiography findings. We would like to thank Editage ( for English language editing.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Informed consent

Informed consent was obtained from all individual participants included in the study.


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Copyright information

© The Japanese Association for Thoracic Surgery 2019

Authors and Affiliations

  1. 1.Department of Cardiovascular SurgeryNippon Medical School HospitalTokyoJapan
  2. 2.Department of Cardiovascular SurgeryKanagawa Children’s HospitalYokohamaJapan
  3. 3.Department of PathologyNippon Medical School HospitalTokyoJapan

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