16-month old baby with CAVC and mitral valve replacement needs urgent help!

[maytime]

My friend's baby girl, born on June 6, 2009, was diagnosed CAVC (Complete Atrioventricular Canal defect) when she was 35-day old in China.  She accepted two main surgeries at the age of 3 and 6 moths respectively.  But it didn't solve her problems and her life is in danger now.  The following is her medical record:

1. Accepted CAVC radical surgery on 2009-9-21.  After the surgery the ultrasound showed that the atrial septal was repaired well without shunt.  Slight mitral stenosis, mild mitral valve and tricuspid regurgitation.
2. 2009-12-20 she had left ventricular failure and was confirmed severe mitral stenosis.  Mitral valve replacement was done on 2009-12-27.  But since the doctors cannot find the appropriate size of the artificial mitral valve, size 17 aortic valve was used . The medication after discharge: warfarin, spironolactone, capoten.
3. The follow-up ultrasound on 2010-7-4 showed severe left ventricular outflow stenosis.
4. The follow-up ultrasound on 2010-10-11 showed a narrow left ventricular outflow(severe), and left ventricular hypertrophy.

The patient baby presents clear consciousness, normal diet and activities.  Height 75cm, weight 8.5kg. Oral drugs: warfarin(1.5mg), spironolactone, Capoten, metoprolol.  Latest INR is 2.39.

The conclusions made by the local pediatricians and surgeons are:
1. LOVT is related to the replaced mitral valve extrusion.
2. Pulse pressure 84mmHg, may causes sudden death;
3. Since the patient is too young and her weight gain is not obvious, the valve ring size is estimated not to change since the MV replacement.  No smaller valve available even if accepting surgery.  Close observation is suggested.

Question:
1. Are there any artificial mitral valves smaller than size 17 available in US or Canada or Hongkong?
2. Does she need immediate surgery?  What is the consequence if the 3rd surgery is postponed?
3. Can any medication or stent solve or alleviate her current severe narrow ventricular outflow problems?

[Marie M Gleason, M.D.]

Unfortunately it sounds like this child has a very serious problem that can occur in a small number of patients with atrioventricular canal defects.  Unfortunately once a mitral valve replacement is placed and causes a secondary left ventricular outflow tract obstruction, there are no good options.  Complex heart surgery to enlarge the left ventricular outflow tract called a Konno operation may be indicated.  This is a high risk surgery given all the childs issues.  It sounds like the amount of blockage is severe and merits some discussion as to the what might help, but there are no guarantees at all that this can be fixed adequately.

[Marie M Gleason, M.D.]

Replacing the valve may or may not work.  It is hard to say because the outflow tract may just be intrinsically small and a few millimters difference in valve size won't make a difference in the amount of blockage.  We are not in the business of recommending referral hospitals on this site, but most major academic medical centers in the USA and Europe do Konno operations.  Good luck.

[maytime]

Thanks a lot Dr. Gleason.  Now I have a question.  Since the secondary left ventricular obstruction is caused by the extrusion of the improper size of aortic valve, would it help to do another mitral valve replacement with the smaller size? A doctor told me that there is 16mm mitral valve available in US.

And if Konno operation is the only option for this baby, do you know which clinic is good at this operation?

Thanks again!