August 3, 2005
Bedrood B.S. and Asher Kimchi M.D.
Boston, MA- Congenital
mitral stenosis (MS) is a rare condition that is often
associated with left heart obstructions. Treatments for MS
include balloon mitral valvuloplasty (BMVP), surgical mitral
valvuloplasty (SMVP) and mitral valve replacement (MVR). A study
by Dr. Doff McElhinney et al from Harvard Medical School
compared the outcomes of patients with severe congenital MS who
underwent BMVP or surgical intervention. The study, which was
published in the August 2, 2005 issue of Circulation
found BMVP effectively relieves left ventricular inflow
obstruction in the majority of cases and is the preferred mode
of treatment in most infants with severe congenital MS.
Between 1985 and 2003, 108
patients with severe congenital MS underwent BMVP or
surgical intervention at a median age of 18 months
(range 1 month to 17.9 years). Anatomic subtypes of
MS were "typical" congenital MS in 78 patients,
supravalvar mitral ring in 46, parachute mitral valve in 28,
and double-orifice mitral valve in 11, with multiple types
50% of patients. Additional left heart anomalies were present
in 82 patients (76%). The first MS intervention was BMVP
in 64 patients, SMVP in 33, and MVR in 11. BMVP
decreased peak and mean MS gradients by a median of
33% and 38%, respectively (P<0.001), but was
complicated by significant mitral regurgitation in
28%. Cross-sectional follow-up was obtained at 4.8±4.2
years. Overall, Kaplan-Meier survival was 92% at 1 month,
84% at 1 year, and 77% at 5 years, with 69% 5-year
survival during the first decade of our experience
and 87% since (P=0.09). Initial MVR and
younger age were associated with worse survival. Survival
free from failure of biventricular repair or mitral valve
reintervention was 55% at 1 year among patients who
underwent BMVP and 69% among patients who underwent
supravalvar mitral ring resection initially. Among
patients who underwent BMVP, survival free from
failure of biventricular repair or MVR was 79% at 1 month
and 55% at 5 years, with worse outcome in younger patients
and those who developed significant post-dilation
The goal of BMVP for
children with congenital MS is to reduce left ventricular inflow
obstruction and left atrial pressure, thereby relieving symptoms
and delaying MVR until the patient is older.
Overall, the procedural
mortality of BMVP is uncommon and is an effective means of
relieving left ventricular obstruction in congenital MS.
However, surgical resection is preferable in patients with MS
due to a supravalvar mitral ring.
Co-authors: Doff B.
McElhinney, MD; Megan C. Sherwood, MBBS, FRACP; John F. Keane,
MD; Pedro J. del Nido, MD; Christopher S.D. Almond, MD, MPH;
James E. Lock, MD .