Transcatheter Ventricular Septal Defect Closures
Most VSDs that are electively closed in the catheterization laboratory
are mid-muscular or apical VSDs that are either difficult to close in the operating
room or would require a left ventriculotomy. Left ventriculotomies are associated
with a high incidence of left ventricular dysfunction and have been relegated to
a position as the least desirable surgical option.
The transcatheter approach requires a blade atrial septostomy
and a retrograde catheter placed through the femoral artery and advanced to the left
atrium. This catheter is pulled across the atrial septum into the right atrium and
is used to guide a superior vena cava catheter (placed through the internal jugular
vein) across the ASD into the left atrium, across the mitral valve, and into the
LV. The VSD defect is approached from the left ventricular side. The large sheath
containing the double-umbrella clamshell device prevents closure of the mitral
valve, resulting in acute mitral regurgitation or, in cases in which the VSD is large
or the mitral annulus small, acute severe mitral stenosis. In this latter case,
systemic output is decreased and a period of severe hypotension is unavoidable.
Judicious use of vasoconstrictors to maintain coronary perfusion may be required
during the catheter placement, followed by volume and inotropic resuscitation after
the VSD device is deployed. This highly specialized application of the clamshell
device is confined to only a few pediatric centers in the United States.
