Key Points :
- Interventional therapies directed at fenestration closure in the
Fontan patient must rely on good hemodynamic data
- The Large Optimus-CVSTM stent is an additional
armamentarium for fenestration closure however, longer term follow up
is needed
- Multi institutional studies defining the long-term benefits of
fenestration closure and outlining fenestration management guidelines
may help improve the long-term morbidity and mortality in this group
of patients.
Fontan and Baudet (1) in 1971 first reported the repair of tricuspid
atresia with a surgical procedure now known as “Fontan repair”. The
Fontan repair has undergone multiple modifications (2-8) to optimize the
physiologic and anatomic factors that play a vital role in the Fontan
circulation. In 1988 Laks et al (7) described the creation of an
adjustable fenestration which in the post-operative period allowed
controlled right to left shunting allowing for improved cardiac output
and decreasing the incidence of post-operative pleural effusions. The
benefit of the fenestration comes at the cost of a lower systemic
arterial saturation and the increased risk of stroke. Closure of the
fenestration spontaneously or intentionally improves the arterial
saturation and may reduce the risk of thromboembolic events (9).
Haddad et al present a case series of three patients with total
cavo-pulmonary connection with an extra-cardiac interposition Gore-Tex
graft (W.L. Gore & Associates, Inc., Flagstaff, AZ, USA) of 16 or 18mm
with a 5-mm punch-hole-type fenestration. After hemodynamic evaluation
the patients underwent fenestration closure with a 43mm/Large
Optimus-CVSTM stent crimped over
a Altosa-XLTMPTA balloon catheter (AndraTec GmbH, Koblenz, Germany) and implanted
through a 10 Fr delivery sheath. The stent was placed across the
fenestration in the extra cardiac Gor-tex graft. At follow up
immediately and at one month there was no residual shunt across the
fenestration. The Optimus-CVSTM is a
balloon-expandable stent with a HD-Cobalt-Chromium-MP35N alloy frame
that is flexible because of the hybrid cell design and has excellent
radial strength. The PTFE-cover on the stent has a unique end-free
sealing design which minimizes the risk of overhanging. The
Altosa-XLTM PTA balloon catheter is a high pressure
low profile balloon catheter which may allow for a smaller sheath size
to deliver the stent making it particularly attractive in children.
There is currently no single ideal device for fenestration closure and
to some extent the selection of the device is dictated by the size and
location of the fenestration and operator preference. Several devices
have been used in fenestration closure including occluder devices and
covered stents (10-12). The occluder devices and the stents have their
merits and drawbacks. Covered stents are effective in closing
fenestrations with good mid-term results (11). The immediate results for
fenestration closure with the Large Optimus-CVSTMstent is promising. Long term follow-up in a larger cohort of patients
is needed to better assess the efficacy and safety of this stent in
closing Fontan fenestrations. Customized covered biodegradable stents
may prove a good alternative to the traditional stents.
The overwhelming unknown factor remains the selection of patients who
would benefit long term from fenestration closure. Hijazi et al (13) in
an elegant study demonstrated that immediately following balloon
occlusion of the fenestration there was an immediate increase in aortic
saturation with decreased cardiac output. The increase in aortic
saturation did not fully compensate for the decrease in cardiac output
resulting in a decrease in systemic oxygen delivery and an increase in
oxygen extraction in the vast majority of patients. In addition, short
term follow-up studies following fenestration closure (14-15)
demonstrate an increase in the arterial oxygen saturation but not
greater event free survival. Multi institutional studies defining the
long-term benefits of fenestration closure and outlining fenestration
management guidelines may help improve the long-term morbidity and
mortality in this group of patients.