CARDIOVASCULAR JOURNAL OF AFRICA • Vol 24, No 9/10, October/November 2013
e6
AFRICA
is uncertain. McKusick reported in his review of more than
100 patients with OI that only two patients were found to
have severe aortic valve regurgitation.
1
The severity of the
skeletal manifestations does not correlate with the extent of
cardiovascular involvement, which appears to be limited mainly
to aortic and mitral valve regurgitation.
1
The clinical presentation, diagnosis and indications for
surgical treatment are similar to those for acquired cardiac
diseases. Since 1965, when Criscitiello
et al
. first attempted
aortic valve repair in a patient with OI, only approximately 45
cases have been reported in the English-language literature, and
its review highlights the importance of surgical considerations.
1
Surgical considerations are the friability and weakness
of the tissues due to underlying connective tissue disorder,
specifically in terms of suture lines and the secure implantation
of the prosthetic valve. Dehiscence of the prosthetic valve
or paravalvular leak has been reported and these potential
complications must be kept in mind during the monitoring of
the patient, not only postoperatively but also in the long-term
follow-up period.
1
In terms of assessment of the coronary arteries, it is better
to avoid coronary angiography because of the friability of the
vessels, and rather perform a CT angiogram or MRI. Eskola
et
al
. reported in 2002 on right coronary artery dissection during
the pre-operative assessment for cardiac catheterisation of an
18-year-old male patient suffering from aortic valve regurgitation
and OI, leading to emergency coronary artery bypass grafting
surgery plus aortic valve replacement for the primary disease.
3
A further surgical consideration is the high risk of bleeding
complications despite normal pre-operative coagulation status.
These complications may be related to tissue friability as well
as capillary fragility and platelet dysfunction, and may be in the
form of epistaxis, melena, haematomas and surgical bleeding.
1
As a result of the high risk of surgical bleeding, haemostatic
glues, antifibrinolytic agents and blood products along with
recombinant factor VIIa should be available to OI patients
undergoing cardiac surgery.
This risk of haemorrhagic complications is significantly
increased if lifelong anticoagulation therapy is considered
necessary following mechanical valve replacement. For this
reason, it is essential to consider very carefully the type of
operation and valve that will be used.
The mini-sternotomy approach involves limited sternal split
and manages the integrity of the lower rib cage. In OI patients,
this approach not only limits rib fractures and postoperative
pain but also improves mobilisation and recovery. Furthermore,
if deemed necessary, the conversion to a median sternotomy
approach is relatively easy to perform.
This is, to our knowledge, the first reported case with a
mini-sternotomy approach, using the inverted T incision to
the lower part of sternum in a patient with OI. There was only
one previous case report by Izzat
et al
., describing aortic valve
replacement through a mini-sternotomy approach where an
upper J incision was utilised.
4
Kypson and Glower reported in
2002 on port-access approach for combined aortic and mitral
valve replacement.
5
During recent years, transcatheter aortic valve implantation
(TAVI) for high-risk patients with symptomatic aortic valve
disease has become an attractive method of surgical intervention
for patients deemed unfit for conventional surgery.
6
Furthermore,
TAVI procedures provide significant improvement in terms of
clinical outcome and subjective health-related quality of life in
very elderly patients with symptomatic aortic valve stenosis.
7
In
intermediate surgical-risk elderly patients with aortic stenosis,
TAVI and AVR were associated with similar mortality rates
during follow up but with a different spectrum of peri-procedural
complications.
8
In our case, the patient was unsuitable for TAVI due to
her young age, severe aortic valve regurgitation, combined
with large aortic annulus. Moreover, due to the friability and
weakness of the tissues because of OI syndrome and a higher risk
of paravalvular leak, even with conventional surgery, we felt that
the choice of mini-sternotomy approach was superior to TAVI.
There are a few types of mini-sternotomy approaches that
have been suggested as alternatives to conventional median
sternotomy in cardiac surgery. These types include mainly the
upper reversed-T and the upper J-shape mini-sternotomies. Both
types give good exposure of the ascending aorta and root and
allow safe arterial and venous cannulation. As a result, cardiac
operations can be safely performed.
9
Perrotta and Lentini, in their recent meta-analysis of the
mini-sternomy approach for surgery of the aortic root and
ascending aorta, reported extensively on the advantages and
disadvantages of the method.
9
The main advantages include
a reduction in postoperative pain as well as blood loss and
transfusion requirements. Furthermore, the smaller incision
may be associated with a reduced risk of postoperative sternal
dehiscence, infections and mediastinitis.
The minimal exposure of the heart, which consequently
leads to a reduced incidence of adhesions, may also prove
advantageous in cases where a redo operation is required.
Additional advantages include improvement in postoperative
respiratory function, early extubation of the patient and shorter
hospital stay. Finally, better cosmetic outcomes associated with a
mini-sternotomy incision may be a preferable option, especially
in younger patients.
9
On the other hand, potential disadvantages of this approach
are the difficulties in dealing with major intra-operative
complications and the need for an urgent conversion to a full
sternotomy, the requirement of a high level of dexterity by
the surgeon, or side effects such as sacrifice of the internal
mammary arteries and intercostal neurovascular bundles, and the
occasional use of specific sternal wiring.
9
Conclusion
We believe that the mini-sternotomy approach for aortic valve
operations in patients with OI is advantageous compared to
median sternotomy. As a result, the mini-sternotomy approach
should be in the armament of surgical treatment along with
other methods such as port-access, transfemoral or transapical
approaches, and each patient should be assessed on an individual
basis.
References
1.
Wong RS, Follis FM, Shively BK, Wernly JA. Osteogenesis imperfecta
and cardiovascular disease.
Ann Thorac Surg
1995;
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: 1439–1443.
2.
Olaus Jacob Ekman. Dissertatio medica descriptionem et casus aliquot
osteomalaciæ sistens. Upsaliæ, J. Edman, 1788.
3.
Eskola MJ, Niemelä KO, Kuusinen PR, Tarkka MR. Coronary artery
dissection, combined aortic valve replacement and coronary bypass
