The prevalence of
bicuspid aortic valve (BAV)
is
1
-
2% and
is
thereby the most
common cardiac malformation. BAV is
highly
associated with
valvular
dysfunction
and aortic co
nditions
such as ascending aortic aneurysm and aortic dissection.
Of BAV
individuals,
25
-
50%
will
develop
indication
s
for
surgical intervention
.
The underlying
molecular mechanisms of BAV formation and the
reason for
the high prevalence of
ascending aortic aneurysm in these patients are unknown.
The overall aim o
f this thesis was to characteris
e morphological, molecular and clinical
aspects of BAV
disease in adult patients undergoing cardiac surgery
due to aortic valve
and/or ascending aortic pathology
. In
the study population of this thesis
more than
50%
of
the
patients ha
d
a BAV.
BAV patients were approxim
ately 10 years younger than
patients
with tricuspid aortic valves (TAV)
at the time of surgery
.
P
atients
that had
additional coronary artery disease
were
older than patients
that did not,
regardless of
whether they had a
BAV or
a
TAV.
Ascending aortic aneurysm
was
substantially more
common in
BAV
patients
than
in
TAV
patients while
aortic
ectasia
was
equally
common regardless of valve morphology.
In patients w
ith ascending aortic dilatation
,
aortic valve stenosis
was
almost exclusively
associated with BAV
whereas
aortic valve
regurgitation
was
associated with
either BAV or TAV.
Study I
assessed the morphology of the aortic root and ascending aorta in relation to
valve morphology and BAV phenotype
(n = 300).
BAV patients ha
d
larger dimensions
of the left ventricular outflow tract and annulus than TAV patients regardless of aortic
morphology. The relative distribution of aortic aneurysm or ectasia
was not
related to
BAV phenotype.
Study II
investigated a possible association
between severity of valve pathology and
morphology of the aortic root and ascending aorta
(n = 500).
The combination of aortic
valve stenosis and ascending aortic aneurysm
was
common in BAV patients but
was
virtually non
-
existent in TAV patients. Increasin
g severity of valve pathology
was
associated with smaller aortic dimensions. The distribution of valve pathology d
id
not
differ with the various BAV
phenotypes.
Study III
evaluated a possible correlation between ascending aortic dilatation and
dilatation o
f the distal
aorta
(n = 97).
BAV patients with ascending aortic aneurysm
s
ha
d
smaller dimensions of the distal aorta than the corresponding group of TAV
patients. Concomitant dilatation of the descending aorta
was
predominantly found in
TAV patients.
Study
IV
analysed
the occurrence of matrix degrading proteases in the media of the
aortic wall
(n = 109).
Expression of m
atrix metalloproteinase 14 and 19
was
associated
with ascending aortic
dilatation
in TAV
patients
,
but not BAV
patients.
Study V
evaluated
patient
characteristics in relation to valve morphology, valve
pathology, aortic morphology and coronary artery disease
(n = 702)
.
BAV patients with
aortic valve pathology and/or ascending aortic dilatation rarely ha
d
concomitant
coronary artery disease. A
scending aortic dilatation and coronary artery disease seldom
co
-
exis
ted
regardless of valve morphology
