Calcific Aortic Valve Disease and Aortic Atherosclerosis –
Two Faces of the Same Disease?
CARMEN GINGHINĂ¹,², ANCA FLORIAN², C. BELADAN¹,², M. IANCU², ANDREEA CĂLIN¹,²,
B.A. POPESCU¹,², RUXANDRA JURCUŢ¹,²
¹Department of Cardiology, “Carol Davila” University of Medicine and Pharmacy, Bucharest, Romania
²Department of Cardiology, “Prof. Dr. C.C. Iliescu” Institute of Emergency for Cardiovascular Diseases, Bucharest, Romania
Calcific (degenerative) aortic valve disease is the most common etiology of acquired aortic
valve stenosis. Historically, it was seen as a degenerative, “senile-like” process, resulting from aging –
“wearing and tearing” – of the aortic valve. However, several lines of evidence suggest that calcific
valve disease is not simply due to age-related degeneration but, rather, it is an active disease process
with identifiable initiating factors, clinical and genetic risk factors, and cellular and molecular
pathways that mediate disease progression. Histopathologically, the early lesions of aortic valve
sclerosis resemble arterial atherosclerotic plaques. Furthermore, atherosclerotic risk factors and
clinical atherosclerotic cardiovascular disease are independently associated with aortic sclerosis
suggesting that it represents an atherosclerosis-like process involving the aortic valve.
Until now, the only established treatment for symptomatic aortic valve stenosis has been valve
replacement. Newer therapies that may modify or reduce the likelihood of developing aortic valve
disease are highly desirable and are currently under investigation.
In this article we tried to review the available data on calcific aortic valve disease, starting
from histological and pathogenic aspects and finishing with therapeutic implications, in order to
characterize its relationship with the atherosclerotic process.
Key words: aortic stenosis, aortic sclerosis, atherosclerosis risk factors.
Calcific aortic valve disease is identified by
thickening and calcification of the aortic valve
leaflets in the absence of rheumatic heart disease. It
is divided, on a functional basis, into aortic
sclerosis, in which the leaflets do not obstruct left
ventricular outflow and aortic stenosis in which
obstruction to left ventricular outflow is present.
Aortic sclerosis is present in more than 25%
of patients over age 65 and is associated with a
50% increase of risk of cardiovascular events [1].
Aortic stenosis is present in 2% to 5% of very
elderly patients, is the second most common
indication for cardiac surgery [2] and carries an
80% 5-year risk of progression to heart failure,
valve replacement, or death [3].
Calcific (degenerative) aortic valve disease is
the most common etiology of acquired aortic valve
stenosis [4]. Historically, it was seen as a
degenerative, “senile-like” process, resulting from
aging – “wearing and tearing” – of the aortic valve
[5]. However, several lines of evidence suggest that
calcific valve disease is not simply due to agerelated degeneration but, rather, is an active disease
process with identifiable initiating factors, clinical
and genetic risk factors, and cellular and molecular
ROM. J. INTERN. MED., 2009, 47, 4, 319–329
pathways that mediate disease progression [6].
Histopathologically, the early lesions of aortic valve
sclerosis resemble arterial atherosclerotic plaques [7].
Furthermore, atherosclerotic risk factors [8] and
clinical atherosclerotic cardiovascular disease [1] are
independently associated with aortic sclerosis suggesting
that it represents an atherosclerosis-like process
involving the aortic valve [9].
CALCIFIC AORTIC VALVE DISEASE:
HISTOLOGIC AND PATHOGENIC FEATURES –
SIMILARITIES AND DISSIMILARITIES WITH
ATHEROSCLEROTIC CARDIOVASCULAR DISEASE
As we mentioned above, emerging data suggest
that calcific aortic valve disease is an active disease
process with initiating factors, “early lesions” and
more advanced processes comprising cellular and
molecular pathways that mediate disease progression.
Among the proposed theories for the initiating
factor that leads to aortic stenosis, there is most
support for a mechanical stress hypothesis [7].
Hydrodynamic studies have shown that a high
mechanical stress occurs at the flexion area of the
aortic cusps near the attachment to the aorta root and
320
Carmen Ginghină et al.
the line of coaptation [10]. Aortic endothelium at
areas of high mechanical stress demonstrates subtle
changes consistent with mild damage and becomes
more susceptible to lipid deposition and infiltration
by macrophages. This process is accelerated in the
bicuspid aortic valve because the abnormal cusps
and raphe are subject to greater mechanical stress
[11]. Although all aortic valves are subject to longterm mechanical stress and this is the initiating
factor, only a minority of elderly individuals develop
aortic stenosis, so other factors must be important in
subsequent disease progression [12].
The “early lesions “of degenerative aortic
stenosis are characterized by subendothelial thickening
with disruption of the basement membrane, intra- and
extracellular lipid deposition, chronic inflammation,
renin-angiotensin system local activation and
accumulation of protein, lipid, and calcium [13].
Similarly to atherosclerosis, the “atherogenic”
lipoproteins, LDL and Lp(a), are deposited in
human aortic valve lesions [14] and aortic valve
cholesterol content is increased in a hypercholesterolemic rabbit model of aortic valve
disease [15]. Oxidized lipids have also been
detected in human aortic valve lesions, particularly
in areas of developing calcification. In vitro studies
have shown that oxidized cholesterol stimulates
calcified nodule formation by valve fibroblasts, and
that calcified nodule formation by these cells is
inhibited by simvastatin [16]. In 1994 a series of
3 studies reported that aortic valve lesions contained
the cell types characteristic of chronic inflammation:
macrophages and T lymphocytes [7][17]. More
recently, mast cells and the proinflammatory cytokines,
IL-1 β and tumor necrosis factor (TNF)-α, also have
been identified in stenotic aortic valves [18][19]. In
addition, aortic valves lesions contain a number of
matrix-metalloproteinases (MMPs), which degrade
various components of the extracellular matrix [18]. In
the case of atherosclerosis, MMPs appear to play
important roles in the regulation of vascular
calcification, but they are also thought to play a key
role in the extracellular matrix degradation and
subsequent plaque instability [20]. Recent studies
have also implicated the renin–angiotensin system,
particularly angiotensin converting enzyme (ACE),
angiotensin II (Ang II), and the angiotensin II Type 1
(AT1) receptor in aortic valve lesion pathogenesis
[21][22]. Aortic valve lesions contain a number of
potential sources of Ang II: LDL-associated ACE,
macrophage associated ACE and mast cells. Ang II
has a number of potential, AT-1 receptor–mediated,
lesion-promoting effects: stimulating inflammation
2
and macrophage cholesterol accumulation, impairing
fibrinolysis, increasing oxidant stress and stimulating
fibroblast expression. The major pathogenic receptor
for Ang II is present in valve lesion fibroblasts [21].
In addition to fibrosis, dystrophic calcification
is the defining feature of aortic valve lesions and in
advanced stages it becomes the dominant process
[11]. Calcification first occurs in the areas of lipid
deposition and, in time, may contribute to lesion
rigidity, thereby worsening obstruction to left
ventricular outflow. Moreover, the extent of lesion
calcification correlates both with more rapid disease
progression and worse clinical outcomes [23]. Aortic
valve calcification now has been shown unequivocally
to be an active, rather than a passive, process.
Valvular calcium deposits contain both calcium and
phosphate as hydroxyapatite, the form of calciumphosphate mineral present in both calcified arterial
tissue and bone [24][25]. Proteins such as osteopontin
[26], implicated in calcification and calcifying valve
cells with osteoblast-like activities, have been
detected in calcified aortic valves [27]. Also, lamellar
bone was found in 13% of valves with dystrophic
calcification.
In summary, calcific aortic disease initiation and
progression consists in an active inflammatory process
with some similarities (lipid deposition, macrophage
and T cell infiltration, and basement membrane
disruption) and some dissimilarity (presence of
prominent mineralization and small numbers of
smooth muscle cells) to atherosclerosis [7].
CALCIFIC AORTIC VALVE DISEASE:
HISTOLOGIC AND PATHOGENIC FEATURES –
ASSOCIATION WITH ATHEROSCLEROSIS
Early atherosclerosis involves the endothelium
of many arteries. Vascular dysfunction has been
implicated as an early event in atherogenesis [28] and,
associated with vascular injury, has been postulated
as the precursor of atherosclerosis [29]. Poggiati et al.
[30] examined the association between aortic valve
sclerosis (imaged by transthoracic echocardiography)
and systemic endothelial manifestations of the
atherosclerotic process in a study population with
known or suspected coronary artery disease, referred
for a stress echocardiography test. They used, among
the investigational tools, an endothelial function
study, with assessment of endothelium-dependent,
post-ischemic, flow-mediated dilation. They
demonstrated that aortic valve stenosis is associated
with systemic endothelial dysfunction with flow-
3
Calcific aortic valve disease and aortic atherosclerosis
mediated dilation being highly predictive of aortic
valve sclerosis. No significant differences were
found in patients with or without aortic valve
sclerosis regarding the presence of significant
coronary artery disease at coronarography.
Agmon et al. [31] examined the association
between atherosclerosis risk factors, anatomically
defined atherosclerosis (atherosclerosis of the thoracic
aorta imaged by transesophageal echocardiography)
and aortic valve sclerosis in the general population
from the SPARC study [32]. “Atherosclerosis” was
defined as irregular intimal thickening (≥2mm) with
increased echogenicity. Aortic valve abnormalities
were examined both morphologically and functionally
(peak transaortic flow velocities). They demonstrated
that atherosclerotic risk factors and proximal aortic
atherosclerosis are independently associated with
aortic valve abnormalities in the general population
(p< 0.001).
Weisenberg et al. [33] evaluated, by intraoperative transesophageal echocardiography, 91
consecutive patients with severe aortic stenosis who
underwent aortic valve replacement (with matching
pairs without valve disease) in order to determine the
presence and characteristics of aortic atheromas. They
found a strong association between the presence of
severe aortic stenosis and the presence and severity of
aortic atheromas, the majority of patients having the
lesions localized in the aortic arch (66% pts, 45.7%
complex atheromas) and descending aorta (77% pts,
50% complex atheromas). They also suggested that
transesophageal echocardiography might become part
of the preoperative evaluation and the presence of
aortic atheromas should be taken into account when
analyzing the risk/benefit ratio for these patients
considering the high incidence of perioperative stroke
associated with complex atheromas.
Goland et al. [34] retrospectively evaluated 105
consecutive patients with severe degenerative aortic
stenosis who underwent aortic valve replacement.
These patients were compared with 54 sex- and agematched patients without aortic stenosis or coronary
artery disease. Aortic atheroma (localized intimal
thickening of >3 mm) prevalence and morphology in
three segments of aorta were assessed with
echocardiography. They found that patients with
severe aortic stenosis and coexisting coronary artery
disease had more extensive atherosclerotic changes in
the thoracic aorta as compared with those with aortic
stenosis alone and control subjects. They also had
more complex atheromas in the aortic arch and a
higher percentage for the presence of plaques in two
321
or three segments (p < 0.0001) as compared with
the other groups.
CALCIFIC AORTIC VALVE DISEASE: RISK
FACTORS – SIMILARITIES AND DISSIMILARITIES
WITH ATHEROSCLEROTIC CARDIOVASCULAR
DISEASE
The effect of hypercholesterolemia on the
development of sclerotic changes involving the
heart valves has been demonstrated on animal
models [35][36]. For example, a recent study
showed that mice with hyperlipidemia due to over
expression of apolipoprotein E4 all developed
severe aortic stenosis in addition to coronary disease
[37]. Also, valvular and supravalvular aortic
stenosis are well known in human subjects with
familial hypercholesterolemia, and aortic stenosis
may regress with aggressive reduction of serum
cholesterol [38].
Several studies have documented overlap in
the clinical factors traditionally associated with
calcific valve disease and atherosclerosis [39–
47][79][80][81]. Some of these studies had obvious
limitations given the fact that they included patients
expected to have a high prevalence of atherosclerotic risk factors: older age (Aronow et al.,
Lindroos et al.), patients referred for cardiac
catheterization (Deutscher et al., Hoagland et al.).
The largest prospective population-based study, the
Cardiovascular Health Study [39], which included
5621 adults over the age of 65 years, reported a
positive association of aortic valve disease with
risk factors including age, male gender, smoking,
history of hypertension and high Lp (a) and LDL
cholesterol levels. Interestingly, the strength of
these associations is comparable to that seen with
atherosclerotic disease [39].
Mohler et al. [41] was one of the less who
compared risk factors for aortic stenosis in bicuspid
versus tricuspid aortic valves. Race, male gender
and low triglyceride levels were correlated with age
at surgery in bicuspid aortic valves, whereas male
gender and smoking were the risk factors for
patients with degenerative tricuspid aortic stenosis.
Many of the studies looking at atherosclerotic
risk factors in aortic stenosis were limited by the
use of retrospective data, varying definition of
aortic valve disease (only five of these studies
assessed the morphology of the aortic valve:
bicuspid vs. tricuspid) and referral bias (surgery,
cardiac catheterization).
Carmen Ginghină et al.
322
4
Jeevanantham et al. proposed Hs-CRP as a tool for
identifying patients in the early stages of calcific
aortic valve disease, in whom medical treatment
may be beneficial to halt the progression to
irreversible aortic valvular calcification and
stenosis. The second risk factor studied was
homocysteine; Novaro et al. [52] failed in finding
any association between aortic valve disease and
serum homocysteine.
Taken together, we may state that atherosclerotic risk factors, particularly hypercholesterolemia,
are associated with calcific aortic stenosis.
However, there are differences between the processes
underlying aortic stenosis and atherosclerosis
(Table I). Only one-half of the patients with aortic
stenosis have coronary artery disease and a minority
of patients with coronary artery disease have
concomitant aortic stenosis [53].
Katz et al. [48], compared the prevalence of
aortic valve calcification, assessed by computed
tomography in 6780 Multi-Ethnic Study of Atherosclerosis (MESA) participants with metabolic
syndrome, diabetes mellitus, or neither condition.
In this cohort, the metabolic syndrome and diabetes
mellitus were associated with increased risk of
aortic valve calcification and its prevalence was
increased with increasing the number of metabolic
syndrome components.
A number of studies analyzed the association
between “novel” risk factors of atherosclerosis and
aortic valve disease. The first one of the risk factors
was Hs-CRP (high sensitivity C-reactive protein)
and the results were various, ranging from no
correlation [49], weak association [50] to
significant association with calcific aortic valve
disease during its early stage [51]. In the last study,
Table I
Comparison of sclerotic process in aortic stenosis with that in atherosclerosis
Aortic stenosis
Atherosclerosis
Inflammatory changes
Systemic markers of inflammation
++++
++++
+
++
Lipid accumulation
Oxidized lipids
++++
++++
Calcification
++++
+++++
++++
++
Role of infective agents
±
±
Dominant cell
Fibroblast
Smooth muscle
Role of genetic factors
++
+++
Modified from Chan KL (13) and Freeman RV (78)
Causes accounting for the discordance
between the two processes have not been well
defined, but may be related to genetic factors acting
through pathways such as those involving
angiotensin-converting enzyme and vitamin D [13].
A recent study by Ortlepp et al. suggested that the
B allele of the vitamin D receptor may be a
predisposing factor for aortic stenosis [54].
Recent studies have emphasized not only the
importance of bicuspid aortic valves as a risk factor
for aortic stenosis [55], but also demonstrated one
specific genetic defect that can contribute to
bicuspid valve morphogenesis [56]. A recent, single
center, consecutive series of 932 surgically excised
nonrheumatic aortic stenosis valves found 49% of
these valves to be congenitally bicuspid. This would
represent a substantial enrichment of the proportion
of congenitally abnormal valves in nonrheumatic
aortic stenosis as compared with the overall
population and suggests that the bicuspid valve has a
much more powerful and widespread influence on
progression to severe disease than recognized
previously [55]. Also, in patients with bicuspid
aortic valves, compared with those having normal
trileaflet aortic valves, ascending aortic dilatation
occurs more frequently and at a younger age and the
presence of associated medial defects lead to a
higher prevalence and faster rate of ascending aortic
dilatation, with increased risk of dissection (Fig. 1).
Other factors that may be associated with aortic
valve sclerosis include: uremia [57], elevated calcium
[58], elevated parathyroid hormone [59], osteoporosis
[60], Paget disease [61], and significant renal failure
[62]. Some of these factors act by accelerating
atherosclerosis, but, in addition, they promote the
valvular disease process by altering systemic calcium
metabolism and by generating a high-output state
with increased valvular mechanical stress.
5
Calcific aortic valve disease and aortic atherosclerosis
A
323
B
C
Fig. 1. – 2D transthoracic and transesophageal echocardiographic images showing an intense calcified bicuspid aortic valve with
severe aortic stenosis (A, B) and a dilated ascending aorta (C).
It is known that in time, not all patients with
aortic sclerosis develop some degree of aortic stenosis,
with a substantial variability in the annual rate of
progression between individuals [63]. A number of
studies that have examined this question found a series
of factors associated with the progression of aortic
sclerosis: increasing age [64–66], male sex [67],
dyslipidemia [65][67][68], tobacco use [65][67][68],
hypertension [67], diabetes mellitus [67], obesity
(69), elevated serum calcium [68], elevated serum
creatinine [68], aortic valve calcification [70],
coronary artery disease [71], baseline aortic valve
area [72][73], baseline pressure gradient [74].
CALCIFIC AORTIC VALVE DISEASE: CLINICAL
AND PROGNOSTIC FEATURES – ASSOCIATION
WITH ATHEROSCLEROSIS
The relationship between aortic calcific
disease and atherosclerosis is bidirectional. On the
one hand, aortic sclerosis was linked to adverse
ischemic cardiovascular events. For example, in the
population based cardiovascular health study, the
presence of aortic sclerosis on echocardiography in
adults over age 65 years, with no known coronary
artery disease at study entry, was associated with a
50% increased risk of cardiovascular mortality and
324
Carmen Ginghină et al.
myocardial infarction over a mean follow-up
interval of 5.5 years [1]. In addition, patients
admitted with chest pain and aortic sclerosis had a
higher incidence of cardiovascular events and worse
event-free survival than did those without aortic
sclerosis [75]. It has been proposed that aortic
sclerosis gives a “window to the coronary arteries”
without the need for an angiogram [76]. These
findings suggest that there is a pathogenic link
between aortic sclerosis and acute coronary
syndromes that is beyond that of shared coronary
risk factors and that aortic sclerosis is an incremental
risk above conventional risk factors. Nightingale
et al. concluded in their review article [77] that
“aortic sclerosis is not an innocent murmur but a
marker of increased cardiovascular risk”.
On the other hand, most patients with coronary
artery disease do not have aortic stenosis and in
adults with severe aortic stenosis, only about 50%
have significant coronary artery disease.
Last, but not least, in aortic stenosis a large
contributor of disease progression is prominent
calcification with a gradual increase in leaflet
thickness and outflow obstruction. In contrast,
events in patients with coronary atherosclerosis are
acute, related to plaque rupture with associated
thrombosis and vascular occlusion. Thus, as a
bridge to the discussion about treatment options in
aortic sclerosis, plaque stabilization and anti
thrombotic treatment strategies are less likely to be
beneficial calcific valve disease [78].
TREATMENT OF CALCIFIC AORTIC VALVE
DISEASE PROGRESSION – TARGETING
ATHEROSCLEROTIC DISEASE PROCESSES
There is no effective therapy for severe
symptomatic aortic stenosis other than surgical
aortic valve replacement.
As we have shown above, calcific aortic valve
disease consists in an active pathobiological process,
having common pathways with atherosclerosis.
Endothelial dysfunction [30] and increased low-grade
systemic inflammation were demonstrated in patients
with calcific aortic valve disease [51] and one
question is if the relationship between these findings
and the valvular degenerative process is bidirectional.
Chenevard et al. [82] hypothesized that altered
hemodynamics in aortic stenosis may be partly
responsible for endothelial dysfunction and thus
potentially normalize after aortic valve replacement.
Their results suggest that there is an ongoing disease
process that may not be entirely halted by removal
6
of the diseased valve, similar to that described in
atherosclerosis. This strengthens even more the need
to pharmacologically control these processes.
Targeted pharmacotherapeutic regimens to
interfere with the disease pathways to either slow or
halt the disease are under investigation [78]. Potential
points of action of these medical regimens would be:
leaflet endothelial layer disruption, activation of
inflammatory cascade, release of inflammatory
cytokines, lipoprotein accumulation and deposition,
lipid oxidation, angiotensin-mediated effects, tissue
calcification and osteogenesis [78].
The two pharmacological agents currently
evaluated for potentially delaying disease progression
are HMG-CoA reductase inhibitors (statins) and ACE
inhibitors.
HMG-CoA reductase inhibitors have mechanisms
of action that expand their effects beyond cholesterol
lowering [83]. Statins may influence both risk factors
and inflammatory pathways by lowering lipid levels
and exerting a range of anti-inflammatory properties,
called “pleiotropic effects”. These pleiotropic effects
include: anti-oxidation [84], improvement of endothelial
function, anti-thrombotic actions, plaque stabilization,
reduction of the vascular inflammatory process and
modulation of the T-cell activation [85][86]. The
hypothesis that lipid-lowering therapy might slow or
prevent disease progression was tested in several
types of studies, first experimental models and
retrospective studies and in the last years, a number of
prospective, randomized controlled trials. In an
experimental hypercholesterolemic rabbit model of
early calcific aortic valve disease, Rajamannan et al.
demonstrated a decrease in cellular proliferation and
bone matrix production within the aortic valve after
administration of atorvastatin [87]. Table II illustrates
some of the available clinical studies that support an
association of statin use and slowed disease
progression. In the retrospective cohorts, statins were
generally prescribed by the primary care providers for
conventional indications, and the association of statin
use with progression of calcific valve disease was
assessed. Interestingly, despite the relatively consistent
slowing of disease progression in those patients
receiving statin therapy, there was a relative lack of
correlation with the effect on serum cholesterol levels,
with some studies showing an association [67][88]
[89][97] and others showing none [66][90–92]. This
inconsistency likely represents some of the limitations
inherent in retrospective analyses but also supports the
theory that statins provide additional, pleiotropic
benefits beyond cholesterol lowering.
7
Calcific aortic valve disease and aortic atherosclerosis
325
Table II
Statin therapy in aortic stenosis: clinical studies
Study (year)
Retrospective
Aronow et al. (2001) (81)
Novaro et al. (2001) (66)
Pohle et al. (2001) (88)
Bellamy et al. (2002) (90)
Shavelle et al. (2002) (91)
Rosenhek et al. (2004) (92)
Antonini-Canterin et al.
(2008) (97)
Prospective
Moura et al. (2007)
RAAVE (93)
Cowell et al. (2005)
SALTIRE (94)
Rosseb et al. (2008)
SEAS (95)
Total number of patients
(% taking statins)
180 (34%)
Average
follow-up
Method of
evaluation
> 2 years
Echocardiography
174 (33%)
104 (52%)
156 (24%)
65 (43%)
211 (39%)
1046 (29.5%)
21 months
15 months
3.7 ± 2.3 years
2.5 ± 1.6 years
2.0 ± 1.5 years
5.6 ± 3.2 years
121 (50.4%)
Parameter followed
p
Echocardiography
EBCT
Echocardiography
EBCT
Echocardiography
Echocardiography
peak transaortic
gradient
AVA decrease
median AVC change
AVA decrease
median AVC change
jet velocity increase
jet velocity increase
0.03
NS
0.04
0.006
<0.0001
0.01
73 ± 24 weeks
Echocardiography
jet velocity increase
0.007
155 (50.3%)
25 months
52.2 months
jet velocity increase
AVC change
primary outcome
NS
1873 (50.3)
Echocardiography
EBCT
Primary outcome:
composite of major
cardiovascular events*
Echocardiography
(In progress)
ASTRONOMER (96)
0.001
NS
AVA indicates aortic valve area; EBCT, electron-beam computed tomography; and AVC, aortic valve calcium.
* death from cardiovascular causes, aortic-valve replacement, nonfatal myocardial infarction, hospitalization for unstable angina
pectoris, heart failure, coronary-artery bypass grafting, percutaneous coronary intervention, and nonhemorrhagic stroke.
Modified from Freeman RV, Otto CM [78]
There are 4 prospective, randomized, placebocontrolled, multicenter studies with conflicting results
regarding the role of statin therapy in calcific aortic
disease progression. In the Rosuvastatin Affecting
Aortic Valve Endothelium (RAAVE) study [93]
prospective treatment of moderate to severe aortic
stenosis with 20 mg rosuvastatin per day by
targeting serum LDL slowed the disease
progression as measured by echocardiography. In
opposition, at least two years of atorvastatin at
80 mg/day in the Scottish Aortic Stenosis and Lipid
Lowering Trial, Impact on Regression (SALTIRE)
study [94], reduced LDL cholesterol by more than
50% but had no significant effect on the extent of
aortic-valve calcification or change in aortic-jet
velocity. But, in SALTIRE the patient aortic
disease was, on average, substantially more
advanced than in RAAVE (mean valve area 1 cm2
vs. 1.23 cm2).
The SEAS trial (Simvastatin and Ezetimibe
in Aortic Stenosis) [95] randomized and followed
for a median of 52 months, 1873 patients with
mild-to-moderate, asymptomatic aortic stenosis,
receiving either 40 mg of simvastatin plus 10 mg of
ezetimibe or placebo daily. Simvastatin and
ezetimibe did not reduce the composite outcome of
combined aortic-valve events and ischemic events
in patients with aortic stenosis. One ongoing trial:
Aortic Stenosis Progression Observation: Measuring
the Effect of Rosuvastatin (ASTRONOMER) assessing
the effects of 40 mg rosuvastatin daily compared to
usual care in patients diagnosed with mild to
moderate aortic valvular stenosis and no clinical
indication for the use of cholesterol lowering
agents should eventually help determine whether
statins and other lipid-lowering agents are indeed
beneficial in patients with aortic stenosis [96].
Another problem to be solved is if and when there
is an optimal time interval in which patients might
benefit from statin therapy in the course of their
disease progression.
Although there are strong proponents of ACE
inhibitor use in aortic stenosis, the basis of the
recommendations to date has been on the potentially
favorable effect of ACE inhibitors on the remodeling
and hypertrophic changes of the myocardium in aortic
stenosis, [98] rather than an effect on delaying disease
progression at the tissue level. However, it is
premature to conclude that ACE inhibition is not
beneficial. Further investigations will be needed to
Carmen Ginghină et al.
326
establish the potential benefit of ACE inhibitors on
disease progression.
CONCLUSION
Calcific aortic disease represents a disease
spectrum ranging from aortic sclerosis to severe
aortic stenosis and consisting in an active process
with risk factors, initiating lesions, clinical factors
8
and pathogenic pathways of progression. Calcific
aortic disease and atherosclerosis share a large number
of common features on different levels from
histologic and pathogenic to, a lesser extent, clinical,
prognostic and therapeutic ones. Nevertheless, from
a clinical and therapeutic point of view, calcific
aortic disease and atherosclerosis remain two
different conditions, both associated with increasing
prevalence and morbidity as the population ages.
Afectarea valvulară degenerativă reprezintă cea mai frecventă cauză
dobândită a stenozei aortice. În trecut, aceasta a fost considerată consecinţa unui
proces degenerativ, asemănător îmbătrânirii, datorat „uzurii” valvei aortice. În
ultimii ani s-au adunat tot mai multe date care sugerează că afectarea valvulară
degenerativă nu se datorează modificărilor legate de îmbătrânire, ci constituie un
proces activ caracterizat prin factori iniţiatori, factori de risc clinici şi genetici şi
procese celulare şi moleculare care mediază progresia bolii. Din punct de vedere
anatomopatologic, leziunile iniţiale din scleroza aortică sunt asemănătoare celor
din placa aterosclerotică. Mai mult decât atât, factorii de risc pentru ateroscleroza
şi boala vasculară aterosclerotică manifestă se asociază independent cu scleroza
aortică sugerând că aceasta reprezintă rezultatul unui proces asemănător aterosclerozei
la nivelul valvelor aortice.
La acest moment, singurul tratament al stenozei aortice severe simptomatice
este înlocuirea valvulară. Terapiile noi, cu potenţialul de a reduce sau modifica
progresia bolii valvulare aortice degenerative, reprezintă o necesitate şi sunt în
curs de evaluare.
În acest articol, am încercat să sumarizăm datele existente până în acest
moment cu privire la afectarea valvulară aortică degenerativă, începând cu
aspectele histologice şi de patogenie şi încheind cu implicaţiile terapeutice, cu
scopul de a caracteriza relaţia dintre aceasta şi procesul aterosclerotic.
Corresponding address: Carmen Ginghina, MD
Department of Cardiology, “Prof. Dr. C.C. Iliescu” Institute of Emergency for Cardiovascular Diseases
Sos. Fundeni no. 258, 022328, Bucharest, Romania
E-mail: carmenginghina2001@yahoo.com
REFERENCES
1.
2.
3.
4.
5.
6.
7.
8.
OTTO C.M., LIND B.K., KITZMAN D.W. et al., Association of aortic valve sclerosis with cardiovascular mortality and
morbidity in the elderly. N. Eng. J. Med., 1999; 341:142–7.
ROBERTS W.C., KO J.M., Frequency by decades of unicuspid, bicuspid, and tricuspid aortic valves in adults having isolated
aortic valve replacement for aortic stenosis, with or without associated aortic regurgitation. Circulation, 2005; 111:920–25.
OTTO C.M., BURWASH I.G., LEGGET M.E. et al., Prospective study of asymptomatic valvular aortic stenosis. Clinical,
echocardiographic, and exercise predictors of outcome. Circulation, 1997; 95:2262–70.
SELZER A., Changing aspects of the natural history of valvular aortic stenosis. N. Engl. J. Med., 1987; 317:91–8.
POMERANCE A., Ageing changes in human heart valves. Br. Heart J. 1967; 29:222–231.
OTTO C.M., Calcific aortic stenosis – time to look more closely at the valve. N. Engl. J. Med., 2008; 359(13):1395–8.
OTTO C.M., KUUSISTO J., REICHENBACH D.D. et al., Characterization of the early lesion of “degenerative” valvular
aortic stenosis; histologic and imunohistochemical studies. Circulation, 1994; 90:844–53.
STEWART B.F., SISCOVICK D., LIND B.K. et al., Clinical factors associated with calcific aortic valve disease. J. Am. Coll.
Cardiol., 1997; 29:630–4.
9
Calcific aortic valve disease and aortic atherosclerosis
327
9. WIERZBICKI A., SHETTY C., Aortic stenosis an atherosclerotic disease? J. Heart Valve disease, 1999; 8:416–423.
10. ZAND T., MAJNO G., NUNNARI J.J. et al., Lipid deposition and intimal stress and strain: a study in rats with aortic stenosis.
Am. J. Pathol., 1991; 139:101–13.
11. DAVIES M.J., TREASURE T., PARKER D.J., Demographic characteristics of patients undergoing aortic valve replacement
for stenosis: relation to valve morpholoy. Heart, 1996; 75:174–8.
12. LINDROOS M., KUPARI M., HEIKKILA J., Prevalence of aortic valve abnormalities in the elderly: an echocardiographic
study of a random population sample. J. Am. Coll. Cardiol., 1993; 21:1220–5.
13. CHAN K.L., State of the art paper: Is aortic stenosis a preventable disease? J. Am. Coll. Cardiol., 2003; 42(4):593–9.
14. O’BRIEN K.D., REICHENBACH D.D., MARCOVINA S.M. et al., Apolipoproteins B, (a), and E accumulate in the
morphologically early lesion of ‘degenerative’ valvular aortic stenosis. Arterioscler. Thromb. Vasc. Biol., 1996; 16:523–32.
15. RAJAMANNAN N.M., SUBRAMANIAM M., SPRINGETT M. et al., Atorvastatin inhibits hypercholesterolemia-induced
cellular proliferation and bone matrix production in the rabbit aortic valve. Circulation, 2002; 105:2660–65.
16. WU B., ELMARIAH S., KAPLAN F.S. et al., Paradoxical effects of statins on aortic valve myofibroblasts and osteoblasts:
implications for end-stage valvular heart disease. Arterioscler. Thromb. Vasc. Biol., 2005; 25:592–97.
17. OLSSON M., DALSGAARD C.J., HAEGERSTRAND A. et al., Accumulation of T lymphocytes and expression of interleukin2 receptors in nonrheumatic stenotic aortic valves. J. Am. Coll. Cardiol., 1994; 23:1162–1170.
18. KADEN J.J., DEMPFLE C.E., GROBHOLZ R. et al., Interleukin-1 beta promotes matrix metalloproteinase expression and cell
proliferation in calcific aortic valve stenosis. Atherosclerosis, 2003; 170:205–211.
19. KADEN J.J., DEMPFLE C.E., GROBHOLZ R. et al., Inflammatory regulation of extracellular matrix remodeling in calcific
aortic valve stenosis. Cardiovasc. Pathol., 2005; 14:80–87.
20. GALIS Z.S., SUKHOVA G.K., LARK M.W. et al., Increased expression of matrix metalloproteinases and matrix degrading
activity in vulnerable regions of human atherosclerotic plaques. J. Clin. Invest., 1994; 94:2493–2503.
21. O’BRIEN K.D., SHAVELLE D.M., CAULFIELD M.T. et al., Association of Angiotensin-converting enzyme with low-density
lipoprotein in aortic valvular lesions and in human plasma. Circulation, 2002; 106:2224–2230.
22. HELSKE S., LINDSTEDT K.A., LAINE M. et al., Induction of local angiotensin II-producing systems in stenotic aortic valves.
J. Am. Coll. Cardiol., 2004; 44:1859–1866.
23. BAHLER R.C., DESSER D.R., FINKELHOR R.S. et al., Factors leading to progression of valvular aortic stenosis. Am. J.
Cardiol., 1999; 84:1044–1048.
24. MOHLER E.R., III, CHAWLA M.K., CHANG A.W. et al., Identification and characterization of calcifying valve cells from
human and canine aortic valves. J. Heart Valve Dis., 1999; 8:254–260.
25. ANDERSON H.C., Calcific diseases. A concept. Arch. Pathol. Lab. Med., 1983; 107:341–348.
26. O’BRIEN K.D., KUUSISTO J., REICHENBACH D.D. et al., Osteopontin is expressed in human aortic valvular lesions.
Circulation, 1995; 92:2163–8.
27. PARHAMI F., MORROW A.D., BALUCAN J. et al., Lipid oxidation products have opposite effects on calcifying vascular cell
and bone cell differentiation: a possible explanation for the paradox of arterial calcification in osteoporotic patients.
Arterioscler. Thromb. Vasc. Biol., 1997; 17:680–7.
28. ANDERSON T, UEHATA A, GERHARTD M, et al., Close relation of endothelial function in the human coronary and
peripheral circulations. J. Am. Coll. Cardiol., 1995; 26:1235–41.
29. ROSS A., Atherosclerosis: current understanding of mechanisms and future strategies in therapy. Transplant Proc., 1993;
25:2041–3.
30. POGGIANTI E., VENNERI L., CHUBUCHNY V. et al., Aortic valve sclerosis is associated with systemic endothelial
dysfunction. J. Am. Coll. Cardiol., 2003; 41:136–41.
31. AGMON I., KHANDHERIA B.K., MEISSNER I. et al., Aortic valve sclerosis and aortic atherosclerosis: different
manifestations of the same disease? J. Am. Coll. of Cardiol., 2001; 38(3):827–34.
32. MEISSNER I., WHISNANT J.P., KHANDHERIA B.K. et al., Prevalence of potential risk factors for stroke assessed by
transesophageal echcardiography and carotid ultrasonography: the SPARC study. Mayo Clin. Proc., 1999; 74:862–9.
33. WEISENBERG D., SAHAR Y., SAHAR G. et al., Atherosclerosis of the aorta is common in patients with severe aortic
stenosis: an intraoperative transesophageal echocardiographic study. J. Thorac. Cardiovasc. Surg., 2005; 130:29–32.
34. GOLAND S., TRENTO A., CZER L.S., Thoracic aortic arteriosclerosis in patients with degenerative aortic stenosis with and
without coexisting coronary artery disease. Ann. Thorac. Surg., 2008; 85:113–119.
35. ZAHOR Z., CZABANOVA V., Experimental atherosclerosis of the heart valves in rats following a long-term atherogenic
regimen. Atherosclerosis, 1977; 27:49–57.
36. SARPHIE T.G., Surface responses of aortic valve endothelia from diet-induced, hypercholesterolemic rabbits. Atherosclerosis,
1985; 54:283–99.
37. FAZIO S., SANAN D.A., LEE Y.L. et al., Susceptibility to diet-induced atherosclerosis in transgenic mice expressing a
dysfunctional human apolipoprotein E. Arterioscler. Thromb. Vasc. Biol., 1994; 14:1873–9.
38. BARR D.P., ROTHBARD S., EDER H.A. et al., Atherosclerosis and aortic stenosis in hypercholesterolemic xanthomatosis.
JAMA, 1954; 156:943–7.
39. STEWART B.F., SISCOVICK D., LIND B.K. et al., Clinical factors associated with calcific aortic valve disease:
Cardiovascular Health Study. J. Am. Coll. Cardiol., 1997; 29:630–634.
40. ARONOW W.S., SCHWARTZ K.S., KOENIGSBERG M., Correlation of serum lipids, calcium, and phosphorus, diabetes
mellitus and history of systemic hypertension with presence or absence of calcified or thickened aortic cusps or root in elderly
patients. Am. J. Cardiol., 1987; 59:998–999.
328
Carmen Ginghină et al.
10
41. MOHLER E.R., SHERIDAN M.J., NICOLS R. et al., Development and progression of aortic valve stenosis: atherosclerosis
risk factors—a causal relationship? A clinical morphologic study. Clin. Cardiol., 1991; 14:995–999.
42. LINDROOS M., KUPARI M., VALVANNE J. et al., Factors associated with calcific aortic valve degeneration in the elderly.
Eur. Heart J., 1994; 15:865– 870.
43. BOON A., CHERIEX E., LODDER J., KESSELS F., Cardiac valve calcification: characteristics of patients with calcification
of the mitral annulus or aortic valve. Heart, 1997; 78:472–472.
44. PELTIER M., TROJETTE F., SARANO M.E. et al., Relation between cardiovascular risk factors and nonrheumatic severe
calcific aortic stenosis among patients with a three-cuspid aortic valve. Am. J. Cardiol., 2003; 91:97–99.
45. DEUTSCHER S., ROCKETTE H.E., KRISHNASWAMI V., Diabetes and hypercholesterolemia among patients with calcific
aortic stenosis. J. Chronic Dis., 1984; 37:407–15.
46. HOAGLAND P.M., COOK F., FLATLEY M. et al., Case-control analysis of risk factors for presence f aortic stenosis in
adults. Am. J. Cardiol., 1985; 55:744–7.
47. CHUI M.C., NEWBY D.E., PANARELLI M. et al., Association between calcific aortic disease and hypercholesterolemia: is
there need for a randomised controlled trial of cholesterol-lowering therapy? Clin. Cardiol., 2002; 24:52–5.
48. KATZ R., WONG N.D., KRONMAL R. et al., Features of metabolic syndrome and diabetes mellitus as predictors of aortic
valve calcification in the Multi-Ethnic Study of Atherosclerosis. Circulation, 2006; 113:2113–2119.
49. GUNDUZ H., AKDEMIR R., BINAK E. et al., Can serum lipids and CRP levels predict the “severity” of aortic valve stenosis?
Acta Cardiol., 2003; 58:321–326.
50. AGMON I., KHANDHERIA B.K., TAJIK A.J. et al., Inflammation, infection, and aortic valve sclerosis: insights from the
Olmsted County (Minnesota) population. Atherosclerosis, 2004; 174:337–342.
51. JEEVANANTHAM V., SINGH N., IZUORA K. et al., Correlation of high sensitivity C-reactive protein and calcific aortic
valve disease. Mayo Clin. Proc., 2007; 82:171–174.
52. NOVARO G.M., ARONOW H.D., SABIK E.M. et al., Plasma homocysteine and calcific aortic valve disease. Heart, 2004;
90:802–803.
53. OTTO C., O’BRIEN K.D., Why is there discordance between calcific aortic stenosis and coronary artery disease? Heart, 2001;
85:601–2.
54. ORTLEPP J.R., HOFFMAN R., OHME F. et al., The vitamin D receptor genotype predisposes the development of calcific
aortic valve stenosis. Heart, 2001; 85:635–8.
55. ROBERTS W.C., KO J.M., Frequency by decades of unicuspid, bicuspid, and tricuspid aortic valves in adults having isolated
aortic valve replacement for aortic stenosis, with or without associated aortic regurgitation. Circulation, 2005; 111:920–925.
56. GARG V., MUTH A.N., RANSOM J.F. et al., Mutations in NOTCH1 cause aortic valve disease. Nature, 2005; 437:270–274.
57. MAHER E.R., PAZIANAS M., CURTIS J.R., Calcific aortic stenosis: a complication of chronic uraemia. Nephron, 1987;
47:119–122.
58. ROBERTS W.C., WALLER B.F., Effect of chronic hypercalcemia on the heart. Am. J. Med., 1981; 71:371–384.
59. STEFENELLI T., MAYR H., BERGLER-KLEIN J., GLOBITS S., WOLOSZCZUK W., NIEDERLE B., Primary hyperparathyroidism:
incidence of cardiac abnormalities and partial reversibility after successful parathyroidectomy. Am. J. Med., 1993; 95:
197–202.
60. STEWART B.F., SISCOVICK D., LIND B.K., et al., Clinical factors associated with calcific aortic valve disease.
Cardiovascular Health Study. J. Am. Coll. Cardiol., 1997; 29:630–634.
61. STRICKBERGER S.A., SCHULMAN S.P., HUTCHINS G.M., Association of Paget’s disease of bone with calcific aortic valve
disease. Am. J. Med., 1987; 82:953–956.
62. MAHER E.R., YOUNG G., SMYTH-WALSH B., PUGH S., CURTIS J.R., Aortic and mitral valve calcification in patients
with endstage renal disease. Lancet, 1987; 2:875–877.
63. FAGGIANO P., ANTONINI-CANTERIN P., ERLICHER A. et al., Progression of aortic valve sclerosis to aortic stenosis. Am.
J. Cardiol., 2003; 91:99–101.
64. PETER M., HOFFMANN A., PARKER C. et al., Progression of aortic stenosis. Role of age and concomitant coronary artery
disease. Chest, 1993; 103:1715–1719.
65. NASSIMIHA D., ARONOW W.S., AHN C. et al., Rate of progression of valvular aortic stenosis in patients > or = 60 years of
age. Am. J. Cardiol., 2001; 87:807–809, A9.
66. NOVARO G.M., TIONG I.Y., PEARCE G.L. et al., Effect of HMG-CoA reductase inhibitors on the progression of calcific
aortic stenosis. Circulation, 2001; 104:2205–2209.
67. ARONOW W.S., AHN C., KRONZON I. et al., Association of coronary risk factors and use of statins with progression of mild
valvular aortic stenosis in older persons. Am. J. Cardiol., 2001; 88:693–695.
68. PALTA S., PAI A.M., GILL K.S. et al., New insights into the progression of aortic stenosis: implications for secondary
prevention. Circulation, 2000; 101:2497–2502.
69. NGO M.V., GOTTDIENER J.S., FLETCHER R.D. et al., Smoking and obesity are associated with the progression of aortic
stenosis. Am. J. Geriatr. Cardiol., 2001; 10:86–90.
70. ROSENHECK R., BINDER T., PORENTA G. et al., Predictors of outcome in severe, asymptomatic aortic stenosis. N. Engl. J.
Med., 2000; 343:611–617.
71. PETER M., HOFFMAN A., PARKER C. et al., Progression of aortic stenosis: role of age and concomitant coronary artery
disease. Chest, 1993; 6:1715–9.
11
Calcific aortic valve disease and aortic atherosclerosis
329
72. BAHLER R.C., DESSER D.R., FINKELHOR R.S. et al., Factors leading to progression of valvular aortic stenosis. Am. J.
Cardiol., 1999; 84:1044–8.
73. PALA S., PAI A.M., GILL K.S. et al., New insights into the progression of aortic stenosis: implications for secondary
prevention. Circulation, 2000; 101:2497–502.
74. FAGGIANO P., GHIZZONI G., SORGATO A. et al., Rate of progression of valvular aortic stenosis in adults. Am. J. Cardiol.,
1992; 70:229–33.
75. CHANDRA H.R., GOLDSTEIN J.A., CHOUDHARY N. et al., Adverse outcome in aortic sclerosis is associated with coronary
artery disease and inflammation. J. Am. Coll. Cardiol., 2004; 43:169–75.
76. CARABELLO B.A., Aortic sclerosis: a window to the coronary arteries? N. Engl. J. Med., 1999; 341:193–5.
77. NIGHTINGALE A.K., HOROWITZ J.D., Aortic sclerosis: not an innocent murmur but a marker of increased cardiovascular
risk. Heart, 2005; 91:1389–93.
78. FREEMAN R.V., OTTO C.M., Spectrum of calcific aortic disease. Pathogenesis, disease progression, and treatment strategies.
Circulation, 2005; 111:3316–3326.
79. WILMSHURST P.T., STEVENSON R.N., GRIFFITHS H. et al., A case-control investigation of the relation between
hyperlipidaemia and calcific aortic valve stenosis. Heart, 1997; 78:475–9.
80. CHAN K.L., GHANI M., WOODEND K. et al., Case-controlled study to assess risk factors for aortic stenosis in congenitally
bicuspid aortic valve. Am. J. Cardiol., 2001; 88:690–3.
81. ARONOW W.S., AHN C., KRONZON I. et al., Association between coronary risk factors and use of statins with progression
of mild valvular aortic stenosis in older persons. Am. J. Cardiol., 2001; 88:693–5.
82. CHENEVARD R., BECHIR M., HURLIMANN D. et al., Persistent endothelial dysfunction in calcified aortic stenosis beyond
valve replacement surgery. Heart, 2006; 92:1862–63.
83. HALCOX J.P.J., DEANFIELD J.E., Beyond the laboratory: clinical implications for statin pleiotropy. Circulation, 2004;
109(Suppl. II):II-42–II-48.
84. ROSENSON R.S., Statins in atherosclerosis: lipid-lowering agents with antioxidant capabilities. Atherosclerosis, 2004; 173:1–12.
85. TAKEMOTO M., LIAO J., Pleiotropic effects of 3-hydroxy-3-methylglutaryl coenzyme a reductase inhibitors. Arterioscler.
Thromb. Vasc. Biol., 2001; 21:1712–1719.
86. KWAK B., MULHAUPT F., MYIT S., MACH F., Statins as a newly recognized type of immunomodulator. Nat. Med. 2000;
6:1399–1402.
87. RAJAMANNAN N.M., SUBRAMANIAM M., SPRINGETT M., SEBO T.C., NIEKRASZ M. et al., Atorvastatin inhibits
hypercholesterolemia-induced cellular proliferation and bone matrix production in the rabbit aortic valve. Circulation, 2002;
105:2660–2665.
88. POHLE K., MAFFERT R., ROPERS D. et al., Progression of aortic valve calcification: association with coronary
atherosclerosis and cardiovascular risk factors. Circulation, 2001; 104:1927–1932.
89. YILMAZ M.B., GURAY U., GURAY Y. et al., Lipid profile of patients with aortic stenosis might be predictive of rate of
progression. Am. Heart J., 2004; 147:915–918.
90. BELLAMY M.F., PELLIKKA P.A., KLARICH K.W. et al., Association of cholesterol levels, hydroxymethylglutaryl coenzyme
A reductase inhibitor treatment, and progression of aortic stenosis in community. J. Am. Coll. Cardiol., 2002; 40:1731–1734.
91. SHAVELLE D.M., TAKASU J., BUDOFF M.J. et al., HMG CoA reductase inhibitor (statin) and aortic valve calcium. Lancet,
2002; 359:1125–1126.
92. ROSENHEK R., RADER F., LOHO N. et al., Statins but not angiotensinconverting enzyme inhibitors delay progression of
aortic stenosis. Circulation, 2004; 110:1291–1295.
93. MOURA L.M., RAMOS S.F., ZAMORANO J.L. et al., Rosuvastatin Affecting Aortic Valve Endothelium to Slow the
Progression of Aortic Stenosis. J. Am. Coll. Cardiol., 2007; 49:554–561.
94. COWELL S.J., NEWBY D.E., PRESCOTT R.J. et al., Scottish Aortic Stenosis and Lipid Lowering Trial, Impact on Regression
(SALTIRE) Investigators A randomized trial of intensive lipid-lowering therapy in calcific aortic stenosis. N. Engl. J. Med.,
2005; 352:2389–2397.
95. ROSSEB A.B., PEDERSEN T.R., BOMAN K. et al., Intensive Lipid Lowering with Simvastatin and Ezetimibe in Aortic
Stenosis. NEJM, 2008; 359:1343–56.
96. RAJAMANNAN N.M., OTTO C.M., Targeted therapy to prevent progression of calcific aortic stenosis. Circulation, 2004;
110:1180 –1182.
97. ANTONINI-CANTERIN F., HÎRŞU M., POPESCU B.A., LEIBALLI E., PIAZZA R. et al., Stage-related effect of statin
treatment on the progression of aortic valve sclerosis and stenosis. Am. J. Cardiol., 2008 Sep. 15; 102(6):738–42.
98. ROUTLEDGE H.C., TOWNEND J.N., ACE inhibition in aortic stenosis: dangerous medicine or golden opportunity? J. Hum.
Hypertens., 2001; 15:659–667.
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330
Carmen Ginghină et al.
12