www.elsevier.com/locate/ijcard

International Journal of Cardio

Echocardiographic anatomy of ascending aorta dilatation: Correlations

with aortic valve morphology and function

Alessandro Della Corte a,b,*, Gianpaolo Romano a, Francesco Tizzano a, Cristiano Amarelli a,

Luca S. De Santo a, Marisa De Feo a, Michelangelo Scardone a, Giovanni Dialetto a,

Franco E. Covino a, Maurizio Cotrufo a

a Department of Cardiothoracic Sciences, Second University of Naples, Department of Cardiovascular Surgery and Transplants,

Monaldi Hospital, Naples, Italyb PhD Program ‘‘Medical and Surgical Physiopathology of the Cardio-Respiratory System and Associated Biotechnologies’’,

Second University of Naples, Italy

Received 2 April 2005; received in revised form 10 October 2005; accepted 15 November 2005

Available online 18 January 2006

Abstract

Background: Different anatomical forms of proximal aortic dilations associated with aortic valve disease can be distinguished by

echocardiography. Differences in the anatomy could reflect different pathogeneses and need for different therapeutic approaches. The present

study assessed the clinical features associated to each anatomical form, particularly focusing on the relations with valve morphology and

function.

Methods: Trans-thoracic and trans-esophageal echocardiography reports of 552 adult patients (mean age 60.4T12.8 years; 379 male) with

mild to severe proximal aorta dilation were reviewed. The relationships between the anatomy of aorta dilatation (distinguished into ‘‘root

type’’ dilatation, with maximal enlargement at the sinuses, and ‘‘mid-ascending type’’, with maximal diameter at the mid-ascending tract) and

aortic valve morphology (tricuspid/bicuspid) and function (normal/stenosis/regurgitation) were assessed. The relations with other clinico-

echocardiographic variables were also tested in univariate and multivariate analysis.

Results: A ‘‘root type’’ dilatation was found in 4.9% tricuspid patients with stenosis, 32.3% with regurgitation, 22.5% with normal valve

function ( p =0.018). Dilatation prevailed at the mid-ascending tract in patients with bicuspid aortic valve, irrespective of valve function

(stenotic: 92.9%, regurgitant: 87.9%, normal: 94.3%; p =0.23). Predominant root involvement was significantly more prevalent in male

patients (24.8% versus 5.2% in females; p <0.001). In multivariate analysis, predominant aortic valve regurgitation (OR=1.83; p =0.028)

independently predicted root site, while predominant aortic valve stenosis (OR=3.70; p =0.001), bicuspidity (OR=2.90; p =0.005) and

female sex (OR=6.10; p <0.001) predicted mid-ascending site.

Conclusions: Pathogenetical considerations arise from the evidence of preferential mid-ascending localization of bicuspid-associated aortic

dilatations. This finding is consistent with previous studies on bicuspid valve models revealing a wall stress overload beyond the sino-tubular

ridge.

D 2005 Elsevier Ireland Ltd. All rights reserved.

Keywords: Echocardiography; Aortic valve disease; Aortic dilatation; Bicuspid aortic valve

0167-5273/$ - see front matter D 2005 Elsevier Ireland Ltd. All rights reserved.

doi:10.1016/j.ijcard.2005.11.043

* Corresponding author. Via A. Modigliani 64, 81031, Aversa-CE, Italy.

Tel.: +39 081 8111987; fax: +39 081 5464594.

E-mail address: aledellacorte@libero.it (A. Della Corte).

1. Introduction

The anatomical heterogeneity of the aneurysms of the

ascending aorta is reflected by the wide spectrum of

available surgical techniques of repair. Among factors

suggesting the most appropriate procedure to choose,

besides patient-related characteristics (i.e. demographics,

logy 113 (2006) 320 – 326

A. Della Corte et al. / International Journal of Cardiology 113 (2006) 320–326 321

co-morbidities, need for concomitant procedures), the most

important are the macroscopic anatomy of the dilatation

and the underlying pathology [1]. The clinico-anatomical

factors to consider also include the presence of aortic valve

acquired disease or congenital malformation. In particular,

congenital bicuspid aortic valve has long been recognized

as a predisposing factor to early development of aortic

aneurysms, suggesting a common defect underlying both

valve malformation and aortic wall weakness [2–4],

although no clear genetic substrate has been identified so

far. Conversely, some authors have argued that the aortic

wall pathology could be mainly secondary to abnormal

wall stress due to altered post-valvular hemodynamics

[5,6]. Flow characteristics are known to possibly influence

the morphology and even the microstructure of the vessel

wall [6].

The observation that different anatomical forms of aortic

dilatation (usually defined as ‘‘fusiform’’ or ‘‘tubular’’ in

case of aneurysms localized at the mid-ascending tract, and

‘‘pear-shaped’’ or ‘‘teardrop’’ in case of predominant

involvement of the sinuses) exist is quite often reported in

the published series, deriving from everyday clinical

experience [7–11]. However, to our knowledge, no study

has so far provided data on the epidemiology of the different

possible anatomical types. During the last decade, the

ascending aorta has passed from being considered a passive

tube structure to being recognized as having crucial

importance in conditioning hemodynamics with its complex

geometry and function. Thereby, every effort must be made

to tailor surgical treatment to the specific anatomy and

underlying disease, trying to respect this functional role.

The purpose of this study was to quantify the respective

prevalence of the two types of ascending dilatation and their

relations with the patient’s clinical characteristics, above all

with valve morphology and function. Epidemiological

insights may also help to go further into the understanding

of the pathogenetic mechanisms and to establish the most

adequate surgical indications.

2. Patients and methods

2.1. Selection criteria

The computerized database of the Echocardiography

Unit of our Institution was retrospectively reviewed and all

trans-thoracic and trans-esophageal examinations performed

between January 1994 and January 2004 evidencing a

dilatation of the proximal aorta were selected. The criteria to

admit a patient’s file into the study included adult age and

aortic dilatation (an aortic diameter exceeding the normal

value for age and body surface area as predicted by the

formulas of Roman [12]: dilatation was considered mild if

the aortic ratio was 1.1–1.25, moderate if it was 1.26–1.49

or severe when it reached or exceeded 1.5) at any of the

following three levels of measurement: sinuses, sino-tubular

junction, mid-ascending aorta. Criteria of exclusion from the

study were: previous cardiac surgery, concomitant non-

aortic cardiac disease (except coronary artery disease), aortic

acute or chronic dissection, Marfan’s syndrome, aortic valve

and/or root endocarditis. Another criterion of exclusion (4

patients) was the impossibility to define the aortic valve

morphology as tricuspid or bicuspid (cases labeled by the

echocardiographist as ‘‘likely bicuspid’’ or ‘‘undefined’’),

unless an adjunctive trans-esophageal examination had been

performed clarifying valve morphology. Thus, 552 patients

constituted the study population (mean age 60.4T12.8,range 19 to 96; 173 female).

2.2. Echocardiography

Echocardiography was always performed by one of the

same two operators, using an Acuson Sequoia C256

machine (Acuson, Mountain View, CA) with a multi-

frequence 3V2C sector-scan. The morphology of the aortic

valve was defined as tricuspid or bicuspid in the parasternal

short-axis view. The severity of aortic stenosis was graded

on the basis of trans-valvular gradients, the degree of aortic

regurgitation was defined by means of standard color-

Doppler criteria [13,14] as absent, trivial/mild, moderate or

severe. Left ventricular ejection fraction was assessed by 2-

dimensional volume measurements from the apical views.

Measurements of the aorta were performed in two-dimen-

sional parasternal (or trans-esophageal) long-axis views at

the sinuses of Valsalva, the sino-tubular junction and the

ascending aorta at the level of the right pulmonary artery

(mid-ascending tract). All measurements were taken at

hemodynamically stable conditions; results were averaged

from three subsequent measurements in sinus rhythm,

according to the leading-edge method. Trans-esophageal

echocardiograms (performed either for definition of bicus-

pidity or for other reasons) constituted 12.9% of the

examinations included in this study. Since our institution

is a tertiary referral centre, serial echocardiograms were

available only for a little subset of patients and they were

not considered in the present study: from each patient’s file

in the echocardiographic database only the most recent

examination was considered.

2.3. Variable definitions

Age and body surface area (BSA) were coded as both

continuous variables and dichotomic categorical variables

(using the median value as cut-off). Other clinical variables

included in the analysis were: sex, sub-optimal blood

pressure control (history of hypertension and blood pressure

>140/90 mm Hg, with or without current treatment [15]),

atherosclerosis (imaging or intraoperative evidence of

atherosclerosis of the aorta or other vascular districts

including coronary, supra-aortic, abdominal aorta, lower

limbs), diabetes, and smoke. Echocardiographic variables

included in the database were: ejection fraction and left

Table 1

Clinical and echocardiographic characteristics in the overall population and

in the two groups of patients divided according to the site of aortic

dilatation

Total

population

(n =552)

Ascending

type

(n =449)

Root type

(n =103)

P*

Age (years) 60.4T12.8 60.5T13.2 60.2T11.2 0.84

Female sex 173 (31.3%) 164 (36.5%) 9 (8.7%) <0.001

BSA (m2) 1.81T0.17 1.81T0.18 1.84T0.13 0.13

Hypertension 167 (30.3%) 133 (29.6%) 33 (32%) 0.35

Atherosclerosis 73 (13.2%) 57 (12.7%) 16 (15.5%) 0.27

Smoke 87 (15.8%) 60 (13.4%) 27 (26.2%) 0.002

Diabetes 31 (5.6%) 26 (5.8%) 5 (4.9%) 0.47

BAV 110 (19.9%) 101 (22.5%) 9 (8.7%) 0.001

Stenosis 193 (35%) 180 (40.1%) 13 (12.6%) <0.001

Regurgitation 301 (54.5%) 229 (51%) 72 (69.9%) <0.001

Sinuses (cm) 4.0T0.8 3.8T0.6 4.9T0.9 <0.001

Sino-tubular (cm) 4.1T0.9 3.9T0.8 4.9T0.9 <0.001

Ascending (cm) 4.9T0.8 5.0T0.8 4.4T0.8 <0.001

* Ascending type versus root type. Stenosis and regurgitation are codified

as dichotomic variables (presence or absence of at least moderate degree).

For the valve function variable see Fig. 1.

Table 2

Comparison of clinical and echocardiographic variables between tricuspid

aortic valve (TAV) and bicuspid aortic valve (BAV) patients with aortic

dilatation

TAV (n =442) BAV (n =110) P

Age (years) 63.3T10.8 49.0T13.7 <0.001

Female sex 140 (31.7%) 33 (30%) 0.41

BSA (m2) 1.81T0.17 1.83T0.18 0.16

Hypertension 143 (32.4%) 23 (20.9%) 0.012

Atherosclerosis 68 (15.4%) 5 (4.5%) 0.001

Smoke 68 (15.4%) 19 (17.3%) 0.36

Valve function 0.016

Normal 102 (23.1%) 35 (31.8%)

Prevalent stenosis 142 (32.1%) 42 (38.2%)

Prevalent regurgitation 198 (44.8%) 33 (30%)

Sinuses (cm) 4.1T0.8 3.8T0.8 0.006

Sino-tubular junction (cm) 4.2T0.9 4.0T0.9 0.08

Ascending (cm) 4.9T0.8 5.1T0.9 0.06

A. Della Corte et al. / International Journal of Cardiology 113 (2006) 320–326322

ventricular diameters, codified as continuous variables,

valve morphology (tricuspid or bicuspid) and valve func-

tion, codified as follows: one variable indicated the degree

of aortic stenosis and one the degree of regurgitation (four

categories each, from none to severe); two dichotomic

variables indicated the presence/absence of clinically

relevant (�moderate) stenosis and regurgitation respective-

ly; another variable indicated predominant valve dysfunc-

tion, divided into three categories (normally functioning,

defined as absence or mild degree of dysfunction [16];

stenotic, defined as stenosis degree>regurgitation degree;

regurgitant, defined as regurgitation degree>stenosis de-

gree). The aortas included in the study were assigned to one

of two main anatomical groups according to the segment of

the vessel exclusively or predominantly involved by

dilatation: ‘‘mid-ascending’’ type, if the diameter distal to

the sino-tubular junction (mid-ascending tract) exceeded

those at the root; ‘‘root’’ type, if the maximal observed

diameter was at the level of the sinuses or (more rarely) at

the junction.

2.4. Statistical analysis

Continuous variables were summarized as meanT stan-standard deviation and comparisons between groups were

made by mean of Student’s t test. Categorical variables were

expressed in percentages and differences analysed using chi-

square or Fisher’s exact test when appropriate. Comparisons

were made for all the above variables between the two types

of ascending dilatations as well as between subgroups of

patients divided according to valve morphology and disease.

In order to find independent predictors of the anatomical

type of dilatation (mid-ascending or root), stepwise logistic

regression models were developed for the overall population

and also stratified according to valve functional status.

Variables included in multivariate analysis were: age, BSA,

sex, valve morphology, valve function, hypertension,

atherosclerosis, diabetes, smoke, ejection fraction and left

ventricular diameter (all variables were codified as reported

in the previous paragraph). In order to avoid interferences

between the two variables of age and sex (female patients

were older), only age-matched pairs of male and female

patients with tricuspid aortic valve from the present study

(total number=258 patients) were included in a separate

univariate and multivariate analysis. The SPSS (SPSS,

Chicago, IL) software package (ver. 11.0) was used for

statistical analysis.

3. Results

3.1. Demographics and clinical features

Baseline clinical characteristics of the overall population

and of the two groups of patients divided according to the

site of aortic dilatation are shown in Table 1. Mid-ascending

aortic dilatation (449 patients) was more commonly

observed than root dilatation (103 patients). The prevalence

of bicuspid aortic valve in the total study population was

19.9% (110 patients); the most frequent aortic valve

dysfunction was predominant regurgitation (41.8%). The

prevalence of female sex and of bicuspid aortic valve was

significantly higher in the mid-ascending group, while

smoke habit was associated to root site. As to valve

function, the presence of significant stenosis was found to

be associated with mid-ascending site, whereas regurgitation

was more frequently observed in the root group.

3.2. Aortic valve morphology and function

Table 2 shows the comparisons between tricuspid and

bicuspid patients. Patients with a bicuspid valve were

significantly younger than those with tricuspid aortic valve.

No significant difference in body surface was found, none

Fig. 1. Percent distributions of the two types of dilatation (root type and

mid-ascending type) in subgroups of patients divided according to aortic

valve structure and function. BAV=bicuspid aortic valve; TAV=tricuspid

aortic valve.

Fig. 2. Gender-related differences in percent distributions of the two types

of dilatation (root type and mid-ascending type) in subgroups of patients

divided according to aortic valve function.

A. Della Corte et al. / International Journal of Cardiology 113 (2006) 320–326 323

also in sex. Aortic diameters at the sinusal and sino-tubular

levels were significantly greater in the tricuspid group,

while at the mid-ascending level slightly greater diameters

were found in the bicuspid group. When patients were

divided according to valve morphology (bicuspid or

tricuspid), then only among tricuspid patients normal

function, predominant stenosis and predominant regurgita-

tion corresponded to significantly different percentages of

dilatation site (Fig. 1): root dilatation was present in 4.9%

cases of tricuspid aortic valve stenosis (versus 22.5% in

normally functioning tricuspid valves, p<0.001) and 32.3%

of tricuspid regurgitation (versus normal: p =0.049; versus

stenosis: p <0.001). On the contrary, in patients with

bicuspid valve, dilatation prevailed at the mid-ascending

level regardless of different valve function (92.9% in

stenotic bicuspid versus 94.3% in normally functioning

bicuspid, p =0.59; 87.9% in regurgitant valves; p =0.31

versus normal, p =0.36 versus stenosis). On the other side,

after stratification for valve function, the higher prevalence

of mid-ascending level in bicuspid versus tricuspid patients

(Fig. 1), as well as in female versus male patients (Fig. 2),

remained significant in the settings of normal valve function

or regurgitation, but not in stenosis (95.1% for tricuspid

valves versus 92.9% for bicuspid valves, p =0.41; 98.6% in

female patients versus 92.2% in male patients, p =0.06).

3.3. Gender and age

Female patients, accounting for 31.3% of the present

series, were on average older (63.2T12 versus 59.1T13

years; p < 0.001) and had lower body surface area

(1.69T0.15 versus 1.87T0.15 m2; p <0.001) than men. As

regards valve function, women had aortic predominant

stenosis more often and normally functioning valve more

rarely than men (Table 3). The two genders did not differ for

prevalence of hypertension (30.1% in women, 30.3% in

men) and diabetes (6.3% versus 5.3%), while atherosclero-

sis (6.9% versus 16.1%; p =0.002) and smoke (8.7% versus

19%; p =0.002) were more frequent in male patients.

Patients >62 years of age showed a trend towards higher

prevalence of mid-ascending site of dilatation. This differ-

ence approached statistical significance only in tricuspid

patients (81.7% versus 76.4%; p =0.046; bicuspid patients:

95.2% versus 91%; p =0.46). No age-related differences

were observed in terms of valve function. When age-

matched pairs of male and female patients were analysed,

female sex still was associated to significantly higher

prevalence of mid-ascending site (93% versus 69% in

men; p <0.001).

3.4. Poorly controlled hypertension

Patients with suboptimal blood pressure control were

older (63T10.5 versus 58.9T14.3 years; p =0.14), had

significantly greater mean mid-ascending diameters

(5.3T1.0cm versus 5.0T0.8; p =0.012) and mean sino-

tubular junction diameters (4.3T0.9cm versus 4.0T0.8;p =0.002) than normotensive ones (mean sinus diameter

was only by trend greater in hypertensive patients:

4.2T1.0cm versus 4.0T0.8; p =0.06). Hypertensive patientswith tricuspid aortic valve presented more often with

Table 3

Gender-related differences in echocardiographic variables in 552 patients

with aortic dilatation

Men

(n =379)

Women

(n =173)

P

BAV 77 (20.3%) 33 (19.1%) 0.41

Valve function 0.06

Normal 101 (26.6%) 35 (20.2%)

Prevalent stenosis 115 (30.3%) 69 (39.9%)

Prevalent regurgitation 163 (43%) 69 (39.9%)

Absence of stenosisa 220 (58%) 56 (49.7%) 0.17

Absence of regurgitationa 78 (20.6%) 55 (31.8%) 0.02

Ejection fraction (%) 57.7T7 60.2T6 <0.001

Left ventricle end-diastolic

diameter (cm)

5.76T0.8 5.26T0.7 <0.001

Sinuses (cm) 4.2T0.8 3.6T0.7 <0.001

Sino-tubular junction (cm) 4.3T0.8 3.8T1.0 <0.001

Ascending (cm) 4.9T0.8 5.0T0.9 0.64

Aortic ratio (root)b 1.3T0.2 1.2T0.2 <0.001

Aortic ratio (ascending)b 1.5T0.2 1.6T0.3 <0.001

a Computed as a single variable with four possible modalities (from

absence to severe).b Measured values divided by normal diameters for age and BSA [14].

A. Della Corte et al. / International Journal of Cardiology 113 (2006) 320–326324

predominant aortic regurgitation (65.7%) and more rarely

with stenosis (11.2%) than normotensive tricuspid patients

(34.8% and 42.1% respectively; p <0.001); no significant

differences were found between hypertensive and normo-

tensive bicuspid patients as to valve function. Only in the

setting of regurgitant tricuspid aortic valve, hypertension

was associated with significantly higher prevalence of mid-

ascending type (74.5% versus 61.5% in normotension;

p =0.03). Aortic stenosis patients with hypertension were 24

and they all had a mid-ascending type, regardless of valve

morphology (although the difference with normotensive

patients with stenosis was not significant: 100% versus

93.8%; p =0.24).

3.5. Independent predictors of dilation site

In multivariate analysis (Table 4), predominant aortic

valve regurgitation independently predicted root site. Mid-

Table 4

Factors (first column) predicting the site of maximal involvement in 552 patients

regression models)

All patients (n =552) Subgroupsa

Patients wi

function (n

OR 95% CI p OR

Root site

Aortic regurgitation 1.83 1.1–3.1 0.028 –

(Smoke) – – – 26

Mid-ascending site

Female sex 6.10 2.9–12 <0.001 4.9

Aortic stenosis 3.70 1.7–8.1 0.001 –

BAV 2.90 1.4–6.1 0.005 10

(Age>62 years) – – – 3.0

a No predictor was found either of root or of ascending site in the setting of ao

ascending dilation was predicted by predominant aortic

valve stenosis, bicuspid valve and female sex. The results of

stratified regression models are shown in Table 4. Notably,

in the subgroup with normal valve function, smoke emerged

as independent predictor of root dilation, while age >62

years, bicuspidity and, more weakly, female sex predicted

mid-ascending dilation. When age-matched pairs of male

and female patients were analysed, besides aortic valve

stenosis and female sex, also age >62 years appeared among

the predictors of mid-ascending site (OR=2.26; 95%CI

1.1–4.6; p =0.025).

4. Discussion

Differences in the anatomy of proximal aortic dilatations

could reflect differences in their pathogenesis. The multiple

factors predisposing to aortic dilatation, such as medial

degeneration, atherosclerosis, hypertension, aortic valve

disease, could differently combine in the determination of

each clinico-anatomical picture. For instance, the typical

anatomical presentation of aortic aneurysms in Marfan

patients is root enlargement [17,18] and this relates to the

pattern of normal distribution of fibrillin-rich elastic fibers,

which is maximal at the aortic sinuses and then decreases

gradually into the distal segments [19]. In the present study,

the exclusion of patients with inherited elastic tissue

disorders could account for the low prevalence of root type

aneurysms—about one-fifth of the study population.

According to the main finding of the present study, in

patients with aortic dilatation the presence of a bicuspid

valve, irrespective of its functional status, is associated with

a predominant enlargement of the mid-ascending tract,

while root involvement is rare. It is worthy of note that

mean sinus diameter in the bicuspid subgroup of the present

series was 3.8 cm, a normal value for the mean age and

body surface of our bicuspid patients. Consistently, in

previous studies on younger patients with bicuspid valve the

most frequent site of dilatation and the site of maximal

with aortic dilatation and in subgroups of valve function (stepwise logistic

th normal valve

=137)

Patients with aortic

regurgitation (n =231)

95%CI p OR 95% CI p

– – – – –

2–287 0.007 – – –

1.0–23 0.044 6.4 2.6–16 <0.001

– – – – –

1.7–57 0.009 3.5 1.1–11 0.026

1.1–8.2 0.037 – – –

rtic valve stenosis.

A. Della Corte et al. / International Journal of Cardiology 113 (2006) 320–326 325

annual growth rate was the ascending tract [16,20,21].

From a clinical point of view, our findings could provide a

rationale for the high freedom from aortic re-dilatation

previously reported in the follow-up after surgical treat-

ment of bicuspid-associated aneurysms using techniques

that leave the native root untreated, i.e. separate valve and

graft replacement [9] and ascending reduction aortoplasty

[8]. Notably, in recent flow pattern studies the abnormal

opening mechanism of bicuspid valves (even in the

absence of significant gradient) has been found to cause

excessive post-valvular recirculation vortices: unlike in the

trileaflet valve, those vortices were not confined into the

sinuses of Valsalva, but extended into the mid-ascending

tract, where the aortic wall stress was thereby locally

increased [5]. After that evidence, the observation that

aortic dilatation occurs also in the absence of valve

dysfunction [4] could not exclude anymore a pathogenetic

role of the hemodynamic disturbance. The typical locali-

zation of aortic dilatation beyond the sino-tubular junction

in our series reflects those abnormal hemodynamic patterns

associated to bicuspid morphology [5], suggesting an

important pathogenetical role of mechanical stress. The

supposed inherent structural defect of the vessel wall

should not be then considered equally and diffusely

expressed in the whole proximal aorta, but it could consist

of a predisposition of the aortic media to degenerate

Fig. 3. Algorithm showing the distribution of the overall population in subgroups o

valve; hyper=hypertensive; normo=normotensive; R=root; TAV=tricuspid aorti

reg=regurgitant aortic valve.

locally where flow disturbances, due to the mere cusp

malformation [5] or also to superimposed valve stenosis/

regurgitation, cause wall stress to increase. Consistently

with this hypothesis, in immunohistochemical studies

recently performed at our Institution, changes in extra-

cellular matrix protein expression in the dilated aorta of

bicuspid aortic valve patients were locally more severe

where wall stress load was expected to be greater [22].

Along with bicuspidity, other factors were found to

predict the localization of the disease at the mid-ascending

level. Fig. 3 shows an algorithm drawn dividing the study

population according to the most important variables

studied. The finding of aortic valve stenosis increasing the

probability of mid-ascending localization also may highlight

the importance of hemodynamic factors. Aortic post-

stenotic dilatation, which is encountered in about 1/4 cases

of aortic valve stenosis, is usually localized distally to the

sinuses of Valsalva [23]. Trying to quantify the magnitude

of the ‘‘post-stenotic’’ phenomenon in our population of

patients with aortic dilatation, it can be pointed out that

those with a stenotic tricuspid aortic valve had an 18%

increase in the prevalence of mid-ascending type when

compared to those with normally functioning valve.

The predominance of mid-ascending type dilatations in

women was quite striking and deserves further investiga-

tion. As demonstrated in the separate sub-analysis of age-

f clinical features. Abbreviations: A=mid-ascending; BAV=bicuspid aortic

c valve; nor=normally functioning aortic valve; ste=stenotic aortic valve;

A. Della Corte et al. / International Journal of Cardiology 113 (2006) 320–326326

matched pairs of male and female patients, in fact, the older

age of female patients in this study may explain this finding

only in part. It is noteworthy that, while bicuspidity is

reported to occur far more frequently in male than in female

subjects [20], in patients with aortic dilation female sex

prevalence was similar between bicuspid and tricuspid

aortic valve patients.

As regards hypertension, our data confirm in patients

with aortic dilatation the findings already forwarded by

larger studies in population-based samples: Kim and co-

workers [24] found that hypertension is related to signifi-

cantly higher sino-tubular and mid-ascending diameters and

only marginally greater sinus dimensions. However, in that

study mean aortic diameters were obviously lower at all

measured levels than in ours, so the authors did not find the

higher prevalence of aortic regurgitation in hypertensive

than normotensive subjects that we observed.

Some limitations of this study must be acknowledged.

Our findings are drawn from a population of patients with

mild to severe dilatation of the aorta undergoing in-hospital

and out-patient echocardiography: the results reflect the

referral patterns of those patients and may not apply to the

general population with aortic dilatation. Other limitations

derive from the retrospective nature of the study. For

example, not all the patients included in the echocardio-

graphic database were subsequently operated on at our

institution: therefore, we could not properly define the

‘‘atherosclerosis’’ variable by pathology examination of

aortic specimens and this could have caused the lack of

any correlation between atherosclerosis, as it was defined in

this study, and aneurysm type. Finally, the lack of

confirmation of the results with another technique for the

study of the thoracic aorta (e.g. computed tomography) may

be considered another relative limitation.

In conclusion, this was the first study on a large series of

aortic dilatation to address the epidemiology of the two

different anatomical forms. In particular, the finding of a

preferential mid-ascending localization of bicuspid-associ-

ated forms, with commonly unaffected root, seems to be in

contrast with the hypothesis that a diffuse genetically

determined aortic wall weakness may be sufficient to cause

dilatation, whereas it is in accordance with the previous

evidence of a wall stress overload localized beyond the sino-

tubular ridge. If prospectively confirmed, this finding could

also indicate that surgical techniques for patients with

bicuspid aortic valve and dilated ascending aorta could

address only the mid-ascending tract, being the risk of root

involvement significantly lower.

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