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PREVALENCE AND PATTERN OF AORTIC REGURGITATION IN MIDDLE-
AGED TO ELDERLY HYPERTENSIVE NIGERIANS.
*Akintomide AO, *Adebayo RA, *Ajayi OE, *Ogunyemi SA, *Abiodun OO,
˟Onakpoya UU, **Oyedeji AT, ***Ajayi EA, *Adeyeye VO, ****Akintunde AA, *Balogun
MO
*Cardiology Unit, Obafemi Awolowo University Teaching Hospitals Complex, Ile-Ife, Osun
state, Nigeria.
˟ Cardiothoracic Unit, Obafemi Awolowo University Teaching Hospitals Complex, Ile-Ife,
Osun state, Nigeria.
**Chevron Clinic, Lagos state.
***University Teaching Hospital, Ado-Ekiti, Ekiti state.
****Ladoke Akintola University of Technology, Osogbo, Osun state.
Correspondence: Dr A.O.Akintomide FWACP,
Department of Medicine,
Obafemi Awolowo University,
Ile-Ife, Osun State, Nigeria.
tony_akintomide@yahoo.co.uk
ABSTRACT
Background
Hypertension is the commonest cause of sudden cardiac death in Nigeria and a notable cause
or contributor to valvular heart disease in patients with hypertension. It engenders this
catastrophe via several pathophysiological mechanisms. Its prevalence has continued to rise
significantly and the damage it does to the valves poses additional risks to patients. We
therefore look at its contribution to the pattern and prevalence of aortic regurgitation.
Methods
We evaluated and compared demographic, clinical and echocardiographic variables with the
presence and severity of aortic regurgitation in 1225 middle-aged to elderly hypertensives
using chi square, analysis of variance (ANOVA) and post hoc tests to differentiate within
groups after ANOVA. A linear regression analysis was used to compare dependent variable
with independent variables. P value <0.05 was taken as statistically significant.
Results
Two hundred and fifty-five patients (20.7%) had mild AR, 118 (9.6%) moderate AR and 70
patients (5.7%) had severe aortic regurgitation. The occurrence of aortic regurgitation
increases with age (p<0.001) in hypertensive patients. Patients with aortic regurgitation also
have increased left ventricular mass index (p<0.001), left ventricular end-diastolic volume
(p<0.001), left ventricular dimension in diastole (p<0.001) and aortic root diameter
(p<0.001). The ejection fraction and fractional shortening were significantly lower in patients
with aortic regurgitation than those without.
Conclusion
Aortic regurgitation is common in patients with hypertension in our environment and its
presence and severity increases strongly with age in these. The presence of aortic
regurgitation should be considered an additional adverse factor in patients with hypertension.
BACKGROUND
Aortic regurgitation (AR) secondary to marked dilatation of the ascending aorta is now more
common than primary valve disease. The conditions responsible for aortic root disease
include age-related (degenerative) aortic dilation, cystic medial necrosis of the aorta (either
isolated or associated with classic Marfan syndrome), aortic dilation related to bicuspid
valves, aortic dissection, osteogenesis imperfecta, syphilitic aortitis, ankylosing spondylitis,
Behcet’s syndrome, psoriatic arthritis, arthritis associated with ulcerative colitis, relapsing
polychondritis, reactive arthritis, giant cell arthritis, exposure to some appetite suppressant
drugs and systemic hypertension (1). In our preliminary echocardiographic observation,
hypertension is the commonest cause (2).
AR, regardless of its cause, produces dilation and hypertrophy of the left ventricle, dilation
of the mitral valve ring, and sometimes hypertrophy and dilation of the left atrium. In
advanced stages, there is a rise in left atrial, pulmonary artery wedge, pulmonary arterial,
right ventricular (RV), and right atrial pressures and the effective (forward) cardiac output
falls. Symptoms of heart failure, particularly those secondary to pulmonary congestion, then
develop (1). It is important to examine the contribution of hypertension to valvular heart
disease in Nigeria because of increasing prevalence of hypertension, the dearth of skilled
manpower for and unaffordability of surgery for valvular heart disease.
Keywords: Aortic regurgitation, Middle-aged to elderly, Hypertensives
METHODS
One thousand, two hundred and thirty-one hypertensive patients 45 years and older who
presented at the echocardiography laboratory of the cardiac care unit of OAUTHC, Ile-Ife
were evaluated. Hypertension was diagnosed according to the seventh report of the Joint
National Committee on detection, evaluation and treatment of high blood pressure (JNC-V)
criteria (3). Aortic regurgitation was assessed using colour flow doppler echocardiography in
1225 patients because Doppler scan was technically difficult in six, thus they were excluded
from the final analysis.
This study was performed using Siemens Sonoline G60s echocardiography (4.5MHz phased
array transducer) with M-mode, two-dimensional and pulsed, continuous wave and color flow
Doppler modalities (4,5). Examination couch with the head of the couch elevated 30° in a
partial decubitus position was used. The parasternal acoustic window was used for two-
dimensional and M-mode recording of the left ventricular (LV) internal diameter and wall
thickness at or just below the tips of the mitral valve leaflets in long- and short-axis LV views
and long-axis views of the mitral valve. M-mode and two-dimensional short- and long-axis
views of the aortic root and left atrium were also obtained.
Color flow Doppler recordings from the parasternal and apical windows were used to search
for aortic regurgitation (6). Aortic regurgitation (AR) was identified according to the extent of
diastolic turbulent flow in the LV, indicated by a variance signal, with mild (1+) AR
identified by a jet occupying <25% of the aortic annular diameter at its origin and extending
less than half way to the tip of the anterior mitral leaflet; moderate (2+) AR by jets filling
25% to 45% of the annular diameter extending up to the tip of the anterior mitral leaflet; and
severe (3+) AR by jets occupying >45% of the annular diameter extending to or slightly
beyond the tip of the anterior mitral leaflet (6).
Measurements were made by two experienced observers. Correct orientation of planes for
imaging and Doppler recording was verified as previously described (7). Left ventricular
internal dimension and interventricular septal and posterior wall thickness were made at end
diastole and end systole on up to three cycles, according to American Society of
Echocardiography (ASE) recommendations (8). When optimal LV orientation could not be
obtained, as is common in subjects who are overweight or >60 years old, correctly oriented
two-dimensional linear dimensions were made by the ASE leading-edge convention (9).
Aortic root diameter was measured from the leading edge to the leading edge using M-mode
scan from the parasternal long axis view at the aortic valve level. (10).
STATISTICAL ANALYSIS:
Data analysis was performed using a computer equipped with SPSS 16 software (SPSS,
Chicago, Illinois). Data were reported as the mean value ± SD for continuous variables and
proportions for categoric variables. The prevalence of AR delineated by gender was assessed
by the chi-square test. Differences in clinical variables among participants with and without
AR were assessed by one-way analysis of variance and differences within groups were
examined using post hoc tests (10). Independence of an association of other variables with
AR was assessed by logistic and linear regression analyses. p < 0.05 was considered
statistically significant.
RESULT:
A total of 1231 patients had echocardiograms (675 men and 556 women, age range 45 to 90
years [mean 62 ± 10]). Mean systolic blood pressure (SBP) was 146 ±38, mean diastolic
blood pressure (DBP) of 88 ±12 mm Hg while mean body mass index was 27 ± 6 kg/m2.
Six patients with technically poor doppler echocardiograms were excluded from the study
leaving a total of 1225 hypertensive patients for further analysis.
Four hundred and forty-three patients (36%) of the 1225 hypertensives studied had aortic
regurgitation. More males, two hundred and sixty-four (39.5%) had AR compared to one
hundred and seventy-nine (32.3%) females.
Table 1: Demographic, clinical and echocardiographic characteristics of patients with
and without AR.
Variable
No AR
AR present
p value
Gender (M)
409
264 (39.5%)
0.02
Gender (F)
373
179 (32.3%)
Mean age(years)
60.5±9.5
64.3±11
<0.001
Mean duration (years)
7.0±8.5
6.8±7.6
0.79
Mean BMI (kg/m2)
27.9±5.6
26.5±5.5
<0.001
Mean sbp (mmhg)
147.3±45
146.8±23
0.81
Mean dbp (mmhg)
88.3±12.9
88.3±13
0.97
IVST (mm)
12.6±2.3
12.7±2.3
0.22
LVPWT (mm)
12.2±3.1
12.6±3.5
0.02
LVMI (g/m2)
110.1±41
124.6±66
<0.001
LVIDD (mm)
43.0±8.9
44.5±10
0.01
LVEDV
107.0±41
129.0±57
<0.001
EF (%)
62.4±21
57.9±23
<0.001
FS (%)
33.0±11.6
30.3±10.8
<0.001
AOD (mm)
32.8±8.8
35.0±9.7
<0.001
AR- aortic regurgitation, BMI- body mass index, SBP- systolic blood pressure, DBP-
diastolic blood pressure, IVST- interventricular septal thickness, LVPWT- left ventricular
posterior wall thickness, LVIDD- left ventricular internal diameter in diastole, EF- ejection
fraction, FS- fractional shortening and AOD- aortic diameter in millimetres.
Two hundred and fifty-five patients (20.7%) had mild AR, one hundred and eighteen (9.6%)
had moderate AR while seventy patients (5.7%) were found with severe aortic regurgitation
as shown in table 2.
Table 2: Demographic, clinical and echocardiographic characteristics according to
severity of AR
Mild AR
Moderate AR
Severe AR
p value
Gender (M)
143
86
35
<0.05
Gender (F)
112
32
35
Mean
age(years)
62.9±10
66.4±9
65.6±10
<0.001
Mean duration
of hypertension
(years)
6.1±7
6.6±7
10.0±10
ns
Mean BMI
(kg/m2)
27.1±6
25.9±5
24.9±4
ns
Systolic BP
(mmHg)
148.0±24
147.1±23
144.0±23
ns
Diastolic BP
(mmHg)
89.1±13
87.8±13
86.6±13
ns
IVST (mm)
12.8±2.4
12.7±2.3
12.6±2.5
ns
LVPWT (mm)
13.1±6.8
12.7±2.79
12.7±3.3
ns
LVMI(g/m2)
123.5±75
129.5±49.7
124.6±50.5
ns
LVIDD (mm)
43.8±10
46.2±11
44.6±8
ns
LVEDV
121±53
134±70
107±43
ns
EF (%)
57.7±23.7
56.9±21.3
60.6±22.2
ns
FS (%)
30.1±10.7
29.3±10.7
30.9±9.5
ns
AOD (mm)
35.6±10
34.4±9
33.6±9
ns
ns- not significant.
The Tables 1& 2 show other clinical, demographic and echocardiographic variables as they
affect the prevalence and severity of AR. AR occurred with increased age of patients with
60.5±9.5years for those without AR and 64.3±11 years for those with mild AR (p<0.05)
while in table 2 the mean age of patients increased with severity of AR (p<0.05). The mean
duration of illness for those with AR (6.8±7.6) was shorter compared to those without AR
(7.0±8.5) but table 2 shows increased duration of illness for patients with severe AR at10±10
years. The presence and severity (particularly between mild and moderate AR) of AR was
associated with a lower body mass index (p<0.05).
There were no differences in the systolic (SBP) and diastolic (DBP) blood pressures in
patients with or without AR.
Table1 shows that left ventricular posterior wall thickness (LVPWT) is more in those with
AR than those without AR. There is also a significant increase in the left ventricular mass
index in those with AR (p<0.05) than those without AR.
The left ventricular internal dimension in diastole (LVIDD) and end-diastolic volume
(LVEDV) are higher in patients with AR (p<0.05) than in those without.
Left ventricular ejection fraction (EF) and fractional shortening (FS) (p<0.05) were
significantly lower in patients with AR. Also, EF and FS in severe AR ranged from 38.4 to
82.8% and 21.4 to 40.4% respectively.
Aortic root diameter (AOD) was higher in patients with AR (p<0.05) than those with no AR
and particularly in those with mild and moderate AR.
A linear regression analysis in which the grades (0 to 4+) of severity of AR were used as the
dependent variables were compared with independent variables like age, sex, duration of
symptoms, BMI, SBP, DBP, IVSD, LVPWD, LVIDD, EDV, EF, FS and AOD. Older age
was the strongest predictor of presence and severity of aortic regurgitation (p<0.05), while
BMI negatively predicted the severity of AR (p<0.05).
DISCUSSION
This study shows that over a third of middle-aged to elderly hypertensives studied had AR,
with mild AR more than moderate or severe AR. It also shows that age is the strongest
predictor of the presence and severity of AR. This agrees with other studies and suggests that
aortic valve is damaged over a long period of time due to haemodynamic stress (11, 12). This
study also shows shorter period of hypertension in patients with AR than those without. This
may be as a result of pre-existing asymptomatic valvular disease (13) or genetically pre-
determined early-onset myxomatous aortic valvular degeneration seen in blacks compared
with Caucasians (14, 15, 16).
BMI was found to be negatively correlated with both the presence and severity of AR as
observed by Lebowitz et al (17) in their study. The cause is uncertain but may not be
unrelated to subtle symptoms and medical advice for their hypertension as noted in the same
study.
Aortic root diameter (AOD) was significantly higher in those with AR compared with
patients without AR, and particularly so in mild AR. This positive association between AOD
and the presence and severity of AR has been documented in various studies (18, 19, 20).
This study also shows a positive though insignificant correlation with mild AR probably
because while transthoracic imaging is often satisfactory for assessing the aorta,
transesophageal echocardiography often provides more detail, particularly of the aortic root
(1). Another plausible explanation is the presence of some degree of stenosis associated with
myxomatous or age-related degeneration and calcification of valves observed in patients with
moderate and severe aortic regurgitation in this study.
Left ventricular systolic function as measured by EF and FS were lower in patients with AR
than those without. Some patients with severe AR also showed normal EF and FS, indicating
that severe AR may occur with a normal EF and stroke volume, together with an elevated LV
end-diastolic volume, pressure and stress (21, 22, 23).
Patients with AR showed significant increase in their left ventricular mass index. Left
ventricular hypertrophy (LVH) has been shown to be an independent risk factor for sudden
cardiac death by contributing to the development of potentially lethal arrhythmias (24, 25).
LVH also predisposes patients to stroke and heart failure (26). Hypertension and valvular
heart disease are independent causes of ventricular hypertrophy (1), and patients with
hypertension and AR may be at a more increased risk of sudden cardiac death than patients
with either of these two alone. Patients with AR will therefore benefit from
pharmacotherapeutic agents that significantly reverse cardiac remodelling (27, 28).
CONCLUSION
This study shows that AR is common in patients with hypertension in our environment and
the presence and severity of AR increases strongly with age in these set of patients. The
presence of AR should be considered an additional adverse factor in patients with
hypertension. With increasing prevalence of hypertension, prompt diagnosis and adequate
treatment of hypertension is essential in preventing hypertension-induced valvular disease as
surgery is largely unavailable and unaffordable in Nigeria.
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