Download Mean Arterial Pressure may affect LV Mass even when Clinic BP is

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Journal of the association of physicians of india • october 2013 • VOL. 61 Original Article
Mean Arterial Pressure may affect LV Mass
even when Clinic BP is 120/80 mmHg or Less
SR Mittal*
Abstract
Detailed echocardiographic evaluation was performed on sixty-four normal persons without any
cardiovascular risk factor and clinic blood pressure of 120/80 mm of Hg or less with an aim to find, if there
are subclinical echocardiographic changes even in this population. There was significant positive linear
correlation between mean arterial pressure and LV mass index.
On dividing the patients according to mean arterial pressure, those with mean arterial pressure of more
than 85 had significantly higher LV mass index (P < 0.01). There may be a relationship between mean arterial
pressure and LV mass index in this population, but this needs to be further explored in a larger study.
Introduction
J
NC-7 has defined normal Blood pressure (BP) as < 120 mmHg systolic and < 80
mmHg diastolic. 1 Prehypertension (BP-120-140/80-89) is associated with increased
cardiovascular risk. 2 A meta analysis of prospective studies has revealed continuous
positive relationship between the risk of vascular events with systolic and diastolic BP
down to values as low as 115/75 mm of Hg. 3 However, there are no studies regarding
evidence of target organ damage in persons with BP of 120/80 mm of Hg or less. We
did echocardiographic and tissue Doppler study of persons with “normal” BP to see,
if there are subclinical changes even in this population.
Material and Methods
Study was performed in the Cardiology department of St. Francis Hospital, Ajmer.
Participants were recruited consecutively from the out patients over a period from
January 2009 to June 2010. Informed consent was taken from participants. Criteria for
inclusion in study-Asymptomatic, no drug therapy, no family history of hypertension,
diabetes or premature coronary artery
disease, non-smoker, Age 20- 40 Table 1 : Demographic data (Over all No 65)
Mean ± SD
years, normal physical examination, Parameter
30.35±8.56
Body Mass Index (BMI) 25 or less, Age (Yrs)
S y s t o l i c B P ( S B P ) 1 2 0 m m H g o r BMI
19.93±2.7
less, Diastolic BP (DBP) 80 mmHg BSA (m²)
1.52±0.17
or less, normal electrocardiogram, Pulse (per min.)
79.52±10.31
sinus rhythm, no intraventricular
SBP (mmHg)
107.84±8.96
conduction defect, negative treadmill
DBP (mmHg)
74.2±6.59
stress test at target heart rate, 2 hr
MAP
(mmHg)
85.30±6.20
post prandial blood sugar < 120 mg%,
33.32±9.34
normal lipid profile, no wall motion PP (mmHg)
abnormality, valvular or pericardial Abbreviations :BMI : Body mass index, BSA : Body surface
disease on echocardiography. Clinic area, SBP- Systolic blood pressure, DBP : Diastolic blood
BP measurement was done as per pressure, MAP : Mean arterial pressure, PP : Pulse pressure
Department of Cardiology,
St. Francis Hospital, Beawar
Road, Ajmer, Rajasthan
Received: 03.11.2010;
Revised: 03.01.2011;
Accepted: 20.02.2011
*
© JAPI • october 2013 • VOL. 61
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Journal of the association of physicians of india • october 2013 • VOL. 61
Table 2 : M-mode, 2-dimensional and pulsed doppler data
(Over all no 64)
Parameter
IVSd (mm)
PWd (mm)
LVIDd (mm)
LVIDs (mm)
RWT
LVMI(gm/m2)
2 D EF(%)
Mean ± SD
9.01±1.81
6.45±1.55
41.48±6.65
25.25±5.42
0.39±0.15
81.30±21.75
69.82±9.01
Parameter
Mitral flow
E (cm/sec)
A (cm/sec)
E/A
Pulmonary vein
S (cm/sec)
D (cm/sec)
AR (cm/sec)
Mean ±SD
92.01±16.70
58.43±10.32
1.74±0.52
46.68±11.23
57.37±14.95
26.15±5.51
Abbreviations : IVSd : Interventricular septum (diastolic), PWd :
Posterior wall (diastolic), LVIDd : Left ventricular internal diameter
(diastolic), LVIDs : Left ventricular internal diameter (systolic), RWTRelative wall thickness, LVMI : LV mass index, 2D EF : 2 Dimensional
echocardiographic ejection fraction, E : Early diastolic flow velocity,
A : Flow velocity during atrial contraction, S : systolic, D : Diastolic,
AR : Atrial reversal.
Table 3 : Tissue doppler imaging data (Over all no 64)
Parameters
MMA
Ea (cm/sec)
Aa (cm/sec)
Sa (cm/sec)
E/Ea
IVRT (m.sec)
MPI
Mean ± SD
13.56±2.72
9.98±2.13
10.37±1.51
6.64±1.41
100.67±29.85
0.70±0.25
Parameters
LMA
Ea (cm/sec)
Aa (cm/sec)
Sa (cm/sec)
E/Ea
IVRT (m.sec)
MPI
Mean ±SD
18.91±3.83
10.05±2.42
12.60±2.62
5.09±1.42
89.12±27.69
0.71±0.28
Abbreviation : MMA : Medial mitral annulus, Ea : early relaxation
wave, Aa : relaxation wave during atrial systole, Sa : systolic wave,
IVRT : Isovolumic relaxation time, MPI : Myocardial performance
index, LMA : Lateral mitral annulus
Table 4 : Linear correlation (Over all No 64)
Linear Correlation
Age vs. LV Mass Index
BMI vs. LV Mass Index
BSA vs. LV Mass Index
SBP vs. LV Mass Index
DBP vs. LV Mass Index
PP vs. LV Mass Index
MAP vs. LV Mass Index
r
-0.1547
0.1121
0.1975
0.1768
0.2290
-0.0199
0.2472
t
-1.2333
0.8886
1.5862
1.4142
1.8524
-0.1571
2.0084
p
NS
NS
NS
NS
NS
NS
<0.05
Abbreviations : LVMI : LV Mass Index, BMI : Body mass index, BSA
: Body surface area, SBP : Systolic BP, DBP : Diastolic BP, PP : Pulse
pressure, MAP : Mean arterial pressure
Table 5 : Showing differences in LVMI according to MAP
MAP (mmHg)
No
<85
29
LVMI gm/m2
(mean SD)
75.54 ± 14.80
>85
35
87.02 ± 23.60
P
< 0.01
Abbreviations : MAP : Mean arterial pressure, LVMI : LV mass index
Detailed M-Mode, 2-D, pulsed Doppler, and
tissue Doppler evaluation was performed according
to standard recommendations. 4-6 Average of three
consecutive beats was calculated. Statistical analysis
was performed by a person qualified in statistics.
Data are presented as mean ± SD. Linear correlation
between echocardiographic findings and Age, BMI,
BSA, SBP, DBP, mean arterial pressure (MAP) and
pulse pressure (PP) were determined by “Karl
Pearson’s” direct method. Multiple regression
analysis was performed using SPSS software. P < 0.05
was considered as significant.
Results
Fig. 1 : Showing significant positive linear correlation between
mean arterial pressure and LV mass index
JNC-7 guidelines. 1 Sixty-four persons qualified.
Echocardiographic recording and analysis of recorded
images was done by one of the four qualified (diploma
in Cardiac Instrument Technology) echocardiography
technicians with more than six years experience. They
studied the patients in routine and had no idea of
study.
714 
All persons completed the study. No person
dropped out. Demographic data are shown in Table
1. M-Mode, 2-Dimensional and pulsed Doppler
echocardiographic data are shown in Table 2. Left
ventricular wall thickness, left ventricular mass
index (LVMI), cavity dimensions and 2-D ejection
fraction were within normal limits. Mitral valve flow
velocities were within normal limits. Pulmonary vein
flow systolic flow velocity and velocity during atrial
reversal were normal. Diastolic flow velocity was
slightly higher than systolic flow, velocity (Table 2).
Results of tissue Doppler imaging are presented in
Table 3. Systolic velocity, early relaxation velocity
and late relaxation velocity of medial and lateral
mitral annulus were within normal range. There
was significant positive linear correlation between
systemic mean arterial pressure and LV mass index
(r- 0.2472, t-2.0084, P < 0.05) (Figure 1). Other
demographic parameters did not show statistically
significant correlation with LVMI (Table 4). On
dividing patients according to MAP, those with MAP
© JAPI • october 2013 • VOL. 61
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Journal of the association of physicians of india • october 2013 • VOL. 61 of more than 85 mmHg had significantly higher LV
mass than those with MAP of less than 85 mmHg (P
< 0.01) (Table 5).
Discussion
Technical assistance : Mokshda Singariya, Yasmin
Chouhan, Gayatri Anand, Nazeem Khan
References
1.
Previous studies on ‘normals’ have not excluded
prehypertensives, diabetics, smokers and obese. 7
These conditions have independent effects on LV
function. 2-8 Therefore, these studies do not represent
truly normal persons. We studied persons after
excluding all these confounding factors.
Chobanian AV, Bakris GL, Black HR. Cushman WC, Green LA, Izzo
JL Jr et al. The seventh report of the Joint National Committee on
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2.
Kaplan NM, Systemic hypertension: Therapy. In Libby P, Bonow RO,
Mann DL, Zipes DP ed. Braunwald’s Heart Disease.8th ed, Saunders,
Philadelphia, 2008:1049-1068
Importance of mean systemic arterial pressure in
patients with essential hypertension is known. 9 Our
observations show that even in persons with “normal”
blood pressure, mean arterial pressure may have
relation with LV mass index. This could happen even
when other echocardiographic parameters are within
normal range.
3.
Lewingston S, Clarke R, Qizilbasch N. Age specific relevance of usual
blood pressure to vascular mortality: A meta analysis of individual
data for one million adults in 61 prospective studies. Lancet
2002;360:1903-1911.
4.
Schiller NB, Shah PM, Crawford M, De Maria A, Devereux R,
Feigenbaum H et al. Recommendations for quantitation of the left
ventricle by two-dimension echocardiography: American Society
of Echocardiography committee on standards, subcommittee
on quantitation of two-dimensional echocardiograms. J Am Soc
Echocardiogr 1982;2:358-367
5.
Quinones MA, Otto CM, Stoddard M, Waggoner A, Zoghbi WA.
Recommendations for quantification of Doppler echocardiography:
A report from the Doppler quantification task force of the
nomenclature and standards committee of the American Society
of Echocardiography. J Am Soc Echocardiogr 2002;15:167-184
6.
Naguesh SF, Appleton CP, Gillebert TC, Marino PN, Oh JK, Smiseth OA
et al. Recommendations for the evaluation of left ventricular diastolic
function by echocardiography. J Am Soc Echocardiogr 2009;22:107133
7.
Alam M, Wardell J, Anderson E, Samed BA, Norlander R. Characterstics
of mitral and tricuspid annulus velocities determined by pulsed wave
Doppler tissue imaging in healthy subjects. J Am soc Echocardiogr
1999;12:618-628.
8.
Powell BD, Redfield MM, Bybee KA, Freeman WK, Rihal CS.
Association of obesity with left ventricular remodeling and diastolic
dysfunction in patients without coronary artery disease. Am J Cardiol
2006;98:116‐120 .
9.
Pickering TG , Ogedebe G. Epidemiology of hypertension . In Fuster
V, O' Rourke RA, Walsh RR , Poole Wilson P ed. Hurst's The Heart, 12th
ed, Mc Graw Hill , New York , 2008:1551‐1569.
Cardiovascular events start increasing with
increasing LV mass. Framingham Heart Study has
shown that increase in LV mass is associated with
increase in mortality even in subjects free of clinically
apparent cardiovascular disease and independent of
other cardiovascular risk factor. 10 Our results show
that there could be some relation between MAP and
LVMI in this population but this needs to be further
explored in a larger study.
Limitations
Our study is based on “clinic BP” which is the
standard method of diagnosis.
We did not perform ambulatory blood pressure
recording. Average level of ambulatory blood pressure
predicts the risk of cardiovascular events better
than clinic BP. 11 Strict inclusion criteria resulted in
a smaller sample size. Study of larger number of
subjects is required to confirm our observations.
Acknowledgement
Statistical Assistance : Varun Choudhary
© JAPI • october 2013 • VOL. 61
10. Levy D, Garrison RH, Savage DD. Prognostic implications of
Echocardiographically determined left ventricular mass in the
Framingham heart study. N Eng J Med 1990;322:1561‐1566.
11. Rashidi A , Rahman M, Wright Jr JT . Diagnosis and Treatment of
Hypertension. In Fuster V, O' Rourke RA , Walsh RR , Poole Wilson P ed.
Hurst's The Heart. 12th ed. Mc Graw Hill, New York 2008:1610‐1629 .
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