CARDIOVASCULAR JOURNAL OF AFRICA • Vol 22, No 2, March/April 2011
AFRICA
85
Serum high-sensitivity C-reactive protein, amyloid-
associated protein and N-terminal proBNP levels do not
predict reversible myocardial ischaemia
M BAŞKURT, F AKTÜRK, K KESKIN, P CANBOLAT, B KARADAG, A KAYA, A YILDIZ, U COSKUN,
K KILICKESMEZ, O ESEN, SK MUNIBOGLU
Summary
Aim:
The aim of this study was to detect any relationship
between serum high-sensitivity C-reactive protein (hs-CRP),
serum amyloid-associated protein (SAA) and N-terminal pro
B-type natriuretic peptide (NT-proBNP) levels, and revers-
ible myocardial ischaemia during cardiovascular exercise
tests and to determine whether these biomarkers could
predict transient myocardial ischaemia.
Methods:
Ninety-six patients (36 women, 60 men, mean age
57
±
8.5 years) were included in the study. Venous blood
samples were taken from patients before and 15 minutes
after exercise testing. SAA and hs-CRP were analysed
using immunonephelometric assays (Dade-Behring, BN II,
Marburg, Germany). NT-proBNP (pg/ml) was determined
using the immulite 1 000 chemiluminescence immunoassay
system (Siemens Medical Solution Diagnostics, Deerfiled,
USA). Forty-eight patients (18 women, 30 men) with positive
exercise tests were allocated to the exercise-positive group
and 48 (18 women, 30 men) with negative exercise tests were
put in the exercise-negative group. Coronary angiography
was performed on all patients in the exercise-positive group.
Results:
There was no difference between the levels of
hs-CRP, SAA and NT-pro-BNP before and after exercise
testing in both of the exercise groups.
Conclusion:
Serum levels of hs-CRP, SAA and NT-proBNP
could not predict the occurrence of reversible myocardial
ischaemia during exercise. Large-scale clinical studies are
needed to clarify the status of hs-CRP, SAA and NT-proBNP
with exercise.
Keywords:
brain natriuretic peptide, coronary artery disease,
exercise, ischaemia
Submitted 15/12/09, accepted 22/4/10
Cardiovasc J Afr
2010;
21
: 85–89
DOI: CVJ-21.027
As a response to inflammatory cytokines, high-sensitivity
C-reactive protein (hs-CRP) is synthesised mainly by the liver
and to a lesser extent by macrophages and blood vessel walls.
hs-CRP circulates freely in the plasma because there are no
specific transporters for it.
1,2
It has been shown that hs-CRP
is a powerful predictor of cardiovascular adverse events and
mortality in unstable coronary heart disease.
3-5
However, its role
in predicting transient myocardial ischaemia in stable coronary
heart disease is not clear. While some studies found a strong rela-
tionship between serum hs-CRP levels and reversible myocardial
ischaemia in exercise electrocardiographic testing,
6
others did
not find such a relationship.
7,8
Serum amyloid-associated protein (SAA) is an acute-phase
reactant and its concentration can reach up to 1 000-fold of the
normal plasma concentration in the presence of inflammation.
SAA is mainly synthesised by the liver.
9
Serum levels of SAA
rise with obesity, diabetes and the metabolic syndrome.
10,11
Some
studies point to a positive correlation between SAA and angio-
graphically proven coronary artery disease, and serum concen-
tration of SAA is reported to be a powerful predictor of cardio-
vascular events.
12,13
It has been shown that patients with a high
SAA concentration have more active atherosclerotic disease,
14
but the relationship between serum SAA levels and transient
myocardial ischaemia during exercise is not known.
B-type natriuretic peptide (BNP) is synthesised by the ventric-
ular myocardium as a response to wall stress and is not stored.
15
Myocardial ischaemia activates the pre-proBNP gene expression
and secretion. Especially newly synthesised proBNP is secreted
from the myocardium in response to ischaemia.
16
BNP is the
biologically active form and N-terminal proBNP (NT-proBNP)
is the inactive form of proBNP. In one study, increase in serum
BNP levels during electrocardiographic exercise testing was
found in patients with stable angina pectoris. Also, the rise in
serum BNP levels was correlated with the size of the ischaemic
myocardium, assessed with positron emission tomography.
17
In
patients with angiographically proven coronary artery disease,
serum NT-proBNP levels were related to the extent and severity
of coronary artery disease.
18
The purpose of this study was to detect any relationship
between serum hs-CRP, SAA and NT-proBNP levels, and
reversible myocardial ischaemia during cardiovascular exercise
testing, and to determine whether these biomarkers could predict
transient myocardial ischaemia.
Cardiology Department, Institute of Cardiology, Istanbul
University, Haseki, Istanbul
M BAŞKURT, MD,
F AKTÜRK, MD
K KESKIN, MD
P CANBOLAT, MD
A YILDIZ, MD
U COSKUN, MD
K KILICKESMEZ, MD
O ESEN, MD
SK MUNIBOGLU, MD
Cardiology Department, Cerrahpasa Medical Faculty,
Istanbul University, Haseki, Istanbul
B KARADAG, MD
Biochemistry Department, Institute of Cardiology, Istanbul
University, Haseki, Istanbul
A KAYA, PhD
