CARDIOVASCULAR JOURNAL OF AFRICA • Vol 23, No 1, February 2012
AFRICA
25
compared to only seven in the control group. Similarly, higher
incidence of the other risk factors for CAD, namely smoking,
hypertension and previous history of CAD was noticed in the
patients with stenosis compared to those in the control group.
The levels of total cholesterol, triglycerides, LDL-C, ferritin,
Apo B and nitric oxide were higher in the patients with stenosis
compared to the controls. The levels were also higher in those
with triple-vessel disease compared to those with single- and
double-vessel disease (Table 2).
It can be inferred from Table 3 that dyslipidaemia, oxidative
stress and inflammation interacted in the pathogenesis of CAD
as total cholesterol, LDL-C and apo B, and they had a significant
positive correlation with ferritin and NO. Among the markers of
dyslipidaemia, Apo B had a very strong interrelationship with
ferritin and NO (
r
=
0.709,
r
=
0.776, respectively). NO emerged
as the best marker of CAD in our study, with an area under the
curve of 0.992 compared to 0.901 and 0.955 for Apo B and ferri-
tin, respectively (Table 4).
Table 4 highlights the odds ratio and the predictive values of
nitric oxide, ferritin and apolipoprotein B. It can be seen that the
sensitivity and specificity of NO was highest compared to ferritin
and apo B (97 and 98%; 92 and 87%; 89 and 81%, respectively).
The superior predictive power of NO for the assessment of risk
for CAD was also substantiated by the high positive predictive
value, positive likelihood ratio and odds ratio compared to the
other two parameters under study.
Discussion
The prevalence of CAD in Asian Indians has been increas-
ing rapidly and has reached alarming levels.
15-18
It was the
CAD-prone North Indian population that constituted our study
population. A better appreciation of the atherogenic effects of
well-known cardiovascular risk factors has been accompanied
by understanding the sum of these factors, i.e. the global risk
profile provides better predictive power than any single risk
factor. In addition, a number of more recently identified and less
well-known factors have received intense investigation over the
past few years.
19-21
The availability of effective therapies for preventing a first
myocardial infarction renders imperative the need to identify
individuals at risk, for concerted intervention, before problems
manifest.
22,23
In the present study, it was found that serum ferritin
levels increased from those with normal coronary angiography to
those with increased arterial stenotic states. These results are in
accordance with those obtained in other studies, which favoured
the ‘iron hypothesis’ in coronary artery disease.
5-7
One of the
studies
8
demonstrated that protein expression of ferritin light
chains increased 1.9-fold in diseased coronary arteries compared
to normal ones.
A few studies have documented an increase in nitric oxide
concentration in stenosed coronary vessels in comparison with
normal vessels.
24,25
In our study, the concentration of nitric oxide
also increased in accordance with the level of stenosis. With
TABLE 1. BASELINE CHARACTERISTICS INALL THE
GROUPS
Parameter
Normal
angiography
(G0)
Single
vessel
(G1)
Double
vessel
(G2)
Triple
vessel
(G3)
Number
53
135
174
114
Age (years)
54.3
±
8.9 55.6
±
9.5 55.8
±
7.5 56.8
±
8.6
Gender (M/F)
42/11
95/45
99/65
87/27
Diabetes (
n
)
7
34
59
73
Smoking (
n
)
8
28
40
55
Hypertension (
n
)
18
33
55
59
Previous H/O MI (
n
)
0
22
45
56
TABLE 2. BIOCHEMICAL PARAMETERS IN PATIENTSWITHVARYING LEVELS OF STENOSIS
Parameter
No stenosis (G0)
Single-vessel stenosis (G1) Double-vessel stenosis (G2) Triple-vessel stenosis (G3)
Total cholesterol (mg/dl)
143.6
±
28.3
147.9
±
28.6
154.7
±
30.7
d
175.9
±
34.5
ce
Triglyceride (mg/dl)
136.3
±
42.4
147.7
±
36.6
152.3
±
35.5
148.7
±
42.9
High-density lipoprotein (mg/dl)
36.8
±
9.8
37.5
±
9
35.0
±
9.7
34.6
±
6.7
Low-density lipoprotein (mg/dl)
80.7
±
30.1
80.8
±
27.9
88.9
±
30.4
111.6
±
33.2
cef
Apolipoprotein B (mg/dl)
70.8
±
17.1
91.8
±
17.6
a
97.4
±
14.4
d
148.1
±
24.9
cef
Small dense LDL (sdLDL)
1.85
±
1.47
1.16
±
0.65
a
1.19
±
0.62
d
0.91
±
0.38
f
Nitric oxide (
μ
mol/IU)
24.7
±
2.2
34.1
±
3.3
a
48.7
±
6.3
bd
69.9
±
5.7
cef
Ferritin (ng/ml)
45
±
21.2
93.4
±
39.0
a
177.8
±
58
bd
245.6
±
40
cef
Statistically significant difference between the groups is expressed as follows:
a
G0 vs G1;
b
G1 vs G2;
c
G1 vs G3;
d
G0 vs G1;
e
G2 vs G3;
f
G0 vs G1.
TABLE 3. PEARSON’S CORRELATION BETWEEN
THE DYSLIPIDAEMIA, INFLAMMATORY
AND OXIDATIVE STRESS PARAMETERS
Parameter
R
-value
p
-value
Apolipoprotein B with ferritin
0.709
<
0.01
Apolipoprotein B with nitric oxide
0.776
<
0.01
Ferritin with nitric oxide
0.860
<
0.01
Cholesterol with ferritin
0.275
<
0.01
Cholesterol with nitric oxide
0.351
<
0.01
Low-density lipoprotein with feritin
0.267
<
0.01
Low-density lipoprotein with nitric oxide
0.358
<
0.01
TABLE 4. COMPARISON OF THEATTRIBUTES OF THE
VARIOUS PARAMETERS UNDER STUDY
Nitric oxide
Apolipo-
protein B Ferritin
Area under curve
0.992
0.901
0.955
Sensitivity
97.3
88.9
92.3
Specificity
98
81.2
87.4
Positive likelihood ratio
49
4.72
7.34
Negative likelihood ratio
0.03
0.14
0.08
Positive predictive value
99.4
95.3
96.6
Negative predictive value
91.7
63.1
75.2
Odds ratio (95% CI)
158
(94.5–264.1)
44.1
(26.6–72.9)
81.5
(49.9–133)
