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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 30, No 2, March/April 2019
76
AFRICA
S5 probe (2–4 MHz). Standard two-dimensional and colour-flow
Doppler views were acquired according to the guidelines of the
American Society of Echocardiography and European Society
of Echocardiography.
8
The ejection fraction was measured
according to Simpson’s method. We evaluated MAC, best
achieved on short-axis views of the mitral valve (parasternal
short axis at the base on transthoracic echocardiography).
All patients underwent elective coronary angiography
according to the Judkins technique. Angiograms were reviewed by
at least two non-blinded reviewing cardiologists. The left anterior
descending coronary artery (LAD), the left circumflex coronary
artery (LCX) and the right coronary artery (RCA) were observed
at various angulations. CorT was evaluated at special angulations,
the LAD was assessed in the right anterior oblique view with
cranial angulations, and the LCX in the left anterior oblique view
with caudal angulations. The RCA was evaluated in the right
anterior oblique view. CorT was identified by three or more bends
(defined as ≥ 45° change in vessel direction) along the main trunk
of at least one artery, present both in systole and in diastole.
Patients with DM were identified on admission as those
with documented DM using either oral hypoglycaemic agents
or insulin treatment. HL was defined as total cholesterol level
at least 200 mg/dl (5.18 mmol/l) or using antihyperlipidaemic
therapy on admission. HT was defined as blood pressure above
140/90 mmHg or using antihypertensive therapy on admission.
Statistical analysis
Statistical analysis was performed using the SPSS (version 20.0,
SPSS Inc, Chicago, Illinois) software package. Continuous variables
were expressed as mean
±
standard deviation (SD), and categorical
variables were expressed as a percentage (%). The Kolmogorov–
Smirnov test was used to evaluate the distribution of variables. The
Student’s
t
-test was used to evaluate continuous variables showing
normal distribution, and Mann–Whitney
U
-test was used to
evaluate variables that did not show a normal distribution.
To identify predictors of CorT, the following variables
were initially assessed in a univariate model: age, HT, female
gender, DM, HL and MAC. Significant variables in univariate
analysis were then entered into a multivariate logistic regression
analysis using backward stepwise selection. A
p
-value
<
0.05 was
considered statistically significant.
Results
The prevalence of MAC was found in 14.3% in the study group.
The MAC and control groups comprised 392 and 687 patients,
respectively. The demographic characteristics of both groups are
summarised in Table 1.
There was no significant difference between the groups
regarding current smoking and DM (32.1 vs 29.9%,
p
= 0.762;
27.0 vs 29.4%,
p
= 0.684, respectively) (Table 1). There was a
significant difference between the groups regarding age, HT, HL,
female gender and CorT (71.6
±
8.2 vs 61.4
±
7.4 years,
p
<
0.001;
72.4 vs 44.5%,
p
<
0.001; 40.3 vs 28.2%,
p
<
0.001; 68.6 vs 41.7%,
p
<
0.001; 23.9 vs 12.1%,
p
<
0.001, respectively) (Tables 1, 2).
There was no significant difference between the groups regarding
biochemical parameters such as levels of urea, creatinine,
low-density lipoprotein cholesterol, high-density lipoprotein
cholesterol, total cholesterol and triglycerides (Table 2).
The results of univariate analysis are presented in Table 3.
On univariate analysis, advanced age, HT, female gender, HL
and MAC were associated with CorT (Table 3). On multivariate
analysis, MAC, advanced age and HT were independent
predictors for CorT (OR 2.174, 95% CI: 1.637–4.253,
p
<
0.001;
OR 1.938, 95% CI: 1.362–3.463,
p
<
0.001; OR 2.068, 95% CI:
1.539–3.861,
p
<
0.001, respectively) (Table 4).
Discussion
This study revealed that advanced age, HT and MAC were
associated with CorT. To the best of our knowledge, our study
is the first to evaluate the association between MAC and CorT.
Our results may be related to the fact that both MAC and CorT
have the same predisposing factors, such as advanced age, HT,
DM, HL, female gender and smoking.
1-7
Table 2. Laboratory, echocardiographic and angiographic parameters
Laboratory and echocar-
diographic variables
Mitral annular
calcification
(
n
= 392)
No mitral annular
calcification
(
n
= 687)
p
-value
White blood cell count
(× 10
3
/µl),
n
(%)
6.96
±
1.72 (7.63)
6.67
±
1.93 (7.51)
0.634
Haemoglobin (g/dl)
13.8
±
1.9 (14.6)
14.1
±
2.1 (14.8)
0.869
Total cholesterol (mg/dl)
174
±
18 (186)
165
±
21 (178)
0.457
(mmol/l)
(4.51
±
0.47) (4.82) (4.27
±
0.54) (4.61)
High-density lipoprotein
(mg/dl)
39.4
±
9.7 (45.9)
42.1
±
10.6 (46.8)
0.624
(mmol/l)
(1.02
±
0.25) (1.19) (1.09
±
0.27) (1.21)
Low-density lipoprotein
(mg/dl)
127.9
±
24.6 (138.8) 129.7
±
28.7 (136.4)
0.623
(mmol/l)
(3.31
±
0.64) (3.59) (3.36
±
0.74) (3.53)
Triglycerides (mg/dl)
138.2
±
21.5 (146.9) 131.5
±
20.8 (144.8)
(mmol/l)
(1.56
±
0.24) (1.66) (1.49
±
0.24) (1.64)
0.761
Urea (mg/dl)
31.6
±
6.9 (33.7)
28.4
±
5.7 (31.4)
0.643
Creatinine (mg/dl)
0.96
±
0.18 (1.02)
0.91
±
0.15 (0.99)
0.627
Ejection fraction (%)
62.4
±
5.2 (64.3)
63
±
6.1 (65.6)
0.783
Coronary tortuosity,
n
(%)
94 (23.9)
83 (12.1)
<
0.001
Table 1. General characteristics of the patients
Patient characteristics
Mitral annular
calcification
(
n
= 392)
No mitral annular
calcification
(
n
= 687)
p
-value
Age (years)
71.6
±
8.2 (76.8)
61.4
±
7.4 (58.4)
<
0.001
Female gender,
n
(%)
269 (68.6)
287 (41.7)
<
0.001
Hypertension,
n
(%)
284 (72.4)
306 (44.5)
<
0.001
Diabetes mellitus,
n
(%)
106 (27.0)
202 (29.4)
0.684
Current smoking,
n
(%)
126 (32.1)
206 (29.9)
0.762
Hyperlipidaemia,
n
(%)
158 (40.3)
194 (28.2)
<
0.001
Table 3. Univariate analysis of predictors for coronary tortuosity
Predictor variables
OR (95% CI)
p
-value
Age
1.962 (1.628–2.945)
<
0.001
Hypertension
2.681 (1.862–4.348)
<
0.001
Female gender
2.053 (1.528–3.067)
<
0.001
Hyperlipidaemia
1.358 (1.127–1.963)
<
0.001
Mitral annular calcification
2.462 (1.816–3.258)
<
0.001
Table 4. Multivariate analysis of predictors for coronary tortuosity
Predictor variables
OR (95% CI)
p
-value
Age
1.938 (1.362–3.463)
<
0.001
Hypertension
2.068 (1.539–3.861)
<
0.001
Mitral annular calcification
2.174 (1.637–4.253)
<
0.001