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Med. J. Cairo Univ., Vol. 89, No. 2, June: 787-796, 2021
www.medicaljournalofcairouniversity.net
Coronary Artery Bifurcation Angle Degree; Bifurcation Lesion
Development and the Prognostic Impact
AHMED GAAFAR, M.D.*; ALAA MOHAMMED, M.Sc.** and MOUSTAFA ABDEL KAWI, M.D.***
The Department of Cardiology, Faculty of Medicine, Helwan University* and Mabarret Misr El-Kadima Hospital** and
The Department of Radio Diagnosis, Faculty of Medicine, Helwan University***, Cairo, Egypt
Abstract
Background:
Coronary artery bifurcation lesion is one of
the challenges in coronary arteries revascularization. Hemo-
dynamic factors, as bifurcation angle is widely recognized
for its involvement in atherosclerotic plaque formation.
Aim of Work:
Our aim of this study was to detect the
effect of coronary artery bifurcation angle degree on the
development of bifurcation atherosclerosis using Computed
Tomography Coronary Angiography [CTCA] and its prognos-
tic impact.
Patients and Methods:
The study was included 221 patients
having low and intermediate pretest probability for Coronary
Artery Disease [CAD]. Coronary arteries were investigated
with CTCA for detection of bifurcation lesions, assessment
of bifurcation angle and bifurcation lesion type, then 1 year
follow-up period for Acute Coronary Syndrome (ACS).
Results:
138 patients were males (62%) and 83 were
females (38%). The meanage group was 55.7
±
9.8 years old.
Bifurcation lesions were higher at LAD-LCx (125 patients,
56.5%) than at LAD-major diagonal (104 patients, 47%), than
at LCx-OM (56 patients, 25%) (
p
-value <0.0001). At LAD-
LCx sites there were higher bifurcation angles in patients
with atherosclerotic bifurcation lesions than patients without
bifurcation lesions (77.32º
±
18.1º vs. 62.24º
±
18.2º,
p
-value
0.001), while there was no statistically significant difference
as regard bifurcation angels at LAD-diagonal and LCx-OM
bifurcation sites. There was no relation between bifurcation
angle and type of atherosclerotic plaque at the three studied
bifurcation sites. Patients with wider bifurcation angels
regardless lesions severity or management protocol had higher
rates of ACS.
Conclusion:
A strong relation between LM bifurcation
angel and the development of atherosclerotic lesions was
noted, where wider bifurcation angles are more prone for
atherosclerotic lesions, and more prone to develop ACS.
Key Words:
CT coronary angiography – CAD – Bifurcation
lesion – Bifurcation angel – ACS – Plaque type.
Correspondence to:
Dr. Ahmed Gaafar,
E-Mail: Gaafar911@hotmail.com
Introduction
THE
National Center for Health Statistics [NCHS]
had reported cardiovascular diseases as the major
cause of death in USA, occurring in all ethnic
populations involving both genders. It is considered
the cause of 25% of deaths in USA in 2011 which
accounted more than 600.000 deaths (Wolk, 2014
#48)
[1]
.
During coronary intervention, one of challenges
that face any interventionist is bifurcation coronary
artery lesions due to its complex nature and higher
complication incidence. It is accounting about 20%
of all Coronary Artery Disease (CAD) cases at
coronary catheterization
[2]
. The technical difficul-
ties inherent in the treatment of bifurcation lesions,
associated with their lower success and higher
complication rates compared with non-bifurcation
lesions have always been the object of intense
research activity
[3]
.
List of Abbreviations:
CAD
: Coronary Artery Disease.
CA
: Coronary Angiography.
IHD
: Ischemic Heart Disease.
CTCA
: Computed Tomography Coronary Angiography.
MSCT
:
Multi-slice Computed Tomography.
CT
: Computed Tomography.
LM
: Left Main Coronary Artery.
LAD
: Left Anterior Descending Coronary Artery.
LCx
: Left Circumflex Coronary Artery.
OM
: Obtuse Marginal Coronary Artery.
MB
:
Main Branch Coronary Artery.
SD
: Side Branch Coronary Artery.
PCI
: Percutaneous Coronary Intervention.
CABG
: Coronary Artery Bypass Graft.
MPR
:
Multiplanar Reconstruction.
MIP
:
Maximal Intensity Projection.
LDL
: Low Density Lipoproteins.
ACS
:
Acute Coronary Syndrome.
787
Men
Women
Men
Women
Men
Women
Men
Women
Intermediate.
Intermediate
High
Intermediate
High
Intermediate
High
High
Intermediate
Low
Intermediate
Low
Intermediate
Intermediate
Intermediate
Intermediate
Low
Low
Intermediate
Low
Intermediate
Low
Intermediate
Intermediate
30-39
40-49
50-59
60-69
Age
(years)
Gender
Typical
angina
Atypical
angina
788
Prognostic Impact on Coronary Artery Bifurcation Angle Degree
The formation of athermanous plaques can be
explained as a response of the arterial wall to an
injury which defined atherosclerosis as chronic
inflammatory reaction to endothelial injury
[4]
. It
is an interactive multi factorial disease
[5]
.
The atherosclerosis development is higher at
coronary artery bifurcation sites due multiple in-
teracting factors, as increased endothelial shear
stress, as well as, specific flow dynamics which
lead to endothelial injury
[6]
. Flow characteristics
at bifurcation sites depends on the anatomy of
coronary bifurcations, such as diameters of the
Main Vessel (MV) and the Side Branches (SB),
atherosclerotic plaque burden in the proximal and
distal part of the MV and the SB, and bifurcation
angle
[7]
. The flow induced endothelial shear stress
and subsequent changes lead to alteration in the
patterns of gene expression which also mediate
the transcription activation of pro-atherogenic
factors
[8]
. Shear stress has an essential role in
plaque formation and also atherosclerosis progres-
sion
[9]
.
In previous pathologic study, they found coro-
nary atherosclerosis mainly involves the lateral
wall of artery bifurcations opposite to carina, which
corresponds to low and oscillatory endothelial
shear stress areas
[10]
.
The development of Multi Slice Computed
Tomography (MSCT) and improvement of imaging
quality for coronary artery imaging made MSCT
and acceptable alternative to invasive coronary
angiography for coronary artery imaging and as-
sessment of significant coronary artery disease
with high accuracy
[11]
.
Aim of the work:
The main aim of the study was to detect the
i
mpact of coronary artery bifurcation angle degree
on the development of coronary artery bifurcation
atherosclerosis using MSCT Coronary Angiography
(MSCTCA), and to find its prognostic impact.
Patients and Methods
This study included 221 patients (138 males,
83 females), having low and intermediate pretest
probability for CAD. They were referred from
Helwan Health Insurance Cardiac Committee to
Nile-Scan Radiology Centers in the period 5/2019
and 11/2020, for non-invasive evaluation of the
coronary arteries by MSCTCA and revealed coro-
nary artery atherosclerotic bifurcation lesions.
Twelve months follow-up study was performed
for all patients for incidence of new ACS events.
Exclusion criteria:
Previous Percutaneous Cor-
onary Intervention (PCI) at bifurcation sites or
Coronary Artery Bypass Graft (CABG) surgery,
patients with known allergy or hypersensitivity to
contrast media, irregular heart rhythms (e.g. atrial
fibrillation), obese patients (body mass index
>35kg/m
2
), elevated calcium score (calcium score
>800), renal insufficiency with serum creatinine
greater than 1.5mg/dl, inability to follow breath
holding instructions and pregnancy.
Pretest probability was calculated as regard
chest pain, sex, and age as it was demonstrated at
(Table 1)
[12]
.
Table (1): Estimation of pretest probability.
Mon-anginal
chest pain
Multi-slice CT coronary angiography protocol:
The studies were done at heart rate <70b/m
with 10 seconds breathe holding.
Scanning:
A retrospectively Electrocardiograph-
ic (ECG)-gated scan without contrast media was
performed to determine the total calcium burden
of the coronary tree.
Injection:
70-90ml of contrast was injected
though the IV line followed by a 50ml of saline
chaser, at rate 5-6ml/sec for both the contrast and
the saline but injection speed rate was 7ml/sec in
patient with large IV access and patient with high
BMI.
Scan protocol and parameters:
We used the
256-slice MSCT row scanner Brilliance iCT;
(Philips Medical Systems; Eindhoven, Netherland).
Scanning parameters were 256 X 0.625mm colli-
mation, tube rotation time of 400msec, tube voltage
of 120KV (increased to 140KV in obese patients)
and current of 440-550mA. The field of view was
25cm with an image matrix of 512 X 512 pixels.
Scanning direction was cranio-caudal.
Image reconstruction: The reconstructed axial
i
mages at different points of the cardiac cycles
Ahmed Gaafar, et al.
789
were sent to an off-line workstation (Vitrea 2, vital
i
mages, USA). A slice thickness of 0.6mm recon-
structions was used. Axial images, three dimen-
sional volume rendering reconstruction, Multiplanar
Reconstruction (MPR), Maximal Intensity Projec-
tion (MIP) and volume rendering techniques were
used.
Analysis of coronary artery lesions:
A system-
atic analysis of a coronary artery MSCT study was
done for detection and localization of coronary
artery lesions at any of the three major bifurcations
of the left coronary artery, carefully avoiding
sections or interposed structures with potential
i
mage artifacts. We had evaluated the composition
and morphology of the lesions, and characterized
them based on CT attenuation, where calcified
plaques indicated plaques with high density, non-
calcified plaques had lower density compared with
the contrast enhanced vessel lumen, mixed plaques
indicated plaques with non-calcified and calcified
elements within a single plaque or within coronary
artery segment
[13]
. Qualitative and quantitative
assessment of the obstruction degree of the vessel
caused by the lesion was done. The most sever
lesion was considered in the main vessel or any
one of the two daughters
[14]
.
Stenosis was considered as a non-significant if
less than 50% of the vessel lumen, including mild
and moderate degrees of obstruction, while signif-
icant stenosis was equal or more than 50%, includ-
ing critical sub-occlusive and occlusive lesions
[15]
.
Measurement of the major bifurcation angles
in the left coronary arterial system:
3D volume
rendering and curved planar reformatted images
were generated for the assessment of the 3 major
bifurcation angles in the left coronary artery in-
cluding (LAD-LCx), (LAD-major diagonal artery)
and (LCx-OM). The MPR view (where the angu-
lation between the main vessel and SB was maxi-
mal) was used to determine the bifurcation angle
values. The angle was delineated by two centerline
vectors drawn along the initial 5-mm course of the
distal main vessel and SB, respectively. Only
diastolic data sets were used for BA measurements.
Examples of angle measurements are shown at
Fig. (1), and examples of bifurcation lesions at the
three studied sites are shown at Fig. (2).
(A)
(B)
Fig. (1): Left coronary artery bifurcation angles and
dimensions measurement by MSCT in a normal individual.
Multi-planer reconstructions were rendered exactly in the
plane described by the main vessel and side branch at the
bifurcation site. (A) Angle between LAD-LCx (38.10). (B)
Angle between LAD-diagonal (50.70). (C) Angle between
LCx-OM (22.20).
MSCT
:
Multi-Slice Computed Tomography.
LAD
: Left Anterior Descending Artery.
LCx
: Left Circumflex Artery.
OM
: Obtuse Marginal.
Diagonal : Diagonal Artery.
(C)
790
Prognostic Impact on Coronary Artery Bifurcation Angle Degree
(A)
(B)
(C)
Statistical analysis of data;
Descriptive statis-
tics: Data were statistically described in terms of
mean
±
Standard Deviation (
±
SD), median and
range, or frequencies (number of cases) and per-
centages when appropriate. Analytical statistics:
Student
t
-test: Was used for independent samples
in comparing 2 groups when normally distributed.
Mann Whitney U-test: Was used for independent
samples in comparing 2 groups when not normally
distributed. ANOVA (one-way analysis of variance)
test: Was used for comparison of normally distrib-
uted numerical variables between more than two
groups. Kruskal Wallis test: Was used for compar-
ison of non-normal numerical variables between
more than two groups. Accuracy was represented
using the terms sensitivity, and specificity. Multi-
variable analysis with Chi-Square test was done.
Statistical significance was defined as:
p
-value
>0.05: Insignificant,
p
-value <0.05: Significant
and
p
-value <0.01: Highly significant. All statistical
calculations were done using computer program
SPSS (Statistical Package for the Social Science;
SPSS Inc., Chicago, IL, USA) release 15 for Mi-
crosoft Windows (2006).
Fig. (2): (A) LCx-om; a non-calcific plaque in mid lCx
seen extending along the ostial to proximal segment of om
causing significant lumen stenosis. (B) LAD-diagonal; a
proximal LAD showed non calcific plaque extending along
the ostial diagonal branch causing significant lumen stenosis.
(C) LM bifurcation; the distal LM shows a non-calcific plaque
causing mild lumen stenosis and seen extending along the
ostial to proximal LAD showing partially calcific plaque
causing significant lumen stenosis and extended to ostial to
proximal lCx causing partially calcific significant lesion.
Results
Of the subjects who are referred with low and
intermediate probability for CAD for CTCA as-
sessment in the study period, 221 (24.6%) revealed
coronary artery bifurcation lesions, 128 patients
(58%) had intermediate pretest probability for
CAD and 93 patients (42%) had low pretest prob-
ability. 138 of the studied patients were males
(62%) and 83 were females (38%), with age ranged
between 48 and 76 years; mean age 60.7
±
9.8 years.
We found 65.5% of the patients were hyperten-
sive, 53.5% of them had dyslipidemia, 54% were
smokers, 42.3% were diabetics and 41.1% had a
family history of ischemic heart disease. There
were no significant differences between low and
intermediate pretest probability groups regards
clinical and laboratory data except in LDL level
and incidence of DM where both were significantly
higher in intermediate probability group (95
±
35
vs. 125
±
45,
p
0.01) and (32 patients vs. 61 patients,
p
0.045) respectively (Table 2).
Ahmed Gaafar, et al.
791
There was a statistically significant difference
as regard prevalence of significant CA bifurcation
lesions between both groups, where it was higher
in intermediate probability group (39.8% vs. 55.5%,
p
0.02) Table (2).
The mean degree of LAD-LCx bifurcation angle
was 71.4º
±
18.5º with range 26º-132º. The mean
degree of LAD-diagonal bifurcation angle was
49.5º
±
18.7º with range 17º-137º. The mean degree
of the LCx-OM bifurcation angle was 44.6º
±
21.4º
with range 15º-128º (Table 3).
Bifurcation lesion prevalence was higher at
LAD-LCx (125 patients, 56.5%) than at the LAD-
diagonal bifurcation (84 patients, 38%), than at
the LCx-OMbifurcation (56 patients, 25%) (
p
-
value <0.0001) (Table 3).
There were no significant differences as regard
atherosclerotic plaque type found at different bi-
furcation lesion sites (Table 3).
As regard relation between bifurcation angel
degree and development of atherosclerotic plaque,
at LAD-LCx site there were wider bifurcation
angles in patients with atherosclerotic bifurcation
lesions than patients without bifurcation lesions
(77.32º
±
18.1º vs. 62.24º
±
18.2º,
p
-value 0.001).
While there were no statistical significant differ-
ences at LAD-diagonal and LCx-OM bifurcation
sites, (49.5º
±
16.5 vs. 44.3º
±
15.8) and (41.3º
±3 vs.
43.3º
±
19.4) respectively (Table 3).
There was no relation between bifurcation angle
and type of atherosclerotic plaque at the three
studied bifurcation sites (Table 3).
As regard patients with significant CAD bifur-
cation lesions, 21 patients (19%) were managed
with medical treatment due to patients' preference,
while 19 patients (17.4%) underwent CABG, and
69 patients (63.3%) were treated with PCI and
stenting.
During the one year follow-up, as regards pa-
tients with non-significant bifurcation lesion by
CTCA (113 patients), the patients who developed
ACS events (17 patients, 15%) had wider bifurca-
tion angles than those who didn't developed ACS
events (96 patients, 85%), (70.88º
±
10.9 vs. 62.66º
±
13.8, respectively,
p
0.0002). As regards medically
treated patients with significant bifurcation lesions
(21 patients, 19%), patients who developed ACS
events; 4 patients (19%) had wider bifurcation
angle than those who didn't; 17 patients (81%),
(69.25º
±
9.9 vs. 57.7º
±
8.6, respectively,
p
0.016).
Regards PCI treated patients with significant bi-
furcation lesions (69 patients, 63.3%), patients
who developed ACS events (3 patients, 4%) had
wider bifurcation angles than those who didn't; 66
patients (96%), (80.33º
±
8.2 vs. 67.2º
±
7.8, respec-
tively,
p
0.003).
By multivariate regression analysis we found
that bifurcation angle degree is an independent
factor for development of ACS (coefficient 0.1230,
slandered error 0.029 1,
p
-value 0.0001, odds ratio
1.1309).
As regards, DM, HTN, dyslipidemia, gender,
smoking, Optimal Medical Treatment (OMT) and
age, there were no statistical significant differences
between ACS group and asymptomatic group.
Q: Why didn't you identify a cut off point for
angle bifurcation?
A: Actually, we didn't have this idea and the
statistician didn't suggest this test.
Table (2): Clinical data and CAD distribution in studied groups.
No (%)
Low pretest probability
93 (42%)
Intermediate pretest
probability 128 (58%)
p
-
value
BP
HR
LDL
S.creat
DM
HTN
Smoker
CAD
Sig. BF. lesion
Significant bifurcation lesion %
110
±
20
62
±
7
95
±
35
1.1
±
4
32 patients
41 patients
55 patients
59 patients (63.5%)
13 patients (14%)
39.8
130
±
20
61
±
6
125
±
45
1.3
±
3
61 patients
59 patients
64 patients
90 patients (70.3%)
47 patients (36.7%)
55.4
NS
NS
0.01
NS
0.045
NS
NS
NS
0.0003
0.02
BP
HR
LDL
S.creat
DM
: Blood Pressure.
: Heart Rate.
: Low Density Lipoprotein.
: Serum creatinine.
: Diabetes Mellitus.
HTN
CAD
Sig. BF. lesion
NS
: Hypertension.
: Coronary Artery Disease.
: Significant Bifurcation lesion.
:
Non-Significant.
0
100
90
80
70
60
50
40
30
20
10
Bifurcation angel
p
70.88
62.66
Patients
with non-
significant
bifurcation
lesions
792
Prognostic Impact on Coronary Artery Bifurcation Angle Degree
Table (3): Demonstrates mean Bifurcation Angels (BA), comparison between bifurcation
angles in patients with Bifurcation Lesions (BL) and patients without BL,
distribution of different types of plaques and the relation between plaque type
and BA at bifurcation sites, also showed prevalence of BL at bifurcation sites.
LAD, LCx
LAD, Diag
LCx, OM
Bifurcation angle (mean
±
SD)
Type of bifurcation lesion No (%):
71.4º
±
18.5º
49.5º
±
18.7º
44.6º
±
21.4º
Non-calcific
20 (17%)
17 (16.3%) 10 (17.85%)
Calcific
53 (41.6%)
43 (41.3%)
31 (55.4%)
Mixed
52 (41.4%)
44 (42.3 %)
15 (26.75%)
p
-value
NS
NS
NS
Bifurcation angle (mean
±
SD):
Patients with bifurcation lesion
77.32º
±
18.1
49.5º
±
16.5
41.3º
±
3
Patients without bifurcation lesion
62.24º
±
18.2
44.3º
±
15.8
43.3º
±
19.4
p-
value
0.001
NS
NS
Type of bifurcation lesion vs bifurcation angel:
Non-calcific
75º
±
21
50º
±
11.4
75.2º
±
21
Calcific
72.4º
±
20
48.5º
±
12
46º
±
19
Mixed
75.2º
±
21
43.6º
±
31.1
44.3º
±
30.7
p-
value
NS
NS
NS
Prevalence of bifurcation lesion:
No (%)
125 (56.5%) 84 (47%)
56 (25%)
p
-value
0.0001
LAD : Left Anterior Descending Artery.
OM
: Obtuse Marginal.
LCx : Left Circumflex Artery.
Diagonal : Diagonal artery.
p
0.016
p
0.003
69.25
80.3
67.2
57.7
Medically
treated patients
with significant
bifurcation
lesions
PCI treated
patients with
significant
bifurcation
lesions
ACS
Asymptomatic
Fig. (3): Comparison of bifurcation angel degree as regards
the prevalence of ACS in patients with significant
bifurcation lesions and patients with non-significant
bifurcation lesions in one year follow-up.
Discussion
ACS and patient risk depend on plaque compo-
sition and its degree of instability beside the luminal
narrowing of the coronary artery. Many studies
proved the feasibility and accuracy of MSCT for
detection of CAD and also its accuracy for differ-
entiation of plaque types into calcific, non-calcific
and mixed plaques
[16,17]
.
The bifurcation angle influences the endothelial
shear stress which in turn affects the size of athero-
sclerotic plaque
[13]
. It was reported that wider
bifurcation angles were related to increased flow
turbulence and associated to low shear stress and
it possibly causes proliferation of atherosclerosis
plaques at bifurcation sites
[18,19]
.
Many Intra-Vascular Ultrasound (IVUS) studies
found that atherosclerotic plaques were uncommon
in left main coronary, but it was common to find
plaques in left coronary artery branches especially
at the proximal segments with higher incidence at
LAD artery
[20]
.
Previous studies which studied coronary artery
bifurcation angles and their nature of distribution
concluded that LAD-LCx bifurcation angle of 80º
was a cut off value to find atherosclerotic plaque
[21,22]
.
In a study done by Papadopoulou et al.,
[23]
on
33 patients with CAD bifurcation lesions distributed
as LAD-diagonal in 14 patients (42%) and LCx-
OM in 8 patients (24%) and the remaining bifur-
cations were in the right coronary artery. They
reported that wider bifurcation angles were found
in bifurcations with proximal segments atheroscle-
Ahmed Gaafar, et al.
793
rosis plaques in comparison with those without
(
p
=0.002) and this in agreement with our study.
Z. Sun and Y. Cao
[24]
studied 30 patients with
suspected coronary artery disease. They found the
mean (LAD-LCx) bifurcation angle was 89.1º
±
13.1.
The mean bifurcation angle in normal left coronary
arteries was measured 75.5º
±
19.8º, which was
smaller than bifurcation angle in diseased LAD
(
p
=0.02) which was 94º
±
19.7º, and also this is in
concordance with our results, but they didn't study
other bifurcation angles in this study which was
an important limitation.
In a study by Rodriguez-Granillo et al.,
[17]
which included 50 patients, the median LAD-LCx
bifurcation angle was 88.5º (range 68.5º-101.4º).
In 18 patients with normal ostial LAD, 13 (72%),
the bifurcation angle was <88.5º, while those with
LAD disease the bifurcation angle was
≥
88.5º. In
33 patients with normal ostial LCx, 19 (58%) had
a bifurcation angle <88.5º, while those with dis-
eased LCx had larger angle
≥
88.5º (
p
=0.136). Also
the bifurcation angle of patients with normal LMCA
was <88.5º, while those with diseased LM had
bifurcation angle
≥
88.5º (
p
=0.037). They concluded
that there was strong relationship between left
main bifurcation angle and presence of bifurcation
plaque. And this is in line with our study.
In a study based on of 100 human hearts, Reig
and Petit studied the hearts of 100 human autopsies
and found an average angle of 86.7º
±
28.8º for
patients with LAD-LCx bifurcation lesions
[21]
.
Also Pflederer et al., in a study on 100 CAD patients
found an average bifurcation angle of 80º
±
27º
[22]
, and Kawasaki et al., found that LAD-LCx
bifurcation lesion angle was 72º
±
22º in 209 CAD
patients
[25]
.
In our study, the incidence of bifurcation lesions
was 24% of patients with CAD which in agreement
with Collins et al., how found the incidence about
20%
[26]
.
Our results are in line with the average bifur-
cation angle reported by previous studies. The
average LAD-LCx bifurcation angle in 221 patients
with CAD (56.5%) was 74.24º
±
20.14º and this
was wider than the average angle in normal coro-
naries (43.5%) which was 63.14º
±
19.22º, with
p
-
value (0.001).
In our study, all major bifurcation angles of the
left coronary system (LAD-LCx, LAD-major di-
agonal and LCx-OM) were investigated and corre-
lation between degree of angulation and develop-
ment of atherosclerotic plaques was proved only
at the bifurcation of LAD-LCx (as described
above), where wider bifurcation angels had higher
incidence of atherosclerosis, while no relation was
found at the bifurcation of LAD-diagonal and at
LCx-OM bifurcation sites. We explained the ab-
sence of correlation between angle degree and the
development of bifurcation lesions at LAD-diagonal
and LCx-OM groups due to narrow angels that
were found at these sites in the study group and it
was one of the study limitation, the results could
be different if LAD-LCx and LCx-OM groups had
wider angels.
Regards the relation between left coronary
artery bifurcation angel and type of atherosclerotic
plaques, while Z. Sun and Y. Cao
[9]
mentioned
that they couldn't detect the relationship between
bifurcation angle and the type of plaque due to the
limited sample size as non-calcified plaques were
present only in two patients, but in our study there
were sufficient number of patients with different
types of atherosclerotic plaque for statistical anal-
ysis and we found no relation between bifurcation
angle and plaque type.
In our study during the one year follow-up, the
patients without significant bifurcation lesions who
developed ACS had wider bifurcation angles than
asymptomatic ones. The same was found in patients
with significant lesions, whether they were man-
aged with medical treatment only or who were
managed with PCI plus medical treatment. This
means that wider bifurcation angles have worse
prognosis than narrower bifurcation angels. This
is in agreement with Takao Konishi et al.
[27]
,
who
concluded that wide LMT-LAD angle is associated
with a higher risk of proximal LAD artery disease
stenting restenosis. Also Dzavik et al.
[28]
, found
that angle >50º was an independent predictor of
MACE, Collins et al.
[26]
, stated that bifurcation
angle <50º was associated with better outcomes in
the crush/culotte group. Adriaenssens et al.,
[29]
found increasing bifurcation angle was an inde-
pendent predictor of angiographic restenosis. Chen
et al.
[30]
,
mentioned that bifurcation angle B was
an independent predictor of MACE. Freixa et al.,
[31]
, found that bifurcation angle <50º was associ-
ated with a lower risk of MACE.
Limitations:
One of the limitations in our study is that no
correlation with invasive coronary angiography
was performed. The relationship between calcified,
non-calcified or mixed plaques with patients' symp-
toms or cardiac events was not studied. Finally,
we didn't investigate the bifurcations of the right
coronary artery as they are small sized branches.
794
Prognostic Impact on Coronary Artery Bifurcation Angle Degree
Conclusion:
There was a strong correlation between LM
bifurcation angel and the development of athero-
sclerotic bifurcation lesions and ischemic events,
where wider bifurcation angles were more prone
for development of atherosclerotic lesions. ACS
events incidence was higher in higher bifurcation
angels whether the bifurcation lesions were signif-
icant or not and in with different management
strategies.
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