World Journal of Cardiovascular Diseases, 2013, 3, 487-492 WJCD
http://dx.doi.org/10.4236/wjcd.2013.38077 Published Online November 2013 (http://www.scirp.org/journal/wjcd/)
Long-term clinical efficacy of ostial stenting to the left
anterior descending artery with deep caudal projection
Kenji Sadamatsu*, Yuya Yoshidomi, Keiki Yoshida
Department of Cardiology, Saga-Ken Medical Centre Koseikan, Saga, Japan
Email: *k-sadamatsu@umin.ac.jp
Received 3 September 2013; revised 5 October 2013; accepted 15 October 2013
Copyright © 2013 Kenji Sadamatsu et al . This is an open access article distributed under the Creative Commons Attribution License,
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
ABSTRACT
Purpose: Overlapping and foreshortening on conven-
tional coronary angiography is one reason why the
presence of ostial lesions in the left anterior descend-
ing artery (LAD) is an independent predictor of in-
segment restenosis. Our previous study using 3-di-
mensional reconstruction coronary angiography de-
monstrated the superiority of a deeper caudal projec-
tion in clearly showing the ostium of the LAD com-
pared to the standard right or left anterior oblique
caudal view. Therefore, the aim of this study was to
determine the short- and long-term efficacy of the
ostial stenting technique using a deep caudal projec-
tion angle. Metho d s: A total of 30 consecutive patient s
who underwent stent deployment to treat LAD lesions
positioned at the proximal edge of the stent in the
ostium with a deep caudal projection were analyzed
retrospectively. Results: The projection of right ante-
rior oblique caudal 40˚ was used in 26 patients and
that of left anterior oblique caudal 40˚ was used in
four patients. Intravascular ultrasound examinations
showed complete coverage of the ostium by the stent
in 29 patients. In one patient, the stent did not cover
the ostium. The mean protrusion of the stent over the
ostium was 0.66 ± 0.85 mm. During the follow-up
period (1203.5 [982 - 1329] days), the rate of target
lesion failure was 16.7%, and there were no cases
with in-stent restenosis of the main branch in which a
drug-eluting stent covering the ostium of the LAD
was successfully deployed. Conclusions: Focal stent
placement using a deep caudal projection is a feasible
and effective therapeutic strategy for treating ostial
lesions in the LAD.
Keywords: Coronary Artery Disease;
Three-Dimensional Imaging; Angiography; Bifurcation
Lesions; Intravascular Ultrasound
1. INTRODUCTION
Performing percutaneous coronary intervention to the
ostial left anterior descending artery (LAD) is challeng-
ing, even in the era of drug-eluting stents, because the
presence of ostial lesions is an independent predictor of
in-segment restenosis [1]. While such restenosis is asso-
ciated with numerous factors, among which incomplete
lesion coverage seems to be the most critical one, which
thus highlights the technical difficulties encountered in
achieving precise stent positioning in the ostium [2]. These
technical difficulties primarily result from foreshortening
of the LAD and overlapping of the LAD and the left
circumflex artery (LCX) on conventional coronary angio-
graphy. Therefore, focal stenting, which is often attem-
pted in patients with ostial lesions, may result in in-
complete lesion coverage or protrusion of the proximal
stent margin into the ostium of the circumflex artery [3].
Furthermore, the presence of plaque and/or carina shift
with compromise of the adjacent vessels [4-6] and the
difficulty of performing repeat intervention for in-stent
restenosis are also important issues that lead to many
patients with ostial lesions being referred for bypass sur-
gery. On the other hand, favorable outcomes of un-
protected left main coronary artery stenting with drug-
eluting stents have been recently reported, and the cross-
over stenting technique has emerged as a new stenting
strategy for treating ostial LAD lesions. The easier stent
positioning guaranteeing full coverage of the lesions
achieved with this method may lead the cross-over stent-
ing technique to become a mainstream therapy for treat-
ing ostial LAD lesions [7-10]. However, there are some
disadvantages associated with the cross-over technique.
Jailing the ostium of the LCX with the stent is the pri-
mary problem and requires the use of the kissing balloon
inflation technique in almost all cases [8,9]. This com-
plex inflation technique results in longer procedure and
fluoroscopic times and the use of larger contrast volumes.
In order to cover the area from the left main trunk to the
*Corresponding author.
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K. Sadamatsu et al. / World Journal of Cardiovascular Diseases 3 (2013) 487-492
488
LAD, the stent length must become longer [10]. A dis-
crepancy in lumen size between the left main trunk and
the ostial LAD is a concern of incomplete stent apposi-
tion in the left main trunk. In spite of these disadvantages,
the cross-over stenting technique is often adopted for
fear of achieving incomplete lesion coverage with ostial
stenting.
Recently, we investigated the optimization of the
projection angle to clearly show the ostium of the LAD
using 3-dimensional reconstruction coronary angiogra-
phy and demonstrated the superiority of a deeper caudal
projection over the standard right or left anterior oblique
caudal view [11]. Therefore, the use of focal ostial
stenting to the LAD with a deep caudal projection may
be able to overcome concerns of incomplete lesion co-
verage. The aim of this study was to determine the short-
and long-term efficacy of the ostial stenting technique to
the LAD with a deep caudal angle.
2. METHODS
2.1. Study Population
The institutional review board approved this study.
Written informed consent was obtained from all patients.
All patients were at least 18 years of age and presented
with either stable/unstable angina or documented silent
myocardial ischemia. A total of 30 consecutive patients
who underwent stent deployment to treat LAD lesions
positioned at the proximal edge of the stent in the ostium
with a deep caudal projection between April 2008 and
June 2009 were analyzed retrospectively. In addition to
those with significant LAD ostial lesions, patients with
diffuse significant proximal LAD lesions originating
from the ostium in whom the ostial lesions were not sig-
nificant were also included. Patients with significant left
main lesions and LCX ostial lesions were excluded. The
final decision to perform ostial stenting was left to the
operators.
2.2. Techniques
All procedures were performed using standard techni-
ques. Unfractionated heparin at a dose of 10,000 units
was administered at the start of the procedures. Dual
antiplatelet therapy with aspirin at a dose of 100 mg/day
and clopidogrel at a dose of 75 mg/day or ticlopidine at a
dose of 200 mg/day was recommended to be continued
for at least 12 months in patients with drug-eluting stents
and six months in patients with bare metal stents.
A deep caudal projection (right anterior oblique or left
anterior oblique caudal 40˚) was used to implant the stent
positioned at the proximal edge of the stent in the LAD
ostium. We previously demonstrated that the right ante-
rior oblique caudal 40˚ projection is optimal for stent
placement in patients with ostial LAD lesions in most
cases [11]. As a result, we first selected the right anterior
oblique projection. If the projection did not work, we
changed it to the left anterior oblique caudal 40˚. In addi-
tion, we used intravascular ultrasound (IVUS) in all
cases and confirmed that the position of the IVUS trans-
ducer showing the LAD ostium was just in the LAD
ostium on angiography with a deep caudal projection.
Under the guidance of the images, we positioned the
stent to guarantee complete LAD ostium scaffolding with
minimum protrusion of the stent at the level of the LCX
ostium. A representative case is shown in Figure 1.
2.3. Patient Follow-Up
The patients were followed up at six months after the
procedure and once a year routinely, unless symptoms or
events required earlier consultation. Angiographic fol-
low- up at eight months was encouraged for all patients.
Follow-up data were collected until October 2012. Tar-
get lesion failure was defined as cardiac death, target
vessel-related nonfatal myocardial infarction, target le-
sion revascularization or stent thrombosis.
2.4. Statistical Analysis
Quantitative data are presented as the mean value ± SD
or the median [interquartile range], and qualitative data
are presented as frequencies. The Kaplan-Meier method
and logrank test were used to assess the time to target
lesion failure. All statistical analyses were performed
with the SPSS software program (SPSS, Inc., Chicago,
Ill).
3. RESULTS
The clinical and lesion characteristics of the patients are
shown in Table 1. Stenosis of the ostial lesions was not
severe because we included not only patients with signi-
ficant ostial lesions, but also patients with diffuse LAD
lesions requiring coverage with the stent to the ostium.
The procedural characteristics are shown in Table 2. All
procedures were successful. In most cases, the right an-
terior oblique caudal 40˚ projection was used. Stent de-
ployment following pre-dilation without post-dilation
was the most frequent technique. Plaque or carina shift to
the LCX ostium was minimal, and we dilated the LCX
ostium with a conventional balloon in only one patient.
Bare metal stents were used in two patients with acute
myocardial infarctions. The IVUS findings (Table 3)
demonstrated that the stents were deployed precisely in
the LAD ostium with minimal protrusion to the left main
trunk, except in one patient.
The median period of clinical follow-up was 1203.5
[982-1329] days. 1-, 2- and 3-year follow-up was com-
pleted in 29 (96.7%), 28 (93.3%) and 21 (70.0%) patients,
respectively. Follow-up angiography was performed in
Copyright © 2013 SciRes. OPEN ACCESS
K. Sadamatsu et al. / World Journal of Cardiovascular Diseases 3 (2013) 487-492 489
Figure 1. A representative case. A control angiogram (right
anterior oblique 30˚ - caudal 30˚) showing overlap of the
proximal left anterior descending artery and the circumflex
artery (A). A deep caudal view (right anterior oblique 15˚ -
caudal 40˚) clearly demonstrating appropriate positioning of the
intravascular ultrasound probe (arrow), which was placed in the
ostium of the left anterior descending artery (B). A stent was
deployed under the same projection (C). Intravascular ultra-
sound images revealing that the proximal edge of the stent was
accurately deployed in the ostium (D). The lesion was success-
fully dilated without any complications (E).
Table 1. Clinical and lesion characteristics of patients.
Age (years) 70.5 ± 9.6
Male 20 (67)
Risk factors
Diabetes mellitus 13 (43)
Hypertension 25 (83)
Dyslipidemia 21 (70)
Smoking 9 (30)
Diagnosis
Acute myocardial infarction 3 (10)
Unstable angina 5 (17)
Stable coronary disease 22 (73)
Quantitative coronary angiography
Baseline
Lesion length (mm) 10.50 ± 6.70
LAD reference diameter (mm) 2.89 ± 0.55
Minimal lumen diameter (mm) 1.50 ± 0.63
Diameter stenosis (%) 47.0 ± 22.2
Post-procedure
Minimal lumen diameter (mm) 3.01 ± 0.53
Diameter at the LCX ostium (mm)2.60 ± 0.72
Data are expressed as mean ± SD or number (percentage). LAD denotes left
anterior descending artery; LCX, left circumflex artery.
27 (90.0%) patients, while myocardial ischemia was ex-
amined on myocardial scintigrams in the other three pa-
tients. During the follow-up period (Table 4), acute
myocardial infarction with occlusion of the right coro-
nary artery occurred in one patient and target lesion re-
vascularization occurred in five patients, including two
patients with severe stenosis at the ostium of the LCX
only. In the remaining three patients with target lesion
revascularization, two patients were treated with bare
metal stents for acute myocardial infarction and, in one
patient, we failed to cover the ostium of the LAD with
the stent. Repeated coronary intervention to the site of
restenosis at the distal stented lesion was performed in all
five patients. Noncardiac death was observed in two pa-
tients. Consequently, the target lesion failure rate was
16.7%, while there were no cases of in-stent restenosis of
the main branch in which a drug-eluting stent covering
the ostium of the LAD was successfully deployed. Kap-
lan-Meier curves for freedom from target lesion failure
in all patients and the patients treated with drug-eluting
stents are shown in Figure 2.
4. DISCUSSION
The present observational study evaluated the short- and
long-term efficacy of the ostial stenting technique with a
deep caudal projection angle. The main findings were as
follows: 1) the protrusion of the stent over the ostium
was very small; and 2) target lesion failure defined as
Table 2. Procedural characteristics.
Direct stent 3 (10)
Post dilation 6 (20)
RAO-caudal 40˚ 26 (87)
Drug-eluting stent 28 (93)
Stent size (mm) 3.43 ± 0.22
Stent length (mm) 25.6 ± 6.6
Ballooning / stenting to ostial LCX 1/0
Data are expressed as mean ± SD or number (percentage). RAO denotes
right anterior oblique; LCX, left circumflex artery.
Table 3. Intravascular ultrasound findings.
Baseline findings
LMCA
Lumen area (mm2) 13.57 ± 3.59
Vessel area (mm2) 15.25 ± 3.45
LAD ostial lesion
Lumen area (mm2) 3.53 ± 0.82
LAD reference segment
Vessel area (mm2) 14.22 ± 4.64
Post-procedural findings
Mean distance (mm) 0.66 ± 0.85
0 < Distance 1.0 mm 20 (67)
Uncovered LAD ostium 1 (3)
Lumen area in LAD ostium (mm2) 7.08 ± 1.12
Data are expressed as mean ± SD or number (percentage). LMCA denotes
left main coronary artery; LAD, left anterior descending artery.
Copyright © 2013 SciRes. OPEN ACCESS
K. Sadamatsu et al. / World Journal of Cardiovascular Diseases 3 (2013) 487-492
490
Table 4. Major adverse cardiac events during follow-up period.
Events 0 - 180
days
181 - 365
days
>366
days
Cardiac death 0 0 0
Non-cardiac death 0 0 2
Non-fatal myocardial infarction 1 0 0
Target lesion revascularization 0 4 1
Target vessel revascularization 0 6 4
Stent thrombosis 0 0 0
Figure 2. Kaplan-Meier curves for freedom from target
lesion failure in all patients (All) and the patients treat-
ed with drug-eluting stents (DES).
cardiac death, target vessel-related nonfatal myocardial
infarction, target lesion revascularization or stent throm-
bosis occurred in 16.7% of the patients.
The precise positioning of the stent in the ostium of
the LAD is the most important technical factor in ostial
LAD stenting. Several techniques have been proposed to
assist in achieving accurate stent positioning in patients
with ostial lesions. First, the Szabo technique anchors the
stent in the ostial lesion using two wires [12]. The second
wire is positioned in the aorta or the opposing branch
with the most proximal end passed through the last cell
of the stent inhibiting advancement, thus anchoring the
stent in the accurate position. The reported success rates
achieved with this technique are high [13], however, this
method is technically demanding [3]. In addition, recent
bench testing showed significant and asymmetric defor-
mations in the proximal end of the stent protruding into
the main branch, and the clinical data demonstrated that
the technique failed to implant stents in the ostium pre-
cisely [14]. Second, the floating stent technique is a
method used to deploy the proximal edge of the stent to
the angiographic carina between the LAD and the LCX
to guarantee complete LAD scaffolding with minimal
protrusion of the stent at the LCX ostium. Medina et al.
demonstrated using this technique that the mean protru-
sion of the stent over the origin of the LCX was 2.48 ±
0.91 mm and that the major adverse cardiac event rate
was 4% [15]. Third, IVUS-guided positioning of the
stent is a simple technique that involves marking the ac-
curate point of the ostium on a coronary angiogram [16].
The floating stent and IVUS-guided positioning tech-
niques are essentially the same as our technique; how-
ever, protrusion of the proximal edge of the stent into the
left main trunk in the present study was shorter than that
observed with the floating stent technique, which sug-
gests that clear visualization of the ostial lesions with a
deep caudal projection contributes considerably to achie-
ving an accurate stent position, even with these tech-
niques.
We recently demonstrated the usefulness and feasibi-
lity of a 3-dimensional reconstruction system for select-
ing the optimal view to provide clear images of the ostial
LAD. Deep caudal projection angles are optimal in most
cases [11]. Tu et al. assessed obtainable optimal bifurca-
tion viewing angles in four main coronary bifurcations
and reported similar findings to ours in that the optimal
view for left main bifurcation distributes primarily at the
deep caudal view (35˚ ± 16˚ caudal) and spreads across
the left anterior/right anterior oblique view (4˚ ± 39˚ left
anterior oblique) [17]. However, this 3-dimensional re-
construction system is not available in all catheterization
laboratories, and we investigated whether the deep cau-
dal projection is applicable for the treatment of ostial
LAD lesions in daily practice without using the 3-dimen-
sional reconstruction system. The excellent short- and
long-term results obtained in the present study confirm
the helpfulness of the deep caudal projection in deploy-
ing stents in the ostium of the LAD, even without using
the reconstruction system.
The optimal projection angles for treating ostial le-
sions depend on the anatomy of the heart of each patient.
Skilled operators are able to find the best view for ostial
stenting without consuming radiation exposure or con-
trast volume. The three-dimensional reconstruction coro-
nary angiography system also easily indicates the opti-
mal view in the practical range. However, for most inex-
perienced or learning operators in catheterization labo-
ratories unequipped with a reconstruction system, a long-
er procedural time and more radiation exposure and con-
trast are required to determine the optimal angle, and, in
some cases, suboptimal projection can lead to unsuc-
cessful results. Therefore, the use of a fixed deep caudal
projection angle, which is a very simple method for all
coronary interventionalists, may be not best, although it
is a better strategy for implanting coronary stents in the
ostium of the LAD.
Copyright © 2013 SciRes. OPEN ACCESS
K. Sadamatsu et al. / World Journal of Cardiovascular Diseases 3 (2013) 487-492 491
There are some important limitations associated with
this study. First, this study was a single-center registry
including a small number of subjects. Second, this study
lacked a control group, and thus we cannot compare the
results obtained with those of conventional projection
angles. Moreover, we must compare our technique with
the cross-over technique. Third, angiographic and clini-
cal follow-up data were not available for some of the
patients, which may have led to some bias in the present
results. Finally, we used IVUS in all cases to verify the
appropriateness of the deep caudal projection angles;
thus, the use of IVUS may have influenced the excellent
outcomes achieved with this technique.
5. CONCLUSION
Performing focal stent placement using a deep caudal
projection is thus considered to be a feasible and effec-
tive therapeutic strategy for treating ostial lesions in the
LAD.
6. ACKNOWLEDGEMENTS
The authors appreciate the support and collaboration of our catheteri-
zation laboratory staff. The authors have no conflicts of interest that are
directly relevant to the content of this study.
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