Long-term clinical efficacy of ostial stenting to the left anterior descending artery with deep caudal projection

doi:10.4236/wjcd.2013.38077

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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: *[email protected]

Received 3 September 2013; revised 5 October 2013; accepted 15 October 2013

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.

OPEN ACCESS

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

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.

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.

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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