efficacy and feasibility of the 3-dimensional wiring …efﬁcacy and feasibility of the...

J A C C : C A R D I O V A S C U L A R I N T E R V E N T I O N S V O L . 1 2 , N O . 6 , 2 0 1 9

ª 2 0 1 9 T H E A U T H O R S . P U B L I S H E D B Y E L S E V I E R O N B E H A L F O F T H E A M E R I C A N

C O L L E G E O F C A R D I O L O G Y F OU N D A T I O N . T H I S I S A N O P E N A C C E S S A R T I C L E U N D E R

T H E C C B Y - N C - N D L I C E N S E ( h t t p : / / c r e a t i v e c o mm o n s . o r g / l i c e n s e s / b y - n c - n d / 4 . 0 / ) .

Efficacy and Feasibility of the3-Dimensional Wiring Techniquefor Chronic Total OcclusionPercutaneous Coronary InterventionFirst Report of Outcomes of the3-Dimensional Wiring Technique

Takamasa Tanaka, MD,a Atsunori Okamura, MD,a Katsuomi Iwakura, MD,a Mutsumi Iwamoto, MD,a

Hiroyuki Nagai, MD,a Tomohiro Yamasaki, MD,a Akinori Sumiyoshi, MD,a Kota Tanaka, MD,a Koichi Inoue, MD,a

Yasushi Koyama, MD,a Tohru Masuyama, MD,b Masaharu Ishihara, MD,b Kenshi Fujii, MDa

ABSTRACT

ISS

Fro

rec

of

Ma

OBJECTIVES This study sought to compare the procedural outcomes of percutaneous coronary intervention for chronic

total occlusion between the periods before and after introduction of 3-dimensional (3D) wiring.

BACKGROUND Previously, we reported a 3D wiring method by which the operator can construct real-time mental

3D images from 2 perpendicular angles of X-ray system monitor during percutaneous coronary intervention for chronic

total occlusion.

METHODS A total of 137 chronic total occlusion lesions that could not be passed by tapered soft wires in our hospital

between 2012 and 2017 were retrospectively enrolled in the study.

RESULTS Overall success rate was significantly higher in the 3D wiring group (n ¼ 69) than the non-3D wiring group

(n ¼ 68) (98% vs. 90%, respectively; p ¼ 0.027). In the primary antegrade cases, the first antegrade approach time was

significantly shorter in the 3D wiring group than the non-3D wiring group (42 � 29 vs. 30 � 16 min, respectively;

p ¼ 0.01). In cases where the antegrade approach was continued throughout the procedure, the success rate was

significantly higher in the 3D wiring group than the non-3D wiring group (100% vs. 89.2%, respectively; p ¼ 0.033).

Vessel perforation by the antegrade wire tended to be lower in the 3D wiring group than the non-3D wiring group

(1% vs. 11%, respectively; p ¼ 0.055).

CONCLUSIONS 3D wiring enables accurate guidewire control, which improves the success rate of antegrade wiring and

reduces the antegrade procedure time, resulting in improvement of the overall success rate. (J Am Coll Cardiol Intv

2019;12:545–55) © 2019 The Authors. Published by Elsevier on behalf of the American College of Cardiology Foundation.

This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

D edicated coronary interventional cardiolo-gists have developed several techniquesand devices to improve the procedural out-

comes of percutaneous coronary intervention (PCI)for chronic total occlusion (CTO) lesions (1–3). Amongthe CTO-specific guidewires, the Conquest and Gaia

N 1936-8798

m the aSakurabashi-Watanabe Hospital, Osaka, Japan; and the bHyogo C

eived speaking fees from Terumo Corp. All other authors have reported tha

this paper to disclose.

nuscript received July 24, 2018; revised manuscript received December 1

guidewires (Asahi Intecc Co., Ltd., Aichi, Japan)enable accurate control in CTO lesions becauseof the excellent torque transmission and torqueforce. We developed a CTO-specific intravascular ul-trasound (IVUS) system, Navifocus WR, in partner-ship with Terumo Corp. Pranex Center (Tokyo,

https://doi.org/10.1016/j.jcin.2018.12.014

ollege of Medicine, Hyogo, Japan. Dr. Okamura has

t they have no relationships relevant to the contents

0, 2018, accepted December 12, 2018.

http://creativecommons.org/licenses/by-nc-nd/4.0/

https://doi.org/10.1016/j.jcin.2018.12.014

http://crossmark.crossref.org/dialog/?doi=10.1016/j.jcin.2018.12.014&domain=pdf

http://creativecommons.org/licenses/by-nc-nd/4.0/

FIGURE 1 Advantages of 3-D

(A) Two angiographic images of

hypothesized that the operator

guidewire 90� in the counterclo

guidewire in the clockwise direct

The operator first discovers tha

ABBR EV I A T I ON S

AND ACRONYMS

2D = 2-dimensional

3D = 3-dimensional

CTO = chronic total occlusion

IVUS = intravascular

ultrasound

MACCE = major adverse

cardiac and cerebrovascular

event(s)

PCI = percutaneous coronary

intervention

Tanaka et al. J A C C : C A R D I O V A S C U L A R I N T E R V E N T I O N S V O L . 1 2 , N O . 6 , 2 0 1 9

3D Wiring During CTO Intervention M A R C H 2 5 , 2 0 1 9 : 5 4 5 – 5 5

546

Japan) (4). Our clinical experience with IVUS-guided wiring for CTO lesions indicated that3-dimensional (3D) imaging is important foraccurate guidewire control. Therefore, usingthe images of 2 perpendicular angles fromthe X-ray monitor without IVUS guidance,intentional rotation with an image ofclockwise/counterclockwise rotation whileconstructing a mental 3D image should beperformed. However, there have been noreports regarding this method because it isdifficult to construct a real-time mental 3D

image from 2-dimensional (2D) images obtainedfrom the X-ray system monitor during PCI for CTO

SEE PAGE 556

lesions. Therefore, we developed a 3D wiring methodto manipulate these stiff CTO-specific guidewiresunder real-time construction of a mental 3D imagein 2015 (5). Since then, we have performed the 3D wir-ing method during PCI for CTO in our clinical practice.

imensional Wiring

perpendicular directions 90� apart (RAO 45� and LAO 45�) and c

is now observing the image from LAO 45�. If the operator can con

ckwise direction toward the target with minimum damage. (C) If no

ion and stop the rotation only 90� in the clockwise direction becau

t the tip is facing the wrong direction after viewing from RAO 45

This study was performed to assess the efficacyand feasibility of the 3D wiring method during PCI forCTO in clinical practice to compare the proceduraloutcomes of CTO-PCI between the periods before andafter the introduction of 3D wiring.

METHODS

METHODOLOGY OF 3D WIRING AND EXPERIMENTAL

TRAINING MODEL. The 3D wiring technique iseffective in the antegrade wiring but not in theretrograde wiring because the torque response of theretrograde guidewire cannot be maintained. We re-ported the methodology for 3D wiring previously (5).A guidewire can only be rotated in 2 directions, eitherclockwise or counterclockwise. 3D wiring involvesrotating and advancing the guidewire by constructinga 3D image of its relationship to the target (i.e., theroute within the CTO, the distal end of the CTO, or theretrograde wire) to determine which direction ofrotation (clockwise or counterclockwise) provides the

ross-sectional image constructed from these 2 images. (B) If it is

struct the cross-sectional image, the operator will simply rotate the

t, there is a 50% possibility that the operator will instead rotate the

se the tip of the guidewire coincides with the target from LAO 45�.�. LAO ¼ left anterior oblique; RAO ¼ right anterior oblique.

FIGURE 2 Method of 3D Wiring

(A) Cross-sectional image of 64 rotation direction patterns to determine the degree of guidewire rotation within 45�. (B) When manipulating the guidewire from one

view and rotating the detector to the perpendicular view at the right (left) side, the position of the shaft relative to the target is in the opposite (same) direction to the

rotational direction of the X-ray detector and the tip faces in the same (opposite) direction as the rotational direction. (C) When viewing from the perpendicular view at

the right side after rotation, the shaft is behind the target and the tip is facing the front in all 9 possible patterns. (D)When viewing from the perpendicular view at the

left side after rotation, the shaft is in front of the target and the guidewire tip is to the rear. (E) Construction of a mental 3D image with information that the shaft is to

the rear and the tip is in front, which reveals that the tip should be rotated 45� in the clockwise direction. (F) Construction of a mental 3D image with information that

the shaft is in front and the tip is to the rear, which reveals that the tip should be rotated 45� in the counterclockwise direction. 3D ¼ 3-dimensional.

J A C C : C A R D I O V A S C U L A R I N T E R V E N T I O N S V O L . 1 2 , N O . 6 , 2 0 1 9 Tanaka et al.M A R C H 2 5 , 2 0 1 9 : 5 4 5 – 5 5 3D Wiring During CTO Intervention

547

shortest route to the target. Figure 1 illustrates theadvantages of 3D wiring. With construction of the 3Dimage, the guidewire tip can be accurately directedtoward the target with minimum damage. However,without constructing a 3D image, the guidewire tipcannot be positioned accurately, an unnecessarilylarge space is created that compresses the distal endof the CTO, and the possibility of advancing into afalse lumen is increased.

To allow the operator to construct real-time mental3D images during CTO-PCI, it is necessary to dividethe guidewire into the shaft and tip sections and todetermine their relationships with the target. As wereported previously (5), it is difficult to determine theextent of rotation within 45� when the guidewireis directed toward the target because there are8 possible positional relationships between the targetand the shaft combined with 8 possible tip directions,resulting in 64 possibilities (Figure 2A). Because thecoronary arteries may run perpendicularly or

horizontally, these variations also complicate theconstruction of a 3D image. To overcome theseproblems, we use the following rule: the object (shaftor tip) is always in front (behind) on the next imageafter rotation if the object is in the same (opposite)direction as the rotational direction of the X-ray de-tector. By unifying the horizontal and vertical di-rections on the X-ray monitor with the rotationaldirection of the X-ray detector, it becomes possible toeasily construct a real-time 3D image of the guidewireand target at any site in the coronary artery. Theapplication of this 3D image rule is shown inFigures 2B to 2E.

To determine whether Confianza and Gaia wirescan be used for the previously mentioned 3D wiringand in training ourselves in this method, we created atarget pinpoint penetration model for 3D wiring (5).The target, which is a tube with a lumen 1.0, 0.6, or0.4 mm in diameter, was placed in the distal part of aCTO 20 mm in length made of 2% to 2.5% agar in a

FIGURE 3 Study Population

CTO ¼ chronic total occlusion; other abbreviation as in Figure 2.

FIGURE 4 Represe

(A) Pre-procedural c

angiography by the

contrast media from

intravascular ultraso

oblique 40� and cran



548

vessel model with a diameter of approximately3.0 mm, and pinpoint penetration was performed by3D wiring. To perform the procedures in these modelsunder the same conditions as for actual PCI, wiring

ntative Case of 3-Dimensional Wiring

oronary angiography by the injection of contrast media from right coronary

injection of contrast media from left coronary artery in left anterior oblique 4

left coronary artery in left anterior oblique 45�. (D) Fluoroscopic radiography

und image. A region surrounded by a dotted line showed the space created by

ial 25�. CTO ¼ chronic total occlusion.

was done with an X-ray monitor using an experi-mental heartbeat model (Terumo Corp. PranexCenter). All operators at our institute were able toconstruct 3D images in real-time and penetrate the

artery in left anterior oblique 45�. (B) Pre-procedural coronary

0� and cranial 25�. (C) Coronary angiography by the injection of

during the pinpoint penetration to the distal end. (E) Cross-sectional

the XT-R guidewire. (F) Final coronary angiography in left anterior

FIGURE 5 3-Dimensional Wiring to Perform Pinpoint Penetration for the Target

The procedure of 3-dimensional wiring was performed in the 2 perpendicular angles (LAO 45� and RAO 45�) in chronological order of the angiographic images. (1, 2) In

LAO 45�, the shaft was on the left of the distal end and the tip was directed to the right and the X-ray detector was rotated to the left side to observe the next image

(RAO 45�). Therefore, z-axis information of RAO 45� was that the shaft was in front and the tip was facing away (behind) and the tip needed to be rotated in the

counterclockwise direction to the distal end. (3, 4) In RAO 45�, the shaft was on the right of the distal end and the tip was directed to the left and the X-ray detector

was rotated to the right side to observe the next image (LAO 45�). Therefore, z-axis information of LAO 45� was that the shaft was in front and the tip was facing

away (behind) and the tip needed to be advanced to the distal end in this direction. (5, 6) In LAO 45�, the shaft was on the left of the distal end and the tip was directed

to the right and the X-ray detector was rotated to the left side to observe the next image (RAO 45�). Therefore, z-axis information of RAO 45� was that the shaft was in

front and the tip was facing away (behind) and the tip needed to be slightly rotated to the distal end in the clockwise direction. (7, 8) In RAO 45�, the shaft was on the

right of the distal end and the tip was directed to the left and the X-ray detector was rotated to the right side to observe the next image (LAO 45�). Therefore, the

z-axis information of LAO 45� was that the shaft was in front and the tip was facing away (behind) and the tip needed to be slightly rotated to the distal end in the

counterclockwise direction and be pushed to perform pinpoint penetration. Abbreviations as in Figures 1 and 3.


549

targets accurately and with confident reproducibility.We have been using 3D wiring in clinical practicesince 2015.

STUDY POPULATION. Figure 3 presents a summary ofthe study population. From March 2015 to July 2017after we introduced 3D wiring, a total of 88 consec-utive patients who underwent PCI for CTO recanali-zation by a single operator (A.O.) at SakurabashiWatanabe Hospital (Osaka, Japan) were retrospec-tively enrolled in the 3D wiring group. A.O. was thefirst or second operator and in the latter situation thefirst operator was M.I., H.N., T.Y., S.N., A.S., or T.T.The 19 CTO lesions crossed by only the tapered softguidewires with a tip load of #1 g (XT-R and XT-A,Asahi Intecc Co., Ltd.) were excluded. Therefore,

69 CTO lesions (69 patients) were included in thisstudy. From February 2012 to March 2015 before theintroduction of 3D wiring, 93 consecutive patientswho also underwent PCI for CTO recanalization by thesame operators as described for the 3D wiring groupwere included as the non-3D wiring group (i.e., thecontrol cohort). Twenty-five CTO lesions crossed byonly the tapered soft wires were excluded. Therefore,68 patients (68 CTO lesions) were included in thisstudy. The protocol was approved by the reviewboard of our institution and all patients providedwritten informed consent to participate in the clinicalstudy.

INTERVENTIONAL PROCEDURE. We used the onlysingle-plane angiographic machine (Allura Xper FD

TABLE 1 Demographics and Angiographic Characteristics

Overall(N ¼ 137)

Non-3D WiringGroup (n ¼ 68)

3D WiringGroup (n ¼ 69) p Value

Demographics

Age, yrs 65 � 10 67 � 10 63 � 12 0.069

Male 114 (83) 56 (82) 58 (84) 0.798

Clinical presentation

Asymptomatic 60 (43) 28 (41) 32 (46) 0.539

Stable angina 77 (56) 40 (58) 37 (53)

History of CABG 11 (8) 5 (7) 6 (9) 0.772

Coronary risk factor

Hypertension 93 (68) 47 (69) 46 (67) 0.758

Diabetes mellitus 64 (47) 31 (46) 33 (48) 0.793

Dyslipidemia 114 (84) 53 (79) 61 (88) 0.139

Smoker 66 (50) 31 (48) 35 (54) 0.364

Family history 19 (14) 10 (13) 9 (15) 0.712

PAD 18 (14) 10 (15) 8 (13) 0.096

eGFR (<45 ml/min/1.73 m2) 24 (18) 18 (26) 6 (9) 0.001

Hemodialysis 12 (9) 8 (12) 4 (6) 0.213

LVEF <35% 14 (10) 8 (11) 6 (9) 0.553

Angiographics

Target vesselRCA 69 (51) 33 (54) 36 (49) 0.306LAD 37 (27) 16 (26) 21 (28)LCX 28 (21) 11 (18) 17 (23)LMT 1 (1) 1 (2) 0 (0)

CABG 10 (7) 4 (7) 6 (8) 0.731Collateral filling grade

CC 0 21 (16) 9 (15) 12 (16) 0.874CC 1 44 (33) 18 (30) 26 (35)CC 2 70 (52) 34 (56) 36 (49)

CTO entry typesBlunt 60 (44) 29 (43) 31 (45) 0.788

Severe calcification 22 (16) 13 (22) 8 (11) 0.057Bending (>45�) 44 (32) 20 (29) 24 (35) 0.501Occluded length (>20 mm) 92 (67) 45 (66) 47 (68) 0.809Reattempted lesion 28 (20) 12 (18) 16 (23) 0.421ISR 30 (22) 16 (24) 14 (20) 0.647J-CTO score 2.12 � 1.29 2.12 � 1.31 2.11 � 1.28 0.423

Values are mean � SD or n (%).

3D ¼ 3-dimensional; CABG ¼ coronary artery bypass graft; CC ¼ collateral connection grade; CTO ¼ chronictotal occlusion; eGFR ¼ estimated glomerular filtration rate; ISR ¼ in stent restenosis; J-CTO score ¼ Japanesechronic total occlusion score; LAD ¼ left anterior descending coronary artery; LCX ¼ left circumflex coronaryartery; LMT ¼ left main trunk; LVEF ¼ left ventricular ejection fraction; PAD ¼ peripheral arterial disease;RCA ¼ right coronary artery.



550

10, Philips Healthcare, Best, the Netherlands) toobserve angiographic images in 2 directions as closeto 90� as possible. The single-plane angiographicmachine is better because the angle of the 2 directionsof the biplane angiographic machine is limited. TheCTO revascularization strategy was determined atthe discretion of the single operator (A.O.) mainlyaccording to the hybrid algorithm (6) and the algo-rithm for CTO crossing from AP-CTO club (7).The dissection re-entry (Stingray system, BostonScientific Corp., Natick, Massachusetts) was not per-formed because it was not introduced before August2017 at our institution.

In the non-3D wiring group, the operator per-formed 2D wiring, in which the guidewire was rotatedtoward the target on the X-ray monitor withoutconsidering the direction of rotation (i.e., clockwiseor counterclockwise). In the 3D wiring group, theoperator selected 2D wiring or 3D wiring dependingon the lesion morphology and the interventionalsituations but attempted to use 3D wiring wheneverpossible. The tip shape of the tip of Gaia and Con-fianza guidewires is around 1-mm curve at an angle of45� in both groups. A Corsair microcatheter (AsahiIntecc Co., Ltd.), which has sufficient backup supportfor the guidewires, was mainly used during manipu-lation of the CTO guidewires in both groups.

STUDY DEFINITION. CTO were defined as totallyoccluded lesions with an estimated duration of atleast 3 months with Thrombolysis In MyocardialInfarction grade 0 (8). Indication for PCI was based ontypical effort angina or documented ischemia and leftventricular viability by positive stress-test findings.The Japanese chronic total occlusion score (multi-center CTO registry of Japan) score was applied fordifficulty grading of CTO lesions as reported previ-ously (9). The angiographic classifications, such ascollateral connection grade, CTO entry type, calcifi-cation, bending, and lesion length, were defined asreported previously (10). Procedural success wasdefined as when both the guidewire and ballooncrossed the occluded lesion completely, successfullydilating the occluded artery, and achieving restora-tion of antegrade flow (Thrombolysis In MyocardialInfarction grade flow score 3) with <50% residualstenosis on final angiography. In-hospital majoradverse cardiac and cerebrovascular events (MACCE)consisted of cardiac and noncardiac death, Q-wavemyocardial infarction, non-Q-wave myocardialinfarction, target vessel failure followed by emergenttarget vessel revascularization with PCI or coronaryartery bypass grafting, and stroke. Myocardialinfarction was defined as an increase in creatine ki-nase level to more than twice the normal upper limit.Complications related to the antegrade approachconsisted of vessel perforations without tamponadeby the antegrade guidewire at the CTO site and per-forations leading to cardiac tamponade.

STATISTICAL ANALYSIS. Numerical data areexpressed as the mean � SD or median (interquartilerange), whereas categorical values are expressed aspercentages. Continuous data were compared usingthe unpaired Student’s t-test (for parametric data)and the Mann–Whitney U test (for nonparametricdata). Frequency functions were assessed using

FIGURE 6 Flow Diagram of the Procedure in the Non-3D Wiring Group

IVUS ¼ intravascular ultrasound; other abbreviations as in Figures 2 and 4.


551

Fisher exact test and the chi-square test. In all ana-lyses, p < 0.05 was taken to indicate statistical sig-nificance. All statistical analyses were performedusing JMP version 13 for Windows (SAS Institute,Cary, North Carolina).

FIGURE 7 Flow Diagram of the Procedure in the 3D Wiring Group

Abbreviations as in Figures 5 and 6.

RESULTS

REPRESENTATIVE CASE OF 3D WIRING. A woman inher 70s was admitted to our hospital with stableangina pectoris. Coronary angiography revealed CTO

TABLE 2 Procedure Outcomes

Overall(N ¼ 137)

Non-3D WiringGroup(n ¼ 68)

3D WiringGroup

(n ¼ 69) p Value

The frequency of the parallel wiretechnique’s usage, %

13 19 7 0.047

Number of wires 5.4 � 1.9 5.7 � 1.9 5.1 � 1.8 0.029

Procedure time, min 135 � 59 140 � 59 137 � 70 0.192

Fluoroscopic time, min 77.9 � 36.1 80 � 35 74 � 41 0.164

RAD, mGy 4,393 � 1,865 4,271 � 1,950 4,095 � 1,911 0.565

Contrast dose, ml 195 � 65.4 205 � 71 171 � 70 0.003

Success rate, % 94 90 98 0.027

Values are mean � SD or n (%).

RAD ¼ radiation absorbed dose; other abbreviation as in Table 1.

TABLE 3 In-Hospital

MACCECardiac deathNoncardiac deathQMINon-QMIEmergent target ves

with PCI or CABGStroke

Complications related tantegrade approa

Vessel perforation byantegrade guidew

Cardiac tamponade

Duration of hospitaliza

Values are n (%) or median

MACCE ¼ major adversQMI ¼ Q wave myocardial



552

lesion in the mid right coronary artery with a collat-eral flow from circumflex artery (Figures 4A and 4B).An 8-F SAL 1.0 guide catheter (Medtronic AVE, SantaRosa, California) was inserted into the right coronaryartery. Contralateral injection was performed fromthe left coronary artery using a diagnostic catheter. AXT-R guidewire was advanced under a Corsair butcould not be passed through the distal end(Figure 4C). A Confianza 9-g guidewire, was theninserted into the route created by the XT-R guidewireand was stopped 1 cm before the distal end. TheConfianza guidewire was accurately advanced andpinpoint penetration to the distal end was performedwith 3D wiring (Figure 4D). IVUS examination showedthat the Confianza guidewire was advanced throughthe intima and the cylinder-like space, which had

MACCE and Complications Related to the Antegrade Approach

Overall(N ¼ 137)

Non-3D WiringGroup

(n ¼ 68)3D Wiring Group

(n ¼ 69) p Value

2 (2) 2 (3) 0 (0) 0.1510 0 00 0 00 0 0

1 (1) 1 (1) 0 0.312sel revascularization 1 (1) 1 (1) 0 0.312

1 (1) 1 (1) 0 0.312

o thech

theire

7 (5) 6 (9) 1 (1) 0.05

1 (1) 1 (1) 0 (0) 0.312

tion, days 6 (4–10) 7 (4–12) 5 (4–7) 0.019

(25th–75th percentile).

e cardiac and cerebrovascular event(s); PCI ¼ percutaneous coronary intervention;infarction; other abbreviations as in Table 1.

been created by the XT-R guidewire in the intima butoutside of the lumen beyond the distal end(Figure 4E). The CTO lesion was dilated with 3 drug-eluting stents and normal antegrade blood flow wasachieved (Figure 4F). Figure 5 explains the 3D wiringin this pinpoint penetration. The guidewirewas accurately controlled using 3D wiring, which ledto the successful pinpoint penetrate even for thissmall target.

DEMOGRAPHIC AND ANGIOGRAPHIC CHARACTERISTICS.

Table 1 presents a summary of patient and lesioncharacteristics. The frequency of low estimatedglomerular filtration rate (<45 ml/min/1.73 m2) wassignificantly higher in the non-3D wiring group thanthe 3D wiring group (26% vs. 9%, respectively;p ¼ 0.001).

PROCEDURE OUTCOMES OF THE TOTAL PATIENT

POPULATION. Figures 6 and 7 show flow diagramsof the procedure. In the non-3D wiring group,the antegrade approach was the primary strategy in88% of cases (n ¼ 60 of 68), followed by the rescueretrograde approach in 34% (n ¼ 23 of 68) and ante-grade IVUS-guided rewiring in 3% (n ¼ 2 of 68). Theprocedure failed in the following 7 cases: 4 weretreated only with the antegrade approach and theremaining 3 were treated with the antegradeapproach followed by a rescue retrograde approach.In the 3D wiring group, the antegrade approach wasthe primary strategy in 84% of cases (n ¼ 58 of 69),followed by rescue retrograde approach in 26% (n ¼18 of 69) and antegrade IVUS-guided rewiring in 6%(n ¼ 4 of 69). The procedure failed in 1 case. Table 2presents a summary of the procedural outcomes.The number of guidewires used for all PCI procedureswas significantly lower in the 3D wiring groupcompared with the non-3D wiring group (6.9 � 2.9 vs.7.9 � 3.0, respectively; p ¼ 0.024). The amount ofcontrast was significantly lower in the 3D wiringgroup than the non-3D wiring group (171 � 70 vs. 205� 71 ml, respectively; p ¼ 0.003). Overall success ratewas significantly higher in the 3D wiring group thanthe non-3D wiring group (98% vs. 90%, respectively;p ¼ 0.027). There was no significant difference inoverall success rate in the cases of severe calcificationbetween both groups (84% of cases [n ¼ 11 of 13] inthe non-3D group vs. 87% [n ¼ 7 of 8] in the 3D wiringgroup; p ¼ 0.854). The overall success rate of thecases of bending tended to be higher in the 3D wiringgroup than in the non-3D wiring group (80% of cases[n ¼ 16 of 20] vs. 96% [n ¼ 23 of 24], respectively;p ¼ 0.099). Table 3 presents a summary of in-hospitalMACCE and complications related to the antegradeapproach. There were no significant differences in the

TABLE 4 Crossing Guidewire in the Primary Antegrade Cases

Overall(N ¼ 73)

Non-3D WiringGroup

(n ¼ 33)

3D WiringGroup

(n ¼ 40) p Value

Conquest family 48 (66) 18 (55) 30 (75) 0.063

Gaia family 17 (23) 12 (36) 5 (13)

Ultimate bros 3 2 (3) 0 2 (5)

Others 6 (8) 3 (9) 3 (7)

Values are n (%).

Abbreviation as in Table 1.


553

MACCE rate between the 2 groups. Vessel perforationby the antegrade wire tended to be lower in the 3Dwiring group than the non-3D wiring group (1% vs. 9%,respectively; p ¼ 0.05).

PROCEDURE OUTCOMES IN THE PRIMARY

ANTEGRADE APPROACH CASES. Table 4 presents asummary of the guidewires successfully crossing theCTO lesion in the primary antegrade cases (non-3Dwiring group, n ¼ 33; 3D wiring group, n ¼ 40). Thepercentage of Confianza family was slightly higher inthe 3D wiring group compared with the non-3D wiringgroup (75% vs. 55%, respectively; p ¼ 0.063). TheCentral Illustration shows the procedure outcomes of

CENTRAL ILLUSTRATION Procedure Outcom

First AntegradeApproach Time

70(min)

P = 0.01

60

50

40

30

20

10

0Non-3DWiringGroup

(n = 60)Primary

Antegrade Approach Cases

3D WiringGroup

(n = 58)

A Success Rate ofAntegrade Appr

100(%)

P = 0

80

60

40

20

0Non-3DWiringGroup

(n = 60)Primary

Antegrade Approac

3D WGro

(n =

33/60cases

40/cas

B

Tanaka, T. et al. J Am Coll Cardiol Intv. 2019;12(6):545–55.

(A) First antegrade approach time in primary antegrade approach cases.

rate of only antegrade approach in cases in which the antegrade approac

procedures in primary antegrade approach cases.

the primary antegrade cases. In the primary ante-grade cases, the first antegrade approach time wassignificantly shorter in the 3D wiring group than thenon-3D wiring group (42 � 29 vs. 30 � 16 min,respectively; p ¼ 0.01). The success rate of only theantegrade approach was increased from 55% (n ¼ 33of 60) in the non-3D wiring group to 69% (n ¼ 40 of58) in the 3D wiring group, but the difference was notsignificant. In the antegrade alone cases (i.e., in thecases in which the antegrade approach was primarilyselected and was continued throughout the proced-ure) the success rate of only the antegrade approachwas significantly higher in the 3D wiring groupcompared with the non-3D wiring group [100% [40 of40 cases] vs. 89.2% [33 of 37 cases], respectively;p ¼ 0.033). In the primary antegrade cases, the suc-cess rate of all procedures was significantly higher inthe 3D wiring group compared with the non-3D wiringgroup (100% [58 of 58 cases] vs. 94.6% [53 of 56cases], respectively; p ¼ 0.007).

DISCUSSION

In the present study, we compared the proceduraloutcomes of CTO-PCI between the periods before

es of the Primary Antegrade Cases

Onlyoach

.118

h Cases

iringup58)

58es

Success Rate of OnlyAntegrade Approach

100(%)

P = 0.033

80

60

40

20

0Non-3DWiringGroup

(n = 37)Only


3D WiringGroup

(n = 40)

33/37cases

40/40cases

C Success Rate ofAll the Procedures

100(%)

P = 0.007

80

60

40

20

0Non-3DWiringGroup

(n = 60)Primary


3D WiringGroup

(n = 58)

53/60cases

58/58cases

D

(B) Success rate of only antegrade approach in primary antegrade approach cases. (C) Success

h was primarily selected and was continued throughout the procedure. (D) Success rate of all



554

and after introduction of 3D wiring in our clinicalpractice to assess the efficacy and feasibility of thistechnique. The results of this study demonstratedthat the overall success rate was significantlyincreased after the introduction of 3D wiring becausethis method was associated with an improved suc-cess rate of the antegrade approach itself andreduced first antegrade procedure time, resulting inmoving on to further strategies at an earlier stage;and 3D wiring did not increase the in-hospitalMACCE rate but instead decreased the rate ofvessel perforation by the antegrade guidewire eventhough the main guidewire crossing the CTO lesionwas of the Confianza family.

PROCEDURAL SUCCESS. The overall success ratewas significantly increased from 90% to 98% after weintroduced 3D wiring into our clinical practice, whichis acceptable because the Japanese CTO-PCI expertregistry in which A.O. is one of the certified operatorshas reported an overall success rate of 89.9% (11).The first operator was not only A.O., but also the6 younger operators in our institution, which meansthat 3D wring is one of the methods that can stan-dardize guidewire manipulation in CTO PCI. Theresults of the present study revealed the reasons forimprovement of the overall success rate after intro-duction of 3D wiring. Although the total proceduretime was similar between the 2 groups, the antegradeapproach time was significantly reduced in the3D wiring group, and therefore there was enough timefor further strategies. In cases of primary antegradeapproach, the success rate of the antegrade approachwas not significantly improved in the 3D wiringgroup. If the success rate of the antegrade approach isevaluated literally, the antegrade approach shouldalways be continued without moving on to theretrograde approach. However, in some cases of pri-mary antegrade approach, although there was still apossibility of success with the antegrade approach,the operator moved on to the retrograde approach atan earlier stage because of interventional collateralchannels, which increased the probability of success.The decision of success or failure in these cases wasantegrade approach failure but retrograde approachsuccess, which decreased the success rate of theantegrade approach in the primary antegradeapproach. However, in cases in which the antegradeapproach was primarily selected and was continuedthroughout the procedure, the success rate wassignificantly improved in the 3D wiring group.

The percentage of Confianza family among theguidewires successfully crossing the CTO lesion inthe primary antegrade cases was slightly higher inthe 3D wiring group compared with the non-3D wir-ing group. The technique of 3D wiring advances theguidewires after directing the tip toward the target,therefore high rigidity around the tip area is neededto advance the guidewires only by the force of beingpushed. Because of this technical reason, we had touse Confianza family in most of the situations in the3D wiring group. The frequency of the parallel wiretechnique’s usage decreased in the 3D wiring groupcompared with the non-3D wiring group, becausethe 3D image was constructed directly from therelationship between the guidewire and the 1 pointof the target that was visualized when necessary bythe selective collateral injection.

PROCEDURE-RELATED COMPLICATIONS. The MACCErate in the present study was 1.5%, which wasacceptable because it matches that in the Japanesemulticenter registry (also 1.5%) (12). During antegradeapproach 3D wiring reduced vessel perforation,although the Confianza guidewires were used morefrequently in the 3D wiring group. This shows thatthe Confianza guidewires can be manipulated safelyusing the 3D wiring method.

STUDY LIMITATIONS. The present study was basedon retrospective data analysis of a relatively smallnumber of patients from a single center. Furthermulticenter and prospective randomized studies areneeded to evaluate whether this 3D wiring methodis effective and feasible for use in daily clinicalpractice including the cases of severe calcification orbending.

CONCLUSIONS

3D wiring enables accurate guidewire control, whichimproves the success rate of antegrade wiring andreduces the antegrade procedure time, resulting inimprovement of the overall success rate.

ACKNOWLEDGMENT The authors thank Mr. SatoshiAsai (Terumo Corp. Pranex Center, Odawara, Japan) forpreparation of the experimental model for 3D wiring.

ADDRESS FOR CORRESPONDENCE: Dr. AtsunoriOkamura, Division of Cardiology, Sakurabashi WatanabeHospital, 2-4-32 Umeda, Kita-ku, Osaka 530-0001, Japan.E-mail: [email protected].

mailto:[email protected]

PERSPECTIVES

WHAT IS KNOWN? In CTO-PCI, our clinical experience

with IVUS-guided wiring indicated that 3D imaging is

important for accurate guidewire control. Therefore, in

2015, we reported a 3D wiring method that uses images

obtained at 2 perpendicular angles from the X-ray

monitor that can be applied in real-time by most

operators.

WHAT IS NEW? After training using the experimental

model for 3D wiring, all of the operators, including

younger doctors at our institute, became able to

construct 3D images in real-time and penetrate the

targets accurately and with reproducibility. Since 2015,

we have performed 3D wiring during PCI for CTO in our

clinical practice. We demonstrated the efficacy and

feasibility of 3D wiring to compare the procedural out-

comes of CTO-PCI between the periods before and after

the introduction of 3D wiring.

WHAT IS NEXT? Because this 3D wiring method can

clearly explain how to manipulate the stiff guidewires, it

will improve and standardize guidewire manipulation in

CTO-PCI, which should be further evaluated by multi-

center and prospective randomized studies.


555

RE F E RENCE S

1. Surmely JF, Tsuchikane E, Katoh O, et al. Newconcept for CTO recanalization using controlledantegrade and retrograde subintimal tracking: theCART technique. J Invasive Cardiol 2006;18:334–8.

2. Okamura A, Iwakura K, Fujii K. ViewIT improvesintravascular ultrasound-guided wiring in coronaryintervention of chronic total occlusion. CatheterCardiovasc Interv 2010;75:1062–6.

3. Jessup DB, Lombardi W. Re-canalization of pe-ripheral chronic total occlusions using theBridgePoint Stingray re-entry device. J IntervCardiol 2011;24:569–73.

4. Okamura A, Iwakura K, Date M, Nagai H,Sumiyoshi A, Fujii K. Navifocus WR is the promisingintravascular ultrasound for navigating theguidewire into true lumen during the coronaryintervention for chronic total occlusion. Car-diovasc Interv Ther 2014;29:181–6.

5. Okamura A, Iwakura K, Nagai H, Kawamura K,Yamasaki T, Fujii K. Chronic total occlusion treated

with coronary intervention by three-dimensionalguidewire manipulation: an experimental studyand clinical experience. Cardiovasc Interv Ther2016;31:238–44.

6. Brilakis ES, Grantham JA, Rinfret S, et al.A percutaneous treatment algorithm for crossingcoronary chronic total occlusions. J Am Coll Car-diol Intv 2012;5:367–79.

7. Harding SA, Wu EB, Lo S, et al. A new algorithmfor crossing chronic total occlusions from the AsiaPacific Chronic Total Occlusion Club. J Am CollCardiol Intv 2017;10:2135–43.

8. Di Mario C, Werner GS, Sianos G, et al. Europeanperspective in the recanalisation of chronic totalocclusions (CTO): consensus document from theEuroCTO Club. EuroIntervention 2007;3:30–43.

9. Morino Y, Abe M, Morimoto T, et al. Predictingsuccessful guidewire crossing through chronic to-tal occlusion of native coronary lesions within 30minutes: the J-CTO (Multicenter CTO Registry inJapan) score as a difficulty grading and time

assessment tool. J Am Coll Cardiol Intv 2011;4:213–21.

10. Suzuki Y, Muto M, Yamane M, et al. Indepen-dent predictors of retrograde failure in CTO-PCIafter successful collateral channel crossing. Cath-eter Cardiovasc Interv 2017;90:E11–8.

11. Suzuki Y, Tsuchikane E, Katoh O, et al. Out-comes of percutaneous coronary interventions forchronic total occlusion performed by highlyexperienced Japanese specialists: the first reportfrom the Japanese CTO-PCI expert registry. J AmColl Cardiol Intv 2017;10:2144–54.

12. Okamura A, Yamane M, Muto M, et al. Com-plications during retrograde approach for chroniccoronary total occlusion: sub-analysis of Japanesemulticenter registry. Catheter Cardiovasc Interv2016;88:7–14.

KEY WORDS 3-dimensional wiring,coronary occlusion, percutaneous coronaryintervention

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