Mini-crush versus T-provisional techniques in bifurcation lesions: clinical and angiographic long-term outcome after implantation of drug-eluting stents.

Abstract

This retrospective study sought to assess the clinical and angiographic long-term outcome after implanting drug-eluting stents in bifurcation lesions with the T-provisional (T-prov) technique and mini-crush (MC) technique.
The best option on the treatment of coronary bifurcation lesions is a subject of considerable debate. However, recent evidence suggests that bifurcation lesions might be treated by drug-eluting stent on both branches using the MC technique with a low rate of major adverse cardiac event and restenosis.
From April 2004 to July 2006, 457 patients were consecutively treated with either MC technique (n = 199) or T-prov technique (n = 258). Of these latter, 170 patients were treated with 1 stent and 88 patients with 2 stents. The 9-month angiographic follow-up was completed in 188 of 229 (82.1%) bifurcation lesions of MC patients and in 207 of 266 lesions (77.8%) of T-prov patients.
After a propensity score adjustment, 2-year cumulative major adverse cardiac events were similar between groups (p = 0.16). The MC group compared with the T-prov 1-stent group had significantly lower main and side branches restenosis (hazard ratio [HR]: 0.52, 95% confidence interval [CI]: 0.27 to 0.99; p = 0.047; and HR: 0.41, 95% CI: 0.20 to 0.85; p = 0.016, respectively). However, the MC group compared with the T-prov-only group had significantly lower side branch restenosis (HR: 0.55, 95% CI: 0.37 to 0.82; p = 0.004).
Both techniques of bifurcation treatment met high procedural success with low complication rates and similar major adverse cardiac event long-term outcome. However, the MC technique yields a lower restenosis rate at both main and side branches. These results may confirm the advantage of using prescheduled 2-stent technique to give a complete coverage of the side branches' ostium.

Full text

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doi:10.1016/j.jcin.2008.12.005
2009;2;185-194
J. Am. Coll. Cardiol. Intv.
Barrano, Gian Paolo Ussia, and Corrado Tamburino
Alfredo R. Galassi, Salvatore D. Tomasello, Davide Capodanno, Giovambattista

Stents
and Angiographic Long-Term Outcome After Implantation of Drug-Eluting
Mini-Crush Versus T-Provisional Techniques in Bifurcation Lesions: Clinical
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CLINICAL RESEARCH
Mini-Crush Versus T-Provisional Techniques
in Bifurcation Lesions
Clinical and Angiographic Long-Term Outcome After Implantation
of Drug-Eluting Stents
Alfredo R. Galassi, MD, FACC, FSCAI, FESC, Salvatore D. Tomasello, MD,
Davide Capodanno, MD, Giovambattista Barrano, MD, Gian Paolo Ussia, MD, FSCAI,
Corrado Tamburino, MD, FSCAI, FESC
Catania, Italy
Objectives This retrospective study sought to assess the clinical and angiographic long-term out-
come after implanting drug-eluting stents in bifurcation lesions with the T-provisional (T-prov) tech-
nique and mini-crush (MC) technique.
Background The best option on the treatment of coronary bifurcation lesions is a subject of con-
siderable debate. However, recent evidence suggests that bifurcation lesions might be treated by
drug-eluting stent on both branches using the MC technique with a low rate of major adverse car-
diac event and restenosis.
Methods From April 2004 to July 2006, 457 patients were consecutively treated with either MC
technique (n ? 199) or T-prov technique (n ? 258). Of these latter, 170 patients were treated with
1 stent and 88 patients with 2 stents. The 9-month angiographic follow-up was completed in 188 of
229 (82.1%) bifurcation lesions of MC patients and in 207 of 266 lesions (77.8%) of T-prov patients.
Results After a propensity score adjustment, 2-year cumulative major adverse cardiac events were
similar between groups (p ? 0.16). The MC group compared with the T-prov 1-stent group had sig-
nificantly lower main and side branches restenosis (hazard ratio [HR]: 0.52, 95% confidence interval
[CI]: 0.27 to 0.99; p ? 0.047; and HR: 0.41, 95% CI: 0.20 to 0.85; p ? 0.016, respectively). However,
the MC group compared with the T-prov-only group had significantly lower side branch restenosis
(HR: 0.55, 95% CI: 0.37 to 0.82; p ? 0.004).
Conclusions Both techniques of bifurcation treatment met high procedural success with low com-
plication rates and similar major adverse cardiac event long-term outcome. However, the MC tech-
nique yields a lower restenosis rate at both main and side branches. These results may confirm the
advantage of using prescheduled 2-stent technique to give a complete coverage of the side
branches’ ostium.(J Am Coll Cardiol Intv 2009;2:185–94) © 2009 by the American College of
Cardiology Foundation
From the Department of Internal Medicine and Systemic Disease, Clinical Division of Cardiology, Ferrarotto Hospital, University
of Catania, Catania, Italy.
Manuscript received April 17, 2008; revised manuscript received November 24, 2008, accepted December 17, 2008.
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Treatment of bifurcation lesions remains a technical
challenge for the interventionalist, but it is still hampered
by an increased rate of restenosis as compared with non-
bifurcation lesions (1–3). Part of this treatment complexity
is related to the different anatomic patterns of the stenosis,
considering the possible involvement with the proximal and
the distal part of the main branch and/or the side branches,
and the close proximity of side branches origins (4), besides
the angle that the side branch takes off and the size of both
main and side branches. Various studies on the drug-eluting
See page 195
stent era indicate the absence of a real advantage over
restenosis considering the potential for both early proce-
dural complications (stent distortion, plaque shift, dissec-
tion, side branching trapping) and late in-stent restenosis
when using a complex strategy (5–8). Indeed, anatomical
characteristics of bifurcation le-
sion may influence the treatment
strategy, choosing between 1-
and 2-stent approaches.
More recently further refine-
ments of the 2-stent technique
(9–11) have shown that the
2-stent strategy technique, when
appropriately performed, may sig-
nificantly reduce the restenosis
rate and potentially target lesion
revascularization (TLR) and ma-
joradversecardiacevent(MACE)
in complex bifurcation lesions.
This study aims to compare the
long-term clinical and angio-
graphicoutcomesafterimplanting
the drug-eluting stent in bifurcations lesions using the mini-
crush (MC) and T-provisional (T-prov) techniques.
Materials and Methods
Study population. The ethics committee approved the pro-
tocol, and all patients gave written informed consent.
Demographic and procedural data regarding all patients
undergoing angioplasty with drug-eluting stents—either
sirolimus-eluting (Cypher/Cypher Select, Cordis Johnson
& Johnson, Warren, New Jersey) or paclitaxel-eluting
(Taxus Liberte, Boston Scientific, Natick, Massachusetts)—
were prospectively put into a dedicated database.
Between April 2004 and July 2006, 3,480 patients un-
derwent a percutaneous coronary intervention in our insti-
tution. Among them, 544 patients (16%) had de novo
bifurcation lesions excluding left main trunk location, with
a visually estimated percent diameter stenosis ?50% involv-
ing the main vessel at or within 5 mm proximal or distal to
the origin of a side branch ?2 mm in diameter (12). All
bifurcation lesions were classified by visual assessment
according to a classification previously described by Medina
et al. (12). The MC technique was performed in 199
patients (this group included 45 patients from a previous
pilot study); T-prov in 170 patients with a single stent in the
main vessel across the origin of the side branch (T-prov
1-stent); T-prov in the other 88 patients where an addi-
tional stent was required in the side branch because of the
presence of severe impairment in the side branch during the
angioplasty procedure (dissection or severe ostial stenosis
due to plaque shift) (T-prov 2-stent). Other different
techniques such as crush, culotte, and V-stenting were used
in 87 patients. The bifurcation treatment strategy was chosen
according to the operator’s personal experience and prefer-
ences. All consecutive patients with a bifurcation lesion treated
with either sirolimus- or paclitaxel-eluting stents by the MC or
by a T-prov stenting technique with and without the addi-
tional implantation of a side branch stent were retrospectively
identified in the operator’s reports and checked through an
independent review of all angiograms.
Angioplasty procedure. All patients were previously treated
with aspirin 100 mg and either ticlopidine or clopidogrel. A
300-mg loading dose of clopidogrel before the index pro-
cedure was administered if patients were not pretreated.
During the procedure, patients received intravenous unfrac-
tionated heparin (80 IU/kg) to maintain activated clotting
time between 250 and 300 s. The administration of glyco-
protein IIb/IIIa inhibitors was left to the operator’s discre-
tion. After the procedure, all patients were prescribed
aspirin (100 mg daily) and clopidogrel (75 mg daily) or
ticlopidine (500 mg daily) to be continued for at least 9
months after drug-eluting stent implantation. The MC and
T-prov techniques have been previously described (9–13).
Briefly, the MC technique as compared with the standard
crush approach consisted of a minor retraction of the side
branch stent into the main branch and using a balloon to
crush the side branch stent instead of the main branch stent.
Following this approach, a jailed wire technique and final
kissing balloon would have been employed if possible, using
wire recrossing into the side branch followed by high-
pressure balloon inflation. As regards the T-prov approach,
balloon dilatation of the side branch or kissing balloon were
recommended before stent deployment in the parent vessel.
The side branch was then rewired, and the balloon dilata-
tion of the ostium was repeated across the metal structure of
the stent; patients treated with this kind of approach were
included in the T-prov 1-stent group. Stenting of the side
branch origin was considered in the presence of a residual
stenosis ?50% or coronary Thrombolysis In Myocardial
Infarction (TIMI) flow grade ?3; patients treated with this
approach were included in the T-prov 2-stent group.
Consistent with the standard of care in our laboratory, final
kissing balloon inflation was recommended in all patients.
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Abbreviations
and Acronyms
AMI ? acute myocardial
infarction
CI ? confidence interval
HR ? hazard ratio
MACE ? major adverse
cardiac event
MC ? mini-crush
TBR ? target bifurcation
revascularization
TLR ? target lesion
revascularization
T-prov ? T-provisional
stenting
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All patients were monitored for any post-procedure
events of chest pain, heart failure, bleeding, or any ischemic
events. Creatine kinase-myocardial band and troponin I
were measured at 6 to 8 and 12 to 24 h post-procedure.
Clinical definition and follow-up. Clinical follow-up was
performed by office visit or by telephone interviews at 1
month, 6 months, 1 year, and 3 years. All events were
confirmed by review of death certificates and hospital charts.
Stress test or functional imaging test were recommended to
be performed between 5 and 6 months, after the procedure
for all patients. Angiographic follow-up was recommended
as a laboratory standard of care, to be performed approxi-
mately at 9 months after the procedure unless indicated
earlier by clinical suspicion or positive functional imaging
test.
Major adverse cardiac events were defined as cardiac
death, acute myocardial infarction (AMI), and target vessel
revascularization, either percutaneous or surgical. All deaths
were considered cardiac in origin unless alternatively docu-
mented. A non–Q-wave AMI was defined as creatine
kinase-myocardial band enzyme elevation ?3 times the
upper limit of the normal value; when in addition to enzyme
elevation there were new pathological Q waves in the
electrocardiogram, the event was defined as a Q-wave AMI.
Reintervention for restenosis was decided by taking into
consideration the patient’s symptoms, functional imaging
testing, and angiographic findings. Target lesion revascular-
ization was defined as a repeat revascularization with a
stenosis ?50% within the stent or in the 5-mm distal or
proximal segments adjacent to the stent. Target vessel
revascularization was defined as repeat revascularization
within the treated vessel. Target bifurcation revasculariza-
tion (TBR) was defined as a repeat revascularization with a
stenosis ?50% within 5 mm proximal or distal to the carina
of bifurcation, both onto the main branch and/or side
branch as previously described (9).
Stent thrombosis was defined as an acute coronary syn-
drome with angiographic documentation of either vessel
occlusion or thrombus within or adjacent to a previously
successful stented vessel or, in the absence of angiographic
confirmation, either AMI in the distribution of the treated
vessel or death not clearly attributable to any other causes
(14). Stent thromboses were categorized according to the
timing of the event into intraprocedural, subacute throm-
bosis (from the end of the procedure to 30 days), and late
stent thrombosis (?30 days).
Quantitative coronary angiographic analysis. Coronary an-
giograms obtained at baseline, at completion of the stenting
procedure, and at 9.6 ? 4.3 months for MC-treated
patients, at 10.4 ? 3.7 months for T-prov 1-stent treated
patients, and at 10.8 ? 5.6 months of T-prov 2-stent–
treated patients (analysis of variance) (p ? 0.147) were
analyzed using CardiOp-B, a computer-based algorithm
3-dimensional reconstruction dedicated to bifurcations
(Paieon Medical Ltd., Park Afek, Israel) (15). This system
integrates information from at least 2 single-plane angio-
graphic images taken from different angles of projection.
One experienced technician who was blinded to patients’
identities, outcomes, and sequence of the film, performed
quantitative analyses of all angiographic data. Minimal
lumen diameter and the nearest normal reference diameter
were measured in millimeters using the catheter as a scaling
factor. Percent stenosis was calculated as: 100 (1 ? minimal
lumen diameter/normal reference diameter). Binary angio-
graphic restenosis was defined as ?50% diameter stenosis of
the target lesion. Late lumen loss was defined as the
difference in minimal luminal diameter at completion of the
stent procedure and during follow-up. Quantitative angio-
graphic measurements of the target lesion were made at the
“in-stent” zone (only the stented segment) and at the
“in-segment” zone (stented segment and margins 5 mm
proximal and distal to the stent). Angiographic success was
defined as a final residual stenosis ?30% with TIMI flow
grade 3 in either the main branch or the side branch (16).
Procedural success was defined as the achievement of
angiographic success without in-hospital MACE. In pa-
tients who had restenosis, the pattern of restenosis was
assessed according to the classification of Mehran et al. (17).
Each patient’s baseline, post-procedure, and follow-up cor-
onary angiograms were analyzed. Patients for whom 1 of the
angiograms was unreadable were cut out of the analysis: 15
from the MC group, 12 from the T-prov 1-stent group, and
5 from the T-prov 2-stent group. A total of 188 lesions out
of 229 (82.1%) in 160 patients were analyzed for the MC
group, 138 lesions out of 176 lesions (78.4%) in 132 patients
were analyzed for the T-prov 1-stent group, and 69 lesions
out of 90 lesions (76.7%) in 69 patients were analyzed for
the T-prov 2-stent group
Statistical analysis. Continuous variables were presented as
mean ? SD and were compared using Student unpaired t
test or analysis of variance. Categorical variables were
presented as counts and percentages and compared with the
chi-square test when appropriate (expected frequency ?5).
Otherwise, the Fisher exact test was used. A 2-sided p value
of ?0.05 was considered to indicate statistical significance.
Propensity score was used to create a covariate that
summarizes confounders within baseline demographic and
angiographic characteristics and assesses the independent
effect of treatment technique on all outcome measures. For
each considered comparison (MC vs. T-prov 1-stent and
MC vs. T-prov) a separate propensity score was derived.
The details of the propensity-score method, with the
resulting models and their predictive characteristics, are
described in the Online Appendix. Calibration of the
propensity score model was assessed using the Hosmer-
Lemeshow test.
All data were processed using the Statistical Package for
Social Sciences, version 15 (SPSS Inc., Chicago, Illinois).
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Results
Baseline and procedural characteristics. Baseline clinical
characteristics are shown in Table 1 among the 3 groups of
the patients. Table 2 shows the angiographic locations and
types of treated bifurcation lesions. It is interesting to note
that type 1,1,1 bifurcation was present in the great majority
of cases in all the groups of patients and as type 1,1,1 more
frequently in MC groups than in T-prov groups. Procedural
details are shown in Table 3.
Clinical and angiographic outcomes are shown in Table
4. A higher rate of hospital MACE albeit small was shown
in both T-prov groups of patients, which may be explained
by the higher rates of unstable angina as clinical presenta-
tion in this cohort of patients. Successful delivery of stent to
both main and side branch, in the case of MC was
accomplished adequately in each case. An additional stent in
the main branch to cover the full lesion length or to seal
significant dissections at edges of study stent was required in
58 of 229 lesions (25.3%) in the MC group, in 58 of 176
lesions (32.9%) in the T-prov 1-stent group, and in 15 of 90
lesions (16.6%) in the T-prov 2-stent group. Two additional
stents in the main vessel were implanted in 10 out of 229
lesions (4.4%) in the MC group, in 4 out of 176 lesions
(2.3%) in the T-prov 1-stent group, and in 3 out of 90
lesions (3.3%) in the T-prov 2-stent group. An additional
stent in the side branch was required in 8 of 229 (3.5%) in
the MC group, but in only 1 case (1.1%) in the T-prov
2-stent group. Stress test or functional imaging test were
performed in 96% of MC patients, in 93% of T-prov 1-stent
patients, and in 92% of T-prov 2-stent patients.
The 9-month angiographic follow-up was completed in
188 of 229 (82.1%) bifurcation lesions of MC patients, in
138 of 176 (78.4%) lesions of T-prov 1-stent patients, and
in 69 of 90 (76.7%) lesions of T-prov 2-stent patients.
Angiographic quantitative coronary angiography results for
both the main and the side branch at baseline, after
procedure, and at follow-up are summarized in Table 5.
Clinicalfollow-upwasavailableforallpatientsat752 ? 445
days (25 ? 15 months). Based on the average follow-up time,
no significant differences were observed among the groups.
CumulativeMACEatfollow-upwassimilarbetweenMCand
both T-prov patient groups (20.6% vs. 25.9% vs. 26.1%, p ?
NS among all 3 groups) and TLR (16% vs. 20.3% vs. 26.1%,
p ? NS among all 3 groups). However, it is interesting to note
that TBR was significantly lower in MC patients as compared
with T-prov 2-stent patients (8.5% vs. 17.4%, p ? 0.05). The
MC group compared with both T-prov groups showed a
similarmainbranchrestenosis(11.7%vs.17.4%vs.18.6%,p?
NS among all 3 groups) but significantly lower side branch
restenosis (8.5% vs. 18.8% vs. 25.7%, p ? 0.01 of MC vs.
T-prov 1-stent and p ? 0.001 of MC vs. T-prov 2-stent,
respectively). There were 37 focal restenosis at the ostium of
side branch, 6 in the MC group, 17 in the T-prov 1-stent
Table 1. Baseline Clinical Characteristics
Mini-Crush
(n ? 199 Patients)
T-Prov
Overall
(n ? 258 Patients)
1-Stent
(n ? 170 Patients)
2-Stent
(n ? 88 Patients)
Age, yrs62.17 ? 9.65 64.33 ? 10.41*63.88 ? 10.6165.20 ? 10.00†
Male167 (83.9)188 (72.9)‡ 122 (71.8)§66 (75.0)
Hypertension104 (52.3)175 (67.8)‡114 (67.1)§61 (69.3)?
Hypercholesterolemia121 (60.8)153 (59.3)108 (63.5) 45 (51.1)
Family history of CAD93 (46.7)138 (53.5)92 (54.1)46 (52.3)
Current smokers126 (63.3) 140 (54.3) 100 (58.8)40 (45.5)?¶
Diabetes mellitus 61 (30.7)86 (33.3)56 (32.9)30 (34.1)
Prior CABG8 (4)17 (6.6)14 (8.2) 3 (3.4)
Prior MI50 (25.1) 95 (36.8)‡ 64 (37.6)§31 (35.2)
LVEF50.9 ? 9.249.7?10.249.9 ? 10.249.3?10.2
Clinical presentation
Asymptomatic 16 (8)21 (8.1)12 (7.1)9 (10.2)
Stable angina 68 (34.2) 49 (19.0)# 36 (21.2)§13 (14.8)*
Unstable angina55 (27.6)113 (43.8)# 68 (40.0)§ 45 (51.1)**
Acute MI 60 (30.2)75 (29.1) 54 (31.8)21 (23.9)
1-vessel 50 (25.1) 69 (26.7) 52 (30.6)17 (19.3)
2-vessel 72 (36.2)87 (33.7)54 (31.8) 33 (37.5)
3-vessel77 (38.7) 102 (39.5)64 (37.6)38 (43.2)
Values are presented as mean ? SD or n (%). *p ? 0.05 for MC versus T-prov; †p ? 0.05 for MC versus T-prov 2-stent; ‡p ? 0.01 for MC versus T-prov; §p ? 0.01 for MC versus T-prov 1-stent; ?p ? 0.01 for MC
versus T-prov 2-stent; ¶p ? 0.05 for T-prov 1-stent versus T-prov 2-stent; #p ? 0.001 for MC versus T-prov; **p ? 0.001 for MC versus T-prov 2-stent.
CABG ? coronary artery bypass graft; CAD ? coronary artery disease; LVEF ? left ventricular ejection fraction; MC ? mini-crush; MI ? myocardial infarction; T-prov ? T-provisional.
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