Safety and efficacy of coronary stent implantation. Acute and six month outcomes of 1,126 consecutive patients treated in 1996 and 1997

Article (PDF Available)inArquivos Brasileiros de Cardiologia 73(1) · July 1999with9 Reads
DOI: 10.1590/S0066-782X1999000700003 · Source: DOAJ
Abstract
Purpose: The authors analyzed the 30-day and 6-month outcomes of 1,126 consecutive patients who underwent coronary stent implantation in 1996 and 1997. Methods: The 30-day results and 6-month angiographic follow-up were analyzed in patients treated with coronary stents in 1996 and 1997. All patients underwent coronary stenting with high-pressure implantation (> 12 atm) and antiplatelet drug regimen (aspirin plus ticlopidine). Results: During the study period, 1,390 coronary stents were implanted in 1,200 vessels of 1,126 patients; 477 patients were treated in the year 1996 and 649 in 1997. The number of percutaneous procedures performed using stents increased significantly in 1997 compared to 1996 (64% vs 48%, p = 0.0001). The 30-day results were similar in both years: the success and stent thrombosis rates were equal (97% and 0.8%, respectively). The occurrence of new Q wave MI (1.3% vs 1.1%, 1996 vs 1997, p = NS), emergency coronary bypass surgery (1% vs 0.6%, 1996 vs 1997, p = NS) and 30-day death rates (0.2% vs 0.5%, 1996 vs 1997, p = NS) were similar. The 6-month restenosis rate was 25% in 1996 and 27% in 1997 (p = NS); the target vessel revascularization rate was 15% in 1996 and 16% in 1997 (p = NS). Conclusions: Intracoronary stenting showed a high success rate and a low incidence of 30-day occurrence of new major coronary events in both periods, despite the greater angiographic complexity of the patients treated with in 1997. These adverse variables did not have a negative influence at the 6-month clinical and angiographic follow-up, with similar rates of restenosis and ischemia-driven target lesion revascularization rates.
30
Mattos et al
Safety and efficacy of coronary stents
Arq Bras Cardiol
volume 73, (nº 1), 1999
Instituto Dante Pazzanese de Cardiologia – São Paulo – Brazil
Maling address: Luiz Alberto Mattos - Av. Jandira 550/121 - São Paulo, SP - Brazil
Arq Bras Cardiol, volume 73 (nº 1), 30-36, 1999
Luiz Alberto Mattos, Ibraim Pinto, Alexandre Abizaid, Andrea Abizaid, Aurea Chaves, Fausto Feres,
Galo Maldonado, Luiz Tanajura, Marinella Centemero, Amanda G. M. R. Sousa, J. Eduardo Sousa
São Paulo, SP - Brazil
Safety and Efficacy of Coronary Stent Implantation.
Acute and Six Month Outcomes of 1,126 Consecutive Patients
Treated in 1996 and 1997
Original Article
Purpose - The authors analyzed the 30-day and 6-
month outcomes of 1,126 consecutive patients who
underwent coronary stent implantation in 1996 and 1997.
Methods - The 30-day results and 6-month angiogra-
phic follow-up were analyzed in patients treated with coro-
nary stents in 1996 and 1997. All patients underwent co-
ronary stenting with high-pressure implantation (>12 atm)
and antiplatelet drug regimen (aspirin plus ticlopidine).
Results - During the study period, 1,390 coronary
stents were implanted in 1,200 vessels of 1,126 patients; 477
patients were treated in the year 1996 and 649 in 1997. The
number of percutaneous procedures performed using stents
increased significantly in 1997 compared to 1996 (64 % vs
48%, p=0.0001). The 30-day results were similar in both
years; the success and stent thrombosis rates were equal
(97% and 0.8%, respectively). The occurrence of new Q
wave MI (1.3% vs 1.1%, 1996 vs 1997, p=NS), emergency
coronary bypass surgery (1% vs 0.6%, 1996 vs 1997, p=NS)
and 30-day death rates (0.2% vs 0.5%, 1996 vs 1997, p=NS)
were similar. The 6-month restenosis rate was 25% in 1996
and 27% in 1997 (p= NS); the target vessel revasculari-
zation rate was 15% in 1996 and 16% in 1997 (p = NS).
Conclusions - Intracoronary stenting showed a high
success rate and a low incidence of 30-day occurrence of
new major coronary events in both periods, despite the
greater angiographic complexity of the patients treated
with in 1997. These adverse variables did not have a
negative influence at the 6-month clinical and angiogra-
phic follow-up, with similar rates of restenosis and ische-
mia-driven target lesion revascularization rates.
Key words: stents, angioplasty, restenosis
Coronary stent implantation has modified the treat-
ment of patients with coronary artery disease who undergo
percutaneous myocardial revascularization.
In December 1987, the first human coronary balloon
expandable stent was implanted at the Instituto Dante
Pazzanese de Cardiologia in São Paulo, Brazil. Since then,
clinical and angiographic indications for this new percu-
taneous coronary revascularization method have expanded
after many caveats have been refuted and the safety and
efficacy required have been firmly established in clinical
practice
1
.
In the first years of its usage, randomized trials and
many consecutive series of patients showed higher rates of
thrombotic occlusion after coronary stent implantation (5 to
20%). This adverse event stimulated the use of one of the
most severe antithrombotic drug regimens ever applied in
interventional cardiology in an attempt to reduce the
incidence of this major coronary complication. However,
the series of procedures that followed this pharmacological
approach did not demonstrate a reduction in the subacute
occlusion rates, and major bleeding, a serious side effect,
occurred. It is natural to conclude that this approach resul-
ted in longer hospital stays with increasing costs, making
physicians leery of recommending this new percutaneous
coronary revascularization method
2-3
.
The scenario changed, however, with the publication
of the results of two major randomized studies in 1994,
which compare balloon PTCA with stents. The comparison
demonstrates that, stents can create significancy higher
coronary lumen diameters, reduce the restenosis rate at the
end of the first 6 months and as a consequence the need for
further revascularization procedures, percutaneous or
surgical, compared with the standard balloon PTCA
method
4-7
. In 1995, Colombo et al
8
demonstrated that
intravascular ultrasound could optimize stent delivery and
implantation, applying higher balloon pressures (>12
ATM), promoting better stent symmetry, with a nearly full
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Mattos et al
Safety and efficacy of coronary stents
31
apposition of the stent struts in the vessel wall. These
benefits of stent geometry led the author to recommend the
complete cessation of the old antithrombotic pharmacologi-
cal regimen, introducing a new one, aimed at a more intensi-
ve antiplatelet blockage, with the combination of aspirin and
ticlopidine. This new technique was called “optimal stent
implantation”
8-9
.
The purpose of the present analysis is to verify in a
consecutive series of patients who underwent coronary
stent implantation at a single high-volume center, the impact
of this new approach on clinical and angiographic outco-
mes at the acute and 6-month periods, comparing the results
achieved in 1996 with those obtained in 1997.
Methods
For the current analysis, we selected all consecutive
patients who underwent coronary stent implantation at our
hospital from 01/1996 until 12/1997.
A specific pharmacological regimen was applied
related to coronary stent implantation: in elective proce-
dures, patients received aspirin (200mg PO) and ticlopidine
(500mg PO), twenty-four hours before the implant. Thirty
days after the index procedure, ticlopidine was stopped but
aspirin was maintained indefinitely.
In nonelective stent implantation (acute myocardial
infarction or after suboptimal results of balloon PTCA),
aspirin and ticlopidine were started in the catheterization
laboratory. Before the procedure, patients received a full
dose of intravenous heparin (100 UI/kg).
Patients with successful procedures were discharged
from the hospital 24 to 48 hours afterwards. The exception
was patients with acute myocardial infarction who were
usually discharged between day 5 and 7 after the acute
event.
All patients treated during this period of time followed
a protocol of serial lab analyses that included the dosage of
CK-MB fraction prior to the procedure and 6 and 24 hours
after it. New measurements were only required in cases of
abnormal values (>10 UI). Routine ECGs was obtained
before and immediately after the procedure, and before hos-
pital discharge. On all clinical follow-up dates, a new ECG
was performed.
The success of the procedure was defined as the
ability to cross the target lesion and implant the stent, obtai-
ning a residual stenosis of less than 50% by quantitative
coronary angiography (QCA), with normal coronary flow
(TIMI flow 3). Clinical success required the absence of the
occurrence of any new major coronary event after the index
procedure: new Q wave MI, urgent myocardial revascu-
larization or death.
A new Q wave MI was defined as the presence of
typical chest pain for more than 30 minutes without relief
after nitrate usage, ST segment elevation higher than 1 mm
in more than one contiguous ECG lead and elevation of the
CK-MB fraction twice that of the normal value (10 UI).
Urgent bypass surgery operation and death were
verified in all patients at the end of the first month after the
stent implantation.
The clinical follow-up protocol applied followed these
rules: at day 30, the clinical success and occurrence of new
major coronary events were checked; between day 30 and
day 180, at least one new clinical visit was required, prior to
any new coronary angiography procedure. A new coro-
nary angiography was routinely indicated in all patients
even in asymptomatic ones. In patients without angina or
with a negative functional test, coronary angiography was
performed at the end of 180 days. Patients who presented
with early recurrence of angina or positive functional tests
underwent a new angiography as soon as possible.
Femoral access was the most common pathway for
performing coronary angioplasty with stent implantation.
The stent procedure employed the QCA of the target
coronary lesion performed after intracoronary adminis-
tration of nitrates and followed these steps: a) Predilatation
of the target lesion with conventional balloon PTCA, in the
same size as the index reference diameter vessel or 0.5 mm
less than this; b) Stent positioning in the coronary or graft
segment desired, in order to cover the entire diseased
segment; c) The stent (s) was (were) deployed with 8 to 12
ATM; d) Post-dilation with noncompliant balloons, with the
same diameter size or until 1 mm higher than the index
reference diameter vessel, inflated from 12 to 20 ATM; d)
Measurement of the residual stenosis with QCA to obtain
final stenosis smaller than 10%.
The procedure endpoint was the obtainance of an
optimal stent result defined as the absence of dissections at
the stent edges, negative images suggestive of thrombus
and severe peri-stent stenosis, plus the presence of a resi-
dual diameter stenosis <10% with coronary TIMI 3 flow.
Routine intravascular ultrasound was not performed,
being reserved for use only in the presence of nonoptimal
stent procedural results, when the specified criteria above
were not met.
The stent diameters employed ranged from 2.5 to
4.0mm, and lengths from 9 to 40mm. The stent chosen was
based on the operator’s discretion.
In the statistical analysis, continuous variables were
verified with the Student t test or by variance analysis, when
the same sample sizes were tested. The categorical variables
were analyzed by the chi-square test, with Fisher adjust-
ment when necessary. All these tests used the Kwikstat
computerized package and p values less than 0.05 were
considered statistically significant.
Results
During the period of this analysis, 1,390 coronary
stents were implanted in 1,200 vessels of 1,126 patients.
In 1996 and 1997, 477 and 649 patients were treated, res-
pectively.
The clinical profile is displayed in table I, according to
the year of the procedure (1996 or 1997).
32
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Safety and efficacy of coronary stents
Arq Bras Cardiol
volume 73, (nº 1), 1999
We observed a significant increase in the usage of
coronary stent procedures. In 1996, our hospital performed
percutaneous coronary revascularizations in 976 patients
and 477 (48%) employed the stent technique, compared to
499 (52%) that were treated with balloon PTCA. In 1997, the
use of balloon PTCA only as a revascularization method
was reduced to 371 patients (36%) and the number of stents
implanted increased to 649 patients (64%), an absolute
increase of 33% for coronary stenting (p=0.0001).
The clinical profile of the patients treated demons-
trated the following statistical differences when the com-
parison between both years was performed. The proportion
of patients with serum cholesterol levels >200 mg/dl was
lower in 1996 than in 1997, 24% and 19%, respectively;
patients with previous bypass surgery decreased from 20%
in 1996 to 14% in 1997. In contrast, the proportion of
patients with previous MI increased from 16 % in 1996 to
22% in 1997. All the other variables were similar in both
periods of time, but we observed an excessive number of
patients with acute coronary syndromes who underwent
percutaneous revascularization with stents, nearly half of
the entire group treated (58% and 56%, p=NS, 1996/97,
respectively).
The angiographic profile for both years is demons-
trated in table II. We observed a significant reduction in the
number of venous bypass grafts treated from 1996 to 1997
(9.2% vs 6.3%, respectively) and also in lesions located in
ostial segments (11% vs 7%, respectively). In 1997, the
index reference diameter of the vessels treated decreased
significantly (3.5mm vs 3.2mm, 1996 and 1997 respectively,
p=0.0001), which was demonstrated by QCA analysis
(table III). The multivessel stent procedures increased by a
significant proportion, accounting for 2.7% of 1996 vs 9.2%
of 1997 stent implants (p=0.0001).
The left ventricular function exhibited mean normal or
small decreases in global ejection fraction in 86% of 1996 vs
84% of 1997 patients (p=NS).
Acute success and major complications did not de-
monstrate any statistical difference (table IV). The clinical
success rates were high and similar in both periods of time
(97%). The occurrence of stent occlusion was rare, 0.8% for
both years. The incidence of new Q wave MI was also simi-
lar, below 1.3%. The need for urgent bypass surgery and
the occurrence of death were uncommon, less than 1%. The
incidence of non-Q wave MI detected only by the presence
the abnormal elevation of CK-MB fraction after the stent
procedure was not analyzed.
Four deaths occurred in this series in the 30-day analy-
sis, one in 1996 and three in 1997. The table V demonstrates
the clinical profile, stent indication and cause of these
deaths.
The results of QCA analysis are demonstrated in table
III. The mean final balloon pressure after stent deployment
was 17.9±3 ATM versus 16.3±2 ATM, 1996 and 1997,
respectively (p=0.0001). The mean final diameter size of the
balloon employed to optimize stent delivery was 3.48 mm ±
0.4 mm versus 3.29±0.5mm, 1996 and 1997, respectively
(p=0.0001). The balloon vessel ratio was similar between
these periods of time, 1.06.
In 1996, 42 (9%) patients exhibited lesion length
greater than 20mm and 31 (7%) had index reference vessel
diameter less than 3.0mm. These angiographic variables
were modified in the 1997 analysis. The presence of lesion
length greater than 20mm was detected in 143 (22%) of the
patients treated, and in 87 (14%) patients, small vessels with
less than 3.0mm of reference diameter (p=0.0001 and
p=0.0001, 1996/97, respectively) were detected.
Table I - Clinical profile of the patients who underwent coronary stenting in 1996 and 1997
Variables 1996 1997 P Total
Patients (n
o
) 477 649 1.126
Stents (n
o
) 583 804 0.9 1.387
Stents per patient 1,22 1.23 0.3 1.23
Male gender 372 (78%) 477 (74%) 0.08 849 (75%)
Mean age (years) 58.3±8 58.4±9 0.7 58.3±8
Age >70 years 74 (16%) 109 (17%) 0.6 183 (16%)
Coronary risk factors
Diabetics 89 (19%) 125 (19%) 0.8 214 (19%)
Current smokers 86 (18%) 139 (21%) 0.1 225 (20%)
Cholesterol >200mg/dL 115 (24%) 122 (19%) 0.03 237 (21%)
Previous coronary events
Acute myocardial infarction 76 (16%) 145 (22%) 0.01 221 (20%)
CABG 94 (20%) 93 (14 %) 0.02 187 (17%)
PTCA 77 (16%) 114 (17%) 0.5 191 (17%)
Restenotic lesions 29 (6%) 34 (5%) 0.6 63 (5.5%)
Clinical presentation
Stable angina 202 (42%) 288 (44%) 0.5 490 (44%)
Unstable angina 226 (47%) 287 (44%) 0.2 513 (45.5%)
Post intravenous thrombolysis 29 (6%) 45 (7%) 0.6 74 (6.5%)
Primary PTCA 20 (5%) 29 (5%) 0.9 49 (4%)
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Safety and efficacy of coronary stents
33
The mean hospital stay was 2.81±2 days in 1996 de-
creasing to 2.33±3 days in 1997 (p=0.001).
At the end of the 6-month follow-up, a higher number
of patients treated in 1996 had undergone a new coronary
angiography compared to patients in 1997 (53% versus
38%, p=0.0001). The mean time between the index proce-
dure and the new angiography was 154±125 days, for both
years.
The recurrence of angina symptoms was detected in
45% of the patients treated in 1996 versus 57% of 1997, and
the occurrence of AMI was 1.6 % in 1996 versus 0.8 % in
1997 (p=NS).
Coronary stent restenosis by binary definition were
demonstrated in 62 (25%) of the 1996 patients versus 66
(27%) of 1997 patients (p=NS). The need for further
revascularization procedures for the treatment of the target
lesion, either percutaneous or surgical procedures, was si-
milar in both periods of time, 37 (15%) and 39 (16%) patients
in 1996/97, respectively (p=NS).
The late follow-up QCA analysis revealed some
statistical differences. The mean diameter stenosis was
greater in 1997 than in 1996 (36.4±22% versus 30.2±20.7%,
respectively, p=0.001). The late lumen loss was higher in the
1996 period, 1.2mm, decreasing to 1.1m in 1997 (p=0.0001).
Discussion
The results presented here demonstrate the high rate
of efficacy and safety currently associated with percu-
taneous coronary stent implantation.
In 1997, we observed a significant increase in the an-
giographic complexity in patients who underwent coronary
stent implantation in our hospital. The number of multi-
vessel coronary stenting procedures increased from 2.7% to
Table II - Angiographic characteristics of the patients who underwent coronary stenting during 1996 and 1997
Variables 1996 1997 p Total
Number of vessels treated 491 709 1.200
Left main 4 (0.8%) 3 (0.5%) 0.6 7 (0.6%)
Left anterior descending 216 (45.3%) 296 (45.6%) 0.4 512 (43%)
Circumflex 87 (18.2%) 139 (21.4%) 0.4 226 (19%)
Right coronary 137 (29%) 228 (35%) 0.1 365 (30%)
Saphenous venous grafts 44 (9.2%) 41 (6.3%) 0.04 85 (7%)
Left internal mammary 3 (0.6%) 2 (0.3%) 0.6 5 (0.4%)
Segment treated
Ostial 55 (11%) 50 (7%) 0.01 105
Proximal 283 (58%) 419 (59%) 0.6 702
Medial/distal 153 (31%) 240 (34%) 0.3 393
Lesion type
A 38 (8%) 40 (6%) 0.3 78 (6.5%)
B1 162 (33%) 257 (36%) 0.8 419 (35%)
B2 212 (43%) 288 (41%) 0.4 500 (41.5%)
C 79 (16%) 124 (17%) 0.5 203 (17%)
Number of stents per patient
1 Stent 387 (81%) 520 (80%) 0.3 907 (80.5%)
2 Stents 77 (16%) 107 (16.5%) 0.4 184 (16.3%)
3 Stents 9 (2%) 18 (2.8%) 0.5 27 (2.3%)
4 Stents 3 ( 0.6%) 3 (0.6%) 0.2 6 (0.5%)
5 Stents 1 (0.4%) 1 (0.1 % ) 0.3 2 (0.4%)
Table III - Quantitative coronary angiography of patients treated with coronary stents in 1996 and 1997
Variables/mean values 1996 1997 p
Pre Stent
Reference diameter (mm) 3.2±0.4 3.1±0.4 0.0001
Minimal lumen diameter (mm) 0.8±0.4 0.8± 0.4 0.1
Stenosis diameter (%) 75.1±10.7 75.4±102 0.6
Lesion lenght (mm) 16±8.6 18±7.7 0.001
Post stent
Reference diameter (mm) 3.5±0.4 3.2±0.4 0.0001
Minimal lumen diameter (mm) 3.2±0.5 3.1±0.6 0.003
Stenosis diameter (%) 4.5±8.2 3.7±6.1 0.06
Acute gain (mm) 2.4±1 2.3±0.8 0.5
34
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volume 73, (nº 1), 1999
9.2%, 1996/97, respectively (p=0.0001) and twice as many
patients with the target lesions located in small vessels
(<3.0mm) were treated with stents, 7% to 14%, 1996/97,
respectively (p=0.0001). In the same fashion, long lesions
(>20mm) more often were treated with stenting in 1997
compared to 1996 (22% vs 9%, p=0.0001).
In contrast, the number of saphenous venous graft
lesions treated with coronary stenting was reduced in 1997
compared to 1996 as the lesions located in ostial segments.
However, these were the only variables that did not
have a significant increase during 1997 and were usually
associated with more severe complexity. This finding did
not reduce the impact of treating many more patients with
multivessel coronary disease, located in small vessels and
with tandem lesions.
The predictable results offered with stent implan-
tation justify their increased usage in 1997, in an absolute
order of 33% compared to 1996. The analysis of the acute
procedural and major coronary complication rates obtained
with stents demonstrates better results than those ever
reached with balloon PTCA. These results become more
pronounced when associated with the increasing angio-
graphic complexity observed here in this series. The acute
success rates were high in both years (97%) with a low rate
of subacute occlusion (<1%). The death rate at the end of 30
days was also low (<0.5%). The low rate of mortality
becomes more impressive when related to the fact that more
than 50% of the patients were treated in the setting of an
acute coronary syndrome. The need for urgent bypass
surgery was also reduced from 1% in 1996 to 0.6% in 1997.
The need for urgent surgical revascularization is becoming
rare after percutaneous procedures that employ the stent
technique. The incidence of new Q wave MI was lower than
1% and, it is in accordance with the results from the major
randomized trials recently published
7-10
.
Four deaths occurred in the first 30 days after the
procedure, but only one was related to stent thrombosis,
confirming the safety of coronary stenting, employing the
optimal stent implantation technique and antiplatelet
pharmacological regimen.
These optimal results obtained in a large random
consecutive series of patients confirms the great techno-
logical development related to coronary stent usage, new
adjunctive pharmacological measures and the operator’s
experience.
It is important to emphasize the need for a continuous
search for a perfect angiographic outcome after stent
deployment. This concept is called “optimal stent techni-
que“. Stents have the potential for equalizing all the clinical
and angiographic complexities found in many different
subgroups of patients suffering from coronary heart
disease. However, it is important to plan the stent implan-
tation in a meticulous way. We must choose the stent most
suitable to cover the entire target lesion length and with
enough flexibility to cross the curves that exist in coronary
anatomy. Actually, more than 30 different types of stents are
available for clinical use in our country. So, the process starts
with the correct interpretation of the coronary angiogram,
selecting the target lesion/vessel to be treated percuta-
neously and the specific stent size and length needed. The
major obstacles to stent delivery are the presence of massive
calcification and excessive tortuosity. The correct assess-
ment of these variables will determine the stent selected or
may even contraindicate the procedure.
Success should be defined by adjunctive use of QCA
analysis. The operator should seek for the lowest diameter
Table IV - Acute procedural results and new major coronary events after coronary stenting in the years 1996 and 1997
Variables 1996 1997 P Total
Clinical success 461 (97%) 633 (97%) 0.4 1094 (97%)
Acute occlusion (< 24h) 1 (0.2%) 3 (0.5%) 0.8 4 (0.3%)
Subacute occlusion (>24h) 3 (0.6%) 2 (0.3%) 0.7 5 (0.4%)
New Q wave MI 6 (1.3%) 7 (1.1%) 0.9 13 (1.1%)
Urgent bypass surgery 5 (1%) 4 (0.6%) 0.6 9 (0.7%)
Death (30 days) 1 (0.2%) 3 (0.5 %) 0.8 4 (0.3%)
MI - myocardial infarction
Table V - Clinical and procedural profile from the four 30 day deaths
Gender/Age Clinical presentation Stent indication Procedural result Death
1) Male, 62 years Post MI angina Elective Success Sudden death (24 hours)
2) Male, 60 years Stable angina Non elective Failure deliver to stent Urgent CABG + MI (18 d)
3) Female, 68 years Post MI angina Elective Success Sepsis (24 d)
4) Female, 76 years Unstable angina Elective Success Sub acute occlusion + MI (7 d)
MI - myocardial infarction
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Mattos et al
Safety and efficacy of coronary stents
35
stenosis without dissections, uncover diseased segments
and thrombus formation. The complementary safety
measure is related to the prescription of antiplatelet pharma-
cological regimen (aspirin plus ticlopidine) maintained for at
least 30 days.
At the end of the 6-month follow-up period different
rates of new coronary angiographies were observed
between the comparison of both years, but this accounts for
less than 60% of the whole group initially treated with
stents. In addition, more than half of the patients had
recurrent angina before the follow-up angiography. Howe-
ver, even in the presence of these adverse variables, the
restenosis rate was lower than 30% and similar between
both years (25 % and 27%, p=NS).
The need of ischemia-driven new revascularization
procedures for the target stent lesion (s) was also similar in
both years here analyzed, 16% and 15%, 1996/97, respec-
tively (p=NS).
The evidence obtained at the end of the 6-month
outcome period demonstrated that even with the inclusion
and treatment of more significant adverse variables noted on
angiography in 1997 (small vessels, long lesions and
multivessel procedures), did not increase the restenosis rate
and the ischemia-driven target lesion revascularization rates.
The randomized study BENESTENT II
7
compared the
implant of heparin coated Palmaz-Schatz stents with balloon
PTCA in 827 patients, with stable and unstable angina. This
clinical trial demonstrated better results in patients treated
with stents, with a low rate of acute major events (1.2%) and
with only 0.2% of sub/acute occlusion rate related to stent
thrombosis. The restenosis was 16% for coronary stenting
versus 31% in balloon PTCA patients (p=0.0008).
Many other interventional trials have tested coronary
stents in different clinical and angiographic settings. The
majority of these trials report favorable outcomes with
stenting. Coronary stents have been shown to be superior
in terms of better hospital results with a lower incidence of
new major coronary events, offering the lowest residual
diameter stenosis ever obtained in interventional cardio-
logy and promoting a positive and quantitative influence
toward lower restenosis and new target vessel revascu-
larization rates. This outcome was observed in vein grafts
(SAVED)
11
, restenotic lesions (REST)
12
, chronic occlusions
(SICCO
13
and GISSOC
14
) and in the first twenty-four hours
of AMI (Zwole
15
, FRESCO
16
and PAMI Stent
17-19
).
The significant knowledge gained from the use of
stent techniques and the interaction of stents with the
vessel wall led to the employment of slightly lower pressu-
res in 1997 without affecting the acute results. The lower
lumen loss observed in 1997 might be related to this
measure. However, researchers should be cautious of this
conclusion because further evidence is needed from
intravascular ultrasound and histological studies.
The optimization of the stent technique and the use
of antiplatelet drugs (aspirin + ticlopidine)
2-3
led to a
reduction in the mean hospital stay in 1997 compared to
1996 (2.3 days versus 2.8 days, respectively, p=0.0001).
In current interventional cardiology practice, stenting
is the main percutaneous technique used. Stents offer a
predictable result and have become the great equalizer in the
face of many different clinical and angiographic charac-
teristics. The results from a consecutive series of patients
like ours and randomized trials confirm the superiority of
stents to balloon PTCA, both in the hospital and late follow-
up outcomes. In the presence of some high-risk subgroups
of patients, such as those with diabetes
20-21
, unstable angi-
na
7
, acute myocardial infarction
15-19
, vessels with reference
size <3.0mm
7
, balloon PTCA failures
6
, lesions located in he
proximal left anterior descending artery
7,22
, chronic
occlusions
13-14
, vein grafts
11
, restenotic lesions
12
and
multivessel coronary disease
23
, who undergo percu-
taneous coronary revascularization, stents will promote
better results and should be the technique of first choice.
1. Mattos L, Chaves A, Feres F, et al. Optimal coronary stent implantation wihtout
ultrasound guidance withholding subsequent anticoagulation. Can it be done
safely? J Invas Cardiol 1995; 7: 10A.
2. Schomig A, Neumann FJ, Kastrati A, et al. A randomized comparison of
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  • Article · · Arquivos Brasileiros de Cardiologia
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