(Circulation. 2000;101:131.)
© 2000 American Heart Association, Inc.
Clinical Investigation and Reports |
From the Division of Cardiology, Lille University Heart Institute, Lille, France (M.E.B.); Hospital de Bellvitge Princeps DEspanya, Barcelona (E.E.); Nycomed Amersham, Oslo, Norway; and Universitair Ziekenhuis Gasthuisberg, Leuven, Belgium (J.P.).
Correspondence to M.E. Bertrand, MD, Division of Cardiology, Lille University Heart Institute, Boulevard du Professeur Leclercq, Lille, France. E-mail mbertrand{at}univ-lille2.fr
| Abstract |
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Methods and ResultsIn a randomized, parallel-group, double-blind study, 1411 patients received either iodixanol (a nonionic, iso-osmolar contrast medium) or ioxaglate (an ionic, low-osmolar contrast medium) during PTCA. A standardized anticoagulation regimen was followed. Patients were monitored in the hospital for 2 days and followed-up at 1 month. The primary end point, a composite of MACE (death, stroke, myocardial infarction, coronary artery bypass grafting, and re-PTCA) after 2 days, occurred in 4.3% of the total population, with no statistically significant difference between groups (iodixanol, 4.7%; ioxaglate, 3.9%; P=0.45). Further, between 2-day and 1-month follow-ups, no significant difference (P=0.27) existed between the groups in the rates of MACE. Hypersensitivity reactions (P=0.007) and adverse drug reactions (P=0.002) were significantly less frequent in the iodixanol group. The only significant predicting factors for the occurrence of MACE were dissection/abrupt closure and country.
ConclusionsNo significant differences were observed between the iodixanol and ioxaglate groups with regard to MACE, although hypersensitivity and adverse drug reactions were significantly less frequent in patients who received iodixanol.
Key Words: contrast media angioplasty angiography stents
| Introduction |
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| Methods |
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Patients
Between November 21, 1996, and September 22, 1997, 1541 patients
18 years of age who had stable (Canadian
Cardiovascular Society functional classification) or
unstable angina (Braunwalds classification system) or silent
ischemia and who were undergoing PTCA were enrolled in the
study. Exclusion criteria were recent (<7 days) acute MI, unprotected
left main stenosis, or the need for oral anticoagulation with
antivitamin K. Patients were also excluded if they had
contraindications to heparin, aspirin, or ticlopidine therapy or to
iodinated contrast media. Patients who had received
iodinated contrast media within the 18 hours before PTCA
were not included to minimize the possible influence of nonstudy
contrast media on the results. The use of rotablator, directional
atherectomy, or pretreatment with glycoprotein IIb/IIIa
receptor inhibitors was not allowed. Left
ventricular ejection fraction was required to be >35%. In
a few centers, recruitment of patients was performed before
diagnostic catheterization, and trial
contrast medium was then used for that purpose to ensure identical
contrast media throughout the procedures. Among the 1541 patients
enrolled, 81 did not have PTCA, 27 had major protocol violations (the
majority due to an ejection fraction <35% or to the presence of a
recent MI), 26 were excluded because they received a mixture of
different contrast media, 3 were excluded due to loss of their case
report form or contrast medium vials, and 7 were excluded for >1 of
the above-mentioned reasons. Of the 1411 patients who constituted the
per-protocol population, 697 received iodixanol and 714 received
ioxaglate.
All patients received heparin, and all but 4 received an
antiplatelet agent (
100 mg of aspirin and/or ticlopidine). An
intravenous bolus of heparin (10 000 IU) was administered
at the start of the procedure. The ACT was measured 5 minutes after the
first injection of heparin, and further heparin was given if necessary
to maintain the ACT above 250 or 300 s (depending on the
apparatus used). If PTCA lasted >1 hour, ACT was
recorded again, and additional heparin was given when required. ACT
was measured again at the end of the procedure. Ticlopidine was given
to patients after stent implantation or if otherwise indicated (eg,
allergy to aspirin). Overall, 68.6% of patients received ticlopidine
either before, as routine medication, or before/during/after
PTCA. All other medications and procedures were at the discretion of
the investigator.
Follow-Up
Procedural and safety outcomes were recorded for all
patients during the hospital stay (2-day follow-up). The primary end
point was a composite of MACE during the 2-day follow-up period (2-day
MACE); it was defined as death, stroke, Q-wave or non-Q-wave MI
(NQWMI), and CABG and/or emergency re-PTCA at the target lesion or in
the target vessel. The definition of a NQWMI was an increase in serum
creatine kinase (CK) to twice the upper normal reference range limit or
more, coupled with an increase in the CK-isoenzyme MB fraction. An
independent end point classification committee evaluated CK for all
patients to determine NQWMI cases. This independent end point
classification committee, which consisted of 3 cardiologists, also
evaluated, in a blinded fashion, all reported MACE-2 day cases. The
committees decision was based on information from the case report
form, ECGs, vital signs, laboratory test results (pre- and post-PTCA),
and films/videos from the PTCA procedure. In addition to the
in-hospital follow-up, the patients were contacted by telephone (by the
investigator or a study nurse) 1 month after discharge from the
hospital to ascertain if they had been rehospitalized due to MACE. The
end point classification committee did not evaluate occurrence of MACE
between the 2-day and 1-month follow-ups.
Statistical Analysis
To assess the influence of contrast media and other factors on
the occurrence of 2-day MACE, the factors were individually evaluated
through odds ratio (OR) estimates and their associated 95% confidence
intervals (single-factor analyses). Testing OR deviations from
1 was done through the 2-tailed likelihood
2
test; P
0.05 was considered statistically significant. In
addition, an exploratory multiple logistic regression analysis
was performed based on the results of the single-factor
analysis to identify the predictors for 2-day MACE; it took
into account possible interactions between factors. Other adverse
events, including hypersensitivity reactions, were compared between
contrast media groups at 2 days and at 1 month using the
2 test.
The comparability of the 2 contrast media groups with regard to
baseline characteristics was assessed through the dependency of the
primary end point on each baseline characteristic. For each baseline
characteristic, the
2 P value for
testing independence between the baseline characteristic and primary
end point was calculated per contrast medium group; P<0.05
indicates dependency. In cases where dependency is found, a
large difference in the baseline characteristics between the contrast
media groups might then have unwanted effects on the comparability of
the groups.
| Results |
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The majority of the patients underwent single-vessel PTCA (73.0% versus 71.1%, iodixanol group versus ioxaglate group). A total of 23% of the patients (22.2% in the iodixanol group versus 23.4% in the ioxaglate group) had 2-vessel PTCA, whereas the remaining patients underwent 3-vessel PTCA. Glycoprotein IIb/IIIa receptor inhibitors were given during or after the PTCA procedure in 23 patients (12 iodixanol and 11 ioxaglate) who had abrupt closure, stent occlusion, or coronary dissection.
Procedural Outcome
The percent diameter stenosis at baseline and after PTCA
are reported in Table 2
. No difference in percent residual
stenosis existed between the 2 groups immediately after PTCA.
The proportion of angiographically identifiable thrombus (visual
assessment) before and after PTCA was similar in both contrast media
groups (all lesions included) (Table 2
). The rates of abrupt
closure (all lesions) occurring during the procedure did not differ
significantly between groups (P=0.39). Procedure-related
dissections were reported somewhat less frequently in patients
allocated to the iodixanol group compared with the ioxaglate group, but
the difference was not statistically significant (P=0.18)
(Table 2
). Implantation of intracoronary stents was
similar in both groups: 59.8% in the iodixanol group and 60.9% in the
ioxaglate group. The implantation rate varied from 36.0% in the
country with the lowest stent implantation rate (France) to 76.9% in
the country with the highest rate (Belgium).
Primary End Point
On the basis of the intention-to-treat population (1538 patients,
765 in iodixanol group and 773 in ioxaglate group), which consisted of
all enrolled patients but the 3 who had a lost case report form or
contrast medium vials, the primary end point (2-day MACE) occurred in
4.2%, with no statistically significant differences between the
iodixanol and the ioxaglate groups (4.6% versus 3.8%, respectively;
P=0.42). Among the MACE, NQWMI was the most frequent
complication (2.7%). The analysis of the per-protocol
population (1411 patients) showed similar results (Table 3
). No statistically significant
differences existed between the iodixanol and the ioxaglate groups
(4.7% versus 3.9%; P=0.45). Among the 2-day MACE, NQWMI
was the most frequent complication (2.9%). The majority (76%)
of these patients had a >4-fold increase in CK values. Two cardiac
deaths occurred during the 2-day follow-up period, both in the
ioxaglate group. The 2-day MACE rate varied among the centers, from 0%
to 18.2% among those completing their inclusion. One center enrolled
only 7 patients and reported 2 patients with 2-day MACE.
Patients who underwent stent implantation had a 4.6% chance of
developing 2-day MACE; the chance was 3.3% when stenting was planned
and 5.3% when it was unplanned. The rate for nonstented patients was
3.9%.
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Table 4
shows the ORs with 95%
confidence intervals for potential predictive factors of the occurrence
of 2-day MACE. Results from the single-factor analyses showed
that only dissection/abrupt closure (P<0.001) and country
(P=0.005) were significant predictors of the occurrence of
2-day MACE. The presence of the most severe kind of lesion, type C, was
borderline with respect to its significance as a predictor
(P=0.06). As shown in Table 4
, contrast medium, sex,
age, clinical condition of the patient, and stenting condition were not
significant predictors for the occurrence of 2-day MACE. The
multifactorial analysis gave similar results.
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One-Month Follow-Up
Similarly, in the per-protocol population, no statistically
significant differences between the 2 groups were observed
(P=0.27) with regard to rehospitalization due to MACE during
the period between the 2-day and 1-month follow-up. The number of
patients hospitalized for each event in each group
(iodixanol/ioxaglate) are as follows: cardiac death (2/0), stroke
(1/0), Q-wave MI (2/0), NQWMI (1/1), CABG (2/1), and Re-PTCA (6/7). In
total, 23 patients (1.6%) were rehospitalized during this time period,
2.0% in the iodixanol group and 1.3% in the ioxaglate group. These
events were not validated by the end point classification committee.
Combining MACE noted at 2-day follow-up and those occurring between the
2-day to 1-month follow-ups showed no statistically significant
difference between the iodixanol and ioxaglate groups (6.3% versus
5.2%; P=0.42).
Adverse Events
The percentage of patients reporting
1 adverse event during the
2-day follow-up, including MACE, was similar in the 2 groups (27.5%
versus 27.6%; Table 5
). Chest pain was
the most common event reported; this was followed by hypotension,
hematoma at the puncture site, nausea or vomiting, and bradycardia. As
seen in Table 5
, patients randomized to the ioxaglate group had
an increased risk (P=0.002) of experiencing adverse events
that were classified by the investigators as having a certain
relationship to the contrast medium. These were mainly nausea,
vomiting, and rash. When pooling contrast mediarelated adverse events
and events having an uncertain relationship to contrast media, the
overall adverse drug reaction frequencies were 9.9% in the iodixanol
group and 11.9% in the ioxaglate group (P=0.23). Among the
most common adverse drug reactions with an uncertain relationship to
contrast medium were hypotension, bradycardia, chest pain, and
hematoma.
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Patients randomized to receive the ionic contrast medium ioxaglate had
an increased risk of developing hypersensitivity reactions
(P=0.007) (Table 5
). A total of 23 patients had such
reactions, 5 (0.7%) in the iodixanol group and 18 (2.5%) in the
ioxaglate group.
| Discussion |
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The major finding of this multicenter study was that no difference was
found in MACE between the nonionic iso-osmolar and the ionic
low-osmolar contrast media after both 2 days and 1 month. These results
agree with the recently reported single-center trial performed by
Schräder et al.25 In this randomized study comparing
the nonionic iomeprol (Iomeron, Bracco-Byk-Gulden) to the ionic
ioxaglate in a large series of 2000 patients, no differences were found
with regard to angiographic or clinical end points. Fewer than 20% of
their patients had unstable angina, and glycoprotein
IIb/IIIa receptor inhibitors were not used. However, the
present studys results differ from those reported in a
single-center study by Grines et al.4 They compared
ioxaglate and the low-osmolar, nonionic contrast medium iohexol
(Omnipaque, Nycomed Imaging AS) in 211 patients with acute MI and
unstable angina undergoing PTCA. Their conclusion was that the use of
the ionic contrast medium ioxaglate reduced the risk of
ischemic complications, both acutely and at 1-month follow-up.
Results from recently published studies on the effects of iohexol,
iodixanol, and ioxaglate on vessel-wall biocompatibility and on
arterial thrombus formation23 24 do not
support the findings of Grines et al.4 However, it is
difficult to directly compare the results from the present study
with those from Grines et al,4 because many essential
differences exist between the studies. We think that the main reasons
for discrepancies in results are that the present study included a
much larger patient population (it was a multicenter study, with
7
times as many patients), patients with acute MI were excluded, adjuvant
anticoagulation was strictly controlled, and intracoronary
stenting was done according to current practice. Finally, the nonionic
contrast medium was different in the 2 studies; the present study
used the new iso-osmolar iodixanol.
With regard to predictive factors for the occurrence of MACE, only the procedure-related factors dissection and abrupt closure were significant, in addition to country (P=0.45 for contrast medium). Regarding the procedural aspects, we noted no difference between the 2 groups in thrombus, abrupt closure, or dissection. However, the identification of thrombus is based on angiographic assessment, and it is well known that angiography has a poor sensitivity for the detection of thrombus.
This study reflects the present situation in Western Europe regarding the implantation of intracoronary stents. On average, 60% of the patients were stented, but the country-to-country variation was large (from 36.0% to 76.9%). This variation is due to international differences in reimbursement systems rather than to angiographic indications.
Our results confirm that hypersensitivity and adverse drug reactions
related to contrast medium injection are less frequent after the
administration of nonionic contrast medium26 27 28 29 30 31 (Table 5
). These reactions were independent of the volume of contrast
media injected, which was similar in both groups (Table 2
).
Schräder et al25 concluded that nonionic contrast medium minimized the risk of allergic reactions in patients undergoing intervention, and Gertz et al31 recommended that nonionic contrast medium should be used in patients undergoing cardiac angiography to minimize allergic reactions, especially in patients with known allergies. This recommendation is now also valid for patients undergoing PTCA.
Study Limitations
The implantation of intracoronary stents is increasing,
both in Europe and worldwide. During the planning phase of the study,
we anticipated an average stenting rate of
40% of patients. The
results showed an
20% higher rate of stenting, and this fact might
have contributed to the lower MACE rates reported than was expected.
The study was planned with a 6% anticipated MACE rate. However, the
lower rate of 4.3% seen at the completion of the study did not affect
the studys ability to detect a difference between the contrast media
groups, because the observed contrast group OR of 1.2 is well within
the confidence limits specified in the study protocol.
Only the 2-day MACE were evaluated by the independent end point classification committee, and this should be considered when looking at the overall results, which combine the MACE reported after 2 days with those reported after 1 month. In total, 1541 patients were enrolled, but 1411 were included in the per-protocol population. However, the fact that the intention-to-treat population results were in accordance with the per-protocol population results regarding MACE indicates that the exclusion of these patients had no influence on the results.
In total, 32 centers participated in the trial, and the individual centers enrolled 2 to 112 patients. The disparity between the number of enrolled patients could have influenced the final results, but due to stratification by center, the comparison between the 2 contrast medium groups was unbiased.
The use of glycoprotein IIb/IIIa receptor inhibitors was not the current practice at the enrolling centers, and it was not allowed as a preparation to intervention. Only 23 patients (1.6%) received this type of medication during or after PTCA.
Conclusions
No statistically significant differences were found between the
iso-osmolar, nonionic contrast medium iodixanol and the low-osmolar,
ionic contrast medium ioxaglate on the occurrence of MACE, either at
the 2-day follow-up or during the 1-month follow-up period. In
addition, the rate of abrupt closure was similar in both groups.
Thus, we can conclude that in patients, including those with both stable and unstable angina, receiving iodixanol, no increase in major cardiac complications occurs when compared with those patients given ioxaglate. Furthermore, hypersensitivity and adverse drug reactions classified as certainly related to contrast medium occurred significantly less frequently in patients receiving iodixanol.
| Appendix |
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The Netherlands: H. Suryapranata, Ziekenhuis De Weezenlanden, Zwolle; J.J.R.M. Bonnier, Catharina Ziekenhuis, Eindhoven.
Belgium: G. Heyndrickx, Onze Lieve Vrouw Ziekenhuis, Aalst; C. Hanet, Cliniques Universitaires St Luc, Bruxelles; F. Van den Branden, Middelheim Ziekenhuis, Antwerpen; M. Vrolix, St. Jan Ziekenhuis, Genk; J.H. Piessens, Universitair Ziekenhuis Gasthuisberg, Leuven; Y. Taeymans, Universitair Ziekenhuis, Gent; V. Legrand, Center Hospitalier Universitaire, Liège; J. Dekeyser, Hôpital Civil, Jumet; P. Lafontaine, Clinique St Jean, Bruxelles.
Spain: C. Macaya, Hospital Universitario San Carlos, Madrid; E. Garcµa-Fernández, Hospital General Gregorio Marañón, Madrid; E. Esplugas and J. Mauri, Hospital de Bellvitge Princeps DEspanya, Barcelona; A. Betriu and A. Serra, Hospital Clinic I Provincial, Barcelona; A. Iñiguez, Clínica Nuestra Señora de la Concepción, Madrid; C. Morís, Hospital General de Asturias, Oviedo; T. Colman, Hospital Marqués de Valdecilla, Santander; M. Gómez-Recio, Hospital de la Princesa, Madrid.
Sweden: L. Grip, Sahlgrenska Sjukhuset, Göteborg.
| Acknowledgments |
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Received March 17, 1999; revision received July 7, 1999; accepted July 28, 1999.
| References |
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