(Circulation. 2000;102:2930.)
© 2000 American Heart Association, Inc.
Clinical Investigation and Reports |
From the Thoraxcenter, Rotterdam, the Netherlands (P.W.S., S.C.); the Cardiovascular Center, OLV Hospital, Aalst, Belgium (B.d.B.); Instituto Dante Pazzanese, Sao Paulo, Brazil (J.E.S.); Academisch Medisch Centrum, Amsterdam, the Netherlands (J.P.); Kawasaki Central Hospital, Kawaka-Shi Kanagawa, Japan (T.M.); University Hospital Antwerp, Edegem-Antwerp, Belgium (C.V.); Allgemeines Krankenhaus der Stadt Wien, Vienna, Austria (P.P.); Hospital Santa Cruz, Linda-A-Velha, Portugal (R.S.-G.); Wessex Cardiology Center, Southampton, United Kingdom (I.S.); Onassis Cardiac Surgery Center, Athens, Greece (V.V.); Hôpital Universitaire de Mont-Godinne, Yvoir, Belgium (O.G.); Catharina Hospital, Eindhoven, the Netherlands (N.P.); Instituto Cardiovascular de Buenos Aires, Buenos Aires, Argentina (J.B.); Cardialysis, Rotterdam, the Netherlands (G.-A.v.E., M.-A.M.); Erasmus University, Rotterdam, the Netherlands (E.B.); and the Institute for Medical Technology Assessment, Rotterdam, the Netherlands (B.v.H.).
| Abstract |
|---|
|
|
|---|
Methods and ResultsTo analyze the cost-effectiveness of provisional angioplasty, patients scheduled for single-vessel angioplasty were first randomized to receive primary stenting (97 patients) or balloon angioplasty guided by Doppler flow velocity and angiography (523 patients). Patients in the latter group were further randomized after optimization to either additional stenting or termination of the procedure to further investigate what is "optimal." An optimal result was defined as a flow reserve >2.5 and a diameter stenosis <36%. Bailout stenting was needed in 129 patients (25%) who were randomized to balloon angioplasty, and an optimal result was obtained in 184 of the 523 patients (35%). There was no significant difference in event-free survival at 1 year between primary stenting (86.6%) and provisional angioplasty (85.6%). Costs after 1 year were significantly higher for provisional angioplasty (EUR 6573 versus EUR 5885; P=0.014). Results after the second randomization showed that stenting was also more effective after optimal balloon angioplasty (1-year event free survival, 93.5% versus 84.1%; P=0.066).
ConclusionsAfter 1 year of follow-up, provisional angioplasty was more expensive and without clinical benefit. The beneficial value of stenting is not limited to patients with a suboptimal result after balloon angioplasty.
Key Words: stents angioplasty balloon random allocation cost-benefit analysis
| Introduction |
|---|
|
|
|---|
It has been suggested that optimal balloon angioplasty could
yield a clinical outcome similar to
stenting.9 10 11 12
The Doppler Endpoints Balloon Angioplasty Trial Europe (DEBATE) I
results support this hypothesis in that the outcome for patients with
both a diameter stenosis (DS)
35% and a coronary
flow reserve (CFR) >2.5 was comparable to that achieved with
stenting in the Belgian Netherlands Stent (BENESTENT)
trials.3 13 Thus,
the following provisional approach emerges: stent only those patients
likely to reap an additional benefit. Such an approach challenges the
intervener who must decide on overall patient care. "Provisional
angioplasty" refers to a status of angioplasty that satisfies
predefined criteria of optimal results based on pressure
gradients,11 early loss of
minimal lumen diameter,10 or
intravascular ultrasound
measurements.12 A failure to
meet the criteria would change the intended treatment and results in
stent implantation.
DEBATE II was a prospective, randomized study that used criteria identified in DEBATE I. It addressed the following questions. (1) Should elective treatment be by stenting or balloon angioplasty (provisional angioplasty being guided by the stated criteria)? (2) What is the relative cost/benefit ratio of these strategies? (3) Do patients with optimal balloon angioplasty obtain an additional benefit from stenting?
| Methods |
|---|
|
|
|---|
Study Objectives and Trial Design
The primary trial objective was to compare the
cost-effectiveness of elective stent implantation (primary stenting)
with provisional balloon angioplasty guided by quantitative angiography
and Doppler flow velocity measurements. The strategy after
provisional angioplasty was to limit stent implantation to bailout
situations and cases in which an "optimal result" (DS
35% and
CFR >2.5)13 was not
achievable. The secondary objective was to evaluate the benefit
differences from additional stenting in patients with and without an
optimal result. Therefore, double randomization was required
(Figure 1
).
|
It would be incorrect to estimate the costs and benefits of provisional angioplasty using average costs and benefits combining (1) patients with bailout stents, (2) patients with optimal balloon angioplasty, and (3) patients with stenting after a suboptimal result. Patients left after bailout stenting would then receive too much weight, because the bailout decision was made before the second randomization, leading to 4 groups instead of the 2 created by the provisional angioplasty strategy. Therefore, a weighted average was used that weighted bailout stenting by the probability of bailout stenting and stenting in patients who did not require bailout stenting by the probabilities of belonging to either the optimal balloon angioplasty or suboptimal angioplasty groups. Thus, the provisional angioplasty group is a constructed or virtual group.
Primary Stenting
A conventional guidewire was used in patients
randomized to primary stenting, and predilatation was performed in all
patients before stent implantation.
Guided Balloon Angioplasty
During guided balloon angioplasty, quantitative
angiography and CFR measurements were made using standardized
protocols13 15 to
achieve an optimal result (criteria defined earlier in
article).
A 0.014-inch Doppler guidewire (Cardiometrics FloWire, EndoSonics) was advanced distal to the lesion, and velocity recordings were obtained under basal and hyperemic conditions. Maximal hyperemia was induced by adenosine, which was administered as an intracoronary bolus (right coronary artery, 12 µg; left coronary artery, 18 µg) or as an intravenous infusion (140 µg · kg-1 · min-1).16 17 These 2 methods were proven to be equivalent.
If an optimal result was not achieved, the operator was
urged to perform iterative dilatations by upsizing the balloon,
increasing the inflation pressure, or both. Bailout stenting was
allowed in the presence of residual stenosis >50%; dissection
types D, E, or F; persistent myocardial ischemia with
dissection type C; reduction of TIMI
flow18 by
1 grade; or the
existence of TIMI grades 0 or 1. The final DS and CFR were assessed
after an optimal result was achieved or when the operator considered
further improvement attempts unsafe. A second randomization was then
performed that disregarded the measurements.
Efficacy End Points
The efficacy end point compiled major adverse cardiac
events within 12 months of the procedure; these included death from any
cause, nonfatal myocardial infarction, and percutaneous
or surgical target lesion revascularization.
Myocardial infarction was defined as the development of a new Q-wave or
a rise of serum creatinine kinases with an abnormal plasma
concentration of myocardial isoenzymes. Enzymes were sampled twice in
the first 24 hours. Patients visited the outpatient clinic 1, 6, and 12
months after hospital discharge. At each visit, records were kept
of anginal status, cardiac medication, 12-lead ECG, and complete
physical examination. No follow-up angiogram was performed unless
clinically indicated.
Costs
Cost analysis was limited to direct medical
costs, which were calculated as resource utilization volume x unit
costs in 1999 at the University Hospital Rotterdam-Dijkzigt, the
Netherlands.19 Resources
included the materials used in the initial procedure (eg, stents,
balloons, and Doppler wires); length of stay in the intensive care
unit, coronary care unit, or general ward; major curative and
diagnostic procedures; and rehospitalization within 12
months of the initial procedure. Although it could be expected that a
guided strategy would lengthen procedures, we decided not to estimate
the cost consequences of such an action. We hypothesized that the
increased duration would not reduce the number of procedures possible
per day; thus, the "fixed costs" would remain fixed. Also, the data
may be biased by the time taken for a second randomization, thus
breaking the continuity of procedures.
Cost Effectiveness
The balance between costs and benefits was addressed
by calculating incremental cost-effectiveness ratios (ie, additional
costs per additional event-free survivor after 1 year) and by
estimating the probabilities that the provisional angioplasty was (1)
more effective and cost saving, (2) more effective and more costly, (3)
less effective and cost saving, or (4) less effective and more
costly.
Sample Size
Assumptions for sample size calculation were based on
BENESTENT-1, BENESTENT-2 pilot, and DEBATE I
experiences.2 3 13
All additional benefits of stenting were attributed to patients with
suboptimal results. With these assumptions, it was calculated that for
the randomization scheme in
Figure 1
, 600 patients were needed to detect, with 80%
power, a difference (
=0.05) of EUR 680 between provisional
angioplasty and primary stenting in cost-effectiveness per survivor (no
major adverse cardiac event) after 1
year.20
Statistical Analysis
Continuous variables are expressed as means±SD.
Differences between patient groups were studied using Students
unpaired t test or 1-way ANOVA,
whichever was appropriate. Categorical variables are
presented as percentages, and differences between groups were
evaluated using Fishers exact test. Kaplan-Meier event-free survival
curves were calculated, and differences between patient groups were
compared by a log-rank test.
Because the costs and benefits of provisional angioplasty
were calculated as weighted averages, bootstrapping techniques were
used to evaluate differences in the balance between costs and benefits
after primary stenting and provisional
angioplasty.21 22
A total of 3000 bootstrap samples were drawn iteratively, with
replacement when sample sizes equalled the total number of patients
studied. Odds ratios and 95% confidence intervals are
presented; a Breslow-Day test for homogeneity of odds ratios
between subgroups and
2 tests were also
applied.
Statistical tests were 2-tailed, with significance stated at the 0.05 level. Uncertainties surrounding cost, benefits, and cost-effectiveness were addressed by probability ellipses in the "cost-effectiveness plane."21
| Results |
|---|
|
|
|---|
|
Procedural Results
Table 2
summarizes the procedural results, and
Figure 2
shows the relative roles of DS and CFR in
classifying patients. Optimal results, with an average DS of 22±8%
and a CFR of 3.1±0.6, were achieved in 35% of patients. In the
suboptimal group, DS was 23±10% and CFR was 2.0±0.4. Additional
stenting in patients with optimal balloon angioplasty resulted in a DS
of 8±8% and a CFR of 3.3±0.7; in patients with suboptimal balloon
angioplasty, additional stenting resulted in a DS of 7±8% but a CFR
of 2.4±0.7.
|
|
Primary Stenting Versus Provisional
Angioplasty
Table 3
shows the incidence of major adverse cardiac events
in both the initial groups and the 4 subgroups, ranked in hierarchical
order. In general, patients with optimal results experienced fewer
major adverse cardiac events than patients with suboptimal results, and
stented patients fared better than those undergoing balloon angioplasty
alone
(Figure 3
).
|
|
Freedom from these events, which were calculated as weighted
averages, was similar for patients undergoing primary stenting (86.6%)
and provisional angioplasty (85.6%)
(Figure 4
). The weight for patients needing bailout stenting
was 129/(129+107+112+86+77) or 25.2%; the weight for patients stented
after a suboptimal result was 38.7% (calculated as the probability of
not needing a bailout stent [100.0%25.2%=74.8%] multiplied by
the probability of a suboptimal result
{[112+86]/[77+107+112+86]=51.8%}); and the weight for patients
with a stent after an optimal result was 36.0% (calculated as the
probability of not needing a bailout stent [74.8%] multiplied by the
probability of an optimal result [100%51.8%=48.2%]).
|
Table 4
presents cost estimates for the 2 initial
groups and 4 subgroups. The cost of FloWire in the initial procedure
was only partially covered by the lower stent use. Costs for the
provisional angioplasty group during follow-up were higher due to
longer hospitalizations and surgical
revascularization. After 1 year, the costs of
provisional angioplasty outweighed those of direct stenting by EUR 688.
Figure 5
presents the estimates of costs, benefits, and
cost effectiveness. The point estimate of the incremental
cost-effectiveness ratio suggests that provisional angioplasty is less
effective and more expensive.
|
|
Stenting Versus Balloon Angioplasty After the
Second Randomization
The analysis of subrandomized patients in the
balloon angioplasty group
(Figure 6
) indicates that stenting was associated with fewer
major adverse cardiac events than balloon angioplasty alone in both
patients with suboptimal (10.7% versus 26.7%; odds ratio, 3.0;
P=0.005) and optimal results
(6.5% versus 15.9%; odds ratio, 2.7;
P=0.066). The Breslow-Day test
for homogeneity of odds ratios was not significant
(P=0.865). The higher
cumulative costs of balloon angioplasty alone during the follow-up
period almost matched the high initial costs of balloon angioplasty
followed by stenting.
|
| Discussion |
|---|
|
|
|---|
Relevance and Critical Appraisal of
Cost-Effectiveness Analysis
Cost considerations dominate many decisions about
therapeutic interventions and are very relevant from a societal
viewpoint. As emphasized in the literature, an independent person
without commercial affiliations must analyze cost-effectiveness
in such studies to avoid financial
bias.23 However,
cost-effectiveness analyses are limited by multiple factors.
First, cost data are transient and are affected by product
acceptance, market dynamics, and reimbursement systems. Second,
changing patterns of practice affect the selection of treatment
devices, how they are used, and overall procedure time. Thus, the costs
used here represent only a snapshot in time. For example,
direct stenting without predilatation (an increasingly used technique)
will undoubtedly affect cost-effectiveness in the future, but this
method of treatment was not applied here.
Two crucial factors in the present study exerted a major influence on overall costs: the costs of FloWire and those of stenting. When the study was designed, its power calculation was based on market prices in 1996 and the cost estimates related to bleeding complications and the longer hospital stays associated with stenting. The reported cost estimates were based on unit costs in 1999 (costs of primary stenting versus provisional angioplasty, EUR 5916 versus EUR 6724; P=0.029). However, an application of 1996 unit costs does not change the conclusion. The absence of expected differences is mainly because in the year 2000, stenting is no longer associated with bleeding complications and longer hospital stays, whereas the bailout rate with the balloon angioplasty group has increased from 15% to 25%.
Moreover, we did not take into account differences in procedure time. The time for guided angioplasty in the present study was 26 minutes longer (mean) than that of stenting, which further tipped the cost-effectiveness balance in favor of primary stenting.
The Additional Value of Stenting After
Optimal Angioplasty: A Flow-Mediated Phenomenon?
An unexpected observation in this study was a further
reduction in the rate of major adverse cardiac events in patients
stented after optimal balloon angioplasty. This observation was made
possible by the trials double randomization design. On the basis of
stent-like angioplasty results in other
trials,9 13 24
we had hypothesized no such additional benefits. However, the perceived
benefits of additional stenting may have resulted from a selection
process that ignored the outcome of patients with unsatisfactory or
complicated balloon angioplasty (ie, bailout and suboptimal
groups).
Although a similar DS was achieved in all patients stented after angioplasty (7%), a diminished CFR persisted after stenting in the suboptimal group (2.4) compared with the optimal group (3.3). Fewer major cardiac events were observed in the latter group (10.7% versus 6.5%). Further investigations are needed to fully understand the underlying mechanisms.
Clinical Relevance of the Findings of
This Study
The present study failed to demonstrate a favorable
economic profile for provisional angioplasty (guided by quantitative
angiography and Doppler flow velocity measurements) compared with
primary stenting. Indeed, although there was no significant difference
in clinical effectiveness, the data pointed to higher costs with
provisional angioplasty. Thus, the current data do not provide economic
arguments to switch from primary stenting, even though clinical
benefits result when stenting follows optimal balloon angioplasty. A
limitation of our study was the inclusion of patients with only a
single, relatively short lesion. However, it would seem from a
literature survey that the patients studied represented
possibly up to 70% of patients presently treated by
percutaneous techniques
worldwide.25 26
| Acknowledgments |
|---|
| Footnotes |
|---|
A complete list of the DEBATE II study group investigators can be found in the Appendix.
| Appendix 1 |
|---|
|
|
|---|
Received May 31, 2000; revision received September 8, 2000; accepted September 19, 2000.
| References |
|---|
|
|
|---|
This article has been cited by other articles:
![]() |
E. Ilkay, L. Tirikli, I. Ozercan, M. Yavuzkir, I. Karaca, A. Rahman, and N. Arslan Oral Mycophenolate Mofetil Prevents In-Stent Intimal Hyperplasia Without Edge Effect Angiology, October 1, 2006; 57(5): 577 - 584. [Abstract] [PDF] |
||||
![]() |
M. J. Kern, A. Lerman, J.-W. Bech, B. De Bruyne, E. Eeckhout, W. F. Fearon, S. T. Higano, M. J. Lim, M. Meuwissen, J. J. Piek, et al. Physiological Assessment of Coronary Artery Disease in the Cardiac Catheterization Laboratory: A Scientific Statement From the American Heart Association Committee on Diagnostic and Interventional Cardiac Catheterization, Council on Clinical Cardiology Circulation, September 19, 2006; 114(12): 1321 - 1341. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. Moreno, C. Fernandez, and C. Macaya Coronary stenting in small vessels Eur. Heart J., August 1, 2005; 26(15): 1562 - 1562. [Full Text] [PDF] |
||||
![]() |
B A van Hout, P W Serruys, P A Lemos, M J B M van den Brand, G-A v. Es, W K Lindeboom, and M-C Morice One year cost effectiveness of sirolimus eluting stents compared with bare metal stents in the treatment of single native de novo coronary lesions: an analysis from the RAVEL trial Heart, April 1, 2005; 91(4): 507 - 512. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. P. van Alem, M. G.W. Dijkgraaf, J. G.P. Tijssen, and R. W. Koster Health System Costs of Out-of-Hospital Cardiac Arrest in Relation to Time to Shock Circulation, October 5, 2004; 110(14): 1967 - 1973. [Abstract] [Full Text] [PDF] |
||||
![]() |
V. M.G. Legrand, P. W. Serruys, F. Unger, B. A. van Hout, M. C.M. Vrolix, G. M.P. Fransen, T. T. Nielsen, P. K. Paulsen, R. S. Gomes, J. M.G. de Queiroz e Melo, et al. Three-Year Outcome After Coronary Stenting Versus Bypass Surgery for the Treatment of Multivessel Disease Circulation, March 9, 2004; 109(9): 1114 - 1120. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. A. Cox, G. W. Stone, C. L. Grines, T. Stuckey, D. J. Cohen, J. E. Tcheng, E. Garcia, G. Guagliumi, R. S. Iwaoka, M. Fahy, et al. Outcomes of optimal or "stent-like"balloon angioplasty in acutemyocardial infarction: the CADILLAC trial J. Am. Coll. Cardiol., September 17, 2003; 42(6): 971 - 977. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. A. Morrison Counterintuitive contributionsto the care of myocardialinfarction and theneed for randomized trials J. Am. Coll. Cardiol., September 17, 2003; 42(6): 978 - 980. [Full Text] [PDF] |
||||
![]() |
J. M. Brophy, P. Belisle, and L. Joseph Evidence for Use of Coronary Stents: A Hierarchical Bayesian Meta-Analysis Ann Intern Med, May 20, 2003; 138(10): 777 - 786. [Abstract] [Full Text] [PDF] |
||||
![]() |
D V Cokkinos, A Manginas, and V Voudris Coronary flow: clinical considerations Heart, April 1, 2003; 89(4): 361 - 363. [Full Text] [PDF] |
||||
![]() |
E. Barbato, J. Marco, and W. Wijns Direct stenting Eur. Heart J., March 1, 2003; 24(5): 394 - 403. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. C. Ferreira, A. A. Peter, T. A. Salerno, H. Bolooki, and E. de Marchena Clinical impact of drug-eluting stents in changing referral practices for coronary surgical revascularization in a tertiary care center Ann. Thorac. Surg., February 1, 2003; 75(2): 485 - 489. [Abstract] [Full Text] [PDF] |
||||
![]() |
M.-C. Morice, P. W. Serruys, J. E. Sousa, J. Fajadet, E. Ban Hayashi, M. Perin, A. Colombo, G. Schuler, P. Barragan, G. Guagliumi, et al. A Randomized Comparison of a Sirolimus-Eluting Stent with a Standard Stent for Coronary Revascularization N. Engl. J. Med., June 6, 2002; 346(23): 1773 - 1780. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Voskuil, R. A. M. van Liebergen, M. Albertal, E. Boersma, J. G. P. Tijssen, P. W. Serruys, J. J. Piek, and the DEBATE II Investigators Coronary hemodynamics of stent implantation after suboptimal and optimal balloon angioplasty J. Am. Coll. Cardiol., May 1, 2002; 39(9): 1513 - 1517. [Abstract] [Full Text] [PDF] |
||||
![]() |
P. W. Serruys, D. P. Foley, M.-J. Suttorp, B. J. W. M. Rensing, H. Suryapranata, P. Materne, A. van den Bos, E. Benit, A. Anzuini, W. Rutsch, et al. A randomized comparison of the value of additional stenting after optimal balloon angioplasty for long coronary lesions: Final results of the additional value of nir stents for treatment of long coronary lesions (ADVANCE) study J. Am. Coll. Cardiol., February 6, 2002; 39(3): 393 - 399. [Abstract] [Full Text] [PDF] |
||||
![]() |
S.J. Brener and E.J. Topol Epicardial versus microcirculatory dissociation Eur. Heart J., February 2, 2002; 23(4): 274 - 276. [Full Text] [PDF] |
||||
![]() |
M. J. Kern The meaning of suboptimal coronary flow reserve after coronary balloon angioplasty Eur. Heart J., January 2, 2002; 23(2): 99 - 100. [Full Text] [PDF] |
||||
![]() |
R. Seabra-Gomes Is there a future for coronary physiological evaluation in clinical decision making? Eur. Heart J., September 2, 2001; 22(18): 1633 - 1635. [PDF] |
||||
![]() |
J.J Piek, E Boersma, M Voskuil, C di Mario, E Schroeder, C Vrints, P Probst, B de Bruyne, C Hanet, E Fleck, et al. The immediate and long-term effect of optimal balloon angioplasty on the absolute coronary blood flow velocity reserve. A subanalysis of the DEBATE study Eur. Heart J., September 2, 2001; 22(18): 1725 - 1732. [Abstract] [PDF] |
||||
![]() |
J. J. Piek and M. J. Kern Interpretation of Trials on Provisional Stent Implantation Circulation, August 28, 2001; 104 (9): e43 - e43. [Full Text] [PDF] |
||||
![]() |
W. J. Cantor, A. S. Hellkamp, E. D. Peterson, J. P. Zidar, P. A. Cowper, M. H. Sketch Jr, J. E. Tcheng, R. M. Califf, and E. M. Ohman Achieving optimal results with standard balloon angioplasty: can baseline and angiographic variables predict stent-like outcomes? J. Am. Coll. Cardiol., June 1, 2001; 37(7): 1883 - 1890. [Abstract] [Full Text] [PDF] |
||||
![]() |
Routine Stenting or Provisional, Doppler-Guided Stenting? Journal Watch Cardiology, February 16, 2001; 2001(216): 2 - 2. [Full Text] |
||||
| |||||||||||