Effect of off-pump coronary artery bypass surgery on clinical, angiographic, neurocognitive, and quality of life outcomes: randomised controlled trial
BMJ 2006; 332 doi: https://doi.org/10.1136/bmj.38852.479907.7C (Published 08 June 2006) Cite this as: BMJ 2006;332:1365
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We would acknowledge Dr Sedrakyan's response to our meta-analysis.
He stated that there is at least one other relatively large and
recent study not
mentioned. We excluded the randomised controlled trials (RCTs) published
in
2005 by Kobayashi et al,(1) because early graft patency was examined
"within
3 weeks" after the operation in their trial. We performed a meta-analysis
of
currently available RCTs, which compared "more than 3-months" patency
rates of off-pump and cardiopulmonary-bypass (CPB) surgery.
Re-analysis using "risk difference (RD)" did not substantively alter
the results
of our previously analysis using "risk ratio". Pooled analysis of the six
RCTs,
which were identified by our comprehensive search, demonstrated
statistically significant increase in overall-graft (including both
internal-
thoracic-artery [ITA] and saphenous-vein [SV] grafts, but excluding radial
-
artery grafts) occlusion with off-pump relative to CPB surgery (RD, 3.2%;
95%
confidence interval [CI], 0.9%-5.6%; P = 0.0072). There was neither trial
heterogeneity of results (P = 0.9287) nor publication bias (P = 0.3476).
Pooled analysis of the 4 trials demonstrated statistically nonsignificant
benefit of CPB over off-pump surgery for patency rates of ITA grafts (RD,
1.5%; 95% CI, -0.9% to 3.8%; P = 0.2199). Pooled analysis of the 5 trials
demonstrated statistically significant increase in SV-graft occlusion with
off-
pump relative to CPB surgery (RD, 4.0%; 95% CI, 0.2% to 7.8%; P = 0.0398).
The most recent meta-analysis of 37 RCTs by Cheng et al(2)
demonstrates
that mortality, stroke, myocardial infarction, and renal failure were not
reduced in off-pump CABG despite decreased arterial fibrillation,
transfusion,
inotrope requirements, respiratory infection, ventilation time, intensive
care
unit stay, and hospital stay. Nevertheless, we again advocate the
following.
At the expense of graft patency, dare we perform off-pump rather than on-
pump CABG to merely improve these selected clinical and resource outcomes?
Competing interests:
None declared
Competing interests: No competing interests
Dear sir,
I enjoyed reading this article very much. It is impressive to know that
patients included in their study did better after having off pump heart
surgery in comparison to those who had conventional heart sugery.People
have known this fact for last many yearsthat patients who have off pump
heart surgery have less hospital stay, less complications etc. but I feel
that it is very difficult to comment with confidence that patients who
underwent off pump cardiac surgerey had better neurocognitive functions
post surgery as compared to their counterpart who had conventional
surgery.
Neurocognitive functions are dependent on varrious factors for e.g. age,
genetic make up, social and enviormental conditions etc. There is no
evidence to suggest that cardiac surgery leads to alteration in a patients
neurocognitive function and therefore I personnaly feel that the authors
need to explore this aspect of there study in depth before reaching to
this final conclusion otherwise it may lead to this myth that cardiac
surgery is one of the causes of altered neurocgnitive behaviour.I would be
greatful if the editorial could correct me if I am wrong. I would be keen
to accept suggestions and guidance.
Kind Regards
yours sincerely
girish chawla
Competing interests:
None declared
Competing interests: No competing interests
Authors should be congratulated for conducting another relatively
large study in this setting.
In response to Dr. Hisato Takagi and colleagues:
We should not rush to perform quick and likely incompete meta-analyses on
this endpoint yet. There is at least one other relatively large and recent
study not mentioned.
Also important issue is how you communicate the risk. You have
mentioned the risk of occlusion being 29% higher for off-pump as compared
to on-pump. However, you did not report the risk difference or NNT(or
number of grafts occluded per 100 performed).
One can also present the results as 97% patentcy(on-pump) vs 96% patentcy
(off-pump). This will represent more than 29% higher risk of occlusion (3%
vs 4%, RR 1.33) with your line of analyses. The difference is unlikely to
be substantial or clinically meaningful in this scenario even if
statistically significant.
Finally, one should weigh and quantify not only the risks but also
the benefits (i.e. possible stroke, afib, wound infection reduction). A
comprehensive systematic review on this topic soon to come.
Disclosure Statement
Dr. Sedrakyan is employed by the Agency for Healthcare Research and
Quality (AHRQ). No statement in this comment should be construed as an
official position of the Agency for Healthcare Research and Quality (AHRQ)
or the U.S. Department of Health and Human Services
Competing interests:
None declared
Competing interests: No competing interests
Al-Ruzzeh et al(1) showed in their randomised controlled trial (RCT)
that
patients in the off-pump group had similar graft-patency rates to patients
in
the cardiopulmonary-bypass (CPB) group. Because a discrepancy has been
found in reported patency rates after off-pump surgery, we performed a
meta-analysis of currently available RCTs, including the trial by Al-
Ruzzeh et
al,(1) which compared more than 3-months patency rates of off-pump and
CPB surgery.
Our comprehensive search identified six RCTs(1-6) of off-pump vs CPB
surgery. In total, our meta-analysis included data on 1098 patients. All
of
the six individual trials demonstrated a statistically nonsignificant
benefit of
CPB over off-pump surgery for patency rates of overall grafts (including
both
internal-thoracic-artery [ITA] and saphenous-vein [SV] grafts, but
excluding
radial-artery grafts). Pooled analysis of the six trials demonstrated
statistically significant 29% increase in overall-graft occlusion with off
-pump
relative to CPB surgery (risk ratio [RR], 1.29; 95% confidence interval
[CI],
1.05-1.58; P = 0.0173). There was neither trial heterogeneity of results
(P =
0.7439) nor publication bias (P = 0.5730). Pooled analysis of the 4
trials(1-4)
demonstrated statistically nonsignificant benefit of CPB over off-pump
surgery for patency rates of ITA grafts (RR, 1.33; 95% CI, 0.68 to 2.58;
P =
0.4072). Pooled analysis of the 5 trials(1-5) demonstrated statistically
significant 28% increase in SV-graft occlusion with off-pump relative to
CPB
surgery (RR, 1.28; 95% CI, 1.06 to 1.55; P = 0.0094).
Despite the results of the RCT by Al-Ruzzeh et al,(1) the present
meta-
analysis of the currently available RCTs obviously demonstrated
significant
increase in overall-graft (ITA and SV grafts) occlusion, especially SV
grafts,
with off-pump relative to CPB surgery. At the expense of graft patency,
dare
we perform off-pump rather than CPB surgery?
1 Al-Ruzzeh S, George S, Bustami M, Wray J, Ilsley C, Athanasiou T,
et al.
Effect of off-pump coronary artery bypass surgery on clinical,
angiographic,
neurocognitive, and quality of life outcomes: randomised controlled trial.
BMJ
2006; 0: bmj.38852.479907.7Cv1.
2 Lingaas PS, Hol PK, Lundblad R, Rein KA, Mathisen L, Smith H-J, et
al.
Clinical and radiologic outcome of off-pump coronary surgery at 12 months
follow-up: a prospective randomized trial. Ann Thorac Surg 2006;81:2089�|
96.
3 Widimsky P, Straka Z, Stros P, Jirasek K, Dvorak J, Votava J, et
al. One-year
coronary bypass graft patency: a randomized comparison between off-pump
and on-pump surgery angiographic results of the PRAGUE-4 trial.
Circulation
2004;110:3418�|23.
4 Puskas JD, Williams WH, Mahoney EM, Huber PR, Block PC, Duke PG,
et al.
Off-pump vs conventional coronary artery bypass grafting: early and 1-year
graft patency, cost, and quality-of-life outcomes: a randomized trial.
JAMA
2004;291:1841�|9.
5 Khan NE, De Souza A, Mister R, Flather M, Clague J, Davies S, et
al. A
randomized comparison of off-pump and on-pump multivessel coronary-
artery bypass surgery. N Engl J Med 2004;350:21�|8.
6 Nathoe HM, van Dijk D, Jansen EW, Suyker WJ, Diephuis JC, van
Boven WJ, et
al. A comparison of on-pump and off-pump coronary bypass surgery in low-
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Competing interests:
None declared
Competing interests: No competing interests
Standard bypass: no longer a standard term
The paper by Al-Ruzzeh et al has the opportunity to add to the
already large amount of data published on the off pump versus on-pump as
it contributes a well constructed randomised controlled trial, albeit in
only 168 patients.
However the paper is let down by the lack of rigour imposed on the
method section of the paper. It is not possible to reproduce, nor fully
interpret this work as too many details are missing. The premise of
publication of science is to be able to reproduce the findings. There is
no such entity as “Standard bypass management included………”, in 2006. The
authors have not told us the type of membrane oxygenator, the type of
arterial line filter and pore size, whether a prebypass filter was in fact
used, how cooling to 32C was achieved, and more importantly how rewarming
was achieved, the type of tubing used in the circuit (coated biopassive
circuit or uncoated), and the type of pH management utilised on bypass.
Each of these factors may contibute to the genesis of clinical outcomes
following surgery utilising cardiopulmonaty bypass, and specifically to
the generation of neurocognitive outcomes.
The authors have recognisede the importance of some of these factors
in their discussion, citing the importance of rewarming rates (1) and pH
managment (2), however they have failed to provide the reader with detail
on their approach.
That the authors were able to show similar angiographic findings and
improved clinical outcomes, shorter hospital stay and improved
neurocogntive outcome in the off pump is significant, it is unfortunate
that detail of the cardiopulmonary bypass utilised is lacking.
1. Grigore A, Grocott H, Mathew J, Phillips-Bute B, Stanley T,
Butler A, et al. The rewarming rate and increased peak temperature alter
neurocognitive outcome after cardiac surgery. Anesth Analg 2002;94:4-10.
2. Murkin J, Martzke J, Buchan A, Bentley C, Wong C. A randomised
study of the influence of perfusion technique and pH management strategy
in 316 patients undergoing
coronary artery bypass surgery: neurologic and cognitive outcomes. J
Thorac Cardiovasc Surg 1995;110:349-62.
Competing interests:
None declared
Competing interests: No competing interests