Condition category
Circulatory System
Date applied
Date assigned
Last edited
Retrospectively registered
Overall trial status
Recruitment status
No longer recruiting

Plain English Summary

Not provided at time of registration

Trial website

Contact information



Primary contact

Prof Cor J Kalkman


Contact details

University Medical Centre Utrecht
Dept of Anesthesiology
Heidelbergln 100
3584 CX

Additional identifiers

EudraCT number number

Protocol/serial number


Study information

Scientific title


Octopus Study

Study hypothesis

The aim of the present study is to compare the effect of coronary bypass surgery with and without cardiopulmonary bypass on cognitive outcome, five years after surgery.

Ethics approval

Not provided at time of registration

Study design

Randomised controlled trial

Primary study design


Secondary study design

Randomised controlled trial

Trial setting

Not specified

Trial type


Patient information sheet


Coronary artery disease


Random allocation to on-pump or off-pump coronary artery bypass grafting

Intervention type



Not Specified

Drug names

Primary outcome measures

The primary endpoint of the present study is cognitive outcome at five years after surgery. Patients will undergo a battery of ten neuropsychologic tests five years after operation. The tests will be administered by a trained psychologist blinded for treatment allocation. Each individual’s performance on the neuropsychologic tests will be compared to his or her performance on the same tests five years earlier, on the day before operation. In accordance to the Statement of Consensus on Assessment of Neurobehavioral Outcomes after Cardiac Surgery the test battery includes tests for motor skills, verbal memory capacity and attention. The principal outcome measure is cognitive decline, defined as a decrease in an individual’s performance of at least 20 percent from baseline, in at least 20 percent of the tests.

Secondary outcome measures

1. Quality of life at five years, assessed with the EuroQol10 and ShortForm-3611 questionnaires
2. The occurence of cardiovascular events i.e. mortality, stroke, myocardial infarction and coronary reintervention. Stroke is defined as focal brain injury, detected by standard neurologic examination, persisting for more than 24 hours, combined with an increase in handicap of at least one grade on the Rankin Scale; Myocardial infarction is considered present when two of the following criteria are met: chest discomfort lasting at least 30 minutes, CK-MB/CK ratio >0.1, and the development of abnormal new Q-waves in the electrocardiogram.
3. Anginal status at five years, defined according to the Canadian Cardiovascular Society and Braunwald classification
4. Use of antianginal medication at five years (Beta-blockers, nitrates or calcium entry-blockers)

Overall trial start date


Overall trial end date


Reason abandoned


Participant inclusion criteria

281 candidates for coronary artery bypass surgery. Patients were eligible if referred for first-time isolated coronary bypass surgery and an off-pump procedure was deemed technically feasible.

Participant type


Age group




Target number of participants


Participant exclusion criteria

1. Patients were excluded in case of emergency or concomitant major surgery, Q-wave myocardial infarction in the last 6 weeks, or poor left ventricular function.
2. Patients who were unlikely to complete 1-year follow-up, unable to give informed consent, or undergo neuropsychologic testing were excluded.
3. There were no restrictions to age.

Recruitment start date


Recruitment end date



Countries of recruitment


Trial participating centre

University Medical Centre Utrecht
3584 CX

Sponsor information


International Anesthesia Research Society (USA)

Sponsor details

2 Summit Park Drive
Suite 140
Ohio 44131
United States of America

Sponsor type

Research organisation



Funder type

Research organisation

Funder name

International Anesthesia Research Society

Alternative name(s)

Funding Body Type

Funding Body Subtype


Funder name

Clinical scholar research award 2004

Alternative name(s)

Funding Body Type

Funding Body Subtype


Results and Publications

Publication and dissemination plan

Not provided at time of registration

Intention to publish date

Participant level data

Not provided at time of registration

Results - basic reporting

Publication summary

1. 2007 results:
2. 2004 results:
3. 2003 results:
4. 2002 results:
5. 2001 results:
6. Rationale and design of the trial:

Publication citations

  1. Results

    Nathoe HM, van Dijk D, Jansen EW, Suyker WJ, Diephuis JC, van Boven WJ, de la Rivière AB, Borst C, Kalkman CJ, Grobbee DE, Buskens E, de Jaegere PP, , A comparison of on-pump and off-pump coronary bypass surgery in low-risk patients., N. Engl. J. Med., 2003, 348, 5, 394-402, doi: 10.1056/NEJMoa021775.

  2. Rationale and design of the trial

    van Dijk D, Nierich AP, Eefting FD, Buskens E, Nathoe HM, Jansen EW, Borst C, Knape JT, Bredée JJ, Robles de Medina EO, Grobbee DE, Diephuis JC, de Jaegere PP, The Octopus Study: rationale and design of two randomized trials on medical effectiveness, safety, and cost-effectiveness of bypass surgery on the beating heart., Control Clin Trials, 2000, 21, 6, 595-609.

  3. van Dijk D, Spoor M, Hijman R, Nathoe HM, Borst C, Jansen EW, Grobbee DE, de Jaegere PP, Kalkman CJ, , Cognitive and cardiac outcomes 5 years after off-pump vs on-pump coronary artery bypass graft surgery., JAMA, 2007, 297, 7, 701-708, doi: 10.1001/jama.297.7.701.

  4. van Dijk D, Moons KG, Keizer AM, Jansen EW, Hijman R, Diephuis JC, Borst C, de Jaegere PP, Grobbee DE, Kalkman CJ, , Association between early and three month cognitive outcome after off-pump and on-pump coronary bypass surgery., Heart, 2004, 90, 4, 431-434.

  5. Van Dijk D, Jansen EW, Hijman R, Nierich AP, Diephuis JC, Moons KG, Lahpor JR, Borst C, Keizer AM, Nathoe HM, Grobbee DE, De Jaegere PP, Kalkman CJ, , Cognitive outcome after off-pump and on-pump coronary artery bypass graft surgery: a randomized trial., JAMA, 2002, 287, 11, 1405-1412.

  6. van Dijk D, Nierich AP, Jansen EW, Nathoe HM, Suyker WJ, Diephuis JC, van Boven WJ, Borst C, Buskens E, Grobbee DE, Robles De Medina EO, de Jaegere PP, , Early outcome after off-pump versus on-pump coronary bypass surgery: results from a randomized study., Circulation, 2001, 104, 15, 1761-1766.

Additional files

Editorial Notes