The Impact of Obesity on Postoperative Outcomes Following Cardiac Surgery (OPOS)
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ClinicalTrials.gov Identifier: NCT03248921 |
Recruitment Status :
Active, not recruiting
First Posted : August 15, 2017
Last Update Posted : July 28, 2021
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Condition or disease | Intervention/treatment |
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Obesity Cardiac Disease Cardiovascular Syndromes, Metabolic | Procedure: cardiac surgery |
Background: Increasing levels of obesity worldwide have led to a rise in the prevalence of obesity-related complications including cardiovascular disease, diabetes, cancers etc. Health care providers believe that obesity has a negative effect on patients undergoing cardiac surgery, with overweight and obese patients being more likely to experience adverse post-operative outcomes. The body mass index (BMI) is the single most used measure for determining obesity classification in clinical practice, without accounting for a patient's level of cardiopulmonary fitness or muscle mass.
Study Design: Patients between the ages of 18 and 75 years undergoing elective cardiac surgery will be consented to participate in this prospective observational trial. Patients are invited to participate in measures of obesity, functional capacity and exercise capacity assessments, quality of life questionnaires, and blood and tissue sampling for biomarker analysis.
Endpoints: Measures other than BMI that could be predictive of short-term and long-term post-operative outcomes. Outcomes of interest include: prolonged length of ventilation, hospital length of stay and all-cause mortality.
Summary: The results of this trial will potentially identify an improved definition of fitness capacity for obese cardiac surgical patients and biomarkers alone or in combination that could identify the potential for adverse outcomes in patients undergoing cardiac surgery. This study will help clinicians better segregate and treat patients pre-operatively based on fitness levels and associated biomarkers.
Study Type : | Observational |
Estimated Enrollment : | 610 participants |
Observational Model: | Cohort |
Time Perspective: | Prospective |
Official Title: | The Impact of Obesity on Postoperative Outcomes Following Cardiac Surgery |
Actual Study Start Date : | November 2014 |
Estimated Primary Completion Date : | November 2025 |
Estimated Study Completion Date : | November 2030 |

Group/Cohort | Intervention/treatment |
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High-Fit obese
Cardiac surgery patients will be segregated into the high-fit group based on 6 minute walk test distance and other measures of functional capacity
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Procedure: cardiac surgery
cardiac surgery including non-emergency, elective coronary artery bypass grafting surgery with or without valve surgery, aortic or mitral valve surgery |
Low-Fit obese
Cardiac surgery patients will be segregated into the low-fit group based on 6 minute walk test distance and other measures of functional capacity
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Procedure: cardiac surgery
cardiac surgery including non-emergency, elective coronary artery bypass grafting surgery with or without valve surgery, aortic or mitral valve surgery |
- Prolonged Hospitalization [ Time Frame: post-operative day (POD) 30 ]A length of stay of more than 5 days
- Prolonged ventilation > 24 hours [ Time Frame: post-operative day (POD) 30 ]mechanical ventilation for more than 24 hours of invasive (via endotracheal tube or tracheostomy) and/or noninvasive (facial/nasal interface) methods of delivery
- all cause mortality [ Time Frame: post-operative day (POD) 30 and 1 year post-op ]Patient death, either in hospital or long-term
- non fatal myocardial infarction [ Time Frame: post-operative day (POD) 30 and 1 year post-op ]Transmural, Subendocardial infarction
- Stroke [ Time Frame: post-operative day (POD) 30 ]Transient, permanent
- Respiratory complications [ Time Frame: post-operative day (POD) 30 ]Pleural effusion, pneumonia
- Prolonged ICU length of stay [ Time Frame: post-operative day (POD) 30 ]length of stay of more than 48 hours
- Re-operation for any cause [ Time Frame: post-operative day (POD) 30 and 1 year post-op ]re-operation due to complications, bleeding and/or other reasons
- Atrial fibrillation [ Time Frame: post-operative day (POD) 30 and 1 year post-op ]post-op occurrence requiring treatment
- Post-operative length of stay and disposition on discharge [ Time Frame: post-operative day (POD) 30 and 1 year post-op ]home, home with care, transfer to other facility, or expired
- Wound infection [ Time Frame: post-operative day (POD) 30 ]infection of sternum or other incisional access sites
Biospecimen Retention: Samples With DNA

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Ages Eligible for Study: | 18 Years to 75 Years (Adult, Older Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | No |
Sampling Method: | Non-Probability Sample |
Inclusion Criteria:
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· Provide informed consent
- Male or female patients who are > 18 years of age
- Patients must be scheduled to undergo elective, first-time cardiac surgery during routine scheduling times
Exclusion Criteria:
- Patients who are > 75 years of age
- BMI is less than 18.5 kg/m2 and classified as underweight according to the World Health Organization
- Any non-elective first time cardiac surgery patient (eg. in-house urgent patients; emergent patients)
- Any cardiac patients to undergo re-operation
- Simultaneous participation in another study with an investigational study agent

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03248921
Canada, New Brunswick | |
Saint John Regional Hospital | |
Saint John, New Brunswick, Canada, E2L 4L2 |
Principal Investigator: | Ansar Hassan, MD, PhD | New Brunswick Heart Centre, Department of Cardiac Surgery |
Publications:
Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
Responsible Party: | Ansar Hassan, MD, PhD, Principal Investigator, Dalhousie University |
ClinicalTrials.gov Identifier: | NCT03248921 |
Other Study ID Numbers: |
RS#: 2014-2006 |
First Posted: | August 15, 2017 Key Record Dates |
Last Update Posted: | July 28, 2021 |
Last Verified: | July 2021 |
Individual Participant Data (IPD) Sharing Statement: | |
Plan to Share IPD: | Undecided |
Heart Diseases Obesity Metabolic Syndrome Overweight Overnutrition Nutrition Disorders |
Body Weight Cardiovascular Diseases Insulin Resistance Hyperinsulinism Glucose Metabolism Disorders Metabolic Diseases |