The Impact of Obesity on Postoperative Outcomes Following Cardiac Surgery

Study Overview
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Brief Summary
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The purpose of this study is to identify measures of obesity, functional capacity, and specific biomarkers that may be predictive of obesity and post-operative outcomes.

Detailed Description
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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.

Official Title
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The Impact of Obesity on Postoperative Outcomes Following Cardiac Surgery

Conditions
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Obesity, Cardiac Disease, Cardiovascular Syndromes, Metabolic

Intervention / Treatment
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* Procedure: cardiac surgery


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: · 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

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 75 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| High-Fit obese<br>Cardiac surgery patients will be segregated into the high-fit group based on 6 minute walk test distance and other measures of functional capacity | Procedure: cardiac surgery<br>* cardiac surgery including non-emergency, elective coronary artery bypass grafting surgery with or without valve surgery, aortic or mitral valve surgery<br>|
| Low-Fit obese<br>Cardiac surgery patients will be segregated into the low-fit group based on 6 minute walk test distance and other measures of functional capacity | Procedure: cardiac surgery<br>* cardiac surgery including non-emergency, elective coronary artery bypass grafting surgery with or without valve surgery, aortic or mitral valve surgery<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Prolonged Hospitalization | A length of stay of more than 5 days | post-operative day (POD) 30 | 
| Prolonged ventilation > 24 hours | mechanical ventilation for more than 24 hours of invasive (via endotracheal tube or tracheostomy) and/or noninvasive (facial/nasal interface) methods of delivery | post-operative day (POD) 30 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| all cause mortality | Patient death, either in hospital or long-term | post-operative day (POD) 30 and 1 year post-op | 
| non fatal myocardial infarction | Transmural, Subendocardial infarction | post-operative day (POD) 30 and 1 year post-op | 
| Stroke | Transient, permanent | post-operative day (POD) 30 | 
| Respiratory complications | Pleural effusion, pneumonia | post-operative day (POD) 30 | 
| Prolonged ICU length of stay | length of stay of more than 48 hours | post-operative day (POD) 30 | 
| Re-operation for any cause | re-operation due to complications, bleeding and/or other reasons | post-operative day (POD) 30 and 1 year post-op | 
| Atrial fibrillation | post-op occurrence requiring treatment | post-operative day (POD) 30 and 1 year post-op | 
| Post-operative length of stay and disposition on discharge | home, home with care, transfer to other facility, or expired | post-operative day (POD) 30 and 1 year post-op | 
| Wound infection | infection of sternum or other incisional access sites | post-operative day (POD) 30 |