Optimizing Pulsatility During Cardiopulmonary Bypass

Study Overview
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Brief Summary
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Cardiopulmonary bypass during cardiac surgery provides blood flow to the body during surgery but has adverse effects on different organs. Blood flow during cardiopulmonary bypass may be pulsatile or non-pulsatile, which may impact normal organ function after surgery. The study will collect data on the type of cardiopulmonary bypass used during surgery and organ function to determine if there is an association between the type of bypass and organ function.

Detailed Description
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Cardiac surgery is a high-risk elective surgical procedure frequently requiring CPB in which a machine pumps blood while the surgeon operates on the heart. CPB contributes to surgical risk by causing endothelial dysfunction and acute kidney injury (AKI). Endothelial dysfunction and AKI happen because heart lung machines typically generate non-pulsatile blood flow, which is abnormal and results in impaired tissue oxygen delivery. Normal blood flow is pulsatile due intermittent contraction and relaxation of the heart during the cardiac cycle, which produces a mechanical signal that induces endothelial cells to produce nitric oxide. Without nitric oxide, blood flow does not penetrate as deeply into organs such as the kidneys which leads to acute kidney injury. AKI increases mortality 10-fold after cardiac surgery placing many people at risk since over 400,000 people have surgery with CPB each year in the United States. Thus, pulsatile CPB may influence endothelial function and renal blood flow after cardiac surgery. This study will observe patients undergoing cardiac surgery with CPB and compare patients who receive pulsatile or non-pulsatile CPB.

Official Title
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Optimizing Pulsatility During Cardiopulmonary Bypass to Reduce Acute Kidney Injury: Prospective Observational Study

Conditions
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Endothelial Dysfunction, Acute Kidney Injury

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age 50 to 70 Able to provide informed consent Scheduled for elective cardiac surgery with cardiopulmonary bypass Exclusion Criteria: Patients undergoing emergency procedures Diagnosed with sepsis Experiencing delirium Experiencing hemodynamic instability (heart rate > 100 and systolic blood pressure < 90) Patients with a mechanical circulatory support device Requiring vasoactive medications before surgery Patients with a reduced left ventricular ejection fraction (less than 50%) Patients with a contraindication to transesophageal echocardiography

Ages Eligible for Study
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Minimum Age: 50 Years
Maximum Age: 70 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 |
| --- | --- |
| Non-pulsatile cardiopulmonary bypass<br>Subjects who undergo cardiac surgery with non-pulsatile cardiopulmonary bypass | |
| Pulsatile cardiopulmonary bypass<br>Subjects who undergo cardiac surgery with pulsatile cardiopulmonary bypass | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Endothelial function | Percent change in flow mediated dilation of the brachial artery after cardiac surgery | From intensive care unit admission after surgery to hospital discharge, up to 30 days | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Acute kidney injury | Acute kidney injury by the KDIGO criteria | From intensive care unit admission after surgery to intensive care unit discharge, up to 7 days | 
| Renal blood flow velocity | Renal blood flow velocity measured by pulse wave doppler | Intra-operative time point: after cardiopulmonary bypass, up to 12 hours | 
| Acute kidney injury risk | Acute kidney injury risk measured by urinary TIMP2*IGFBP7 | Measured 4 hours after the end of cardiopulmonary bypass, up to 12 hours | 
| Perioperative death | Death after surgery during the surgical hospital encounter | From intensive care unit admission after surgery to hospital discharge, up to 30 days | 
| Myocardial infarction | Myocardial infarction after surgery | From intensive care unit admission after surgery to hospital discharge, up to 30 days | 
| Stroke | Stroke after surgery | From intensive care unit admission after surgery to hospital discharge, up to 30 days | 
| New renal failure requiring renal replacement therapy | New renal failure requiring renal replacement therapy after surgery | From intensive care unit admission after surgery to hospital discharge, up to 30 days | 
| Re-exploration for bleeding | Need for surgical re-exploration to control hemorrhage | From intensive care unit admission after surgery to hospital discharge, up to 30 days | 
| Post-operative sepsis | Post-operative sepsis determined by positive blood culture | From intensive care unit admission after surgery to hospital discharge, up to 30 days | 
| New onset atrial fibrillation | Post-operative new onset atrial fibrillation | From intensive care unit admission after surgery to hospital discharge, up to 30 days | 
| Post-operative blood loss | Post-operative blood loss determined by total surgical drain output | From intensive care unit admission to 24 hours after intensive care unit admission, up to 24 hours | 
| Duration of mechanical ventilation | Duration of mechanical ventilation after surgery | From intensive care unit admission after surgery to hospital discharge, up to 30 days | 
| Post-operative delirium | Post-operative delirium determined by the Confusion Assessment Method for the Intensive Care Unit score | From intensive care unit admission after surgery to hospital discharge, up to 30 days | 
| Post-operative hospital length of stay | Duration of hospital stay after surgery | From intensive care unit admission after surgery to hospital discharge, up to 30 days | 
| New requirement for mechanical circulatory support | Post-operative initiation of mechanical circulatory support | From intensive care unit admission after surgery to hospital discharge, up to 30 days | 
| Intra-operative red blood cell transfusion | Intra-operative red blood cell transfusion in units | During the intra-operative time period, up to 12 hours | 
| Post-operative red blood cell transfusion | Post-operative red blood cell transfusion in units | From intensive care unit admission after surgery to hospital discharge, up to 30 days | 
| Post-operative platelet transfusion | Post-operative platelet transfusion in units | From intensive care unit admission after surgery to hospital discharge, up to 30 days | 
| Post-operative plasma transfusion | Post-operative plasma transfusion in units | From intensive care unit admission after surgery to hospital discharge, up to 30 days | 
| Post-operative cryoprecipitate transfusion | Post-operative cryoprecipitate transfusion in units | From intensive care unit admission after surgery to hospital discharge, up to 30 days | 
| Intra-operative platelet transfusion | Intra-operative platelet transfusion in units | During the intra-operative time period, up to 12 hours | 
| Intra-operative plasma transfusion | Intra-operative plasma transfusion in units | During the intra-operative time period, up to 12 hours | 
| Intra-operative cryoprecipitate transfusion | Intra-operative cryoprecipitate transfusion in units | During the intra-operative time period, up to 12 hours | 
| Glycocalyx thickness | Glycocalyx thickness determined by sublingual microcirculation microscopy | Start of the intra-operative period to 24 hours after intensive care unit admission | 
| Microvascular circulatory function | Microvascular circulatory function determined by sublingual microcirculation microscopy | Start of the intra-operative period to 24 hours after intensive care unit admission | 
| New onset of acute lung injury | Diagnosis of acute lung injury by PaO2 to FiO2 ratio | From intensive care unit admission after surgery to hospital discharge, up to 30 days | 
| New onset of left ventricular diastolic dysfunction | Diagnosis new onset diastolic dysfunction by annular e' velocity: septal e' < 7 cm/sec, lateral e' <10 cm/sec, average E/e' ratio > 14, LA volume index > 34 mL/m2, and peak TR velocity > 2.8 m/sec. | From intensive care unit admission after surgery to hospital discharge, up to 30 days | 
| New onset of left ventricular systolic dysfunction | New onset of left ventricular systolic dysfunction determined by a LV ejection fraction <50% | From intensive care unit admission after surgery to hospital discharge, up to 30 days | 
| New onset of right ventricular systolic dysfunction | New onset of right ventricular systolic dysfunction determined by a tricuspid annular plane systolic excursion less than 16 mm | From intensive care unit admission after surgery to hospital discharge, up to 30 days | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Endothelial function, Acute Kidney Injury, Cardiopulmonary bypass, Cardiac surgery