A Study to Understand How Post-operative Acute Kidney Injury Develops in Participants Who Undergo Heart Surgery With the Use of Heart-lung Machine

Researchers are looking for a better way to treat and prevent post-operative acute kidney injury (PO-AKI) in people who undergo heart surgeries.

PO-AKI is a common complication in people undergoing heart surgeries, where the kidneys stop working properly. PO-AKI risk factors include older age and alongside diseases such as kidney disease and diabetes. Longer time with heart-lung machine during heart surgeries also increases the occurrence of PO-AKI.

In this study, researchers want to better understand how PO-AKI develops (also known as the mechanisms involved in the development of PO-AKI) in people under heart surgeries, the presence of certain biomarkers in the body, especially with a focus on the early hours and days after the surgery. (A biomarker is a biological molecule found in blood, other body fluids, or tissues that is a sign of a normal or abnormal process, or of a condition or disease.) These biomarkers will be compared in participants who develop PO-AKI within a week after heart surgery with the participants who do not develop PO-AKI. The relationship with biomarkers will be determined by examining participants' blood and urine samples before and after surgery.

This may help researchers better understand PO-AKI, identify potential treatment targets and develop possible treatments to prevent PO-AKI.

Participants in this study will be people who have heart surgery already scheduled by their own doctors and have a risk of developing PO-AKI. Participants will not receive any treatment as part of this study. They will undergo the heart surgery and related medical processes as per their normal medical treatment and management.

Each participant will be in the study for up to 3 and a half months. During the study, the doctors and their study team will:

* collect participants' blood and urine samples before and after surgery
* assess participants' medical records and test reports during hospitalization
* monitor overall health of the participants throughout the study


Eligibility Criteria:
Inclusion Criteria:

* Participant must be at least 18 years of age at the time of signing the informed consent form (ICF).
* Participants who are scheduled for hospital admission for any of the following cardiovascular surgery interventions, alone or in combination, involving cardiopulmonary bypass (CPB):

  * Aortic, mitral, or tricuspid valve surgery (repair or replacement)
  * Aortic surgery
  * ≥3 coronary artery bypass grafts
* Participant with: chronic kidney disease (CKD): 30 ≤ estimated glomerular filtration rate (eGFR) ≤ 75 mL/min/1.73 m\^2

Exclusion Criteria:

* Emergency surgery situation
* Anemia - hemoglobin \<10 g/dL
* Clinical signs of systemic infection or other infection requiring anti-infective treatment (viral, bacterial, fungal, parasitic; single-dose prophylaxis allowed)
* Systemic immunosuppressive or anti-inflammatory treatment including corticosteroids \>10 mg prednisolone equivalent/day
* Any anti-cancer treatment within 3 months (e.g. immunotherapy, chemotherapy, radiotherapy)
* Major surgery within 2 months
* AKI within the last 3 months
* Prior renal transplants or RRT
* Planned use of contrast media prior/during surgery
* Patient included in an interventional clinical trial involving a pharmacological intervention
* Any reason that would make participation unadvisable, at the discretion of the investigator.