Clinical Research Directory

A Study to Understand How Cardiac Surgery-associated 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 cardiac surgery-associated acute kidney injury (CSA-AKI) in people who undergo heart surgeries. CSA-AKI is a common complication in people undergoing heart surgeries, where the kidneys stop working properly. CSA-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 CSA-AKI. In this study, researchers want to better understand how CSA-AKI develops (also known as the mechanisms involved in the development of CSA-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 CSA-AKI within a week after heart surgery with the participants who do not develop CSA-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 CSA-AKI, identify potential treatment targets and develop possible treatments to prevent CSA-AKI. Participants in this study will be people who have heart surgery already scheduled by their own doctors and have a risk of developing CSA-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 2 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

Venous Congestion and Cardiac Surgery-Associated Acute Kidney Injury

Venous pressure is often overlooked as an important hemodynamic parameter. Elevated venous pressure and blood stasis in organ tissues can lead to interstitial edema. Intraoperative venous blood stasis can rapidly increase interstitial pressures within organ tissues, especially in organs encapsulated by tissue envelopes, such as the kidney, thereby rapidly reducing effective circulating blood flow to the organ. Systemic venous blood stasis, which tends to occur in patients with right heart failure or pulmonary hypertension, as well as in patients with fluid overload, can lead to intraoperative stasis in multiple organs and tissues, mediating the development of multisystem complications, including acute kidney injury. Therefore, timely, effective, and accurate intraoperative assessment of systemic venous blood stasis is particularly important. When right heart failure and/or volume overload occurs in the body, changes in right atrial pressure are transmitted to the venous system of organs throughout the body, with dilatation of the inferior vena cava (IVC), obstruction of blood return from the hepatic, portal, and renal veins, and abnormal venous flow signals and altered ultrasound Doppler flow patterns. The primary objective of this prospective cohort study is to explore if intraoperative systemic venous congestion during cardiac surgery is associated with postoperative CSA-AKI. In doing so, we seek to identify a promising physiological marker that can provide cues for the prediction of CSA-AKI. This study will also investigate the relationship between intraoperative systemic venous congestion and postoperative complications, and explore the relationship between each separate venous congestion and AKI after cardiac surgery.