Venous Congestion and Cardiac Surgery-Associated Acute Kidney Injury

Intraoperative Venous Congestion and Cardiac Surgery-associated Acute Kidney Injury (CSA-AKI): a Prospective Cohort Study

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.

Study Overview

• Status: Recruiting
• Conditions: Venous Congestion; Intraoperative; Cardiac Surgery-associated Acute Kidney Injury
• Intervention / Treatment: Other: collection of demographic characteristics and comorbidities; Other: surgery-related parameters and kidney function assessments; Other: collection of biological (laboratory) parameters; Other: collection of hemodynamic parameters; Other: collection of echocardiographic parameters and venous ultrasound assessments

• Study Type: Observational
• Enrollment (Estimated): 114

Contacts and Locations

• Study Contact: Name: Zhuan Zhang, MD; Phone Number: +8615062791355; Email: zhangzhuancg@163.com

Study Locations

• China
  • Jiangsu
    • Yangzhou, Jiangsu, China, 225012
      • Recruiting
      • No. 368 Hanjiang Middle Road
      • Contact: Zhuan Zhang, MD; Phone Number: +8615062791355 +8615062791355; Email: zhangzhuancg@163.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Probability Sample

Study Population

Patients scheduled to undergo elective cardiac surgery

Description

Inclusion Criteria:

1. Patients scheduled to undergo elective cardiac surgery;
2. ≥ 18 years.

Exclusion Criteria:

1. Contraindications for TEE;
2. Emergency cardiac surgery;
3. Major vascular surgery;
4. Redo cardiac surgery;
5. Abnormal preoperative renal function;
6. Severe chronic kidney disease (estimated glomerular filtration rate < 15 ml/min/1.73 m2 or dialysis);
7. History of kidney transplantation;
8. Severe infection requiring continuous antibiotic therapy；
9. Severe preoperative heart failure with left ventricular ejection fraction < 30%;
10. A critical preoperative state (mechanical circulatory support, extracorporeal membrane oxygenation, current renal replacement therapy [RRT], mechanical ventilation, or cardiac arrest necessitating resuscitation);
11. Multi-organ dysfunction;
12. Known conditions that may interfere with the assessment or interpretation of hepatic vein, portal vein blood flow (such as liver cirrhosis or portal vein thrombosis) or the renal vein blood flow and renal artery blood flow (such as urinary tract obstruction);
13. Planned cardiac transplantation or ventricular assist device implantation;
14. Pregnancy;
15. Insufficient ultrasonographic imaging;
16. Restarting CPB after first CPB cessation during surgery;
17. Requirement for cardiac assist devices (ECMO, IABP, or ventricular assist device) after CPB intraoperatively.

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort

Intervention / Treatment

Participant; Adult patients scheduled to undergo elective cardiac surgery

Other: collection of demographic characteristics and comorbidities; gender, age, BMI, ASA classification, NYHA (New York Heart Association) classification.; smoking history, medical history (hypertension, diabetes mellitus, Hyperlipidemia, stroke, anaemia, chronic obstructive pulmonary disease, pulmonary hypertension, preoperative atrial fibrillation, peripheral artery disease), preoperative ACEI, ARB, beta-blockers, loop diuretics, contrast agent, aspirin, and spironolactone use.; Other: surgery-related parameters and kidney function assessments; surgery type, surgery duration, CPB duration, aortic cross-clamp duration, blood loss, intraoperative fluid infusion, intraoperative urine output, intraoperative blood transfusion, intraoperative anesthetics and vasoactive medications.; baseline and postoperative eGFR, duration of mechanical ventilation, duration of vasopressor support, postoperative CRRT initiation, major bleeding, deep sternal wound infection/mediastinitis, surgical re-intervention, ICU LOS, hospital LOS, postoperative stroke, postoperative delirium, complications up to 30 days after surgery, 30-day inpatient mortality, survival status at discharge, and one year follow-up.; a composite endpoint of major complications after surgery defined as at least one of the following: death, prolonged ventilation (>24 h), stroke, severe AKI, deep sternal wound infection, and reoperation for any reason.; CSA-AKI diagnosed using the KDIGO criteria.; acute kidney disease assessment.; major adverse kidney events.; Other: collection of biological (laboratory) parameters; WBC, CRP, IL-6, IL-1β, TNF-α, serum Amyloid A, procalcitonin, catecholamines, cortisol, SOD.; creatinine, uric acid, BUN, CysC, β2-MG, eGFR.; CK-MB, high-sensitivity troponin, NT pro-BNP, BNP.; hemoglobin, hematocrit, sodium, arterial lactate, liver enzymes.; Other: collection of hemodynamic parameters; blood pressure, heart rate, CVP;; CO, CI, SV, SVI,SVV;; intra-abdominal pressure;; vasoactive drug doses in the first hour in the ICU.; Other: collection of echocardiographic parameters and venous ultrasound assessments; Left ventricle systolic function, including LVOT, LVEF, MPI; left ventricular diastolic function, including mitral flow-derived Doppler indices, pulmonary vein Doppler indices.; Right ventricular systolic function, including TAPSE. Right ventricular diastolic function, inferred from an hepatic vein flow in the absence of a dysrhythmia or pacing.; Inferior vena cava (IVC) measurements.; Hepatic vein Doppler parameters.; Portal vein Doppler parameters.; Renal vein Doppler parameters.; Renal artery blood flow Doppler parameters.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Acute kidney injury defined by an increase in serum creatinine of ≥150% of baseline or an elevation of 0.3 mg/dL or more within a contiguous period of 48 hours. (KDIGO criteria)	7 days after surgery

Collaborators and Investigators

• Sponsor: Zhuan Zhang
• Investigators: Principal Investigator: Zhuan Zhang, MD, The Department of Anesthesiology, The Affiliated Hospital of Yangzhou University, Yangzhou University

Study record dates

Study Major Dates

• Study Start (Actual): October 15, 2024
• Primary Completion (Estimated): September 30, 2026
• Study Completion (Estimated): September 30, 2026

Study Registration Dates

• First Submitted: December 2, 2024
• First Submitted That Met QC Criteria: November 13, 2025
• First Posted (Actual): November 18, 2025

Study Record Updates

• Last Update Posted (Actual): November 18, 2025
• Last Update Submitted That Met QC Criteria: November 13, 2025
• Last Verified: November 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Vascular Diseases; Cardiovascular Diseases; Hyperemia; Health Care Quality, Access, and Evaluation; Quality of Health Care; Public Health; Environment and Public Health; Health Care Facilities Workforce and Services; Non-Medical Public and Private Facilities; Health Facilities; Epidemiologic Factors; Comorbidity; Laboratories
• Other Study ID Numbers: 20240916

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No