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NCT Number: NCT07232277

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.

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Key information

Conditions

Intraoperative Cardiac Surgery-associated Acute Kidney Injury Cardiovascular Diseases Hyperemia Vascular Diseases Venous Congestion

Age range

18 year and older

Sex eligibility

All sexes

Study type

Observational

Primary location

No. 368 Hanjiang Middle Road

Yangzhou, Jiangsu, 225012, China

Location status: Recruiting

Location contact

Zhuan Zhang, MD

CONTACT

[email protected]

+8615062791355 ext. +8615062791355

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

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

Exclusion criteria

  • Contraindications for TEE;
  • Emergency cardiac surgery;
  • Major vascular surgery;
  • Redo cardiac surgery;
  • Abnormal preoperative renal function;
  • Severe chronic kidney disease (estimated glomerular filtration rate < 15 ml/min/1.73 m2 or dialysis);
  • History of kidney transplantation;
  • Severe infection requiring continuous antibiotic therapy；
  • Severe preoperative heart failure with left ventricular ejection fraction < 30%;
  • A critical preoperative state (mechanical circulatory support, extracorporeal membrane oxygenation, current renal replacement therapy [RRT], mechanical ventilation, or cardiac arrest necessitating resuscitation);
  • Multi-organ dysfunction;
  • 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);
  • Planned cardiac transplantation or ventricular assist device implantation;
  • Pregnancy;
  • Insufficient ultrasonographic imaging;
  • Restarting CPB after first CPB cessation during surgery;
  • Requirement for cardiac assist devices (ECMO, IABP, or ventricular assist device) after CPB intraoperatively.

Treatment and study plan

collection of demographic characteristics and comorbidities

Other
  • 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.

surgery-related parameters and kidney function assessments

Other
  • 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.

collection of biological (laboratory) parameters

Other
  • 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.

collection of hemodynamic parameters

Other
  • blood pressure, heart rate, CVP;
  • CO, CI, SV, SVI,SVV;
  • intra-abdominal pressure;
  • vasoactive drug doses in the first hour in the ICU.

collection of echocardiographic parameters and venous ultrasound assessments

Other
  • 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.

Primary outcomes

  1. 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)

    Time frame: 7 days after surgery

Study contacts

Contact information is provided by the study sponsor or research team.

Zhuan Zhang, MD

CONTACT

[email protected]

+8615062791355

Sponsors and collaborators

Lead sponsor

Zhuan Zhang

Other

Registry information

Official study title

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

Important dates

Study start
2024
Primary completion
2026
Study completion
2026
First posted
Nov 18, 2025
Registry last updated
Nov 18, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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