Renin as a Biomarker of Haemodynamic Normalisation

Renin as a Biomarker of Haemodynamic Normalisation: Associations With Outcomes After Cardiac Surgery

Study design Observational, single centre, prospective cohort study Planned sample size 100 participants

Inclusion criteria The study will evaluate a cohort of participants meeting the following inclusion criteria:

1. admission to the Intensive Care Unit (ICU) after elective and emergency cardiac surgery using cardiopulmonary bypass
2. age 18 years and above
3. arterial, central venous and pulmonary arterial catheters have been inserted as part of routine care Study procedures In addition to routine clinical postoperative data and blood collection, serum renin levels will be analysed on admission, 6 and 24 hours after admission to ICU Study duration 6 months

Study Overview

• Status: Completed
• Conditions: Shock
• Intervention / Treatment: Diagnostic test: blood sampling

Detailed Description

The renin-angiotensin aldosterone system (RAAS) is integral to cardiovascular homeostasis and involved in the regulation of blood pressure, electrolyte balance and intravascular volume. Renin is produced from the renal juxtaglomerular cells and converts angiotensinogen to angiotensin. Angiotensin is subsequently converted to angiotensin II by angiotensin-converting enzyme (ACE). Angiotensin II also promotes the release of aldosterone.The RAAS has an important role in hypotension to retain water through aldosterone and increase systemic vascular resistance mainly through angiotensin II but also through the release of vasopressin.

The RAAS can become dysregulated in critically ill shocked patients. In states such as septic shock the effects of the RAAS are antagonized through the production of vasodilators such a nitric oxide and both angiotensin I and angiotensin II receptors are down regulated. Activation of angiotensin I receptors may furthermore result in the production of pro-inflammatory cytokines that results in further vasodilation and contributes to cardiovascular compromise.

While the RAAS has been extensively investigated in cardiovascular patients there is a paucity of studies relevant to ICU. A recent study suggested that raised serum renin levels in patients with sepsis is associated with acute renal failure. Another study of a small heterogeneous cohort of critically ill patients compared renin to lactate as marker of tissue perfusion.

As RAAS is closely related to the volume state, there is a physiological rationale to investigate serum renin levels together with variables to monitor the intravascular volume, including assessment of the mean systemic filling pressure (Pmsf). An analogue of the Pmsf will be calculated in this study based on routine postoperative haemodynamic monitoring (mean arterial pressure, MAP, central venous pressure, CVP, cardiac output, CO).

Furthermore, there is no current research which looks at serum renin as marker of hemodynamic normalization or association with outcomes after cardiac surgery which is the main purpose of this study.

Serum renin as a candidate sensitive biomarker of hemodynamic homeostasis will be compared to current clinical markers of resuscitation and perfusion including cardiac index, mixed venous oxygen saturation, lactate and venoarterial carbon dioxide gradients.

If the serum renin concentration is found to be a marker of resuscitation and hemodynamic status, the study will examine any associations with lack of hemodynamic normalization and morbidity in cardiothoracic patients. A pragmatic, composite morbidity outcome at 30 days will be used as the primary endpoint. This includes renal impairment, myocardial infarction, persistent cardiogenic shock, arrythmia, respiratory failure, delirium and stroke. An exploratory, secondary outcome will focus on whether serum renin concentrations are associated with acute kidney injury and the need of renal replacement therapy in post cardiac surgical patients.

• Study Type: Observational
• Enrollment (Actual): 104

Contacts and Locations

Study Locations

• Australia
  • New South Wales
    • Sydney, New South Wales, Australia, 2170
      • Dr Wajid Khan

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Admission to ICU after elective and emergency cardiac surgery following cardiopulmonary bypass

Description

Inclusion Criteria:

1. Admission to ICU after elective and emergency cardiac surgery following cardiopulmonary bypass
2. Age 18 years and above
3. Arterial, central venous catheters and pulmonary arterial catheters are inserted preoperatively

Exclusion Criteria:

1. Age under 18 years
2. Known pregnancy
3. Arterial, central venous catheters and pulmonary arterial catheters that are not indicated as part of routine care
4. End stage renal disease requiring renal replacement therapy
5. Participants with known Child Pugh A cirrhosis or greater
6. Treatment with any steroids
7. Participant is not expected to live beyond the day after the day of admission

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort

Intervention / Treatment

Study group; The study will evaluate a cohort of participants meeting the following inclusion criteria: Admission to ICU after elective and emergency cardiac surgery following cardiopulmonary bypass; Age 18 years and above; Arterial, central venous and pulmonary arterial catheters have been inserted as part of routine care Data collection, serum renin among routine blood collection on admission, 6 and 24 hours after admission to ICU

Diagnostic test: blood sampling; sampling serum renin

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Patterns of changes in serum renin concentrations are associated with composite morbidity at 30 days in participants who have undergone cardiac surgery.	30 days

Secondary Outcome Measures

Outcome Measure	Time Frame
Patterns of changes in serum renin concentrations correlate with current markers of resuscitation in participants who have undergone cardiac surgery ( C.I, SvO2, MAP, urine output, serum lactate, based deficit, venoarterial CO2 gradients)	24 hours
Serum renin concentrations correlate with Pmsa in postoperative cardiac surgical patients	24 hours
Patterns of changes in serum renin concentrations are associated with AKI or the need for CRRT in participants who have undergone cardiac surgery	30 days

Collaborators and Investigators

• Sponsor: South West Sydney Local Health District

Publications and helpful links

General Publications

• Nguyen M, Denimal D, Dargent A, Guinot PG, Duvillard L, Quenot JP, Bouhemad B. Plasma Renin Concentration is Associated With Hemodynamic Deficiency and Adverse Renal Outcome in Septic Shock. Shock. 2019 Oct;52(4):e22-e30. doi: 10.1097/SHK.0000000000001285.
• Myles PS. Meaningful outcome measures in cardiac surgery. J Extra Corpor Technol. 2014 Mar;46(1):23-7.
• Hall A, Busse LW, Ostermann M. Angiotensin in Critical Care. Crit Care. 2018 Mar 20;22(1):69. doi: 10.1186/s13054-018-1995-z.
• Khanna AK. Tissue Perfusion and Prognosis in the Critically Ill-Is Renin the New Lactate? Crit Care Med. 2019 Feb;47(2):288-290. doi: 10.1097/CCM.0000000000003582. No abstract available.

Study record dates

Study Major Dates

• Study Start (Actual): March 24, 2020
• Primary Completion (Actual): February 15, 2021
• Study Completion (Actual): March 12, 2021

Study Registration Dates

• First Submitted: March 8, 2020
• First Submitted That Met QC Criteria: March 8, 2020
• First Posted (Actual): March 11, 2020

Study Record Updates

• Last Update Posted (Actual): March 24, 2021
• Last Update Submitted That Met QC Criteria: March 22, 2021
• Last Verified: March 1, 2021

More Information

Terms related to this study

• Keywords: Biomarkers of shock; Biomarkers of adverse outcomes in shocked patients; Biomarkers of adverse outcomes in cardiothoracic patients
• Additional Relevant MeSH Terms: Pathologic Processes; Shock
• Other Study ID Numbers: 2019/PID15341

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Results of the study will be shared

Drug and device information, study documents

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