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Inotropic Effects of Vasopressin Versus Noradrenaline In Patients With Vasoplegic Syndrome After Cardiac Surgery

ConditionVasoplegic Syndrome of Cardiac Surgery
Trial statusRecruiting
Trial phasePhase 4
Trial typeInterventional
Biological sexAll
Age18+
SponsorUniversity of Sao Paulo

About this trial

This is a randomized, double-blind clinical trial designed to compare the inotropic effects of vasopressin versus norepinephrine in patients who develop vasoplegic syndrome in the immediate postoperative period following cardiac surgery.

Vasoplegic syndrome is characterized by severe hypotension due to systemic vasodilation, despite adequate fluid resuscitation and preserved or elevated cardiac output. Vasopressors are essential in restoring hemodynamic stability in this context; however, their impact on myocardial performance remains uncertain. While norepinephrine is the standard first-line agent, vasopressin has shown potential benefits, including reduced catecholamine exposure and fewer adverse cardiovascular effects.

This study aims to assess changes in cardiac output and other echocardiographic and hemodynamic parameters after administration of either vasopressin or norepinephrine. The findings are expected to contribute to optimizing vasopressor selection in vasoplegic patients after cardiac surgery and improving clinical outcomes.

Eligibility criteria

This trial accepts healthy volunteers

Qualifiers

Age over 18.

Patients undergoing coronary artery bypass grafting, valve surgery or both, with a diagnosis of vasoplegic syndrome in the immediate postoperative period (<24 hours), defined as mean arterial pressure < 65 mmHg (measured using an invasive blood pressure catheter) and resistance to fluid replacement - at least 1000ml of crystalloids.

Disqualifiers

Pregnancy or breastfeeding.

Aortic surgery.

Surgeries to correct congenital heart disease.

Heart transplants.

Trial design

Design model

Parallel

Treatments tested in this trial

  • Vasopressin intravenous infusion

    Drug

    Vasopressin will be administered intravenously in a blinded 250 mL bag of 5% glucose solution, at a final concentration of 0.12 U/mL. The infusion will begin at 5 mL/h and be increased by 2.5 mL/h every 10 minutes during the first hour, up to a maximum rate of 30 mL/h (equivalent to doses from 0.01 to 0.06 U/min). The target is to reach and maintain mean arterial pressure (MAP) ≥65 mmHg. If this is not achieved, open-label norepinephrine may be added. Hemodynamic and echocardiographic parameters will be measured before and after the target MAP is reached.

  • Norepinephrine intravenous infusion

    Drug

    Norepinephrine will be administered intravenously in a blinded 250 mL bag of 5% glucose solution, at a final concentration of 120 µg/mL. The infusion will begin at 5 mL/h and be increased by 2.5 mL/h every 10 minutes during the first hour, up to a maximum rate of 30 mL/h (equivalent to doses from 10 to 60 µg/min). The goal is to reach and maintain MAP ≥65 mmHg. If the MAP target is not reached, open-label norepinephrine may be initiated. Clinical and hemodynamic parameters will be collected at baseline and after MAP stabilization.

Treatment groups

350 Participants
are divided into 2 treatment groups
Group A: VasopressinExperimental treatment 1 intervention
Group B: NoradrenalineActive comparator 1 intervention

Trial outcomes

Primary outcomes

1

Change in inotropic function assessed by cardiac output between T0 and T1

The primary outcome is the variation in cardiac output (CO), measured by transthoracic echocardiography, from the beginning of the vasopressor infusion (T0) until the achievement of target mean arterial pressure ≥65 mmHg (T1), in patients with vasoplegic syndrome after cardiac surgery. This measurement reflects the inotropic effect of vasopressin versus norepinephrine

Time frame
Up to 1 hour after initiation of vasopressor therapy

Secondary outcomes

1

Change in left ventricular ejection fraction (LVEF) between T0 and T1

LVEF will be measured using transthoracic echocardiography at T0 (baseline) and T1 (after achieving MAP ≥65 mmHg), to assess changes in left ventricular systolic function.

Time frame
Up to 1 hour after vasopressor initiation
2

Time to achieve target mean arterial pressure (MAP ≥65 mmHg)

Time (in minutes) between the start of vasopressor infusion (T0) and the point at which MAP ≥65 mmHg is reached (T1), indicating hemodynamic stabilization.

Time frame
Up to 1 hour
3

Change in heart rate (HR) between T0 and T1

Heart rate will be measured at baseline (T0) and after stabilization (T1) to assess the chronotropic effect of each drug.

Time frame
Up to 1 hour
4

Change in arterial lactate levels between T0 and T1

Arterial lactate will be used as a marker of tissue perfusion, measured at T0 and T1, to evaluate response to vasopressor therapy.

Time frame
Up to 1 hour

Other outcomes

Sponsors and contacts

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University of Sao Paulo

Lead sponsor

Hospital Universitário Cassiano Antônio de Moraes/HUCAM

Collaborator

Hospital Santa Casa de Misericórdia de Vitória

Collaborator

Source ClinicalTrials.gov
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