NCT06934798

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

• Status: Recruiting
• Phase: Phase 4
• Study type: Interventional
• Enrollment: 350 (estimated)
• Sponsor: University of Sao Paulo · Academic / Other
• Sex: All
• Age: 18 Years
• Healthy volunteers: Accepted

Summary

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.

Detailed description

This prospective, randomized, double-blind clinical trial investigates the inotropic effects of vasopressin versus norepinephrine in patients who develop vasoplegic syndrome (VS) in the immediate postoperative period following cardiac surgery. Vasoplegic syndrome is characterized by severe hypotension with low systemic vascular resistance despite adequate cardiac output, often unresponsive to standard fluid resuscitation and catecholamine vasopressors. It is associated with significant morbidity and mortality, especially in cardiac surgery patients. In recent years, vasopressin has been explored as an alternative or adjunctive treatment due to its different mechanism of action and potentially fewer adverse effects compared to catecholamines. Eligible patients (≥18 years) undergoing coronary artery bypass grafting or valve surgery, who develop vasoplegic syndrome within 24 hours postoperatively, will be randomized in a 1:1 ratio to receive vasopressin or norepinephrine. Drug allocation will be blinded to the clinical and research teams, with identically prepared infusion bags. The study protocol includes a detailed vasopressor infusion regimen, beginning at 5 mL/h with titration every 10 minutes to a maximum of 30 mL/h, aiming for a target mean arterial pressure (MAP) ≥65 mmHg. Hemodynamic parameters (SBP, DBP, MAP, HR, lactate, SVO₂, CO₂ gap) and echocardiographic indices (LVEF, TAPSE, VTI, CO, SVR) will be collected at baseline (T0) and upon reaching the MAP goal (T1). Primary endpoint: Comparative assessment of the inotropic effects between the two vasopressors based on echocardiographic and hemodynamic changes from T0 to T1. Sample size: 175 patients per arm, considering a 30% effect size and 5% attrition rate, powered at 80% with a 5% type I error. Statistical analysis will follow an intention-to-treat approach using appropriate parametric and non-parametric tests, with p-values \<0.05 considered statistically significant. This trial is expected to provide clinically relevant data on the efficacy and safety of vasopressin in improving myocardial performance in vasoplegic patients, potentially supporting its use as a first-line vasopressor in this context

Conditions

• Vasoplegic Syndrome of Cardiac Surgery

Interventions

Type	Name	Description
DRUG	Vasopressin intravenous infusion	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.
DRUG	Norepinephrine intravenous infusion	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.

Timeline

• Start date: 2024-04-01
• Primary completion: 2025-07-30
• Completion: 2025-07-30
• First posted: 2025-04-18
• Last updated: 2025-04-30

Locations

1 site across 1 country: Brazil