NCT04884802 · The University of Texas Health Science Center, Houston
The GUARDIAN Trial
What this study is about
An international randomly assigned trial to test the primary hypothesis that perioperative tight blood pressure management reduces a composite of major perfusion-related complications (myocardial injury, stroke, non-fatal cardiac arrest, Stage 2-3 acute kidney injury, deep or organ-space infection, sepsis, and death) in the 30 days after major non-cardiac surgery.
View original scientific description
An international randomized trial to test the primary hypothesis that perioperative tight blood pressure management reduces a composite of major perfusion-related complications (myocardial injury, stroke, non-fatal cardiac arrest, Stage 2-3 acute kidney injury, deep or organ-space infection, sepsis, and death) in the 30 days after major non-cardiac surgery. The treatments will be: 1) norepinephrine or phenylephrine infusion to maintain intraoperative MAP ≥85 mmHg (tight pressure management); or, 2) routine intraoperative blood pressure management (routine pressure management).
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- At least 45 years old;
- Scheduled for major noncardiac surgery expected to last at least 2 hours;
- Having general anesthesia, neuraxial anesthesia, or the combination;
- Expected to require at least overnight hospitalization (planned ICU admission is acceptable);
- Are designated ASA physical status 2-4 (ranging from mild systemic disease through severe systemic disease that is a constant threat to life);
- Expected to have direct intraoperative blood pressure monitoring with an arterial catheter;
- Cared for by clinicians willing to follow the GUARDIAN protocol;
- Subject to at least one of the following risk factors:
- Age \>65 years;
- History of peripheral arterial disease;
- History of coronary artery disease;
- History of stroke or transient ischemic attack;
- Serum creatinine \>175 μmol/L (\>2.0 mg/dl) within 6 months;
- Diabetes requiring medication;
- Current smoking or 15 pack-year history of smoking tobacco;
- Scheduled for major vascular surgery;
- Body mass index ≥35 kg/m2;
- Preoperative high-sensitivity troponin T \>14 ng/L or troponin I equivalent, defined as ≥15 ng/L (Abbott assay), 19 ng/L (Siemens assay, \[Borges, unpublished\]), or 25% of the 99% percentile for other assays - all within 6 months;
- B-type natriuretic protein (BNP) \>80 ng/L or N-terminal B-type natriuretic protein (NTProBNP) \>200 ng/L within six months.
Exclusion criteria
- Are scheduled for carotid artery surgery;
- Are scheduled for intracranial surgery;
- Are scheduled for partial or complete nephrectomy;
- Are scheduled for pheochromocytoma surgery;
- Are scheduled for liver or kidney transplantation;
- Require preoperative intravenous vasoactive medications;
- Have a condition that precludes routine or tight blood pressure management such as surgeon request for relative hypotension;
- Require beach-chair positioning;
- Have a documented history of dementia;
- Have language, vision, or hearing impairments that may compromise cognitive assessments;
- Have contraindications to norepinephrine or phenylephrine per clinician judgement;
- Have previously participated in the GUARDIAN trial.
Where
- Omaha, Nebraska
- Wake Forest, North Carolina
- Cleveland, Ohio
- Houston, Texas
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Aug 29, 2025 · Source of record for eligibility and locations