Comparing Hypothermic Temperatures During Hemiarch Surgery

A Randomized Controlled Trial of Mild vs. Moderate Hypothermia on Patient Outcomes in Aortic Hemiarch Surgery With Anterograde Cerebral Perfusion

Hypothermic circulatory arrest is an important surgical technique, allowing complex aortic surgeries to be performed safely. Hypothermic circulatory arrest provides protection to cerebral and visceral organs, but may result in longer cardiopulmonary bypass times during surgery, increased risks of bleeding, inflammation, and neuronal injury. To manage these consequences, a trend towards warmer core body temperatures during circulatory arrest has emerged. This trial will randomize patients to either mild (32°C) or moderate (26°C) hypothermia during aortic hemiarch surgery to determine if mild hypothermia reduces the length of cardiopulmonary bypass time and other key measures of morbidity and mortality.

Inclusion Criteria:

• Age ≥ 18 years
• Elective aortic hemiarch surgery
• Planned unilateral selective anterograde cardioplegia
• Anticipated lower body arrest time of < 20 minutes
• Able to provide written informed consent

Exclusion Criteria:

• Surgery for acute aortic dissection or emergent operations
• Total arch replacement
• Inability to perform unilateral selective anterograde cerebral perfusion (uSACP)
• Patients with known/documented coagulopathy
• Patients with cold agglutinin disease or those that test positive on routine preop screening
• Pre-existing severe neurological impairment or inability to accurately assess neurocognitive function as determined by the operating surgeon
• Severe carotid disease, defined as: any patient with previously documented carotid stenosis of > 70% (via Doppler ultrasound (US), magnetic resonance angiography (MRA), or computer tomography angiography (CTA)) without neurological deficits; or carotid stenosis > 50% with neurological deficits; or previous carotid endarterectomy or stenting
• Patients in renal failure or currently being treated with renal replacement therapy (RRT) or estimated glomerular filtration rate (eGFR) < 30 ml/min/1.73m2
• Use of an investigational drug or device at time of enrollment
• Participation in another clinical trial which interferes with performance of the study procedures or assessment of the outcomes