Deep Versus Moderate Hypothermia in Acute Type A Aortic Dissection: A Propensity-Matched Analysis

Area of Science:

• Cardiovascular Surgery
• Thoracic Surgery
• Vascular Surgery

Background:

• The optimal temperature for hypothermic circulatory arrest (HCA) in acute type A aortic dissection (ATAAD) repair remains debated.
• This study investigates the clinical outcomes associated with different hypothermia levels during ATAAD repair.

Purpose of the Study:

• To compare the safety and efficacy of moderate hypothermic circulatory arrest (MHCA) versus deep hypothermic circulatory arrest (DHCA) in ATAAD repair.
• To identify independent predictors of adverse short-term outcomes following ATAAD repair.

Main Methods:

• A retrospective analysis of 228 patients undergoing ATAAD repair, divided into MHCA (20-28°C) and DHCA (<20°C) groups.
• 74 pairs of propensity-matched patients were analyzed for operative data and short-term clinical outcomes.
• Logistic regression identified predictors of a composite outcome of 30-day mortality and stroke.

Main Results:

• Mean lowest temperatures were 25.5°C (MHCA) and 16.0°C (DHCA).
• No significant difference in 30-day mortality between MHCA and DHCA groups.
• Antegrade cerebral perfusion (ACP) during HCA was associated with reduced 30-day mortality and stroke risk (OR 0.38).
• Longer cardiopulmonary bypass (CPB) times (>235 mins), female sex, and lower extremity ischemia were associated with worse outcomes.

Conclusions:

• Moderate hypothermic circulatory arrest (MHCA) is a safe alternative to deep hypothermic circulatory arrest (DHCA) for ATAAD repair.
• Antegrade cerebral perfusion (ACP) during HCA is a protective factor against mortality and stroke.
• Female sex, lower extremity ischemia, and prolonged CPB times are risk factors for adverse outcomes in ATAAD repair.