Aortic arch replacement for degenerative aneurysms: advances during the last decade

Area of Science:

• Cardiovascular Surgery
• Neurosurgery
• Vascular Medicine

Background:

• Degenerative aortic arch aneurysms present complex treatment challenges, particularly concerning neurological complications.
• Evolving understanding of brain pathophysiology and the advent of endovascular repair have reshaped surgical strategies.
• Minimizing neurocognitive dysfunction and preventing atheroembolism are critical goals in aortic arch aneurysm management.

Purpose of the Study:

• To review current best practices and emerging techniques for managing degenerative aortic arch aneurysms.
• To evaluate the safety and efficacy of various cerebral perfusion strategies during aortic arch surgery.
• To discuss the role of endovascular and hybrid approaches in treating extensive or distal arch aneurysms.

Main Methods:

• Analysis of current literature on hypothermic circulatory arrest, cerebral perfusion techniques, and endovascular aortic repair.
• Review of proposed modifications to "isolation" techniques for preventing aortogenic brain embolism.
• Discussion of outcomes associated with hybrid operations like frozen elephant trunk procedures.

Main Results:

• Safe deep hypothermic circulatory arrest duration is now considered less than 25 minutes to avoid neurocognitive dysfunction.
• Selective cerebral perfusion (SCP) is safe unless profound hypothermia (<20 °C) is employed; mild to moderate hypothermia is preferred.
• Distal circulatory arrest appears safe for less than 60 minutes at 28 °C to prevent spinal cord injury.
• Modified "isolation" techniques using axillary and left carotid arteries aim to prevent brain atheroembolism.
• Hybrid operations like frozen elephant trunk have risks, including paraplegia, and may not offer superior outcomes for distal arch aneurysms compared to open repair.

Conclusions:

• Modern aortic arch aneurysm treatment prioritizes minimizing ischemic time and preventing emboli.
• Selective cerebral perfusion with mild-to-moderate hypothermia offers neuroprotection, while profound hypothermia may be detrimental.
• Hybrid approaches require careful consideration of risks, particularly for extensive or distal arch aneurysms.