A Comparative Study of Different Hypothermic Circulatory Arrest Strategies on Aortic Surgery.

Hypothermic circulatory arrest (HCA) is the cornerstone of aortic surgery. It provides a bloodless and still operative field. But the side effect of hypothermia also draws people's concern. With the development of surgical techniques and cardiopulmonary bypass (CPB) management, the temperature of HCA has been raised from deep hypothermia (14.1-20 degree) to moderate hypothermia (20.1-28 degree), and it has been a primary choice for many surgeons around the world. Some of surgeons still tried to push the limit and started using mild hypothermia (28.1-34 degree), and satisfactory outcome was obtained. However, the optimal temperature of HCA has not yet been determined.

In this randomized controlled study, 80 informed and consenting patients who are scheduled for total arch replacement with concomitant proximal aortic reconstruction will be randomized to mild (28.1-34 degree) or moderate (20.1-28 degree) hypothermia during circulatory arrest. Clinical outcomes of both groups will be analyzed to determine the optimal temperature for HCA.

• the temperature of hypothermic circulatory arrest (Procedure): Different temperature (mild 30 degree or moderate 25 degree) employed during the hypothermic circulatory arrest on aortic surgery.

Primary outcomes

• Mortality [3 months within surgery.]: In-hospital Mortality or other related death
• Re-thoracotomy [Through the hospitalization, an average of 4 weeks.]: Postoperative bleeding or other conditions require re-thoracotomy
• Neurological disorder [Through the hospitalization, an average of 4 weeks.]: Any neurological event occur after surgery, including transient and permanent.

Secondary outcomes

• HCA time [During the operation]: the time of hypothermic circulatory arrest
• Aorta-cross clamp time [During the operation]: the time of aortic-cross clamp
• CPB time [During the operation]: the time of cardiopulmonary bypass
• Operation time [During the operation]: the time of the entire surgery.
• ICU stay [Through the ICU stay, an average of 1 weeks.]: the day of ICU treatment
• Time of mechanical ventilation [Through the use of ventilation, an average of 3 days.]: the time of using respirator
• Blood transfusion [Through the hospitalization, an average of 4 weeks.]: the number of blood product during the hospitalization, including red blood cell, platelet, plasma and so on.
• Dialysis [Through the hospitalization, an average of 4 weeks.]: postoperative renal failure requiring dialysis
• Hospital stay [Through the hospitalization, an average of 4 weeks.]: the time of hospitalization
• Postoperative aneurysm [1 year within the surgery]: Aortic aneurysm develope after the surgery
• Postoperative endoleak [1 year within the surgery]: Stent-graft endoleak occurs after the surgery.

Sex: All, ages: 18 Years to 70 Years

Inclusion Criteria:

1.Patients with confirmed diagnosis (i.e.aortic dissection, marfan syndrome, aortic arch aneurysm and so on), which require total aortic arch replacement.

Exclusion Criteria:

1. Preoperative heart attack or coma.
2. Patients with surgical contraindication, including but not limited to severe cardiac,pulmonary,renal or hepatic insufficiency.
3. Pre-existing heart condition or neurological disease.
4. Variation of aortic arch or its branch vessels.
5. Patient is currently on anticoagulation therapy or has other medical condition that compromises the coagulation.
6. Patient with active infection.
7. Allergy to anaesthetic or contrast agent.
8. Pregnant or lactating female.
9. Patient is already on other medical trial.
10. Other medical, psychological or socioeconomics condition determined by investigator that is not eligible for the study.

• Xiaoping Fan, PhD, Study director, Guangdong General Hosiptal
• Jie He, MD, Principal investigator, Guangdong General Hosiptal