Antegrade selective cerebral perfusion in thoracic aorta surgery: safety of moderate hypothermia

Although antegrade selective cerebral perfusion (ASCP) has been demonstrated to be the best method of protection of brain ischemia during aortic arch surgery, there is no consensus regarding optimal temperature during ASCP. The study analyzed the outcomes of aortic surgery using ASCP at different degree of systemic hypothermia.

Between November 1996 and November 2005, 305 patients underwent thoracic aorta surgery using ASCP. Patients were divided into two groups according to the lowest systemic temperature: moderate systemic hypothermia (> or =25 degrees C) was used in 189 patients (group A), and a deeper hypothermia (<25 degrees C) in 116 patients (group B). One hundred and five patients suffered from acute type A aortic dissection.

The extension of aortic replacement was significantly larger in group A, while the average ASCP time was not different between groups (63+/-37.7min group A, 58.6+/-35.6min group B; p=0.314). The 30-day mortality rate was 12.7% in group A and 13.8% in group B (p=0.862). Permanent neurologic deficits occurred in eight patients (2.6%) without significant differences between groups (3.1% group A vs 1.7% group B; p=0.715). Twenty-five patients (8.2%) suffered from temporary neurologic dysfunction (7.9% group A vs 8.6% group B; p=0.833).

In our experience, ASCP was a safe technique for thoracic aorta surgery allowing complex aortic repairs to be performed with good results in terms of hospital mortality and neurologic outcomes. The fact that there was no difference between the two groups suggests that moderate systemic hypothermia (26 degrees C) appears to be a safe and sufficient tool for brain protection. Moreover, the well known hypothermia-related side effects may be avoided.