AORTIC-ARCH SURGERY - PROS AND CONS OF SELECTIVE CEREBRAL PERFUSION -A MULTIVARIABLE ANALYSIS FOR CEREBRAL INJURY DURING HYPOTHERMIC CIRCULATORY ARREST

Thirty-five consecutive patients with aortic arch aneurysm who require d surgical reconstruction were operated on with the aid of extracorpor eal circulation between February 1985 and December 1993. Nineteen pati ents (54.3%) were treated with hypothermic circulatory arrest (HCA) (G roup A) and 16 (45.7%) (Group B) with HCA and selective cerebral perfu sion (SCP) through the carotid arteries. Preoperative characteristics didn't show any significant differences between the two groups: mean a ge was 58.7 +/- 12 vs 62.1 +/- 7, p = ns, male sex 73.6% vs 75%, p = n s; atherosclerotic aneurysms were 57.8% vs 43.7%, p = ns; Type A disse ctions 42.2% vs 56.3%, p = ns and emergency operation were 68.4% vs 43 .7%, p = ns in Groups A and B respectively. For SCP, blood was infused initially at a rate of 200-300 ml/min, maintaining the 30-40% of cere bral blood flow in normothermia, successively, with the aid of transcr anial Doppler sonography (TDS) SCP-flow was improved to 500-1000 ml/mi n. The MHz pulsed TDS was used to measure the middle cerebral artery f low velocity in deep hypothermia before the arrest, in order to adjust the SCP flow during the HCA. In all patients we used open aortic anas tomosis; in two cases an extraanatomical ascending-descending aorta wa s required, and in other two the ''elephant trunk'' technique was used in case of combined aortic arch and descending aneurysms. The HCA tim es were similar in the two groups 47.5 +/- 22 vs 47.7 +/- 78, p = ns. Early deaths occurred in 5 patients of the Group A (26.3%) and in 3 pa tients of the group B (18.7%), p = ns. Permanent and transient cerebra l complications did not differ in the two groups: 15.7% vs 12.5%, p = ns, and 10.5% vs 18.7%, p = ns, in Groups A and B respectively. A mult ivariate analysis was performed in order to identify preoperative and operative risk factors for neurologic morbidity and mortality. Presenc e of aortic dissection (p = 0.029), emergency procedure (p = 0.032), a ge (p = 0.038) and length of HCA (p = 0.049) were isolated as predicti ng variables of cerebral injury, while SCP was not found as a protecti ve factor (p = 0.56). In summary, despite a slightly lower incidence o f irreversible cerebral damage with the adjunct of SCP during HCA, thi s technique was not found in our hands free from complications. We thi nk that SCP, which remains and interesting technique when HCA times ex ceed 45-50 min, still shows some controversial features and its risk/b enefit ratio has not been completely cleared.