Study population
A total of 210 patients were analyzed. Mean age was 70 years and 35.2% of the patients were female. Fourteen patients (6.7%) had a previous stroke and 33 (15.5%) were in atrial fibrillation. Baseline characteristics are shown in Table 1.
Surgical details are summarized in Table 1. The most common arterial return was through the axillary artery (61.9% of the cases), followed by direct aneurysm cannulation (23.8%), while venous drainage was mainly atriocaval. Associated surgeries were coronary artery bypass grafting in 21.4% of the patients and aortic valve repair/replacement in 49.6%. Mitral and tricuspid valve repair were performed only in 4 cases (1.9%).
Fifty-nine patients (28.1%) underwent DHCA at ≤ 20°C without any CP. In 151 cases (71.9%) surgery was performed at moderate hypothermia (26°C) and ACP was obtained through the axillary artery only in 51.7% of the cases, direct cannulation only in 13.9% of the cases while in the remaining 34.4% a mixture of the two methods was used. In 42 cases (27.8%) the left subclavian artery was perfused as well. The median CA time was 24 min, shorter when DHCA (21 min) was used and longer in case of MHCA (26 min) without statistical significance. CA time was >40 min in 19 patients (9%) and >50 min in 11 (5.2%), without any difference when deep or moderately hypotermic CA was used.
Total arch replacement was performed in 103 cases (49%) and ascending aorta with hemiarch replacement in the remaining 107 (51%). An elephant trunk was performed in 61 patients (29%), conventional in 4 (1.9%) and frozen in 57 (27.1%). Median CPB time was 150 min and was not affected by the temperature of the CA. Modality of rewarming after CA were different. In all patients who underwent DHCA rewarming was delayed for a period of 10 minutes, with perfusate temperature at 20°C1,2. Patients undergoing MHCA were rewarmed as soon as the perfusion restarted.