PERFUSION WITH LOW SYSTEMIC HEPARINIZATION DURING RESECTION OF DESCENDING THORACIC AORTIC-ANEURYSMS

Two series of 20 consecutive patients with aneurysms of the descending thoracic aorta (TAA) and thoraco-abdominal aorta (TAAA) underwent multisegmental aortic repair using either simple normothermic crossclamping and rapid reanastomosis (historic) or partial cardiopulmonary bypass (CPB) with heparin coated perfusion equipment and low systemic heparinization (actual). Chronic lesions were present in 14/20 patients (70%) for simple versus 13/20 (65%) for CPB (NS). Acute lesions (symptomatic < 24 h) were present in 6/20 patients (30%) for simple versus 7/20 (35%) for CPB (NS). Dissecting lesions were observed in 4/20 patients (20%) for simple versus 8/20 (40%) for CPB (NS). Aneurysmal lesions were found in 16/20 patients (80%) for simple versus 12/20 (60%) for CPB (NS). Mean number of aortic segments (n = 8) resected was 3.2 +/- 1.1 for simple versus 4.0 +/- 1.2 for CPB (P < 0.01). Replacement of the transdiaphragmatic aorta was performed in 10/20 patients (50%) for simple and 13/20 patients (65%) for CPB (NS). A heparin loading dose of 5000 IU for simple versus 100 IU/kg bodyweight for CPB was used. In the latter group, the activated clotting time was kept above 180 s during a mean perfusion time of 46 +/- 28 min at a mean pump flow of 2.2 +/- 0.7 l/min. Thirty-day survival for all (transdiaphragmatic) was 12/20 (5/10) patients for simple versus 20/20 (13/13) for CPB (P < 0.002, P < 0.01). One-year survival (all) was 11/20 patients (55%) for simple versus 19/20 (95%) for CPB (P < 0.005). There were 2 parapareses (1 vascular complication) in 12 survivors (17%, 8%) for simple versus 2/20 (1/20) (10%, 5%) for CPB (NS, NS). Proximal unloading and distal perfusion during repair of TAA and TAAA using partial CPB and low systemic heparinization appears to provide improved clinical results.