Hypothermic cardiopulmonary bypass and circulatory arrest for operations on the descending thoracic and thoracoabdominal aorta.

BACKGROUND: Hypothermic cardiopulmonary bypass with circulatory arrest is an important adjunct for operations on the distal aortic arch, the descending thoracic, and the thoracoabdominal aorta. The safety and efficacy of this technique when compared with other adjuncts (ie, simple aortic clamping, partial cardiopulmonary bypass, regional hypothermia) is not clearly established.
METHODS: One hundred and ninety-two patients (age range, 20 to 83 years) with descending thoracic or thoracoabdominal aortic disease had resection and graft replacement of the involved aortic segments using hypothermic cardiopulmonary bypass and intervals of circulatory arrest (mean, 38 minutes). The technique was used when the location and severity of disease precluded placement of clamps on the proximal aorta (31 patients) or (in 161 patients) when extensive thoracic (47) or thoracoabdominal (114) aortic disease was present, and the risk for development of spinal cord ischemic injury was judged to be increased. Lower intercostal and lumbar arteries were attached separately to the aortic graft in 101 of the 161 patients (63%) who had extensive aortic replacement. No other adjuncts for spinal cord protection were used.
RESULTS: The 30-day mortality was 6.8% (13 patients). It was 40% (8 of 20) for patients having emergent operations (acute aortic dissection or rupture) and 2.9% (5 of 172) for all others (p < 0.001). The 90-day mortality was 12.5% (24 patients). Paraplegia occurred in 4 and paraparesis in 1 (full recovery) of the 186 operative survivors whose lower limb function could be assessed postoperatively (2.7%). Among the 109 survivors with thoracoabdominal aortic disease, early paraplegia occurred in 1 of 36 with Crawford extent I, 0 of 42 with extent II, and 2 of 31 with extent III disease. One patient (extent II) developed paraplegia on the 9th postoperative day after a hypotensive episode. None of the 47 patients with aortic dissection developed paralysis. Among the 186 operative survivors, renal dialysis was required in 4 patients (2.2%), prolonged inotropic support in 18 (10%), reoperation for bleeding in 9 (5%), mechanical ventilation (> or = 48 hours) in 64 (34%), and tracheostomy in 17 (9%). Four patients (2%) sustained a stroke.
CONCLUSIONS: Hypothermic cardiopulmonary bypass with circulatory arrest provides safe and substantial protection against paralysis and renal, cardiac, and visceral organ system failure that equals or exceeds that of other currently used techniques but without the need of other adjuncts.