Use of partial cardiopulmonary bypass for coarctation repair through a left thoracotomy in children without collaterals.

BACKGROUND: Paraplegia is a devastating complication of coarctation of the aorta (COA) repair. Since 1990 we have used left atrium-to-descending aorta cardiopulmonary bypass (CPB) for COA repair in patients with inadequate collaterals. We reviewed the results with that strategy and compared this CPB group with COA repairs in which CPB was not used to see whether there was any increase in morbidity or delay in recovery.

METHODS: From 1990 to 2006, 11 patients with COA were identified to have inadequate collaterals based on preoperative examination and intraoperative arterial monitoring and test clamp. Left thoracotomy with left atrium-to-descending aorta CPB was used in all. Age ranged from 4.2 to 17.4 years (mean, 8.7 +/- 4.6 years). Two were reoperations for recurrent COA, 3 patients had four prior transcatheter balloon dilatations. One patient had aberrant origin of the right subclavian artery. Operative techniques included resection with extended end-to-end anastomosis (n = 6), interposition graft (n = 4), and patch repair (n = 1). During the same period 71 patients older than 1 year of age had COA repair without CPB. Age ranged from 1.1 to 46.1 years (mean, 7.6 +/- 7.1 years; p = 0.6).

RESULTS: Preoperative imaging of CPB patients demonstrated absence of collaterals (n = 7), possible collaterals (n = 2), small collaterals (n = 1), and anomalous origin of the right subclavian artery (n = 1). Preoperative arm leg gradient in CPB patients was 36.0 +/- 9.0 mm Hg versus 49.9 +/- 15 mm Hg in non-CPB patients (p < 0.01). Mean distal femoral artery pressure with aortic test clamp was 34.3 +/- 4.8 mm Hg in CPB patients versus 49.8 +/- 12.4 mm Hg in non-CPB patients (p < 0.01). Mean CPB flow was 53% +/- 7.3% of calculated total flow. Cardiopulmonary bypass time ranged from 17 to 46 minutes (mean, 27.5 +/- 9.7 minutes). Aortic clamp time in CPB patients ranged from 15 to 33 minutes (mean, 21.6 +/- 6.3 minutes). In the non-CPB group aortic clamp time ranged from 10 to 50 minutes (mean, 23.4 +/- 7.5 minutes; p = 0.5). In the CPB group length of stay ranged from 3 to 7 days (mean, 4.9 +/- 1.3 days), and in the non-CPB group length of stay ranged from 3 to 12 days (mean, 4.7 +/- 1.4 days; p = 0.5). No patient had a neurologic complication. There were no other major complications in the CPB group (eg, bleeding, recurrent laryngeal nerve injury, re-COA).

CONCLUSIONS: Preoperative imaging and a lower arm-to-leg gradient in this series of COA patients suggested inadequate collateral circulation with the potential need for CPB. A femoral artery pressure of less than 45 mm Hg during test clamp was used as an indication for partial CPB. The use of left atrium-to-descending aorta CPB with just over 50% calculated total flow protected the spinal cord in a safe and expeditious fashion. Use of left heart bypass did not affect morbidity or recovery time as compared with COA repair in non-CPB patients.