Distal aortic pressure during coarctation operation.

Mean distal aortic pressure (DAP) was monitored continuously during operative repair of coarctation of the aorta in 67 children more than 1 year of age between 1982 and 1987. At initial test clamping a DAP of 45 mm Hg or more was considered adequate. In 42 patients (group A), DAP exceeded 45 mm Hg and the operation proceeded. In 25 patients (group B) the DAP was less than 45 mm Hg, and adjustments were made to the position of the proximal and distal clamps and in the use of hypotensive agents. After these adjustments in group B, DAP rose from 34.7 to 50.6 mm Hg (p less than 0.001), achieving the desired level in all but 5 patients, who required temporary shunts to support the distal circulation. The adjustments were as follows: the left subclavian artery was open in 28% of patients before and 60% after (p less than 0.02); no more than one pair of intercostal arteries was clamped in 64% before and 88% after (p less than 0.05); and no hypotensive agents were used in 56% before and 80% after (p = 0.07). During the first ten minutes of cross-clamping the DAP rose by 5.5 mm Hg (p less than 0.01, n = 52). It is concluded that continuous monitoring of DAP contributed to the operative management of these patients by indicating when adjustments in the position of the clamps or in the use of hypotensive agents were needed. The use of hypotensive agents should be reduced to achieve a higher DAP.