Late complications of surgery for coarctation of the aorta.

The problem of the patient who has had one operation for coarctation of the aorta and who then requires another because of a late complication at or near the coarctation site is a demanding one. The safety of aortic cross-clamping at the second operation depends on the adequacy or otherwise of the collateral circulation, and this in turn depends on the presence or absence of residual or recurrent aortic obstruction. Three illustrative cases are described in which there was complete, incomplete, and no aortic obstruction respectively at the time of reoperation, two of the cases presenting the additional complication of local aneurysm formation. The various aspects of management of such individuals are discussed, and the relevant literature has been reviewed in an attempt to provide a systematic approach to these difficult patients. The methods for assessing collateral circulation are both clinical and radiological with trial clamping of the aorta and pressure measurement as the most reliable ultimate test. A pressure of 50 mmHg in the distal aorta is accepted as indicating an adequate peripheral circulation, but it is recommended that the trial clamping should always include both the left subclavian artery and any particularly large local collaterals. The use of a perfusion technique to sustain the distal tissues is also recommended, although local bypass shunts have a place when their use is dictated in the interests of safety for the patient.