Background: Cross-clamp time has been reported to correlate with risk of neurologic deficit after thoracoabdominal aortic aneurysm repair. Introduction of cerebrospinal fluid drainage and distal aortic perfusion (adjunct) has greatly reduced the incidence of neurologic deficit. We reevaluated the effect of cross-clamp time before and after introduction of adjunct during a 13-year period.
Methods: Between 1991 and 2004, we repaired 1,106 thoracic and thoracoabdominal aortic aneurysms. Four hundred one patients were female and 705 were male (median age, 67 years). Selective use of adjunct was begun in late 1992, with its routine use by 1993.
Results: Aortic cross-clamp times have increased significantly (34 seconds/year; p < 0.0001) since 1991. Despite this increase in cross-clamp time, neurologic deficit rates have declined from the first to the fourth quartile (p < 0.02). This decrease in neurologic deficit is most pronounced with the extent II thoracoabdominal aortic aneurysms (21.1% to 3.3%). The use of the adjunct increased the cross-clamp time by a mean of 12 minutes (p < 0.0001), but was associated with a significant protective effect against neurologic deficit (odds ratio = 0.4; p < 0.0002). Although other previously established risk factors remained significantly associated with neurologic deficit, cross-clamp time is no longer significant.
Conclusions: Adjunct significantly reduced the risk of neurologic deficit, despite increasing cross-clamp time. The use of the adjunct appears to blunt the effect of the cross-clamp time and may provide the surgeon the ability to operate without being hurried. Because cross-clamp time has been effectively eliminated as a risk factor with the use of the adjunct, using this variable to construct risk models becomes irrelevant in our experience.