SELECTIVE APPROACH TO DESCENDING THORACIC AORTIC-ANEURYSM REPAIR - A 10-YEAR EXPERIENCE

Background. A variety of surgical techniques has been developed to att empt to minimize the risk of paraplegia after descending thoracic aort ic aneurysm repair. This study reviews our institutional experience wi th several basic techniques over a period of 10 years. Methods. Sevent y-eight consecutive patients underwent repair of descending thoracic a ortic aneurysm between 1983 and 1993. Two basic repair strategies were used: (1) distal perfusion with somatosensory evoked potential monito ring (n = 54) and (2) cross-clamping (n = 24), alone (n = 6) or with c ontrolled distal exsanguination (n = 18). Results. The operative morta lity rate was 6.5% for elective repair (n = 62), 25.0% for emergent re pair (n = 16), and 10.3% overall. Univariate predictors of increased o perative risk were emergent operation, rupture, and shock. Neither dea th nor paraplegia was related to the operative technique used. The inc idence of paraplegia was 3.7% in perfused patients and 4.2% in crosscl amping patients (p > 0.05). Paraplegia did not occur after any electiv e operation (zero of 62) but occurred in 18.6% of emergent cases (p < 0.01). In perfused patients, paraplegia did not occur when the distal pressure was maintained above 55 mm Hg and somatosensory evoked potent ials remained intact. When somatosensory evoked potentials were lost ( n = 7) in perfused patients, the operative technique was altered succe ssfully in 5 patients, whereas in 2 patients (28.6%), paraplegia devel oped. Conclusions. The risks associated with elective descending thora cic aortic aneurysm repair were extremely low using an operative strat egy that was flexible but skewed toward perfusion with somatosensory e voked potential monitoring. In perfused patients, paraplegia did not o ccur when distal pressure was greater than 55 mm Hg and somatosensory evoked potentials remained intact. However, the risks of death and par aplegia were primarily related to emergent presentation, not to techni que, and the technique of cross clamping with controlled distal exsang uination was found to be valuable in unstable or in anatomically compl icated subsets of patients.