Selective approach to descending thoracic aortic aneurysm repair: A ten-year experience

Background. A variety of surgical techniques has been developed to attempt to minimize the risk of paraplegia after descending thoracic aortic aneurysm repair. This study reviews our institutional experience with several basic techniques over a period of 10 years. Methods. Seventy-eight consecutive patients underwent repair of descending thoracic aortic aneurysm between 1983 and 1993. Two basic repair strategies were used: (1) distal perfusion with somatosensory evoked potential monitoring (n = 54) and (2) cross-clamping (n = 24), alone (n = 6) or with controlled distal exsanguination (n = 18). Results. The operative mortality rate was 6.5% for elective repair (n = 62), 25.0% for emergent repair (n = 16), and 10.3% overall. Univariate predictors of increased operative risk were emergent operation, rupture, and shock. Neither death nor paraplegia was related to the operative technique used. The incidence of paraplegia was 3.7% in perfused patients and 4.2% in crossclamping patients (p > 0.05). Paraplegia did not occur after any elective 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 potentials remained intact. When somatosensory evoked potentials were lost (n = 7) in perfused patients, the operative technique was altered successfully in 5 patients, whereas in 2 patients (28.6%), paraplegia developed. Conclusions. The risks associated with elective descending thoracic aortic aneurysm repair were extremely low using an operative strategy that was flexible but skewed toward perfusion with somatosensory evoked potential monitoring. In perfused patients, paraplegia did not occur when distal pressure was greater than 55 mm Hg and somatosensory evoked potentials remained intact. However, the risks of death and paraplegia were primarily related to emergent presentation, not to technique, and the technique of cross clamping with controlled distal exsanguination was found to be valuable in unstable or in anatomically complicated subsets of patients.