Clinical prospective study of biochemical markers and evoked potentials for identifying adverse neurological outcome after thoracic and thoracoabdominal aortic aneurysm surgery

Neurological deficit after repair of a thoracic or thoracoabdominal aortic aneurysm (TAA/TAAA) remains a devastating complication. The aim of our study was to investigate the clinical value of biochemical markers [S-100B, neurone-specific enolase (NSE) and lactate dehydrogenase (LD)], evoked potentials and their combinations for identifying adverse neurological outcome after TAA/TAAA surgery. From 69 patients, cerebrospinal fluid and blood samples for biochemical analysis were drawn after the induction of anaesthesia, during the cross-clamp period, 5 min, 2, 4, 6, 8, and 19 h, respectively, after reperfusion. In addition, continuous perioperative recording of motor-evoked potentials after transcranial electrical stimulation (tcMEP) and somatosensory-evoked potentials was carried out. Furthermore, neurological examinations were performed. In patients with a defined decrease in lower extremity tcMEP during the cross-clamp period, we found that combinations of the serum concentrations of S-100B and tcMEP ratios at 4, 6, and 8 h after reperfusion had a positive and negative predictive value of 100% in predicting adverse neurological outcome after TAA/TAAA surgery. Furthermore, combinations of the serum concentrations of S-100B and NSE or LD at 19 h after reperfusion had both a positive and negative predictive value of 100% in identifying patients with adverse outcome after TAA/TAAA repair. TcMEP monitoring during TAA/TAAA surgery seems to be an effective but not completely sufficient guide in our protective multi-modality strategy. Combinations of the serum concentrations of S-100B and tcMEP ratios during the early reperfusion period might be associated with adverse neurological complications. Furthermore, biochemical markers could detect central nervous system injury on the first postoperative day and may have prognostic value.