Immediate ischemic preconditioning based on somatosensory evoked potentials seems to prevent spinal cord injury following descending thoracic aorta cross-clamping

• Published in: European journal of cardio-thoracic surgery 2005-08, Vol.28 (2), p.274-279
• Main Authors: Contreras, Ivan S. Bonillo, Moreira, Luiz Felipe P., Ballester, Gerson, de Mônaco, Bernardo A., Lancellotti, Carmem Lúcia P., Dias, Altamiro R., Oliveira, Sérgio A.
• Format: Article
• Language: English
• Subjects: Animals; Aorta, Thoracic - physiopathology; Aortic aneurysm; Biological and medical sciences; Blood and lymphatic vessels; Cardiology. Vascular system; Disease Models, Animal; Diseases of the aorta; Dogs; Evoked potential; Evoked Potentials, Somatosensory - physiology; Ischemia - complications; Ischemia - physiopathology; Ischemic preconditioning; Ischemic Preconditioning - methods; Medical sciences; Necrosis; Paraplegia; Paraplegia - prevention & control; Pneumology; Reperfusion - methods; Spinal cord; Spinal Cord - blood supply; Spinal Cord - pathology; Spinal Cord Injuries - prevention & control; Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases; Surgery of the heart; Time Factors
• ISSN: 1010-7940; 1873-734X
• DOI: 10.1016/j.ejcts.2005.03.018

Objective: Delayed ischemic preconditioning has demonstrated neuroprotective effects in spinal cord ischemia. We investigated the effects of immediate ischemic preconditioning based on somatosensory evoked potentials monitoring in a model of spinal cord injury due descending thoracic aorta occlusion in dogs. Methods: Twenty-one dogs were submitted to spinal cord ischemia induced by descending thoracic aorta cross-clamping for 45 min. Control group underwent only the aortic cross-clamping (n=7), group A underwent one cycle of ischemic preconditioning (n=7) and group B underwent three equal cycles of ischemic preconditioning (n=7), immediately before the aortic cross-clamping. Ischemic preconditioning cycles were determined by somatosensory evoked potentials monitoring. Neurologic evaluation was performed according to the Tarlov score at 72 h of follow-up. The animals were then sacrificed and the spinal cord harvested for histopathology. Results: Aortic pressures before and after the occluded segment were similar in the three groups. Ischemic preconditioning periods corresponded to a mean ischemic time of 3±1 min and a mean recovery time of 7±2 min. Severe paraplegia was observed in three animals in Control group, in four in group A and in none in group B. Tarlov scores of group B were significantly better in comparison to the Control group (P=0.036). Histopathologic examination showed severe neuronal necrosis in the thoracic and lumbar gray matter in animals who presented paraplegia. Conclusions: Immediate repetitive ischemic preconditioning based on somatosensory evoked potentials monitoring seems to protect spinal cord during descending aorta cross-clamping, reducing paraplegia incidence.