Thorac Cardiovasc Surg 2014; 62 - OP136
DOI: 10.1055/s-0034-1367210

Spinal cord ischemia following total aortic arch replacement and endovascular stenting of the descending thoracic aorta (TEVAR). Pathophysiological investigations in a porcine model

P. Haldenwang 1, N. Prochnow 2, A. Baumann 3, L. Häuser 4, M. Schlömicher 1, D. Ziebura 4, I. Schmitz 5, J. Strauch 1
  • 1BG University Hospital Bergmannsheil, Ruhr-University of Bochum, Department of Cardiothoracic Surgery, Bochum, Germany
  • 2Ruhr-University of Bochum, Department of Neuroanatomy and Molecular Brain Research, Bochum, Germany
  • 3BG University Hospital Bergmannsheil, Ruhr-University of Bochum, Department of Anesthesiology, Intensive Care, Palliative Care and Pain Medicine, Bochum, Germany
  • 4Ruhr-University of Bochum, Bochum, Germany
  • 5BG University Hospital Bergmannsheil, Ruhr-University of Bochum, Institute for Pathology, Bochum, Germany

Objective: Combination of open aortic arch replacement and endovascular stenting of the descending thoracic aorta (TEVAR) represent the therapy of choice for complicated aortic diseases. Aim of our study was to analyze if 90 min selective cerebral perfusion (SCP) at 28°C followed by an endovascular stenting of the descending aorta may cause spinal cord ischemia.

Methods: 14 pigs (41 ± 3 kg) were cooled on CPB to 28°C. After clamping of the aortic arch, SCP was established for 90 min: randomly, in n = 7 animals the left sided vertebral artery as well as the T4-T13 thoracic segmental arteries (TSA) were clipped, in order to simulate a TEVAR procedure, whereas the TSA of the other n = 7 animals remained untouched. After systemic reperfusion and CPB weaning, hemodynamic data were registered for 120 min. Microspheres were injected at baseline, reaching of 28°C, during SCP, respectively at 60 and 120 min off-CPB for spinal cord blood flow (SCBF) calculation. Via trans-cranial stimulation myogenic motor-evoked potentials (MEP) were assessed at the same time points. After sacrifice, the thoracic and lumbar spinal cord was analyzed histologically using a 9-point schematic grading system (Kleinman-Score: 0 = normal, 8 = necrosis of the entire section).

Results: SCBF decreased in both groups during cooling and SCP to less than 40% of baseline (4 ± 2 ml/min/100 g). During reperfusion SCBF recovered slowly in the non-clipped-group, with significant lower SCBF in the L1-L5 region of the TSA-clipped animals. At 28°C the MEP amplitude showed a decrease to 80-90% from baseline. After 90 min of SCP the MEP assessed in the m. masseter, used as stimulation output control, didn't differ significantly between groups: 90 ± 3% vs. 92 ± 6%. The m. external oblique (T7-T11) amplitude was comparatively lower, without significant differences between groups 76 ± 7% vs. 74 ± 5%. MEP reached significant lower amplitude levels in the L1-L5 region of the TSA-clipped-animals: 59 ± 7% vs. 84 ± 15% (m. vastus medialis) and 48 ± 6% vs. 82 ± 26% (m. tibialis anterior). It recovered back to baseline only in the non-clipped-group. Histological analysis showed a significant higher ischemia rate in the L1-L5 region of the TSA-clipped-animals (Kleinman-Score: 6.0 ± 0.6 vs.2.5 ± 2.3).

Conclusion: 90 min of SCP provide sufficient spinal cord protection during arch replacement at 28°C. In combination with TEVAR of the descending aorta the lumbar spinal cord perfusion may be altered, which causes functional and structural damage.