CASE REPORT
A 66 years old female admitted to our department for a redo aortic valve replacement. A year before, she underwent successful emergency surgery for an acute type A aortic dissection with reconstruction of the aortic root, resuspension of the aortic valve commissures, replacement of the ascending aorta and proximal hemi-arch. One month later, she underwent a percutaneous endovascular insertion of a stented graft in the thoracic descending aorta, which was critically compressed by the increasing diameter of the false lumen at the residual Type B dissection. She developed progressively severe AR with LV dilatation and therefore she underwent aortic valve replacement with a Trifecta 23 mm bioprosthesis 9 months after the initial procedure. For cerebral perfusion monitoring a NIRS device was placed on the patient before surgery.
After initiating extracorporeal perfusion and to avoid distension of the dilated LV a venting cannula was inserted into the LV through the RSPV. LV venting was initiated with a flow rate of 400 ml/min. The anesthesiologists immediately reported a bilateral significant drop of the brain saturation as evidenced by NIRS device (Fig. 1). After exclusion of the usual causes of cerebral saturation drop, we interrupted the LV venting, as it was the last surgical step done. The values of the cerebral O2 saturations immediately started improving, returning at the baseline level (Fig. 2). The hemodynamic situation of the patient was stable during all this time period (blood pressure, heart rate, ECC-flow and venous return).
To perform the operation safely, LV venting was then reduced to a minimum until aortic cross-clamping. Thereafter it was increased again. The operation could be completed without further NIRS saturation drop incidents. During the first post-operative sedation break, the patient was neurologically intact. The post-operative evolution was without complications.