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.