Non-invasive assessment of cerebral perfusion pressure: Applied towards preoperative planning of aortic arch surgery with selective antegrade cerebral perfusion

Selective antegrade cerebral perfusion (SACP) is a protective procedure to ascertain adequate brain perfusion during aortic arch surgeries requiring moderate hypothermic circulatory arrest. SACP entails catheterization of arteries feeding the brain, which can be done bilaterally (bSACP) or unilaterally (uSACP), but there is no consensus on when to use each approach. bSACP may increase the risk of embolization, while uSACP risks hypoperfusion due to insufficient perfusion pressure in the contralateral hemisphere, since a single catheter must perfuse both hemispheres. We developed and tested the feasibility of a new method for predicting cerebral perfusion pressures (CPP) during SACP, which could potentially aid clinicians in preoperatively identifying which SACP approach to use. Feasibility of the method was evaluated in five patients eligible for aortic arch surgery (65 ± 7 years, 3 men). Patients were investigated preoperatively with computed tomography angiography (CTA) and 4D flow magnetic resonance imaging (MRI) to assess patient-specific arterial anatomy and blood flows. From the imaging, computational fluid dynamics (CFD) simulations estimated the patients' vascular resistances. Applying these resistances and intraoperative SACP pressure/flow settings to the model's boundary conditions allowed for predictions of contralateral CPP during SACP. Predicted pressures were compared to corresponding intraoperative pressure measurements. The method showed promise for predicting contralateral CPP during both uSACP (median error (range): 2.4 (-0.2-18.0) mmHg) and bSACP (0.8 (-3.3-5.4) mmHg). Predictions were most sensitive to collateral artery size. This study showed the feasibility of CPP predictions of SACP, and presents key features needed for accurate modelling.