gms | German Medical Science

Objective: Intra- or postoperative angiography serves as a gold standard to define vessel anatomy and aneurysm occlusion post clipping, but lacks information about critically reduced cerebral blood perfusion (CBP). Intraoperative indocyanine-green videoangiography is helpful to investigate vascular patency in close vicinity of the clip, but not in distant vessel territories. As CBP is crucial for patients' neurological outcome, we investigated the usefulness of intraoperative CT (iCT), CT angiography (CTA) and CT perfusion (CTP) during clipping procedures.

Methods: Out of a prospective database (01/2013 - 11/2017) of consecutive patients with aneurysm clipping with pre- and postoperative angiography, we analyzed those patients who received multimodal iCT imaging with a 40-slice sliding gantry scanner and a radiolucent headholder system. Clinical data, iCT imaging and angiography were analyzed. Clinical outcome was assigned by the modified Rankin scale (mRS) after operation, at time of discharge and after 8 weeks.

Results: Among 251 patients, 52 patients (2 SAH) with 58 aneurysms received iCT imaging. CTA showed reduced vessel enhancement of distal branches in 3 patients (5.8%), whereas CTP was decreased in 8 patients (15.4%). In these patients, re-inspection of clip position was performed immediately. In one patient, clip replacement was necessary, resulting in improved CBP in a second CTP. In the other cases, mean arterial blood pressure was increased as an early intraoperative consequence of CTP. Immediately after surgery, 11 patients presented a neurological deterioriation (mRS1-3 n=10, mRS4 n=1 SAH). At time of discharge, neurological symptoms had completely resolved in 9 patients, remained stable in 1 patient with SAH (mRS4) and resolved after 8 weeks in 1 patient (mRS1, slight hemiparesis). 8 out of 8 patiens with CBP reduction showed a neurological deficit. Out of those patients with neurological deterioriation (n=11/52), 8 patients had CBP reduction and 3 not (positive predictive value: 100%, specificity: 100%, sensitivity: 72.7%). Of those patients (n=3) with neurological deterioriation and normal CBP, 2 had memory deficits due to fornix ischemia undetected due to local clip artifacts and 1 patient developed a seizure which resolved under antiepileptic treatment.

Conclusion: Reduced CBP after clipping is a major risk factor for neurological deterioration and can be detected and treated accordingly early by means of intraoperative CTA and CTP.