Risk prediction of postoperative permanent stroke in acute type A aortic dissection patients with severe common carotid artery stenosis using brain CT perfusion

Abstract

Rationale and objectives: To explore the feasibility and predictive utility for neurological outcomes of brain computed tomography perfusion (CTP) for surgically treated acute type A aortic dissection patients with severe common carotid artery stenosis.

Materials and methods: Consecutive acute type A aortic dissection patients with severe common carotid artery stenosis undergoing preoperative brain computed tomography perfusion and surgery at our center were examined in retrospect. Brain perfusion was assessed using parameters including cerebral blood flow, cerebral blood volume, mean transmit time, time to maximum, penumbra volume and infarct core volume. Univariable and multivariable regression analyses were performed to identify clinical and imaging predictors associated with postoperative permanent stroke.

Results: Out of 44 patients included, 19 patients (43.2 %) presented with postoperative permanent stroke. Univariable analysis revealed that internal carotid artery dissection, cerebral blood flow of the affected side, cerebral blood volume of the affected side, and penumbra volume were implicated in postoperative permanent stroke. Multivariable analysis further showed that cerebral blood flow of the affected side was an independent indicator of a permanent stroke following surgery (odds ratio: 0.820, 95 % confidence interval: 0.684-0.982; p = 0.012). The area under the receiver operating characteristic curve was 0.867 (95 % confidence interval: 0.764-0.970), and the optimal cut-off value was 45.6mL/100 mL/min.

Conclusion: Cerebral blood flow of the affected side was an independent indicator of permanent stroke following surgery in acute type A aortic dissection patients with severe common carotid artery stenosis. Brain CTP could be a helpful modality for quantitative evaluation of cerebral malperfusion and neurological prognostication.

Keywords: Acute aortic dissection; Cerebral malperfusion; Computed tomography perfusion; Permanent stroke; Risk prediction.

Fig. 1

Study flowchart. ATAAD = acute type A aortic dissection, CCA = common carotid artery, CTP = computed tomography perfusion.

Fig. 2

Receiver operating characteristic curve of cerebral blood flow of the affected side to predict postoperative permanent stroke. The area under the receiver operating characteristic curve was 0.867, and optimal cut-off value was 45.6mL/100 mL/min.

Fig. 3

A 61-year-old woman presented with thoracic and back pain for 10 h and no neurological symptoms before admission. Aortic CTA showed ATAAD with occlusion of right CCA (red arrow) and severe true lumen stenosis of left CCA (yellow arrow) (a). Brain CT on the fifth day after the emergency surgery showed an infarct in the right parietal lobe (b, red arrow). CTA = computed tomography angiography, ATAAD = acute type A aortic dissection, CCA = common carotid artery.

Fig. 4

Preoperative brain CTP images of the same patient as Fig. 2.Tmax of the affected side (right) was 4.97s, and Tmax of the contralateral side was 2.11s (a). CBV of the affected side (right) was 3.05mL/100 mL, and CBV of the contralateral side was 3.40 mL/100 mL (b). CBF of the affected side (right) was 23.41 mL/100 mL/min, and CBF of the contralateral side was 54.23 mL/100 mL/min (c). MTT of the affected side (right) was 9.45s, and MTT of the contralateral was 4.35s (d). CTP = computed tomography perfusion, Tmax = time to maximum, CBV = cerebral blood volume, CBF = cerebral blood flow, MTT = mean transit time.