Introduction: Impaired collateral circulation can lead to stroke during carotid
endarterectomy. Carotid stump pressure (CSP) is used as a surrogate measure
of collateral flow. The objective was to determine whether anatomical
features obtained from digital subtraction angiography correlate with CSP
during temporary internal carotid artery occlusion. The second objective was
to use these features in combination to predict CSP. Methods: Digital subtraction angiographies from 102 patients obtained before
endarterectomy were reviewed for anatomical variables including: degree of
ipsilateral and contralateral carotid artery stenosis; patency of the
anterior communicating artery; presence of cross-flow into ipsilateral
middle cerebral artery branches; and size (< or ≥1 mm calibre) of the
ipsilateral proximal anterior cerebral (A1), the contralateral A1, and the
ipsilateral posterior communicating arteries. At surgery, systemic mean
arterial pressure (MAP) and CSP were recorded. Multiple regression analysis
was used to assess for anatomical features significantly associated with
CSP. A “predicted CSP” equation was applied to 54 subsequent patients and
correlated with measured CSP. Results: Variables correlating with CSP included MAP (p=0.001); the presence
of severe contralateral carotid stenosis (p=0.002); patency of the anterior
communicating artery (p=0.013); and the size of the contralateral A1 segment
(p=0.029). Angiographic cross-flow, ipsilateral A1 size, and ipsilateral
posterior communicating artery size were not significant. Predicted CSP
correlated significantly with measured CSP (p<0.0001;
R2=0.34). Conclusions: Anatomical features and systemic MAP are associated with carotid
stump pressure during internal carotid artery occlusion and account for a
significant amount of its variation.