Translesional Pressure Gradient Alters Relationship Between Blood Pressure and Recurrent Stroke in Intracranial Stenosis

Background and Purpose- There is debate over an optimal systolic blood pressure (SBP) in secondary stroke prevention of patients with symptomatic intracranial atherosclerotic stenosis (sICAS). We investigated whether translesional pressure gradient across sICAS would alter the relationship between SBP and risk of recurrent stroke in such patients. Methods- We recruited patients with sICAS (50%-99% stenosis) confirmed in computed tomography angiography. We simulated blood flow across sICAS with computed tomography angiography-based computational fluid dynamics models. Translesional pressure ratio (PR=Pressure(post-stenotic)/Pressure(pre-stenotic)) was calculated in each case. Pressure ratio (PR) <= median was defined as low PR, indicating larger translesional pressure gradient across sICAS. All patients received optimal medical treatment. We investigated the interaction of translesional PR and mean SBP during follow-up (SBPFU) in determining the risk of the primary outcome, recurrent ischemic stroke in the same territory within 1 year. Results- Among 157 patients with sICAS, the median PR was 0.93. Multivariate Cox regression revealed significant PR-SBPFU interaction on the primary outcome (P=0.008): in patients with normal PR, risk of primary outcome significantly decreased with lower SBPFU (hazard ratio for 10 mm Hg decrement =0.46; P=0.018); however, in those with low PR, SBPFU <= 130 mm Hg was associated with significantly increased risk of primary outcome, compared with 130<SBPFU<150 mm Hg (hazard ratio=5.08; P=0.043). Conclusions- Low SBP level may be associated with increased risk of stroke recurrence in patients with sICAS with a large translesional pressure gradient. Translesional PR by computational fluid dynamics models may yield a promising indicator to guide more individualized blood pressure management in patients with sICAS, warranting future studies.