Angiography-based hemodynamic features predict recurrent ischemic events after angioplasty and stenting of intracranial vertebrobasilar atherosclerotic stenosis

Abstract

Objectives: To assess the predictive value of hemodynamic features for stroke relapse in patients with intracranial vertebrobasilar atherosclerotic stenosis treated with percutaneous transluminal angioplasty and stenting (PTAS) using quantitative digital subtraction angiography (q-DSA).

Methods: In this retrospective longitudinal study, patients with intracranial vertebrobasilar atherosclerotic stenosis and who underwent PTAS treatment between January 2012 and May 2020 were enrolled. The q-DSA assessment was performed before and after PTAS. ROIs 1-4 were placed along the vertebral artery, proximal and distal basilar artery, and posterior cerebral artery; ROIs 5-8 were in 5 mm and 10 mm proximal and distal to the lesion, respectively. Relative time to peak (rTTP) was defined as the difference in TTP between ROIs. Cox regression analyses were performed to determine risk factors for recurrent stroke.

Results: A total of 137 patients (mean age, 62 years ± 10 [standard deviation], 83.2% males) were included, and 26 (19.0%) patients had stroke relapse during follow-up (median time of 42.6 months [interquartile range, 19.7-60.7]). Preprocedural rTTP_4-1 (adjusted hazard ratio (HR) = 2.270; 95% CI 1.371-3.758; p = 0.001) and preprocedural rTTP_8-5 (adjusted HR = 0.240; 95% CI 0.088-0.658; p = 0.006) were independently associated with the recurrent stroke. These hemodynamic parameters provided an incremental prognostic value for stroke relapse (AUC, 0.817 [0.704-0.931]; the net reclassification index, 0.431 [0.057-0.625]; and the integrated discrimination index, 0.140 [0.035-0.292]).

Conclusions: In patients with intracranial vertebrobasilar atherosclerosis treated with PTAS, preprocedural prolonged TTP of the target vessel and shortened trans-stenotic TTP difference were associated with stroke relapse. Q-DSA-defined hemodynamic parameters provided incremental predictive value over conventional parameters for stroke recurrence.

Clinical relevance statement: Quantitative DSA analysis enables intuitive observation and semi-quantitative evaluation of peri-therapeutic cerebral blood flow. More importantly, quantitative DSA-defined hemodynamic parameters have the potential for risk stratification of patients with intracranial atherosclerotic stenosis.

Key points: Semi-quantitative angiography-based parameters can reflect pre- and postprocedural subtle changes in blood flow in patients with intracranial atherosclerotic stenosis. Although angioplasty procedures can significantly improve blood flow status, patients with more restricted baseline blood flow still show a higher risk of stroke recurrence. Angiography-based hemodynamic features possess prognostic value and can serve as clinical markers to assess stroke risk of patients with intracranial atherosclerotic stenosis.

Keywords: Cerebral angiography; Hemodynamics; Intracranial atherosclerosis; Recurrence; Stroke.

Fig. 1

Pre- and postprocedural hemodynamic analyses by quantitative digital subtraction angiography. These show the original DSA images (a, b), quantitative DSA images which were color-coded according to the values of time to peak (c, d), and the time-density curve of selected ROIs (e, f) before (a, c, e) and after (b, d, f) the procedure. In this case, it was observed that the stenosis of the fusion segment of the basilar artery was relieved and the cerebral blood perfusion status was significantly improved after the procedure. Abbreviations: ROI, regions of interest

Fig. 2

The comparison of pre- and postprocedural hemodynamic parameters at different ROIs of the target vessel between patients with and without recurrent stroke. The first row shows the values of preprocedural (a) and postprocedural (b) rTTP, and the change of rTTP (c), and the second row shows preprocedural (d) and postprocedural (e) rAUC, and the relative rAUC (f). The green lines represent parameters of patients with recurrent stroke; the red lines represent parameters of patients without recurrent stroke. Abbreviations: ROI, regions of interest; rTTP, relative time to peak; rAUC, relative area under the curve

Fig. 3

The comparison of pre- and postprocedural hemodynamic parameters at trans-stenotic ROIs between patients with and without recurrent stroke. The first row shows the values of preprocedural (a) and postprocedural (b) rTTP, and the change of rTTP (c), and the second row shows preprocedural (d) and postprocedural (e) rAUC, and the relative rAUC (f). The green lines represent parameters of patients with recurrent stroke; the red lines represent parameters of patients without recurrent stroke. Abbreviations: ROI, regions of interest; rTTP, relative time to peak; rAUC, relative area under the curve

Fig. 4

Time-dependent ROC curves (at 5 years) of prediction models. The blue dashed lines represent the ROC curve of model-1 (AUC = 0.703); the green dot-dashed lines represent the ROC curve of model-2(AUC = 0.808); the red solid lines represent the ROC curve of model-3 (AUC = 0.817)

Fig. 5

The Kaplan-Meier curves for recurrent ischemic events of cohorts with different rTTPs (relative time to peak). Kaplan-Meier curves for recurrent stroke (a) and recurrent ischemic events (ischemic stroke or transient ischemic attacks, panel b) of intracranial atherosclerotic stenosis (ICAS) patients with different rTTP_4-1 values, and for recurrent stroke (c) and recurrent ischemic events (d) of ICAS patients with different rTTP_8-5 values

Fig. 6

Subgroup analyses of recurrent ischemic stroke. This forest plot shows the hazard ratios and 95% confidence intervals for the relative risk between patients with high and low rTTP_4-1 before the percutaneous transluminal angioplasty procedure. Abbreviations: rTTP, relative time to peak; IS, ischemic stroke; TIA, transient ischemic attack; ICAS, intracranial atherosclerosis; VA, vertebral artery