Influence of luminal stenosis in aneurysmal and non-aneurysmal blunt cerebrovascular injury

Highlights

• While not significant, higher percentage luminal stenosis within current BCVI grades had higher stroke rates.

• Use of endovascular interventions may confound ability to detect true BCVI severity when used for stroke prevention.

• Grade 3 BCVI with concurrent luminal stenosis may be a high-risk BCVI subgroup.

Abstract

Background

Current blunt cerebrovascular injury (BCVI) grading grossly differentiates injury characteristics such as luminal stenosis (LS) and aneurysmal disease. The effect of increasing degree of LS beyond the current BCVI grading scale on stroke formation is unknown.

Study Design

BCVI over a 3-year period were retrospectively reviewed. To investigate influence of LS beyond the BCVI grading scale within aneurysmal and non-aneurysmal BCVI, grade 2 BCVI were subdivided into BCVI with ≥ 25% and ≤ 50% LS and BCVI with > 50% and ≤ 99% LS. Grade 3 BCVI were subdivided into BCVI with pseudoaneurysm (PSA) without LS and BCVI with PSA and LS. We hypothesized increased LS beyond the current BCVI grade distinctions would be associated with higher rates of stroke formation.

Results

312 BCVI were included, of which 140 were carotid BCVI and 172 vertebral BCVI. Sixteen carotid BCVI underwent endovascular intervention (EI) and 19 suffered a stroke. In carotid BCVI stroke rates increased sequentially with BCVI grade except in grade 3. There was a stroke rate of 12% in grade 1 carotid BCVI, 18% in grade 2, 6% in grade 3, and 31% in grade 4. In subgroup analysis for grade 2 carotid BCVI, BCVI with > 50% and ≤ 99% LS had higher rates of stroke (22% vs. 15%, p = 0.44) than BCVI with ≥ 25% and ≤ 50% LS. In subgroup analysis of grade 3 carotid BCVI, BCVI with PSA and LS had higher rates of stroke (9% vs. 4%, p = 0.48) than BCVI with PSA without LS. Higher rates of EI in grade 2 carotid BCVI with > 50% and ≤ 99% LS (22% vs. 5%, p = 0.14) and grade 3 carotid BCVI with PSA and LS (35% vs. 4%, p = 0.01) were noted in subgroup analysis.

Conclusion

Higher percentage LS beyond the currently used BCVI grading scale has a non-significantly increased rate of stroke in both aneurysmal and non-aneurysmal BCVI. Grade 3 BCVI with PSA and LS seems to be a high-risk subgroup. Use of EI confounds modern measurement of stroke risk in higher LS BCVI.

Introduction

In high grade blunt cerebrovascular injury (BCVI), rates of stroke can be substantial with stroke frequently responsible for patient mortality [1,2]. Pharmacologic therapy with antiplatelet agents or anticoagulation and early BCVI diagnosis decrease stroke rates [[3], [4], [5]]. Focus is placed on rapid screening and initiation of pharmacologic therapy to prevent strokes. Pharmacologic and endovascular BCVI treatment are chosen based on BCVI grade, which stratifies BCVI from 1 to 5 based on radiographic characteristics [6].

As BCVI grade increases so does morbidity, with higher BCVI grade associated with higher stroke rates [1,7]. However, there are many lesion characteristics which comprise BCVI, including degree of luminal stenosis (LS), intraluminal thrombus, intimal flap, and arteriovenous fistula. The presence of pseudoaneurysm (PSA) confounds the grading scale as well. It is difficult to encompass pathophysiology this complex into a watertight grading scale.

The influence of LS on stroke formation is mostly unknown. LS is only grossly differentiated between grade 1 BCVI (< 25% LS), grade 2 BCVI (≥ 25% LS and ≤ 99% LS) and grade 4 BCVI (100% LS or complete vessel occlusion) within the currently used BCVI grading scale. There is no differentiation for LS in grade 3 BCVI, with grade 3 BCVI comprising all degrees of LS with PSA. In chronic carotid stenosis higher degree of LS is associated with need for intervention to decrease stroke risk, and similar principles may hold true in BCVI [8]. For example in BCVI, a 30% LS is a grade 2 injury just as 90% LS is a grade 2 injury, but these BCVI are unlikely to have the same risk of stroke.

The primary aim of this study was to investigate the association between LS and rates of stroke formation for both aneurysmal and non-aneurysmal disease. We hypothesized that higher degree of LS beyond the currently used BCVI grading scale would be associated with higher rates of stroke.