Decreasing Spatial Variability of Individual Watershed Areas by Revascularization Therapy in Patients With High-Grade Carotid Artery Stenosis

BACKGROUND

Carotid artery stenosis can impair cerebral hemodynamics especially within watershed areas (WSAs) between vascular territories. WSAs can shift because of collateral flow, which may be an indicator for increased hemodynamic implications and hence higher risk for ischemic stroke. However, whether revascularization treatment can reverse the spatial displacement of individual WSAs (iWSAs) and impaired hemodynamics remains unknown.

HYPOTHESIS

That iWSAs spatially normalize because of hemodynamic improvement resulting from revascularization treatment.

STUDY TYPE

Prospective.

POPULATION

Sixteen patients with unilateral, high-grade carotid artery stenosis confirmed by duplex ultrasonography and 17 healthy controls.

FIELD STRENGTH/SEQUENCES

A 3 T-magnetization-prepared rapid acquisition gradient echo (MPRAGE), gradient-echo echo planar dynamic susceptibility contrast (DSC), and fluid-attenuated inversion recovery (FLAIR) sequences. Additionally, contrast-enhanced 3D gradient echo magnetic resonance angiography (MRA) and diffusion-tensor imaging (DTI) spin-echo echo planar imaging were performed.

ASSESSMENT

iWSAs were delineated by a recently proposed procedure based on time-to-peak maps from DSC perfusion MRI, which were also used to evaluate perfusion delay. We spatially compared iWSAs and perfusion delay before and after treatment (endarterectomy or stenting). Additionally, the Circle of Willis collateralization status was evaluated, and basic cognitive testing was conducted.

STATISTICAL TESTS

Statistical tests included two-sample t-tests and Chi-squared tests. A P value < 0.05 was considered to be statistically significant.

RESULTS

After revascularization, patients showed a significant spatial shift of iWSAs and significantly reduced perfusion delay ipsilateral to the stenosis. Spatial shift of iWSA (P = 0.007) and cognitive improvement (P = 0.013) were more pronounced in patients with poor pre-existing collateralization. Controls demonstrated stable spatial extent of iWSAs (P = 0.437) and symmetric perfusion delays between hemispheres over time (P = 0.773).

DATA CONCLUSION

These results demonstrate the normalization of iWSA and impaired hemodynamics after revascularization in patients with high-grade carotid artery stenosis.

LEVEL OF EVIDENCE

2 TECHNICAL EFFICACY: Stage 2.

European survey on acute coronary syndrome diagnosis and revascularisation treatment: Assessing differences in reported clinical practice with a focus on strategies for specific patient cases

RATIONALE, AIMS, AND OBJECTIVES

While different imaging and treatment options are available in acute coronary syndrome (ACS) care, there is a lack of data regarding their use across Europe. We examined the diagnostic and treatment strategies in patients with known or suspected ACS as reported by physicians and identified variations in responses across European countries and geographical areas.

METHOD

A web-based clinician survey focusing on ACS imaging and revascularization treatments was circulated through email distribution lists and websites of European professional societies in the field of cardiology. We collected information on respondents' clinical setting and specialty. Reported percentages of patients receiving imaging or treatment modalities and percentages of clinicians reporting to use modalities in a range of clinical scenarios were analyzed. Statistical comparisons were performed.

RESULTS

In total, 69 responses were received (Sweden [n = 20], United Kingdom [n = 16], Northern/Western Europe [n = 17], Southern Europe [n = 9], and Central Europe [n = 7]). Considerable variations between geographical areas were seen in terms of reported diagnostic modalities and treatment strategies. For example, when presented with the scenario of a theoretical 45-year-old smoking female with a suspected ACS, 56% of UK clinicians reported to use coronary computed tomography angiography, compared to only 10% of Swedish clinicians (P = .002). Large variations were observed regarding the reported use of fractional flow reserve by physicians for non-culprit lesions during invasive management of myocardial infarction patients (44% in Sweden, 31% in the United Kingdom, and 30% in Northern/Western Europe vs non-use in Central and Southern Europe).

CONCLUSIONS

In this survey, respondents reported different diagnostic and treatment strategies in ACS care. These variations seem to have geographic components. Larger studies or real world data are needed to verify these observations and investigate their causes. More research is needed to compare the quality and efficiency of ACS care across countries and explore pathways for improvement.