Diabetes mellitus and carotid artery plaques exhibiting high-intensity signals on MR angiography are related to increased platelet reactivity after carotid artery stenting

Intraplaque neovascularisation is associated with ischaemic events after carotid artery stenting: an observational prospective study

Background

Intraplaque neovascularisation (IPN) is a component of vulnerable atherosclerotic plaque, which is a biomarker of cardiovascular events. However, the identification of patients with high probability of ischaemic events after carotid artery stenting (CAS) is mainly based on vascular risk factors. Prospective studies on the development of plaques are lacking.

Objectives

The purpose of this study was to investigate whether IPN detected by contrast-enhanced ultrasound is related to the occurrence of ischaemic events after CAS.

Methods

Sixty consecutive patients receiving CAS were prospectively enrolled in our centre. The patients were evaluated using contrast-enhanced ultrasound before CAS. According to the degree of microbubble enhancement, IPN was graded from 0 to 2. Endpoint events, including ischaemic stroke and other cardiovascular events, were recorded during follow-up. Kaplan-Meier survival curves and Cox proportional-hazards models were used to evaluate the risk factors for endpoint events. At a median follow-up of 30 months, 13 patients (28.9%) experienced endpoint events. Kaplan-Meier survival curves showed that patients with grade 2 IPN had a higher risk of future ischaemic events than those with grade 0 or 1 IPN (p < 0.05). Cox proportional-hazards models showed that grade 2 IPN [adjusted hazard ratio (HR), 4.049; 95% confidence interval (CI), 1.078-15.202] was a significant predictor of endpoint events (p < 0.05).

Conclusion

Grade 2 IPN evaluated by contrast-enhanced ultrasound has predictive value for ischaemic events in patients after CAS and may help clinicians identify high-risk patients who need close follow-up.

Plain Language Summary

Neovascularisation and carotid artery stenting Introduction: Introduction: It is unclear whether intraplaque neovascularisation (IPN) can be used as an biomarker of high probability ischemic events after carotid artery stenting (CAS).Materials and methods: We enrolled 60 patients who underwent CAS, all of whom underwent CEUS before CAS. We recorded ischaemic events during follow-up. Cox proportional-hazards models were used to evaluate the risk factors for ischaemic events.Results: We found that grade 2 IPN was an independent predictor (hazard ratio, 4.049; 95% confidence interval, 1.078-15.202; p < 0.05) of ischaemic events in patients after CAS.Conclusion: This may help clinicians identify high-risk patients who need close follow-up.

Aspirin Resistance in Vascular Disease: A Review Highlighting the Critical Need for Improved Point-of-Care Testing and Personalized Therapy

Aspirin resistance describes a phenomenon where patients receiving aspirin therapy do not respond favorably to treatment, and is categorized by continued incidence of adverse cardiovascular events and/or the lack of reduced platelet reactivity. Studies demonstrate that one in four patients with vascular disease are resistant to aspirin therapy, placing them at an almost four-fold increased risk of major adverse limb and adverse cardiovascular events. Despite the increased cardiovascular risk incurred by aspirin resistant patients, strategies to diagnose or overcome this resistance are yet to be clinically validated and integrated. Currently, five unique laboratory assays have shown promise for aspirin resistance testing: Light transmission aggregometry, Platelet Function Analyzer-100, Thromboelastography, Verify Now, and Platelet Works. Newer antiplatelet therapies such as Plavix and Ticagrelor have been tested as an alternative to overcome aspirin resistance (used both in combination with aspirin and alone) but have not proven to be superior to aspirin alone. A recent breakthrough discovery has demonstrated that rivaroxaban, an anticoagulant which functions by inhibiting active Factor X when taken in combination with aspirin, improves outcomes in patients with vascular disease. Current studies are determining how this new regime may benefit those who are considered aspirin resistant.

Platelet Biomarkers in Patients with Atherosclerotic Extracranial Carotid Artery Stenosis: A Systematic Review

OBJECTIVE

The aim was to enhance understanding of the role of platelet biomarkers in the pathogenesis of vascular events and risk stratifying patients with asymptomatic or symptomatic atherosclerotic carotid stenosis.

DATA SOURCES

Systematic review conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement.

REVIEW METHODS

A systematic review collated data from 1975 to 2020 on ex vivo platelet activation and platelet function/reactivity in patients with atherosclerotic carotid stenosis.

RESULTS

Forty-three studies met the inclusion criteria; the majority included patients on antiplatelet therapy. Five studies showed increased platelet biomarkers in patients with ≥ 30% asymptomatic carotid stenosis (ACS) vs. controls, with one neutral study. Preliminary data from one study suggested that quantification of "coated platelets" in combination with stenosis severity may aid risk stratification in patients with ≥ 50% - 99% ACS. Platelets were excessively activated in patients with ≥ 30% symptomatic carotid stenosis (SCS) vs. controls (≥ 11 positive studies and one neutral study). Antiplatelet-High on Treatment Platelet Reactivity (HTPR), previously called "antiplatelet resistance", was observed in 23% - 57% of patients on aspirin, with clopidogrel-HTPR in 25% - 100% of patients with ≥ 50% - 99% ACS. Aspirin-HTPR was noted in 9.5% - 64% and clopidogrel-HTPR in 0 - 83% of patients with ≥ 50% SCS. However, the data do not currently support the use of ex vivo platelet function/reactivity testing to tailor antiplatelet therapy outside of a research setting. Platelets are excessively activated (n = 5), with increased platelet counts (n = 3) in recently symptomatic vs. asymptomatic patients, including those without micro-emboli on transcranial Doppler (TCD) monitoring (n = 2). Most available studies (n = 7) showed that platelets become more reactive or activated following carotid endarterectomy or stenting, either as an acute phase response to intervention or peri-procedural treatment.

CONCLUSION

Platelets are excessively activated in patients with carotid stenosis vs. controls, in recently symptomatic vs. asymptomatic patients, and may become activated/hyper-reactive following carotid interventions despite commonly prescribed antiplatelet regimens. Further prospective multicentre studies are required to determine whether models combining clinical, neurovascular imaging, and platelet biomarker data can facilitate optimised antiplatelet therapy in individual patients with carotid stenosis.

Intraplaque high-intensity signal on time-of-flight magnetic resonance angiography and restenosis after carotid artery stenting

OBJECTIVE

To test the hypothesis that intraplaque hemorrhage is a predictor of restenosis after carotid artery stenting (CAS), the association between intraplaque high-intensity signal (HIS) on time-of-flight MR angiography (TOF-MRA), as a marker of intraplaque hemorrhage, and restenosis after CAS was assessed in the present observational study.

METHODS

Consecutive patients who underwent initial CAS for atherosclerotic stenosis in the cervical internal carotid artery in the authors' department were enrolled. Of these, patients without preprocedural cervical TOF-MRA were excluded. Outcome measures were ≥ 50% restenosis, defined as a peak systolic velocity of > 1.3 m/sec; or occlusion and ≥ 70% restenosis, defined as a peak systolic velocity of > 2.1 m/sec; or occlusion on carotid duplex ultrasound.

RESULTS

Of 230 consecutive patients who underwent initial CAS, 22 without preprocedural cervical TOF-MRA were excluded. Of the remaining 208 patients (mean age 73 years; 33 women), 46 had intraplaque HIS. Ultrasound follow-up was not performed in 4 patients. The median follow-up duration was 3.2 years (interquartile range 1.7-5.1 years). During the follow-up period, 102 patients had ≥ 50% restenosis and 36 had ≥ 70% restenosis. Intraplaque HIS was significantly associated with increased risk of ≥ 50% restenosis (adjusted hazard ratio 2.18; 95% CI 1.28-3.68) and ≥ 70% restenosis (adjusted hazard ratio 3.12; 95% CI 1.32-7.52).

CONCLUSIONS

Intraplaque HIS on TOF-MRA was associated with increased risk of restenosis after CAS. The present results indicate that intraplaque hemorrhage is a predictor of restenosis after CAS.

Clopidogrel underactivity is a common in patients with acute symptomatic severe carotid stenosis

BACKGROUND

Clopidogrel is commonly used for secondary stroke prevention in patients with large vessel stenosis. Reduced Clopidogrel high on treatment platelet reactivity (CR) can lead to Clopidogrel underactivity (CU) causing acute thrombosis. However, the prevalence of CU among patients with acute symptomatic carotid disease remains unknown. Therefore, we aimed to find the prevalence and identify the predictors for CU among patients with acutely symptomatic carotid stenosis.

PATIENTS AND METHODS

Over the span of 14 months, CR was measured at the time of endovascular procedure in all patients undergoing angiography and stenting because of acute symptomatic carotid stenosis. Only patients treated per institutional protocol with a combination of Clopidogrel and Aspirin were included. CR was measured with VerifyNowP2Y12 reaction units (PRU) and CU was defined as PRU > 208. Patients with CU were compared to those without CU.

RESULTS

Thirty-five patients were included (mean age 71.3 ± 10, 76% men) and twelve (34.3%, mean age 71.8 ± 8.4, 58% men) had CU at the time of endovascular intervention. On univariate analysis more severe carotid stenosis was seen in CU patients (92.6 ± 6.5% vs 81.6 ± 13.6%, p = 0.013) and percent stenosis was independently associated with CU on multivariate analysis (p = 0.023).

CONCLUSIONS

CU is present in 1 of every 3 patients with acutely symptomatic carotid disease. The current results suggest that CR testing should become part of routine care in patients with acutely symptomatic carotid disease.

Optimal platelet function test for in-stent tissue protrusion following carotid artery stenting

Purpose

To determine the best platelet function test for in-stent tissue protrusion following carotid artery stenting (CAS).

Methods

Patients who underwent CAS were recruited prospectively in this observational study. Combination of aspirin 100 mg/day and clopidogrel 75 mg/day was administered for a minimum of 7 days prior to procedure. Platelet aggregation was measured by light transmittance aggregometry (LTA) following stimulation by adenosine diphosphate (ADP), collagen, and thrombin receptor activating peptide (TRAP) and by the point of care assay, VerifyNow which measures aspirin and thienopyridine reaction units.

Results

In-stent tissue protrusion with maximum projection area of ≥1 mm² was detected by optical coherence tomography (OCT) in 10/28 (36%) patients. Baseline characteristics were not significantly different between the two in-stent size groups (i.e., ≥1 mm² vs. <1 mm²) but after stimulation by collagen at 10 and 20 μg/ml, platelet reactivity as measured by LTA was significantly higher in the ≥1 mm² group compared with the <1 mm² group. No other differences in platelet function were detected.

Conclusions

Collagen-induced platelet reactivity was related to in-stent tissue protrusion size following CAS.