Vascular Neurology and Stroke Medicine

Current Research Team:

Professor Dominick J. H. McCabe PhD, FRCPI, FESO, FAHA: Consultant Neurologist / Clinical Associate Professor in Neurology, and Chairperson of the Vascular Neurology Research Foundation (VNRF), Department of Neurology/Stroke Service, AMNCH-Tallaght University Hospital (TUH)/ TCD, Ireland;
Dr Chika Offiah, BSc. Biochemistry, MUDr: Research Registrar in Vascular Neurology (PhD Student)
Dr Deirdre R. Smith MB, BCh, BAO, MICGP, DCh: Research Registrar in Vascular Neurology (MSc Student)
Dr Arun Subramanian, MD, MPH, MRCPI: Research Registrar in Vascular Neurology (MSc Student)
Dr Stephen Murphy MB, BCh (Sch), MRCPI, MRCP (UK), Dip Stat, PhD:  Research SpR in Vascular Neurology (‘Post-Doc’ MSc Student)
Dr Soon Tjin Lim, MRCPI, MRCP (UK): Research SpR in Vascular Neurology (PhD Student).

Research Group Focus on Vascular Neurology / Stroke Medicine:

Stroke is the commonest cause of acquired disability and the second to third commonest cause of death in middle-high incomes countries, including in Ireland.
The main objectives of our research are:
- To improve our understanding of the potential mechanisms causing transient ischaemic attack (TIA) or stroke, including in higher-risk subgroups;
- To identify individuals who should benefit from modified, ‘personalised’ anti-thrombotic (blood thinning) treatment to optimise their response to commonly-prescribed preventive treatments following TIA or stroke to reduce the burden of stroke on patients, care givers and society as a whole.   

Translational Platelet Science / Haemostasis and Pharmacogenetics Research in Ischaemic Cerebrovascular Disease

Prof McCabe’s Vascular Neurology Research group at AMNCH-TUH/TCD has an international reputation for conducting innovative, clinically-relevant, collaborative research studies on translational platelet science (figure 1), haemostasis and thrombosis in patients with ischaemic cerebrovascular disease (CVD) and in assessing the response to commonly-prescribed antiplatelet regimens ex vivo. They also have particular expertise in performing transcranial Doppler ultrasound imaging to detect micro-embolic signals (MES) in the cerebral circulation in vivo (figure 2), and in combining these data with other neurovascular imaging, blood and endothelial biomarkers to understand the pathogenesis of TIA/stroke and potentially improve risk-stratification of patients with moderate-severe asymptomatic and symptomatic extracranial carotid stenosis.  

Some Recent Achievements:

The service at AMNCH-TUH/TCD has facilitated clinical and academic training & education in Vascular and General Neurology, Stroke Medicine, Translational Medicine and enhanced clinical care of TIA and stroke patients, with several clinical PhD candidates having successfully defended their theses to date. Prof McCabe is currently supervising 2 further PhD students and 3 MSc students in Clinical Neurosciences/Clinical Medicine (see above), is the Principal Investigator (PI) / Co-PI in 9 local or multi-centre studies, and is collaborating in 7 national or international multi-centre research studies or trials. Prof McCabe (HRB-Stroke Clinical Trials Network Ireland [SCTNI] ‘Network Lead Investigator’; Chair of the Research and Education Committee, National Stroke Programme’s Clinical Advisory Group for the RCPI/HSE) and his team actively collaborate to support the important work of the SCTNI locally and on the international stage.

They have conducted several original pilot studies in this subspecialty area (e.g. the PACS, HEIST, TRAP & OATS studies) and have and published widely in this field.  These studies have shown that platelets may be excessively activated / hyper-reactive following a TIA or ischaemic stroke and that an important proportion of CVD patients are ‘poorly-responsive’ to antiplatelet agents with ‘high on-treatment platelet reactivity (HTPR)’ in the laboratory. These data have improved our understanding of the clinical, demographic and pharmacodynamic mechanisms influencing ex-vivo HTPR status in this patient population. They have also found an ongoing stimulus to increased platelet production and secretion, and enhanced platelet and endothelial activation and coagulation system potential after TIA/ischaemic stroke in patients with symptomatic compared with asymptomatic moderate-severe carotid stenosis, including in those who do not have micro-emboli on transcranial Doppler ultrasound. These data improve our understanding of the underlying biological mechanisms which may contribute to the disparity in the risk of TIA/stroke in subgroups of patients with recently symptomatic vs. asymptomatic carotid stenosis, and in subgroups of symptomatic patients with different plaque types and MES status.

2 pressing issues which need be resolved within this subspecialty field:

  •  We need to determine whether monitoring ‘antiplatelet-HTPR status’ with platelet function/reactivity assays, in combination with pharmacogenetic testing via a Genome-Wide Association Study (GWAS) approach, definitively predicts the risk of recurrent vascular events in CVD patients on antiplatelet therapy. Such information would facilitate ‘personalised antiplatelet therapy’ to optimise secondary prevention following TIA/ischaemic stroke. To address this issue, we have designed the adequately-sized Optimal Antiplatelet Therapy in TIA and Ischaemic Stroke-International (OATS-I) multicentre observational study.
  • We need to collate established and innovative blood, endothelial and neurovascular imaging biomarker data to aid risk-stratification of patients with symptomatic and asymptomatic carotid stenosis to identify patients who may benefit most from early surgical or endovascular intervention or optimised medical therapy alone.