Document Type

Theses, Masters


Available under a Creative Commons Attribution Non-Commercial Share Alike 4.0 International Licence



Publication Details

Thesis submitted to Technological University Dublin for the award of M.Phil. in Clinical Measurement Science, September 2018.


Purpose: Carotid artery stenosis (CAS) is defined as the presence of significant narrowing of the arteries of the extracranial carotid system due to the presence of atherosclerotic plaque and affects up to 10% of people over 65 years (Goessens et al 2007). Management of 50-69% stenosis is centred on medical optimisation and risk factor modification. Surgical intervention is typically reserved for patients with stenosis of > 70%. The primary aim of the study is to determine if asymptomatic carotid artery disease causing a 50-69% internal carotid artery stenosis (ICAS) typically progressed to a >70% stenosis, thereby evaluating the necessity of annual Colour Duplex follow-up in patients presenting with a 50-69% stenosis. Additionally the study aimed to determine if ultrasound monitoring of moderate ICAS provided markers able to identify any predisposing risk factors associated with progression of ICAS.

Methods: All Carotid Duplex scans performed in the Vascular Laboratory in the Mater Misericordiae University Hospital (MMUH) from January 2007 and December 2009 were retrospectively reviewed by the same experienced vascular physiologist. All patients who presented with unilateral or bilateral asymptomatic internal carotid artery stenosis of 50-69% on their first visit were included in this study and followed up until December 2011. Patients who presented with a non-haemodynamically significant internal carotid artery stenosis of70% bilaterally, a history of carotid surgery or with no follow up scan performed were excluded from the study.

Results: The study examined the results of the scans of 4573 patients. Of the 4573 patients 876 were found to have a 50-69% stenosis at their initial scan. Of these, 287 patients were excluded from the study for various reasons leaving 589 patients in this study. Of the 589 patients included in the study, progression of ICAS was observed 17.3% of patients. A number of risk factors were analysed to determine their impact on disease progression. Positive smoking history, male gender and positive cardiac history were all found to have a significant correlation to disease progression.

Conclusion: As 17.3% of patients progressed to a >70% internal carotid artery stenosis over the course of the study it is evident that there was a significant rate of ICAS progression noted in this cohort of patients.