Comparative analysis of atherosclerotic disease in the carotid and femoral arteries

Thesis

Introduction
Peripheral arterial occlusive disease (PAOD) is a common vascular pathology affecting up to 60% of the population over 85 years. It often presents in a triad of atherosclerotic disease, alongside myocardial ischaemia and cerebrovascular accident. Best medical therapy is used in the treatment for all three; and shows a 16% reduction in stroke events and 10-40% reduction in cardiac events. POAD has not been subject to the same level of research, and primary analysis indicates little reduction in deterioration or amputation rates for 30 years.

Methods
The study aimed to use in vivo and ex vivo analysis of carotid and femoral atherosclerotic plaque from patients enrolled in the OxPVD study. Each participant underwent pre-operative carotid and femoral (ipsilateral) MRI scans, and ex vivo plaque was analysed using micro CT, micro MRI and histological staining. Comparative analysis was completed for carotid versus femoral atherosclerosis.

Results
Results from this study have shown that despite risk factor modification, overall outcomes of patients with POAD remain unchanged. Patients do however present to the services 7 years older. Secondly, novel MRI DANTE sequences can successfully characterise femoral atherosclerotic plaque in vivo.

Using micro CT and micro MRI, we have further quantified differences in the composition of carotid and femoral disease. Smokers tend to have a higher percentage of calcium within the plaque. Femoral plaque calcium is significantly more dense than all carotid plaque calcium.

Finally, histological staining has implied that the disease processes behind femoral and carotid atherosclerosis may be different; with carotid showing fat infiltration and femoral plaque containing osteoblastic/osteoclastic like cells.

Conclusion
These results highlight key compositional differences between carotid and femoral atherosclerosis; femoral atherosclerotic calcium appearing much more dense, and possibly derived from bone-like calcium progenitors. With this in mind, it may be possible to review different therapeutic targets for PAOD.

Authors: Hurst, KV

• DOI: 10.5287/ora-vgvaojmrk
• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: University of Oxford
• Language: English
• Keywords: peripheral arterial occlusive disease; atherosclerosis
• Subjects: Microcomputed tomography; Magnetic resonance imaging; Blood-vessels