Chapters authored
Risk Factors in the Patients with Extracranial Carotid Atherosclerosis
There are vascular risk factors known to be associated with stroke. These risk factors have been shown to either directly or indirectly lead to stroke. The risk factors include hypertension (HT), diabetes mellitus (DM), smoking, hyperlipidaemia, ischemic heart disease (IHD) and atrial fibrillation (AF). Studies have shown that carotid atherosclerosis is a cause of stroke. Extracranial carotid atherosclerosis accounts for up to 40% of the ischemic strokes in the Western countries. The latest stroke guidelines recommend the routine use of Ultrasound Carotid Doppler to assess for extracranial carotid artery atherosclerotic diseases (carotid intima media thickness, plaques, carotid stenosis) in these patients. A previous study emphasized the value of carotid ultrasonography in the detection of early extracranial carotid atherosclerosis.
Part of the book: Peripheral Arterial Disease
Extracranial Carotid Atherosclerosis in the Patients with Transient Ischemic Attack
Management of transient ischemic attack (TIA) is important because potentially fatal ischemic strokes can be prevented. Detection of extracranial carotid atherosclerosis in these patients is beneficial because medical therapy can be given, and in certain cases, surgery can be performed. In a Chinese study conducted on the patients with TIA, only 19% of them had extracranial carotid atherosclerosis. Another study was conducted to compare the location and the severity of atherosclerotic lesions between Americans and the Japanese who presented with carotid system TIA. This study showed that 85% of the American patients had extracranial carotid stenosis (stenosis ≥50%). However, only 16.7% of the Japanese patients had similar lesions.
Part of the book: Peripheral Arterial Disease
Serum Homocysteine and Intracranial Aneurysms
Subarachnoid haemorrhage (SAH) occurs as a result of rupture of intracranial aneurysms. SAH causes significant morbidity and mortality. In addition, SAH leads to significant financial burden. In this chapter, we will look into the association between raised serum homocysteine and intracranial aneurysms. In a study on the Han Chinese patients with intracranial aneurysm who were admitted to the hospital, the mean serum total homocysteine level in the patient group with intracranial aneurysm was significantly higher than those in the control group. In the same study, the patients with raised serum homocysteine had 2.196 higher risk of developing intracranial aneurysms. Ren et al. proposed that homocysteine should be seen as an indicator of the risk of intracranial aneurysm and not a direct cause of intracranial aneurysm. In another study, homocysteine increases the development of intracranial aneurysms in rats. Endothelial damage is an early change in the walls of intracranial aneurysms. Polymorphisms of the genes coding for the various components of the vessel walls may be associated with the formation of intracranial aneurysms. In a previous animal study, the size of intracranial aneurysms is significantly smaller in the mice with inducible nitric oxide synthase (iNOS) compared with the mice without iNOS.
Part of the book: New Insight into Cerebrovascular Diseases
Atherosclerosis at Extracranial Carotid Vessels and Serum Homocysteine
In this chapter we will discuss more about the role of homocysteine in atherosclerosis and also association between serum homocysteine with extracranial carotid atherosclerosis. Carotid atherosclerosis comprises an increase in carotid intima-media (CIMT) thickening, plaque formation and carotid stenosis. Atherogenic property of homocysteine was discovered in 1969. Atherosclerosis is initiated by endothelial dysfunction. One of the causes of endothelial abnormality is homocysteine. The development of aggregates of homocysteinylated lipoproteins with microorganisms obstructs the vasa vasorum in vulnerable plaques. In one study, serum homocysteine in the highest quartile was independently associated with extracranial carotid artery stenosis ≥50%. In another study, raised serum homocysteine was also independently associated with severe extracranial carotid stenosis in both genders. In other studies, serum homocysteine was significantly associated with carotid artery stenosis in internal carotid arteries and external carotid arteries as well as the degree of stenosis. The hypertensive patients who had raised serum homocysteine were reported to have higher risk of developing asymptomatic extracranial carotid artery stenosis.
Part of the book: Inflammatory Heart Diseases