Ischaemic heart disease

Coronary artery disease(CAD) is the leading cause of death worldwide. The rates of mortality and disability due to CAD are increasing in industrialized and developing countries. This is a diffuse disease of the coronary arteries characterized by atheromatous plaques. Plaques may cause stenosis of coronary arteries, producing limitation of blood flow to the myocardium.

Rupture of atherosclerotic plaques with subsequent arterial thrombosis leads to acute cardiac events(acute cardiac syndrome ) such as unstable angina, myocardial infarction and sudden death. Coronary artery disease with multiple arterial stenoses may present clinically with chronic cardiac disease, most commonly cardiac failure. This is caused by pump failure due to ischaemic myocardium. This may be accompanied by chronic stable angina.

 Multidetector row CT is highly sensitive to the presence of coronary artery calcification.  The amount of coronary calcification increases with the overall burden of coronary atherosclerotic disease.  Computer software programs are able to provide a coronary calcium score that represents a reasonable measure of the amount of atherosclerotic plaque.

Computed tomography coronary angiography has a developing role in the diagnosis of CAD; 16- and 64- multislice CT scanners allow accurate depiction of the coronary arteries. As well as imaging the vessel lumen, CT is able to image non- stenotic plaque in the vessel wall. Current research is directed at characterizing plaque based on measurement of CT density; this may further increase the accuracy of risk assessment with this technique.

Initial workup for a cardiac cause includes ECG and serum markers such as CK-MB (creatine kinase isoenzyme MB) and cardiac treponins. Initial imaging assessment in the acute situation consists of a CXR to look for evidence of cardiac failure and to diagnose a non-cardiac cause of chest pain such as pneumonia or pneumothorax. This will be followed by coronary angiography, as well as interventional procedures aimed at restoring coronary blood flow. These include coronary artery angioplasty and stent deployment.

Increasing cardiac MRI is being used to assess myocardial viability and cardiac function in patients with CAD. Cardiac MR is able to provide a quantitative assessment of ventricular wall motion and assess myocardial perfusion, at rest and with pharmacologically induced stress.

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