Forms of cardiovascular disease Coronary heart disease Strokes Gangrene Aneurisms

Forms of cardiovascular disease• Coronary heart disease• Strokes• Gangrene• Aneurisms

Forms of coronary heart disease• Angina

Chest pain after exertionSpreads to neck, jaws, arms, backShortage of blood to heart (no muscle death)Cramp

• Heart attack (myocardial infarction)moderately large coronary artery blockedsudden severe chest paincan be treated

• Heart failureBlockage of main coronary arterygradual damageheart becomes steadily weaker

NEXT

Embolism• A clot breaks off• It may lodge elsewhere

Coronary artery – Heart attackBrain - Stroke

•Gangrene •A thrombus has broken off (embolised) and travelled via the left ventricle to the left leg, where it has blocked an artery, cutting off the blood supply to the foot.

An occlusive stroke

An artery is blocked

Aneurysm

• Atherosclerosis narrows lumen of an artery

• Increases blood pressure• This weakens the wall• Balloons out and may burstNEXT

Strokes due to aneurysm• Aneurysm in brain artery• Haemorrhage within brain• StrokeNEXT

Platelets• An electron micrograph of a

platelet. • It looks like a chocolate chip

cookie. The chocolate chips are granules that contain a variety of mediators.

• When activated, platelets release the granules to promote...coagulation, change of shapestickiness

• They plug small vascular holes.NEXT

Cholesterol

• Useful in small amounts• Stabilises membranes• Used in synthesis of Vitamin D• Used in synthesis of hormones

(testes, ovaries, adrenal glands)NEXT

Lipoproteins

• Very low density lipoproteins (VLDLs) Bad(cholesterol from liver to tissues for storage)

• Low density lipoproteins (LDLs) Bad (made from VLDLs in tissues, cholesterol from liver to tissues)

• High density lipoproteins (HDLs) Good(cholesterol from tissues to liver)

NEXT

Coronary heart disease

• An undamaged arteryNEXT

Endothelial cells

Elastic lamella

Smooth muscle

Coronary heart disease

• Damage to artery• Due to hypertension?• Phagocytes invade wallNEXT

Endothelial cells

Elastic lamella

Smooth muscle

Phagocytes invade

Coronary heart disease

• LDLs in blood plasma enter artery wall

• LDLs carry cholesterol from the liver

• They deposit cholesterol• The cholesterol and LDLs

are attacked by the phagocytes

• The damage prevents LDLs returning to the plasma so they deposit more cholesterol

NEXT

Coronary heart disease

• The phagocytes release growth factors

• These stimulate the growth of smooth muscle

NEXT

Coronary heart disease

• Plaque of fibrous fatty tissue builds up

• Platelets stick to it• They release clotting

factors (thromboxanes)• The endothelium normally

releases prostaglandins to prevent clotting

• At the site of an atheromatous plaque the balance is wrong

• The blood clotsNEXT

Progress of a thrombosis

A thrombosis

Mild Severe

Arteriosclerosis

• Calcification of the deposit• Often in aorta or coronary

arteries• This causes hardening of

arteriesNEXT

Calcification

Risk factors

• Diet – avoid saturated fat

• Exercise – see exercise unit

• Gender – oestrogen increases HDL, testosterone increases LDL

• Heredity – choose parents carefully

• Stress – avoid it!

• Age – arteriosclerosis inevitable as you get older

• Hypertension –stress, obesity, smoking, excessive drinking, lack of exercise, salt intake

• Smoking- carbon monoxide, nicotine, clotting

NEXT

CHD and Cholesterol/Blood pressure/Smoking

• Relative risk (death rates per 10,000 people years)• Factors increase each other’s effectsNEXT

59.7

29.623.3 10.7

30.3

11.2

Nicotine• Nicotine binds to some acetylcholine receptors• reduces arteriole diameter• increases adrenaline release• increases blood pressure• increases heart rate• decreases blood supply to extremities• increases stickiness of platelets• Increases fat levelsNEXT

AChNicotine

Carbon monoxide• Carbon monoxide (and nicotine) damage the endothelium• Binds to haemoglobin and reduces oxygen transport by

15% in smokers

Other effects of smoking• decreases antioxidant concentration (eg Vitamin C • and E)

this increases the damage done by free radicals released by phagocytes

• Raises number of platelets• Increases ratio of VLDLs and LDLs to HDLs in the blood

Saturated fat• Decreases number of LDL receptors on liver cells

so they stay in circulation

• Increases blood cholesterol concentrations• Increases ratio of LDLs to HDLsNEXT

CHD and age

Prevention• Screening• Encouraging lifestyle changes• Problem:

long term nature of cardiovascular diseases – no symptoms until damage is already done

TreatmentPacemaker

helps maintain rhythm

• Bypass Surgeryusing leg blood vessel21000 in UK in 1992

• Transplant Surgerysince 1967140 in UK in 1992