Relationship between diabetes and blood pressure

Having diabetes increases risk of developing high BP
- High blood glucose levels over time --> increased deposits of fatty materials on the insides of the blood vessel walls --> Affect blood flow, increasing the chance of clogging and hardening of blood vessels (atherosclerosis)--> high BP--> untreated- can lead to blood vessel damage, stroke, heart failure, heart attack, or kidney failure.

Statistically, having diabetes means:
• You're 2 to 4 times as likely to have a heart attack or stroke as is someone without diabetes.
• You're > likely to die of a heart attack than you'd be if you did not have diabetes.
• Your risk of sudden death from a heart attack is the same as that of someone who has already had a heart attack.

Role of diabetes in clinical presentation of IHD
1) In diabetic patients, myocardial ischemia due to coronary atherosclerosis is typically asymptomatic-->reflect abnormalities in the perception of pain related to autonomic neuropathy.
2) They are more likely to develop thrombus and more vulnerable to plaque rupture--> due to the prothrombotic and procoagulant state with which diabetes
3) Clinical presentation of IHD: Angina
- diabetes--> coronary atherosclerosis--> reduce blood flow to the heart--> symptoms often appear at times when we are stressed, exercising or climbing stairs-as heart tries to pump faster to meet O2 demands, narrowed arteries struggle to keep, heart deprived of O2-->pain

Abbreviation/definition;
• CHD = coronary heart disease
• IHD = ischemic heart disease
• ACS = acute coronary syndrome
• MI = myocardial infarction

• Ischemia = to suppress or withhold blood flow



Why ischemia happens?
• Increase oxygen demand --> high metabolic demand
• Decrease oxygen supply --> narrowing

Cholesterol and Triglyceride transport



Colour of boxes represents:
• Yellow contains cholesterol
• Blue contains triglyceride
• White contains both cholesterol and triglyceride
* Red arrow represents explanation of CHD

Hypothesis of plaque formation:
• Injury to the endothelial vessel layer, due to:
o Smoking
o Immune mechanism
o Mechanical stress --> hypertension
o Turbulent flow

Determinant of plaques vulnerability to rupture:
• Size of lipid core and stability and thickness of fibrous cap
• Presence of inflammation with plaque degradation
• Lack of smooth muscle cells with impaired healing and plaque stabilization


Site of atherosclerosis in order of frequency
1. abdominal aorta and iliac arteries
2. proximal coronary arteries
3. thoracic aorta, femoral and popliteal arteries
4. internal carotid arteries
5. vertebral basilar and middle cerebral arteries

Lipoprotein

1. chylomicrons - synthesize in intestine and transport dietary;
• triglygeride (adipose and skeletal muscle tissue)
• cholesterol (taken up by liver to form VLDL or secreted by bile)

2. LDL ;
• Main carrier of cholesterol
• LDL is mainly removed by receptor dependent pathway (mainly hepatocytes
• Also remove by non-receptor-dependent mechanism (scavenger cells)
o Can result in formation of foam cells

3. HDL ;
• Reverse transport of cholesterol; ie transport cholesterol from peripheral tissues to the liver to be excreted

General Aetiology of IHD
IHD happens when the blood supply to the myocardium via the coronary arteries is cut. This in effect causes the lack of much needed oxygen and nutrients for the heart muscles to function properly.


Epidemiology of IHD
Ischemic heart disease (IHD) was the commonest cause of cardiovascular mortality and accounted for 2,556 deaths in 2002 with a further 896 deaths due to heart failure of ischemic origin. Despite improvement in health services and facilities, mortality due to IHD has been rising steadily since census began in 1990. Nationally IHD probably accounts for 20-30% of all-cause mortality annually.
The true incidence of IHD and IHD-related deaths in Malaysia is unknown. All the data presented thus far relates only to the 122 MOH hospitals. Data on IHD cases and deaths at the 7 University and other non-MOH Government hospitals, and 211 private hospitals is unavailable although it is suspected the number may be double the figures from MOH hospitals only. This means that there may have been over 110,000 admissions and over 7,500 deaths directly caused by IHD in Malaysia in 2002. And this number is increasing every year.

Risk Factors and Epidemiologic Relevance for IHD
IHD is the result of interaction between polygenic, lifestyle, and environmental factors:
Family history
Several regions of the human genome have been shown to be associated with either IHD or hypertension. A family history of IHD is a strong risk factor for MI and acts synergistically with other risk factors below. Family history is significant if a male relative suffered a IHD event before 55yrs, or a female relative before 65yrs.

Age
The older you get, the stiffer
your arteries become. Risk of death from IHD doubles with every 8 years of age
with the death rates for women the same as for men 10 years younger.

Leader: Christopher
Scribe: Maz

Task to complete:
1. Aetiology of IHD, epidemiology-- Christ Sim
2.Clinical Presentation of IHD + Differential Dx.--Alvin
3.Pathophysiology of IHD. --Yazid
4. Risk factors-- Christ Sim
5. Interpretation of Investigation-- Sareeta?
6. Management of IHD (Primary and Secondary prevention)-- Christine
7.Role of Diabetes in IHD. How diabetes affect BP? -- Maz

Have fun!!! :)
Please be aware that there will be radiology tut on Monday morning 8 AM!!

Alvin