CAD & ACS

CORONARY ARTERY DISEASE

Coronary artery disease is a chronic disease caused by the gradual deposition of fats in the coronary arteries (atherosclerosis).

Narrowed artery reduces oxygen supply to the myocardium.

Ischemia (reduced blood & O2 supply) often causes chest pain or discomfort known as angina pectoris or Myocardial Infarction due to complete blockage.

CAD is also called as IHD & CHD.

CAD

Atherosclerosis :

Deposition of lipids under the intima of arteries. Chronic process that develops in following stages over 30-40 years Fatty streak Fibrous plaque Rupture

ATHEROSCLEROSIS: HARMFUL CONSEQUENCES

Atherosclerosis causes decrease in lumen of arteries and thus decreases blood supply

Artery involved

Organ Condition

Symptoms

Events

Coronary Heart CAD Angina MI

Cerebral carotid

Brain CVD TIA Stroke

Peripheral Peripheral tissue

(sk muscle)

PVD/PAD Intermittent claudication

Gangrene

SYMPTOMS OF CAD

Chest pain (angina) : Patient may feel pressure or tightness in chest, as if someone is standing on chest.

Shortness of breath.

ANGINA PECTORIS

Principle symptom of CAD (IHD, CHD) Sudden, severe & temporary chest pain caused by an

inadequate supply of oxygen to the myocardium due to narrowing of the coronary artery

Pain may radiate to left arm or shoulder, back, neck or jaw

The symptoms usually last for few minutes and pain subsides on rest.

No permanent damage occurs Angina may be is precipitated by exercise, cold,

stress, heavy meal

TYPES OF ANGINA

Chronic Stable angina (CSA)

Unstable angina (UA)

Other names Exertional / classical Preinfarct Angina

Occurrence Usually precipitated by physical activity

Occurs even at rest

Predictability Predictable Unpredictable

Frequency, severity & duration of pain

Less More

Cause Stable plaque (atherosclerosis)

Unstable plaque (atherothrombosis)

Relieving factors Rest or sublingual nitrates

Requires hospitalization

Variant / Vasospastic

Caused by spasm of the coronary arteries

May occur at rest, may not be precipitated by emotion or stress.

MYOCARDIAL INFARCTION

Myocardium : heart muscleInfarction : death of the tissue (necrosis)MI is death of the myocardial tissue due to complete blockade of coronary artery

ISCHEMIA & MYOCARDIAL INFARCTION

Ischemia Myocardial infarction

Partial block of artery Complete block of artery

Temporary decrease in O2 supply

Permanent damage (necrosis)

ST Segment depression Usually ST Segment elevation

ANGINA PECTORIS

Determinants of the myocardial O2

requirement :

Heart rate Myocardial contractility Afterload Preload

ACUTE CORONARY SYNDROME

It is an umbrella term used to describe symptoms and signs occuring because of acute atherothrombosis in coronary artery

It is an emergency condition and patient has to be hospitalized

CLASSIFICATION OF ACS

Unstable angina

NSTEMI STEMI

Typical chest pain Yes Yes Yes

Elevation of serum cardiac enzymes*

No Yes Yes

ST Segment elevation No No Yes

ACS includes 3 syndromes: UA, NSTEMI, STEMI

They are different manifestations of the same clinical syndrome depending upon the period of severity

* Troponin T & CKMB

Investigations in ACS & CAD

ECG

Recording of electrical activity of the heart via electrodes attached to the skin

Net sum of depolarisation and repolarisation potentials of all myocardial cells

P-QRS-T pattern P - atrial depolarisation QRS - ventricular

depolarisation T - ventricular repolarisation

ECG ABNORMALITIES IN ISCHEMIA & MI

ECG (Electrocardiogram)

Stress test (Treadmill Test/TMT/CST)

Patients are asked to walk on a treadmill during an ECG. This is the test to unmask CAD when resting ECG is normal

INVESTIGATION OF CAD

A diagnostic procedure

Cardiac catheterization done

‘Catheter’ refers to a long narrow

rubber tube inserted through

artery of leg & advanced upto

the opening of coronary artery in

aorta

A small amount of contrast

material (dye) is injected through

the catheter into coronary

arteries

INVESTIGATION OF CAD

Coronary angiography

The movement of the dye is recorded as an angiogram and viewed on a television monitor.

Images are then captured

using X-rays.

Disease is described in terms of

Extent & location of block : e.g. 90% block in proximal RCA

Number of arteries involved: Single-vessel, double-vessel or triple-vessel disease

INVESTIGATION OF CAD

Coronary angiography

TREATMENT OF ANGINA (CAD)

Life style modification Regular physical exercise Stop smoking Stop alcohol Dietary controls : weight control

Restrict saturated fats

Pharmacological Organic nitrates : Nitroglycerine, ISMN CCBs : Diltiazem, Verapamil Beta Blockers : Metoprolol, nebivolol K+ Channel opener : Nicorandil

Interventional PTCA CABG

ORGANIC NITRATES

Dilates veins & large arteries

Dilation of veins lead to reduction of the preload

Dilation of the arteries leads to reduction of the afterload

Coronary artery dilation

BETA BLOCKERS

Reduces Myocardial Oxygen Demand

↓ Heart Rate

↓ Force of contraction

Increases Coronary filling

↑ Diastolic time

CCBs

Block Calcium channelsPrevent entry of Ca++ ions

Myocardial Cell Vascular smooth muscle

Decreased force of Coronary Artery Peripheral contraction arteriole

Coronary blood flow PVR

NICORANDIL

Nitrate-like action K+ channel opener ATP

Dilates epicardial Coronary arteries

Venodilatation Dilates peripheral arterioles

Dilates coronaryResistance vessels

DecreasedPreload

Decreased afterload

↑ coronary blood flow

↓ Myocardial O2

requirement

↓ Myocardial O2

requirement

↑ coronary blood flow

Nicorandil dual action

PTCA WITH STENTING(Percutaneous Transluminal Coronary

Angioplasty)

Also known as Balloon angioplasty Angioplasty PCI (percutaneous

coronary intervention)

Done in Cardiac Catheterization Laboratory (Cath Lab) by an interventional cardiologist

PTCA WITH STENTING

Opening of the artery after stenting

The arrow on the angiogram shows block in the artery.

CABG(Coronary Artery Bypass Graft Surgery)

(Done by CVTS in Cardiac OT)

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