Page 272 - Concise Pathology for Exam Preparation ( PDFDrive )

11 Disorders of the Heart 257

Thrombus formation is aided by:
• Thromboxane A 2 and other platelet constituents
• Fibrinogen
• Lipoprotein (a), which inhibits fibrinolysis

Q. Write briefly on the role of vasoconstriction in the pathogenesis
of IHD.

Ans. Vasoconstriction/spasm may contribute to the pathogenesis of prinzmetal angina as
well as acute MI. It is induced by:
• Circulating adrenergics
• Release of platelet contents
• Impaired secretion of endothelial cell relaxing factors, eg, nitrous oxide
• Release of mediators from perivascular cells like mast cells

Q. Write briefly on the role of inflammation in the pathogenesis of IHD?
Ans. Role of inflammation in IHD (Flowchart 11.2):

Interaction between endothelial cells and circulating leukocytes
• Release of chemokines by the
endothelial cells
• Increased expression of adhesion
molecules on the endothelial cells
Accumulation of leukocytes in the arterial wall
Stimulation of T cells and
macrophages to produce
TNF, IL-6, IFN γ
Endothelial cells and macrophages become loaded with
oxidized LDL and form a plaque
Secretion of metalloproteinases by
macrophages
Destabilization and rupture of the plaque
FLOWCHART 11.2. Role of inflammation in IHD.

Note: Inflammation is thought to have an established role in the pathogenesis of athero-
sclerosis and proteins involved in inflammation are considered potential markers of CAD,
eg, CRP (C-reactive protein).
Q. Define and classify angina pectoris. Write briefly on the different
types of angina.
Ans. Angina pectoris is defined as a symptom complex of IHD characterized by paroxys-
mal recurrent attacks of substernal or precordial chest discomfort (constricting, squeezing
and choking, knife like) caused by transient (from 15 s to 15 min) of myocardial ischaemia
that falls short of inducing cellular necrosis that defines infarction.

Three Overlapping Patterns
1. Stable/exertional/classical angina
(a) Reduction of coronary perfusion due to chronic stenosing coronary atherosclerosis
(b) Heart is vulnerable to ischaemia whenever there is increased demand, ie, physical
activity and emotional excitement
(c) Relieved by rest/decreased demand and nitroglycerin (decreases cardiac work by
dilating peripheral vasculature)

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