Histopathology Cardiovascular Disease Flashcards
Ischaemic Heart Disease Definition
Definition
Ischaemic Heart Disease Factors that contribute to the reduction of coronary artery perfusion which results in myocardial ischemia
- Atherosclerotic stenosis
- Platelet aggregation
- Coronary artery vasospasm
- Non-atherosclerotic coronary artery disease
- Systemic Haemodynamic derangement
Atherosclerotic Stenosis: Epi
- Over 90% of patients with ischaemic heart disease have significant (>75% of cross section of the vessel) stenosis of one or more of the three major coronary arteries.
- 30% have single vessel disease (left anterior descending- -LAD)/ Left circumflex/Right coronary.
- 30% → 2 vessels
- 40% triple vessel disease
Atherosclerotic Stenosis: Site of Stenosis
• Usually Proximal (within the first 4 cm) in the LCA (LAD or LC) and somewhat more distal in the RCA.
Platelet aggregation: Definition
Rupture and fissuring of atherosclerotic plaque seems to be the initiating factor in most acute cardiac events in IHD.
Platelet aggregation: The Exposure of the plaque content leads to
Platelet adherence and aggregation with the development of thrombus which may remain localised to occlude the vessel or may embolise downstream,
Vasospasm: Definition
Mechanisms unclear
Non-atheroscleroitc lesions of coronary arteries
• Coronary artery emboli
• Arteritis (Kawasaki’s syndrome, Polyarteritis nodosa)
Coronary artery dissection
Systemic haemodynamic derangements
Left ventricular failure
Vasospasm: Systemic haemodynamic derangements
A drop in blood pressure (shock, haemorrhage, operations etc) may severely reduce coronary artery perfusion in vessels which are already affected by fixed stenosis.
Myocardial infarction: Two classical patterns of infarction
- Localised transmural infarct in which the entire thickness of the wall is involved – definable occlusive disease.
- Subendocardial type where there is extensive infarction involving the inner third of the myocardium. Usually severe triple vessel disease but often-specific occlusive lesions are absent.
Myocardial infarction: LCA disease causes infarct in
Anterior wall, apex and anterior part of the interventricular septum
Myocardial infarction: LC disease causes infarct in
Lateral wall
Myocardial infarction: RCA disease causes infarct in
Posterior wall and posterior part of the septum?
Myocardial infarction: Complications in myocardial infarction
Sudden cardiac death – 25% Arrhythmias – more than 75% Mural (endocardial) thrombosis – 30% +. Clinically significant muscle – 1-5% Cardiogenic shock – 10% Pericarditis – 30% Left ventricular failure- 60%
Cor pulmonale Definition
A right ventricular enlargement secondary to pulmonary hypertension caused by disorders that affect either the structure or function of the lungs.
Cor pulmonale Excluded in the definition
Right ventricular enlargement caused by diseases of the left side of the heart or by congenital heart disease are excluded by this definition.
Cor pulmonale Morphological terms
There is right ventricular dilation (as for instance in PE) and, in those disorders causing chronic cor pulmonale, right ventricular hypertrophy. (RV thickness > 0.5 cm).
