L23 Ischemic Heart Disease PDF

Pathology of Ischemic heart diseases (IHD) By: Dr. Dina Abdallah Elnady Assistant professor of Pathology Faculty of Medicine Mansoura University Ischemic heart diseases (IHD)  Ischemic heart diseases (IHD) Definition: A group of...

Pathology of Ischemic heart diseases (IHD) By: Dr. Dina Abdallah Elnady Assistant professor of Pathology Faculty of Medicine Mansoura University Ischemic heart diseases (IHD)  Ischemic heart diseases (IHD) Definition: A group of related syndromes resulting from myocardial ischemia & it’s also called Coronary Artery Disease (CAD). N.B: -Ischemia: decrease O2 to a certain tissue (e.g. restriction in blood supply to tissues) -Infarction: tissue death (necrosis) caused by an obstruction of the tissue's blood supply Ischemia Injury Infarction  Ischemic heart disease (IHD) Causes: *The vast majority of ischemic heart disease is due to coronary artery atherosclerosis BUT atherosclerosis is not usually the direct cause, the complications of it are, as thrombosis. *Vasospasm: constriction of the vessels. * Vasculitis  Ischemic heart disease (IHD) Risk factors: as atherosclerosis I-Non modifiable: 1-Age…The number and severity of atheromatous lesions increase with age. 2-Sex…More common in males than females up to the age of 55 years (Estrogen has a protective effect). 3-Familial predisposition…Familial hyperlipidemia (hypercholestrolemia) is associated with increased risk of atherosclerosis. II-Modifiable: 1-Hyperlipidemia…Increased level of cholesterol and LDL is associated with increased risk of atherosclerosis. On the contrary, HDL has a protective effect against atherosclerosis. 2- Hypertension 3- Diabetes mellitus…due to associated hyperlipidemia 4- Cigarette smoking 5- Stress and personality…Personality A 6- Overweight….Atherogenic diet high in animal saturated fatty acids and cholesterol. 7- Exercise… Reduces the incidence of atherosclerosis  Ischemic Heart Angina Myocardial Disease pectoris syndromes infarction  Angina Pectoris Definition Cause Patterns  Angina Pectoris Definition: Chest Discomfort (Pain) can be *Prolonged (15 seconds to 15 minutes) *Recurrent *With different qualities (constricting, squeezing, choking, or knifelike) *Can radiate down the left arm or to the left jaw. Cause: Transit myocardial ischemia from seconds to minutes due to inadequate perfusion then perfusion is restored. *In angina pectoris there is no death of heart tissue.  patterns stable Prinzmetal unstable -Most common form & caused -90% vessel block or mainly by -Also called Variant Acute plaque change atherosclerosis angina or Vessel (superimposed -Transient (15 min.) certain levels of -Episodic -Not relived by rest and exertion. -Relived by VD but VD -Relived by rest & not rest -Pre-infarction Angina Nitroglycerin “Can Cause infarction’’ (Vasodilator )  Myocardial Infarction Definition Causes & risk factors Sites Types Clinical picture Morphology (N/E-M/E) Complication  Myocardial Infarction Definition: Area of coagulative necrosis of myocardium due to acute coronary ischemia. Causes & risk factors: It occurs when the severity or duration of ischemia is enough to cause cardiac muscle death. The most common cause is thrombosis on top of preexiting athermoatous plaque  Types Transmural Sub-endocardial Full thickness Inner 1/3 to half of ventricular wall Superimposed thrombus in Decreased circulating blood atherosclerosis volume not actual coronary artery occlusion ( shock, Hypotension)  Clinical Features: Typical features: *Severe, crushing substernal chest pain or discomfort that can radiate to the neck, jaw, epigastrium, or left arm * Rapid weak pulse * Dyspnea * Sweating profusely Silent MI (no pain): *DM (due to peripheral neuropathy).  Morphology (N/E & M/E) Time N/E M/E Up to 4hours Non Non 4-24 hours Pale area Beginning of necrosis: (Beginning of surrounded by myocyte characterized by infarction area) edema and *Pyknosis of nuclei erythema. *Hypereosinophilic cytoplasm. *marginal contraction band necrosis.  Normal cardiac muscle (4-24 hours) The earliest change is hypereosinophilia (above) with an intense pink cytoplasm. Pyknotic nuclei The viable myocardium (left and below marginal contraction band necrosis.  Morphology (N/E & M/E) Time N/E M/E 1-3 days Infarct area more Coagulation necrosis, (well formed pale, well myocte show: infarction) circumscribed and - loss of nuclei hemorrhagic border - Loss of striations. - Contraction bands. - Brisk interstitial infiltrate of Neutrophils 3-7 days Infarct area is yellow, Replacement of neutrophils surrounded by a zone by macrophages which of hyperemia engulf necrotic debris (1-3 days) Coagulation necrosis, myocte show: - loss of nuclei - Loss of striations. - Contraction bands. - Brisk interstitial infiltrate of Neutrophils (3-7 days) Replacement of neurophils by macrophages which engulf necrotic debris  Morphology (N/E & M/E) Time N/E M/E 7-10 days -Red granulation tissue -Well-developed invades the infarct phagocytosis of dead area from outside cells by macophages inwards -early formation of fibrovascular granulation tissue at margins (fibroblast & capillaries) Weeks- months - Well developed grey Progressive maturation white scar is formed. of granulation tissue with collagenization. (7-10 days) Well-developed phagocytosis of dead cells by macophages early formation of fibrovascular granulation tissue at margins (macrophages, fibroblast & capillaries) (weeks-monthes) Progressive maturation of granulation tissue with collagenization  Complications: 1- Arrhythmia…..most common cause of death in the first few hours following infarction 2- Myocardial (pump) failure 3- Myocardial Rupture : Occurs within 4-7 days after Infarction (due to neutrophilic liquifactive enzymes). 4- Myocardial aneurysm with thrombosis inside. 5- Chronic heart failure 6- leg thrombosis &pulmonary embolism due to Prolonged confinement to bed Thank you