Valvular Heart Disease PDF

VALVULAR HEART DISEASE  Definitions: Stenosis: means failure of a valve to open completely, thereby impeding forward flow. Insufficiency: means failure to close completely thereby allowing reversal flow. Functional regurgitation: means: Dilatation of the ventricle which pul...

VALVULAR HEART DISEASE  Definitions: Stenosis: means failure of a valve to open completely, thereby impeding forward flow. Insufficiency: means failure to close completely thereby allowing reversal flow. Functional regurgitation: means: Dilatation of the ventricle which pulls down & outwards the papillary muscles. Dilatation of aortic or pulmonary artery, pulling the valve’s commissures apart.  Acute Rheumatic fever acute, immunologically mediated, multisystem inflammatory disease occurs after group A β-hemolytic streptococcal pharyngitis, 1. Brain 2. Joint 3. Skin & subcutaneous tisse 4. pancraditis(rheumatic heart disease )  Manifestations What are the criteria for diagnosis? We have major criteria which are: Evidence of preceding group A streptococcal infection + → Either 2 of the major manifestations or One major & 2 minor manifestations. Manifestations Major manifestations: Minor manifestations: Migratory polyarthritis of the Fever (note that fever is a large joints. minor manifestation!) Carditis Arthralgia Subcutaneous Elevated acute phase Erythema marginatum of the reactants (CRP) skin. Sydenham’s chorea: a neurologic disorder with involuntary purposeless, rapid movements. PATHOGENESIS 3% infected patients develop rheumatic fever antibodies produced against Bacterial antigens cross-react with host antigens In particular, antibodies against M proteins cause injury through the activation of complement and macrophages 2- to 3-week delay streptococci are completely absent from the lesions.  The presence of M Protein is the most important virulence factor for group A streptococci: Some serotypes of the M protein have a long terminal antigen domain (epitope) that is similar to antigens in various components of the human heart & other tissues. Antibodies against the M protein of strep. Cross-react with the tissue glycoprotein in the heart, joints & other tissues. Strep. Infection evokes an auto-immune response against self-antigens. The site of infection is important. (It does not follow streptococcal cellulitis!). Genetic susceptibility influences the hypersenestivity reaction. (Increased family incidence). Antibody cross reactivity in blood samples from patients with acute rheumatic fever is associated with (HLA B5). Note! only few people are affected. Chronic sequalae are due to fibrosis following inflammation & turbulence caused by valve deformity. MORPHOLOGY Acute rheumatic fever : Pancarditis. Aschoff bodies: Collections of lymphocytes , plasma cells, and activated macrophages called Anitschkow cells +fibrinoid necrosis. Found in any of the three layers of the heart Vegetation: fibrinoid necrosis and fibrin deposition along the lines of closure  What are the morphological features of acute rheumatic fever Widely disseminated focal inflammatory lesions in various sites, but most marked in the heart is (Aschoff bodies). Aschoff bodies: are foci of swollen eosinophilic collagen surrounded by lymphocytes, occasional plasma cells & macrophages called Anitschkow cells. Antischkow cells: have abundant cytoplasm, central round-ovoid nucleus where chromatin is central & slender (caterpillar cell). Some are multinucleated. Inflammation & Aschoff bodies are found in any of the three layers of the heart → Pancarditis: Pericardium: shows a fibrinous or serofibrinous exudate (bread & butter) which usually resolves. What are the morphological features of acute rheumatic fever Myocardium: shows scattered Aschoff bodies within the interstitium, predominantly perivascular. Endocardium & left-sided valves: valves shows fibrinoid necrosis within the cusps or along the chordae tendinae. These are small (1 – 2 mm vegetations or verrucae) & they form along the lines of closure. (Mitral valve, acute rheumatic fever) These vegetation result from the precipitation of fibrin at sites of (erosion related to the underlying inflammation & collagen degeneration). These acute valvular changes cause little disturbances in cardiac function. The endocardium of the left atrium shows irregular thickening called Mac Callum plaque (Batch) caused by regurgitant jets. Chronic rheumatic heart disease Fibrosis & scarring. valve cusps and leaflets become permanently thickened and retracted. Mitral valves : leaflt thickening, commissural fusion shortening, and thickening and fusion of the chordae tendineae “fish mouth” or “buttonhole” stenosis  The most important functional consequence of rheumatic heart disease is valvular stenosis and regurgitation; stenosis tends to predominate. The mitral valve alone is involved in 70% of cases, combined mitral and aortic disease in another 25%; Fibrous bridging & calcification occur, producing fish mouth or (Buttonhole stenosis). The left atrium dilates & may contain a thrombus. Long standing congestion of the lungs may cause pulmonary vascular & parenchymal changes. Eventually it causes right ventricular hypertrophy. In isolated mitral stenosis the left ventricle is normal mitral stenosis, the left atrium progressively dilates owing to pressure overload, precipitating atrial fibrillation. The combination of dilation and fibrillation is a fertile substrate for thrombosis, Long-standing passive venous congestion gives rise to pulmonary hypertension In time, this leads to right ventricular hypertrophy and failure. Clinical Features of Acute rheumatic fever Symptoms begin 2 to 3 weeks after streptococcal infection, fever and migratory polyarthritis 80% in Children (5 – 15); 20% occur in adults : arthritis carditis. (pericardial friction rubs , functional mitral insufficiency and CHF, arrhythmias Chorea subcutaneous nodules; erythema marginatum  Occurs 10 days to 6 weeks after strep. Pharyngitis. Often in children 5 – 15 years of age. Antibodies (ASO & DNAse B) are positive. Migratory polyarthritis & fever. Acute carditis, which causes: Pericardial friction rub Weak heart sounds Tachycardia & arrhythmia Myocarditis may cause: Cardiac dilation Functional mitral valve insufficiency Even failure  Increased susceptibility to reactivation of the disease with subsequent attacks. Carditis worsens with each reactivation & their effects is cumulative. Clinical manifestations appear years after the initial attack. Signs & symptoms depend on which valve or valves are involved, & these are: 1. Murmurs 2. Hypertrophy 3. Dilation 4. Failure 5. Arrhythmias 6. Thrombo-embolic complications 7. & infective endocarditis Long term prognosis is variable.  The diagnosis of acute rheumatic fever serologic evidence of previous streptococcal infection in conjunction with two or more of the so-called Jones criteria: (1) carditis; (2) migratory polyarthritis of large joints; (3) subcutaneous nodules; (4) erythema marginatum skin rashes; and (5) Sydenham chorea, Minor criteria :fever, arthralgias, ECG changes, or elevated acute phase reactants Anti streptolysin O or Anti DNAase  The major manifestations (details): Carditis: Pancarditis: is the most serious & second most common complication of rheumatic fever. Patients may experience: Dyspnea Chest discomfort Pleuritic chest pain Oedema Cough or orthopnea Chronic heart failure (CHF) may develop secondary to severe valve insufficiency or myocarditis.  Arthritis: Polyarthritis is the most the most common symptom & frequently the earliest manifestation. Arthritis begins in large joints of the lower extremity (knees & ankles) & migrates to other joints (elbows & wrists). Affected joints are painful, swollen & show limited movements. Arthritis reaches maximum severity in 12 – 24 hours, & persists for 2 – 6 days but may be longer. Lesions are migratory but not additive. Arthritis responds well to aspirin. Arthritis is more severe & more common in teenagers.  Erythema marginatum: Subcutaneous nodules: Occurs in 5 – 13% of cases. Its incidence is declined. It occurs Begins as (1 – 3 cm in diameter, in 0.8% of cases. red to pink, non-pruritic) The nodules appear over the macules or papules on the trunk extensor surfaces of (elbows, & proximal limbs, but never on knees & ankles). the face. These nodules are (non-tender & Spreads outwards with raised not attached to the overlying skin). erythematous edges & central There range from 1 – 2 cm. clearing. Histologically it has areas May fade & reappear within resembling Aschoff bodies. hours. Clinical Features of chronic rheumatic heart disease Occur after years or decades after acute rheumatic fever. valvular damage ( stenosis or regurgitation) leading to : cardiac murmurs, cardiac hypertrophy and dilation, and CHF, arrhythmias. thromboembolism susceptible to infective endocarditis. Infective Endocarditis serious infection of the valves results in bulky, friable vegetations composed of necrotic debris, thrombus, and organisms  Classification: Acute: Sub acute: highly virulent organism attacking low virulence attacking scarred or a normal valve, deformed valves causing substantial morbidity and insidiously and—even untreated— mortality even with appropriate follows a protracted course of weeks antibiotic therapy and/or surgery. to months ; most patients recover after appropriate antibiotic therapy  New terminology Acute naive valve endocarditis (NVE): Prosthesis valve endocarditis: Involves normal valves & has an aggressive 10 – 20% of cases. course. Occurs healthy or debilitated people. Affects the mitral valve more than the aortic. Typical causative organisms are (staph. & strep. Pyogenes). Occurs within 6 months of the valve Subacute naïve endocarditis: implant. Affects abnormal valves only. IVDA (intra venous drug abuse) Their course is indolent & may continue for infective endocarditis: months. In 75% of cases there is no underlying Causative organisms are (a-hemolytic valve abnormality. streptococci & enterococci). Nosocomial infective endocarditis. PATHOGENESIS predisposing factors: rheumatic heart disease, mitral valve prolapse, Prosthetic heart valves intravenous drug abuse dental or surgical procedure  Pathogenesis: Bacteremia (nosocomial or spontaneous), that delivers the organisms to the surface of the valve. Adherence of the organisms. Eventually invasion of the valve leaflets: The common denominator for adherence & invasion is (non-bacterial thrombotic endocarditis) which is a sterile fibrin platelet vegetation. In acute infective endocarditis this is may be produced by invading organisms or by valve trauma from intravenous catheters  Bacteremia can result from: Endoscopy 0 – 20% Dental extraction Trans-urethral resection of prostate Trans-esophageal echocardiography Host factors: Neutropenia Immunodeficiency & therapeutic immunosuppression. Diabetes mellitus Alcoholism Intravenous drug abuse The causative organisms 60% :Streptococcus viridans, S. aureus enterococci and HACEK group (Haemophilus, Actinobacillus, Cardiobacterium, Eikenella, and Kingella), MORPHOLOGY friable, bulky, and potentially destructive vegetations containing fibrin, inflammatory cells, and microorganisms are present on the heart valves The aortic and mitral valves are the most common sites of infection, the tricuspid valve is a frequent target in the setting of intravenous drug abuse. Vegetations may be single or multiple and can sometimes erode into the underlying myocardium to produce an abscess cavity (ring abscess)  emboli is common because of the friable nature of the vegetations. septic infarcts and mycotic aneurysms.  Clinical Features Fever splenomegaly Murmurs microemboli can give rise to: 1. petechia, 2. nail bed (splinter) hemorrhages, 3. retinal hemorrhages (Roth spots), 4. painless palm or sole erythematous lesions (Janeway lesions), or 5. painful figertip nodules (Osler nodes); Diagnosis is confirmed by: positive blood cultures and echocardiographic findings Complications : glomerulonephritis (antigen-antibody complexes), hematuria, albuminuria, or renal failure. Arrhythmias Systemic embolization Valvular damage (Valvular insufficiency) myocardial abscess Cardiac complications: Valvular incompetence or stenosis. Myocardial ring abscess with possible perforation of the (aorta, septum or free wall). Suppurative pericarditis. Loosening & paravalvular leak in artificial valves. Embolic complications (Of IE): Renal complications: If it is left sided, complications occur at: Embolic infarction. Brain Focal & diffuse Meninges glomerulonephritis → an Heart Spleen immune complex trapping. & other sites Multiple abscess. If it is right sided: Lung abscess or Pneumonia Diagnostic criteria of IE: Pathologic criteria: Demonstration of micro-organisms by culture or histology of (vegetations, an embolus or intra cardiac abscess). Clinical criteria: Major: Positive blood culture. Echo findings: (mass or abscess or separation of an artificial valve) Minor: Predisposing lesion or drug abuse Vascular lesions or immunologic phenomena. Consistent but nit diagnostic echo findings. Nonbacterial thrombotic endocarditis (marantic endocarditis) (NBTE) Here there is deposition of small masses of fibrin, platelets & other blood components on valve’s leaflets. Vegetations are sterile & loosely attached. It occurs in debilitated people & those suffering from cancer especially (mucus secreting adenocarcinoma of the pancreas) & (medullary carcinoma of the thyroid). Its local effect is not significant. It is known to cause emboli to the (brain, heart & other sites).  Morphology of NBTE: Vegetations (smooth or verrucous). The valve is usually normal. The vegetations are (small & sterile & non-destructive) lying along the line of closure. The vegetations are composed of thrombi without accompanying inflammation → do not cause valve damage. If patients survived, these vegetations undergo organization. The pathogenesis is believed to be due to hyper-coagulable state → associated with mucus secreting adenocarcinoma. It also follows trauma due to an indwelling catheter. Endocarditis of SLE (Libman-Sacks) Here there is Mitral & aortic valvittis with small sterile vegetations, but all valves can be affected. Vegetations are single or multiple, frequently on the under surface of valves, but may affect other sites. These vegetation are histologically formed of immune complexes & mononuclear cells → appear (fibrinous & eosinophilic). There is an intense valvitis characterized by fibrinoid necrosis → this can cause fibrosis & deformity of the valve thus resulting in regurgitation & frequently stenosis. Embolic phenomena & secondary infective endocarditis can develop. Clinical presentations: Patients are usually asymptomatic Or present with: Cardiac failure secondary to valve problem Cerebrovascular embolism Rarely systemic thromboembolism Secondary infective endocarditis Symptoms of SLE  Infective endocarditis vegitations Vegitations  This angiogram demonstrates the aortic arch and great vessels. An embolus from a cardiac valvular vegetation from the left side of the heart can travel out the systemic circulation. Shown here is a septic embolus from infective endocarditis travelling up the left common carotid artery, which could result in a cerebral infarction and/or abscess. Splinter haemorrhages  Other valvular lesions Calcific aortic stenosis It is a progressive disorder that results in stiff valve leaflets with eventual obstruction to the left ventricular outflow. Its initiating factor is mechanical stress especially in damaged valves, & this is caused by: Rheumatic heart disease Congenital aortic stenosis Congenital bicuspid valve (0.5 – 0.8) Unknown degenerative Risk factors: Old age Male gender High serum LDL Smoking Hypertension Diabetes Clinical features: Obstruction to outflow tract which leads to:  Concentric left ventricular hypertrophy.  Palpitation, fatigue & dyspnea on exertion.  Angina develops due to impaired microcirculatory perfusion of the hypertrophied muscles.  Cardiac decompensation & heart failure develops.  Poor prognosis if not treated surgically.  Myxomatous degeneration of the mitral valve (mitral valve prolapse) It affects 3% or more adults & is a common form of valvular heart disease in the west. One or both valve leaflets are (enlarged, redundant or floppy) & they prolapse or balloon into the left atrium during systole. It is found incidentally or gives rise to serious complications in a minority of cases. Morphology shows: Ballooning of valve leaflets → leaflets are thickened & rubbery. The chordae tendinae are (elongated, thinned & sometimes ruptured). Annular dilatation is characteristic. (No commissural fusion).  Morphology: Deposition of myxomatous material Focal thickening Secondary changes: Fibrous thickening of the valve Linear fibrous thickening of the left ventricular endocardial surface Thickening of the mural endocardium of the atrium Thrombi on the atrial surface of the leaflets Focal calcification (Floppy mitral valve) Pathogenesis: Unknown It is a developmental anomaly of connective tissue. (Note! There is an association with “Marfan syndrome” caused by mutation of the gene encoding for fibrillin-1). Associations: Extra-cardiac structural abnormalities, example (Scoliosis, high arched palate). Or possibly induced by a long standing (hemodynamic, cellular or metabolic) abnormality.  Clinical features: Most patients are A-symptomatic. → Midsystolic clic (clic murmur syndrome). The valve may become incompetent. → Late or pansystolic murmur. Minority develop (chest pain, dyspnea & fatigue). Psychiatric manifestation. Complications are: Infective endocarditis Mitral insufficiency Stroke or systemic emboli Arrhythmia  Carcinoid heart disease Carcinoid syndrome is characterized by (episodic flushing of the skin, cramps, nausea, vomiting & diarrhoea). The right side’s endocardium & valves are affected in 50% of patients. The left side is not affected because serotonin is inactivated by the oxidase enzyme in the lungs, unless there is a defect. There is a fibrous intimal thickening mainly the right ventricle & tricuspid & pulmonary valves → this is due to (smooth muscle cells & collagen fibers) being in acid mucopolysaccharide matrix.  These changes are due to secretion by a tumor of bioactive substances including (serotonin, histamine, bradykinin & prostaglandins). For GIT carcinoids there must be hepatic secondaries to develop the syndrome. The use of fenfluramine & phentermine (which are used for the treatment of obesity) can be complicated on the left heart side by changes similar to those of the carcinoid syndrome by affecting serotonin metabolism