Cardiovascular pathology II

• stenosis: filaure of valve to open completely > impedes forwards flow of blood
  • almost always has underlying valve abnormality
  • usually chronic
• incompetence/regurgitation: fialure of valve to close completely (allows reverse flow of blood)
  • functional regurgitation: valve becomes incompetent due to dilation of ventricle
  • due either to intrinsic disease of valve cusps or damage/distortion of supporting structures (aorta, mitral valve annulus, tendinous cords, papillary muscles, ventricular free wall)
• clinical consequences depend on:
  • which valve
  • degree of impairment
  • rate of its development
  • rate and quiality of compensatory mechanisms
• can be unimportant (e.g. rheumatic mitral stenosis)
• or rapidly fatal (e.g. acute aortic incompetence 2ary to destruction of valve cusp from infection)

• calcific aortic stenosis
• calcification of congentially bicuspid aortic valve (50-60yro)
• mitral annular calcification
• due to wear and tear
  • clinically apparent in 70yr+

• mitral stenosis > rheumatic heart disease
  • cross reaction following GpA B-haem steptrococcal pharyngitis
  • Ft. migratory polyarthritis of lg joints, carditis, subcut nodules, rash, Sydenham chorea
  • acute RHD > pancarditis (may recur w/ susequent pharyngeal infection adding to damage)
    • endocardium > vegetations
    • myocardium > inflammatory foci w/ Aschoff bodies (rheumatic granuloma - "owl eye")
    • pericardium > pericarditis
  • chronic RHD  
    • "fish mouth/button hole" stenoses, leaflet thickening, commissural fusion and shortening, thickening and fusion of chordae tendinae

• colonisation/invasion of heart valves
• formation of friable vegetations 
  • compris thrombotic debris and organisms
  • oft underlying tissue destruction
  • normal bacterial
• acute IE:
  • valve previously normal
  • acute onset
  • 50% mortality 
  • lesion is necrotising, ulcerative, invasive
• subacute IE:
  • valve usually abnormal
  • insidious onset
  • most recover
  • lesion less destructive

• predisposing factors:
  • abnormal valve: floppy mitral valve, degen calcific valvular stenosis, bicuspid aortic valve, artifical graft
  • host factors: immunosuppression, neutropenia, immunodeficiency, iatrogenic, diabetes, alcohol, IVDU
• organisms involved:
  • A-haem streptococcus: 50-60% abnormal valve, subacute
  • S. aureus: high virulence, normla valve, IVDU
  • mouth commensals
  • staph epidermitis: prosthetic valves
• mechanisms: seeding of blood w/ microbes e.g. dental/surgical procedure, dirty needle
  • thus give prophylactic ABx to at risk pts
• morphology of IE:
  • aortic and mitral most commonly affected, tricuspid in IVDU (can be more than 1 valve)
  • bulky friable vegetations

• complications of IE:
  • myocardial abscess
  • valve rupture/perforation
  • systemic emboli (A/M > body esp kidney; T/P > pulmonary)
    • septic emboli
    • immune complexes
• non-bacterial thrombotic endocarditis (sterile):
  • deposition of fibrin/platelets on valve leaflets
  • either side of heart
  • previously normal heart 
  • non-destructive but emboli risk important
  • occurs in hypercoag state (DIC, malignancy, sepsis)
• NB artificial valves:
  • mechanical
  • bioprostheses (homograft/porcine)
  • Cx: TE (thus longterm anticoag), IE, structural deterioration

"heart disease resulting from primary abnormality in the myocardium"

• causes:
  • inflammatory
  • immunological
  • systemicmetabolic disorders
  • muscular dystrophies
  • genetic abnormalities of myocytes (energy metabolism, structural and contracile proteins)
  • idiopathic
• 3 clinical pictures:
  • dilated cardiomyopathy (DCM, >90%)
  • hypertrophic CM (HCM/HOCM)
  • restrictive CM (RCM)
• pattern can be: idiopathic, specifc identifiable cause, 2ary extramyocardial disease)
• Dx by endomyocardial biopsies of RV

• characterised by:
  • cardiac hypertrophy, dilation, contracatile dysfunction
• results in CCF
• causes: idiopthic (most), alcohol, peripartum, genetic (OX phos, B ox FFA, dystrophin), myocarditis, haemochromatosis, chronic anaemia, drugs (doxorubicin, adriamycin), sacroidosis
• gross morphology:
  • heavy heart (2-3x norm), large and flabby
  • dilation of all chambers, pos 2ary mitral/tricuspid regurg
  • mural thrombi (> TE risk)
  • normal coronary arteries
• histology: hypertrophied fibres, attenuated/stretched fibres, interstitial and endocardial fibrosis
• any age (20-60)
• slowly progressive CCF, 50% mortality in 2 years (from CCF, arrythmias)
• EF 25% (norm= 50-65%)
• Rx - cardiac transplant

• charactarised by:
  • myocardial hypertrophy > abnormal diastolic filling
  • 1/3 intermittent LV outflow obstruction
• gross morphology:
  • massive myocardial hypertrophy, NO ventricular dilatation
  • assymetrical septal hypertrophy (NB 10% symmetrical)
• histology:
  • extensive myocyte hypertrophy
  • myocyte disarray
  • interstitial fibrosis
• 50% genetic, 50% sporadic
• genetic: AD w/ variable penetrance, mutations in 4 genes that encode contractile proteins
  • B-myosin heavy chain, cardiac troponin T, A-tropomyosin, myosin-binding protein C
• angina, AF, CCF, ventricular arrythmias, sudden death

• causes:
  • infection (esp. viral) > most common
  • immune
    • post-viral
    • post-streptococcal (RHF)
    • SLE
    • drug hypersensitivity (methyldopa, sulphonamides)
    • transplant rejection
  • sarcoidosis
• clinical features:
  • asymptomatic
    • DCM years later (e.g. w/ CMV)
    • arrythmias
    • acute heart failure (e.g. in rejection)
    • sudden death 

• pericardial effusion- transudate/exudate
• haemopericardium: cardiac tamponade post-MI/traumatic perforation/ruptured aortic dissection
• purulent pericarditis - pus
• pericarditis
  • 2ary to cardiac disease, thoracic or systemic disorders or metastases
    • infections: virus, B, Tb, fungi
    • immune: RF, SLE, scleroderma, post-MI (Dressler syndrome), hypersensitivity reaction
    • misc: MI, uraemia, post-cardiac surgery, neoplasia, trauma, radiation
  • types:
    • serous, fibrinous, purulent/suppurative, haemorrhagic, caseous
  • outcome:
    • reabsorbed, resolved
    • organise > obliterate pericardial space
    • +/- constrictive pericarditis: heart suurounded by fibrous scar limits filling thus SV/CO

• 2ary - in 5% of pt who die from ca
  • most commonly melanoma or mediastinal primary
• primary - rare
  • myxoma
    • most common primary tumour
    • 90% in atria (majority LA) = atrial myxoma
    • morphologically can be:
      • sessile: firmly immobile, attached like a limpet
      • pedunculated (more common): attached on a stalk
        • can swing into valve: 'ball-valve obstruction'
    • can injure valve
    • embolisation risk

• 'abnormalities of herat or great vessels at birth'
• right to left shunt
  • pulmonary to systemic, thus less oxygenated > cyanosis= 'cyanotic congenital HD'
    • tetralogy of Fallot
    • transposition of great rteries
    • persistent truncus arteriosus
    • tricuspid atresia
    • total anomalous pulmonary venous connection
  • can get paradoxycal embolus as veins > systemic
• left to right shunt
  • systemic > pulmonary thus incr pulm flow > pulm HTN 
    • intially reversible, later will reverse to RtL w/ pr gradient (Eisenmengers syndrome)
    • ASD, VSD (most common CHD). AV septal defect
    • PDA (b/w pulm art and desc aorta)
• obstructive: due to abnormal narrowing of chamber/valve/vessel e.g. coarctation of aorta

• cause:
  • immune
    • immune-complex, ANCA (antineutrophil cytoplasmic antibodies), direct ab mediated, cell mediated, IBD, paraneoplastic
  • infectious
  • unknown
    • giant cell (temporal) arteritis (most common)
    • Takayasu arteritis (granulomatous vasculitis w/ huge intimal fibrosis and vascular narrowing)
    • polyarteritis nodosa (characterised by necrotising lesions in middle sized vessels)

• mitral incompetence > floppy mitral valve, myxomatous degeneration, mitral valve prolapse
  • floppy mitral stenosis: common
  • one or both mitral leaflets enlarhed, hooded, redundant > prolapse into RA in systole
  • usually incidental finding, v rarely can cause sudden death
• aortic stenosis > calcification of normal/congentially bicuspid valves
• aortic incompetence > dilation of ascending aorta related to HTN and age