Difference between pages "PCP" and "Heart valves"

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Heart valves (view source)

Revision as of 23:06, 4 December 2011

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→‎Calcific aortic stenosis: more
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#redirect [[Fungi#Pneumocystis pneumonia]]
'''[[Heart]] valves''' are the domain of the cardiac surgeon and their bread & butter.


[[Category:Abbreviation]]
==Clinical==
===General===
*Insufficiency (regurgitant flow) - murmur in diastole.
*Stenosis (decreased flow area) - murmur in systole.
 
===Pathology===
Which valves cause the most trouble?
*Mostly those on the left side (subjected to higher pressures), i.e. mitral valve (or left atrioventricular v.) and aortic valve.
 
Aortic stenosis - cause?
*Mostly "calcific aortic stenosis".
 
==Quick approach to valves==
===Gross===
*Calcification?
**Consider calcific stenosis.
 
*Vegetations?
**Consider infective endocarditis.
 
*Thin (see-through)?
**Consider myxomatous change.
 
===Microscopic===
*Inflammation?
**Consider endocarditis.
 
*Anitschkow's cells (caterpillar cells)?
**Rheumatic heart disease.
 
*Aschoff bodies?
**Rheumatic heart disease.
 
*Thickening of spongiosa (layer)?
**Myxomatous change?
 
==Normal histology==
===Aortic valve===
General:
*Covered by endothelium.
*Mostly avascular (nutrients supplied by diffusion).
 
Terminology:
*Base - closest to the aortic wall.
*Free edge - closest to the centre of the valve/interacts with other valve cusps.
 
Three layers (from proximal (ventricular side) to distal (valsalva side)):<ref name=Ref_PBoD558>{{Ref PBoD|558}}</ref>
#Ventricularis.
#*Elastic tissue.
#Spongiosa.
#*Loose connective tissue.
#Fibrosa.
#*Mostly collagen, thickest part in a normal valve.
 
Notes:
*The loading of the ventricular aspect is tensile and the valsalva side compressive. Thus, it makes sense that the tissue on the ventricular aspect is good in tensile loading and the tissue on the valsalva side good in compression.  The elastic tissue can be thought of as [http://en.wikipedia.org/wiki/Rebar rebar]... the collagen as concrete.
 
===Mitral valve===
===Gross===
*Cordae tendinae.
**Should be thin.
**No fusion.
 
===Histology===
*Similar to the aortic valve.
 
==Calcific aortic stenosis==
===General===
*Somewhat similar to [[atherosclerosis]]; however, considered a separate entity.<ref>{{cite journal |author=Otto CM |title=Calcific aortic stenosis--time to look more closely at the valve |journal=N. Engl. J. Med. |volume=359 |issue=13 |pages=1395-8 |year=2008 |month=September |pmid=18815402 |doi=10.1056/NEJMe0807001 |url=}}</ref>
*Mitral valve is usually normal.
*Most common cause of aortic stenosis.
 
DDx of aortic stenosis:
#Calcific aortic stenosis.
#[[Bicuspid valve]] with calcific aortic stenosis.
#[[Rheumatic heart disease]].
 
===Microscopic===
Features:<ref name=Ref_PBoD590>{{Ref PBoD|590}}</ref>
*Affects the valsalva side of the valve.
**It affects the fibrosa.
*Primarily at the base of the valve, i.e. there is relative sparing the free edge.
 
==Myxomatous degeneration==
===General===
*Usually affects the mitral valve.
*Female > male,<ref>URL: [http://emedicine.medscape.com/article/759004-overview http://emedicine.medscape.com/article/759004-overview]. Accessed on: 8 June 2010.</ref> disputed by Toronto data.<ref name=leong>{{cite journal |author=Leong SW, Soor GS, Butany J, Henry J, Thangaroopan M, Leask RL |title=Morphological findings in 192 surgically excised native mitral valves |journal=Can J Cardiol |volume=22 |issue=12 |pages=1055-61 |year=2006 |month=October |pmid=17036100 |doi= |url=}}</ref>
*Associated with [[Marfan's syndrome]] and [[Turner syndrome]] (Monosomy X).<ref>{{cite journal |author=Wigle ED, Rakowski H, Ranganathan N, Silver MC |title=Mitral valve prolapse |journal=Annu. Rev. Med. |volume=27 |issue= |pages=165–80 |year=1976 |pmid=779595 |doi=10.1146/annurev.me.27.020176.001121 |url=}}</ref>
 
===Gross===
Features:<ref name=Ref_PBoD591>{{Ref PBoD|591}}</ref>
*No commissural fusion.
**Commissural fusion typical of rheumatic heart disease.
*Thickened.
*Rubbery consistency.
*Reactive/secondary changes.
**Fibrosis due to prolapse/abnormal contact of valve with other structures.
**Clots/organized thrombus - due to stasis.
 
===Microscopic===
*Thinning of ''fibrosa layer''.
*Thickening of ''spongiosa layer'' with mucoid (myxomatous) material. (key feature).
*+/-Secondary changes (due to valvular dysfunction): thrombi, fibrosis.
 
====Staining====
*Movat stain.
**Acid fuchsin, alcian blue, crocein scarlet, elastic hematoxylin, pathology consultation, and saffron.<ref>URL: [http://www.mayomedicallaboratories.com/test-catalog/Overview/9832 http://www.mayomedicallaboratories.com/test-catalog/Overview/9832]. Accessed on: 8 June 2010.</ref><ref name=penn_med>Modified Movat's Pentachrome Stain. University Penn Medicine. URL: [http://www.med.upenn.edu/mcrc/histology_core/movat.shtml http://www.med.upenn.edu/mcrc/histology_core/movat.shtml]. Accessed on: January 29, 2009.</ref>
 
Interpretation of Movat stain:<ref name=penn_med/>
*Black = nuclei and elastic fibers.
*Yellow = collagen and reticular fibers.
*Blue = mucin, ground substance.
*Red (intense) = fibrin.
*Red = muscle.
 
Image:
*[http://commons.wikimedia.org/wiki/File:Myxomatous_aortic_valve.jpg Myxomatous valve (WC)].
 
==Rheumatic heart disease==
===General===
*Classically leads to mitral valve stenosis.
**Rheumatic fever accounts for 99% of mitral stenosis.<ref name=Ref_PBoD594>{{Ref PBoD|594}}</ref>
*Disease less frequent today - as streptococcal pharynigits is treated.
 
===Gross===
*"Fish-mouth appearance".
**Slit-like morphology; elliptical cross-sectional flow area (mitral valve) has an abnormally small semi-minor axis<ref>URL: [http://en.wikipedia.org/wiki/Ellipse http://en.wikipedia.org/wiki/Ellipse]. Accessed on: 13 November 2010.</ref> axis due to valve thickening.
**Image: [http://www.principia-eng.com/services/construction/IMG_3098.jpg Fish-mouth appearance - pipe (principia-eng.com)].
*Significant valvular thickening.
*Thickening of the cordae tendinae.
 
*Images:
** [http://en.wikipedia.org/wiki/File:Rheumatic_heart_disease,_gross_pathology_20G0013_lores.jpg Rheumatic heart disease at autopsy - showing valvular thickening and thickening of the cordae tendinae (WP)].
**[http://commons.wikimedia.org/wiki/File:Aortic_stenosis_rheumatic,_gross_pathology_20G0014_lores.jpg Rheumatic heart disease - showing valvular thickening - aortic valve (WP)].
 
===Microscopic===
Features:<ref name=Ref_PBoD593>{{Ref PBoD|593}}</ref>
*Caterpillar cell ([[AKA]] Anitschkow cells)
**Abundant eosinophilic cytoplasm.
**Moderately-poorly defined cell border.
**Well-defined central ovoid nucleus with a prominent wavy ribbon-like chromatin -- looks vaguely like a caterpillar with some imagination.
**Pathognomonic for rheumatic fever.
 
*Aschoff bodies:
**Usually in the heart itself,
**Jumbled collagen, eosinophilic, and
**Surrounded by lymphocytes (T cells) +/- plasma cells.
 
Images:
*[http://commons.wikimedia.org/wiki/File:Aschoff_Body_in_Rheumatic_Myocarditis.jpg Aschoff body (WC)].
*[http://en.wikipedia.org/wiki/File:Anitschkow_Myocytes_in_an_Aschoff_Body,_Rheumatic_Myocarditis.jpg Anitschkow myocytes (WC)].
 
==Infective endocarditis==
===General===
*Infection of the endocardium - often involves the valves (which are covered by endocardium).
*Before the time of antibiotics -- 100% fatal.
 
====Clinical====
*Diagnosed (clinically) using the ''Duke criteria''.<ref>[http://www.medcalc.com/endocarditis.html http://www.medcalc.com/endocarditis.html]</ref><ref>{{cite journal |author=Durack DT, Lukes AS, Bright DK |title=New criteria for diagnosis of infective endocarditis: utilization of specific echocardiographic findings. Duke Endocarditis Service |journal=Am. J. Med. |volume=96 |issue=3 |pages=200-9 |year=1994 |month=March |pmid=8154507 |doi= |url=}}</ref>
**Positive blood cultures.
**Cardiac involvement - vegetation.
**+/-Febrile.
 
===Microscopic===
*Inflammatory infiltrate (key feature @ low power):
**+/-Plasma cells.
**+/-Neutrophils.
*Microorganisms - '''key feature''' (diagnostic).
**Hard to see (even at high power).
 
===Stains===
*[[GMS stain]] (Gomori Methenamine-silver stain).
**Look for [[fungi]].
*[[Gram stain]].
**Look for bacteria.
 
==Nonbacterial thrombotic endocarditis==
===General===
*Abbreviated ''NBTE''.
*May be associated with catheterization.
 
===Microscopic===
Features:
*No inflammation.
*No organisms.
 
==Libman-Sacks endocarditis==
===General===
*Associated with [[systemic lupus erythematosus]].<ref>URL: [http://dictionary.reference.com/browse/libman-sacks+endocarditis http://dictionary.reference.com/browse/libman-sacks+endocarditis]. Accessed on: 24 May 2011.</ref>
 
===Gross===
*Vegetation. (???)
 
===Microscopic===
Features:
*Hematoxylin bodies. (???)
 
==Biscupid aortic valve==
===General===
*Aortic valve usually tricuspid.
*1-2% of general population.<ref name=pmid18514024>{{cite journal |author=Vallely MP, Semsarian C, Bannon PG |title=Management of the ascending aorta in patients with bicuspid aortic valve disease |journal=Heart Lung Circ |volume=17 |issue=5 |pages=357-63 |year=2008 |month=October |pmid=18514024 |doi=10.1016/j.hlc.2008.01.007 |url=}}</ref>
*Inherited in autosomal dominant pattern.
*Most common congenital heart defect.<ref name=pmid20579534>{{cite journal |author=Siu SC, Silversides CK |title=Bicuspid aortic valve disease |journal=J. Am. Coll. Cardiol. |volume=55 |issue=25 |pages=2789–800 |year=2010 |month=June |pmid=20579534 |doi=10.1016/j.jacc.2009.12.068 |url=}}</ref>
 
===Significance===
*Associated with ascending [[aortic aneurysm]]s - x10 risk of dissection vs. normal population.<ref name=pmid18514024/>
*30% develop serious morbidity.<ref name=pmid18514024/>
*Associated with early development of [[calcific aortic stenosis]].
 
==Tumours==
{{main|Cardiac tumours}}
[[Papillary fibroelastoma]]s are the most common tumour of the valve.
 
==See also==
*[[Heart]].
*[[Cardiomyopathy]].
*[[Forensic pathology]].
 
==References==
{{reflist|2}}
 
[[Category:Cardiovascular pathology]]
Michael
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