Robbins Essential Pathology (PDF) Diseases of Blood Vessels

108 CHAPTER 7 Diseases of Blood Vessels Endothelium...

108 CHAPTER 7 Diseases of Blood Vessels Endothelium Intima Media Adventitia 1. Chronic endothelial “injur y”:  Hyperlipidemia  Hyper tension  Smoking  Homocysteine  Hemodynamic factors  Toxins  Viruses Response to injur y  Immune reactions A 2. Endothelial dysfunction (e.g., increased per meability, Platelet leukocyte adhesion), Monocyte monocyte adhesion, and migration 3. Macrophage activation, B Smooth smooth muscle recruitment, muscle cell accumulation of lipids in Fig. 7.3 Hypertensive vascular disease. (A) Hyaline arteriolosclerosis. vessel wall The arteriolar wall is thickened with the deposition of amorphous pro- teinaceous material (hyalinized), and the lumen is markedly narrowed. Fatty streak (B) Hyperplastic arteriolosclerosis (onion-skinning) (arrow) causing lumi- nal obliteration (periodic acid–Schiff stain). (B, Courtesy Helmut Rennke, MD, Brigham and Women’s Hospital, Boston.) ver or bar y excreon. C onsequeny, ger eves o HDL cor- 4. Macrophages and smooth muscle cells reae w a reduced rsk. S evera oer acors assocaed w an engulf lipid ncreased rsk o aerosceross (de, sedenar y esye, obesy, smokng, dabees) ower HDL eves or eevae LDL eves. Sa- Lymphocyte n drugs, wc nb coesero syness and suppress LDL eves, aso ower e rsk o aerosceross-reaed cardovascuar Fibrofatty atheroma dsease.    Hemody namc fac tors. A eromas end o o cc ur a s es o u r- bu en bo o d  ow :  e os  a o e x  ng vess es , a maj or ar e r  a  branc p ons, and a ong  e p oser  or wa o  e ab d om  na  aor  a. Te roe o y p er e ns on n  e d e veopmen o a e ro - s ceross s presumaby due o emo dy nam  c e e c  s on e nd o e -  a   unc  on. 5. Smooth muscle    Genetcs. Famy sor y s an mporan rsk acor or aeroscero- proliferation, collagen ss. Fama ypercoeseroema, an auosoma domnan dsease, and other ECM Lipid deposition, extracellular and mugenc dseases suc as yperenson and ype 2 dabees, debris lipid aso are assocaed w ncreased rsk. Lymphocyte Collagen    Age. Sympoms rom advanced esons appear n mdde age or aer. Fig. 7.4 Summary of the morphologic features and main pathogenic he ncdence o myocarda narcon ncreases ve-od beween events of atherosclerosis. 40 and 60 years o age, and dea raes rom scemc ear dsease rse w eac successve decade.  CHAPTER 7 Diseases of Blood Vessels 109 A B Fig. 7.5 Atherosclerotic lesions. (A) Aorta with mild atherosclerosis composed of fibrous plaques, one denoted by the arrow. (B) Aorta with severe, diffuse complicated lesions, including an ulcerated plaque (open arrow), and a lesion with overlying thrombus (closed arrow). FIBROUS CAP (smooth muscle cells, macrophages, foam cells, lymphocytes, collagen, elastin, proteoglycans, neovascularization) NECROTIC CENTER (cell debris, cholesterol crystals, foam cells, calcium) MEDIA Fig. 7.6 The structure of an atheromatous plaque.    G ender. Premenopausa women are reavey proeced agans e exraceuar marx (remodeng) and rombus organzaon, and aerosceross compared w age-maced men, possby because oten undergo caccaon, wc can be seen radograpcay. o e beneca efecs o esrogen and progeserone on pd pro- Acue and cronc canges n aeromas can ave serous es. consequences:    Cona ematopoess. he perpera bood ces o over 10% o    Rupture or uceraton exposes rombogenc subsances, nduc- adus over e age o 70 years w norma bood couns ave cona ng rombus ormaon (Fg. 7.7). muaons n genes a are assocaed w varous ypes o myeod    Hemorrage, caused by damage o rage capares n e a- neopasms, suc as acue myeod eukema (see Caper 9). Ind- eroma, eads o rapd paque expanson or paque rupure. vduas w cona emaopoess ave a wo-od eevaed rsk o    Embosm o sma ragmens o aeroma durng paque rupure dyng rom cardovascuar dsease, possby because ese mua- may cause scema n downsream organs. ons dysreguae e uncon o macropages and ereby enance    Aneurysm formaton s caused by oss o easc bers and oer oca nlammaon wn aeromas. supporng srucures rom e meda ayer o e vesse wa. Clncal Features. Myocardia infarcion (ear aack), cerebra Morphology. In descendng order, aerosceross mos oten nvoves infarcion (sroke), aoric aneur ysm, and peripera vascuar dis- e nrarena abdomna aora, e coronary areres, e popea ease (gangrene of exremiies) are e major cinica consequences areres, e nerna carod areres, and e vesses o e crce o of aeroscerosis. Ws. Lesons a varous sages o severy oten coexs (Fg. 7.5). hese compcaons may sem rom sow progresson o aerosce- Aeromaous paques are we o yeow rased esons w sot pd roc esons or rom dramac acue evens, as oows: cores covered by brous caps conanng smoo musce ces and    Ateroscerotc stenoss. Sowy advancng senoss may presen w coagen, assocaed w macropage and T-ympocye nraes sympoms o scema n ssues supped by e afeced vesses. he and varabe degrees o neoangogeness (Fg. 7.6 and Suppemena occuson s descrbed as a crtca stenoss wen  bocks 70% o e eFg. 7.1). Macropages sufed w pd, so-caed oam ces, may be umen, because a s pon and beyond, e ssue demand oten promnen. Exraceuar coesero s oten presen, requeny n e oupaces e bood suppy. Presenaons ncude angna pectors, orm o crysane aggregaes (coesero cets). he meda benea wc ypcay appears w exeron and rems w res; cronc e paque may be aenuaed and broc, w smoo musce aropy. scemc eart dsease, w sympoms reaed o ear aure; and Paques progressvey enarge roug syness and degradaon o ntermttent caudcaton, due o eg scema w exeron.  CHAPTER 7 Diseases of Blood Vessels 109.e1 L F C A B C Supplemental eFig. 7.1 Histologic features of atheromatous plaque in the coronary artery. (A) Overall architecture demonstrating fibrous cap (F) and a central necrotic core (C) containing cholesterol and other lipids. The lumen (L) has been moderately compromised. Note that a segment of the wall is plaque free (arrow); the lesion is therefore “eccentric.” In this section, collagen has been stained blue (Masson trichrome stain). (B) Higher-power photograph of a section of the plaque shown in (A) stained for elastin (black), demonstrating that the internal and external elastic laminae are attenu- ated and the media of the artery is thinned under the most advanced plaque (arrow). (C) Higher-magnification photomicrograph at the junction of the fibrous cap and core, showing scattered inflammatory cells, calcification (arrowhead), and neovascularization (small arrows). 110 CHAPTER 7 Diseases of Blood Vessels A B Fig. 7.7 Atherosclerotic plaque rupture. (A) Plaque rupture without superimposed thrombus, in a patient who died suddenly. (B) Acute coronary thrombosis superimposed on an atherosclerotic plaque with focal disrup- tion of the fibrous cap, triggering fatal myocardial infarction. In both (A) and (B), an arrow points to the site of plaque rupture. (B, Reproduced from Schoen FJ: Interventional and Surgical Cardiovascular Pathology: Clinical Correlations and Basic Principles, Philadelphia, Saunders, 1989, p. 61.)    Acute paque cange. Acue paque canges, suc as rupure, Pathogeness. he pressure wave produced durng sysoe produces nrapaque emorrage, or weakenng o e brous cap by proeases maxma wa sress and urbuence n e nrarena aora, e mos reeased rom nlammaory ces, oten ave serous consequences. common se o AAAs. hese wa sresses are exacerbaed by yperen- Supermposed romboss and rapd, compee occuson may ead o son, wc enances e rae o expanson o AAAs once ey orm. myocarda narcon and sroke, medca emergences a mus be here s a srong assocaon w smokng a s no we undersood, dagnosed rapdy and reaed w ancoaguans (parcuary an- bu  may be reaed o an eevaed rsk o yperenson and aero- paee drugs) and romboyc agens or endovascuar sens. Oer sceross, as we as e efecs o oxns n obacco smoke. Aneur ysma mes, paque rupures ead o ncreased scema, parcuary n e daons oten concde w areas o aerosceross, wc, as aready ear, wou narcon, a cange marked by ncreasngy severe dscussed, can conrbue o meda scarrng. hese acors, aone or “unsabe” angna, wc may srke even wen e paen s a res. n combnaon, may ead o oss o smoo musce and exraceuar marx componens, weakenng e vesse wa and seng e sage or aneur ysma daon. ANEURYSMS AND DISSECTIONS Aneurysms and dissections are caused by congenital or acquired Morphology. Abdomna aorc aneur ysms ypcay occur beween defects in the walls of blood vessels or the heart. e rena areres and e aorc burcaon; ey can be saccuar Aneur ysms are oupoucngs a nvove a ree ayers o an or usorm n sape and up o 15 cm n dameer and 25 cm n arer y (nma, meda, and advena) or e aenuaed wa o e eng (Fg. 7.8). In mos cases, exensve aerosceross s presen, ear, and may sem rom nered deecs, yperenson, aerosce- w nnng and oca desrucon o e underyng meda. he ross, or ransmura myocarda narcons. Dssecons occur wen aneur ysm sac usuay conans band, amnaed, poory organzed g-pressure arera bood gans enr y o e arera wa roug a mura rombus, wc can  muc o e daed segmen. surace deec and puses apar e underyng ayers. Aneur ysms and dssecons cause sass and romboss and ave a propensy o rup- ure—oten w caasropc resus. he mos common and mporan vascuar aneur ysms and dssec- Clncal Features. Mos AAAs are asympomac un an acue comp- ons nvove e aora and are descrbed nex. caon deveops. Pysca examnaon may revea a pusang abdom- na mass. hey are dagnosed and szed by magng sudes, mos Aortic Aneurysms oten abdomna urasound. Acue compcaons o AAAs ncude e Aortic aneurysms most often occur in the abdomen and are prone oowng: to catastrophic ruptures, which often prove fatal.    Obstructon of a brancng vesse (e.g., e rena, ac, verebra, or Aneur ysms n  e  orax and ab domen ave dferen r sk ac- mesenerc areres) due o expanson, exenson, and oten super- ors: horacc aor  c aneur ysms are rea vey uncommon and are mposed romboss, resung n dsa scema o e kdneys, ass o cae d w  n er e d dee c s n  e ex race u ar ma r x, as n egs, spna cord, or gasronesna rac E  ers-D an os syndrome, Mar an syndrome, and cardovas c u-    Embosm rom a rupured aeroma or a mura rombus ar syp s (s e e C aper 6), w ere as ab domna  aor  c aneur ysms    Impngement on adjacent structures (e.g., compresson o a ureer or (AAAs) are muc more common, p ar  c u ary n ma es and n adu s eroson o verebrae by e expandng aneur ysm) over  e age o 60 ye ars w o smoke. A eros ceross and yp er-    Rupture no e peronea cavy or reroperonea ssues, eadng enson are mp or  an pre dsp osng cond ons. I s es mae d  a o massve, oten aa emorrage approxmaey 1,000,000 ndvdua s n  e Une d S aes ave an Women are ess key o ave AAAs, bu ose a occur n women AAA and  a b ewe en 0.5% and 1% o  es e esons w   r upure are more key o rupure. he rsk or rupure s deermned by sze: e ac ye ar. he ds c usson  a o ows s o c us e d on AAAs. Aneur ysms 5 cm n dameer or arger are consdered g rsk and  CHAPTER 7 Diseases of Blood Vessels 111 requre surger y. Tmey ner venon s crca: e moray rae or Pathogeness. Aorc dssecon many occurs n wo sengs: (1) eecve procedures s approxmaey 5%, wereas e rae or emer- men 40 o 60 years o age w aneceden yperenson (>90% o gency surger y ater rupure s rougy 50%. cases) and (2) younger paens w genec dseases o connecve ssue, suc as Maran syndrome and Eers-Danos syndrome (see Aortic Dissections Caper 6). he aoras o agng yper ensve paens sow meda Aortic dissection occurs when arterial blood penetrates the intima yperropy o e vasa vasorum (e sma vesses a suppy e and splays apart the media to form a blood-lled channel within vesse wa); s may dmns peruson o e meda, eadng o oss the aortic wall. o smoo musce ces and degenerave canges n e exraceuar Aorc dssecon may produce aa emorrage  e bood rup- marx. Wa naes e nma earng s unknown, bu once bood ures roug e advena and escapes no adjacen ssues. gans access o e vesse wa  unnes roug e meda aong e pa o eas ressance. Morphology. he nma ear markng e orgn usuay s ound n e ascendng aora wn 10 cm o e aorc vave (Fg. 7.9A). he dssecon pane wn e meda can exend rerograde oward e ear or dsay, occasonay as ar as e ac and emora areres (see Fg. 7.9B). Exerna rupure causes massve emorrage, or resus n cardac amponade   occurs no e percarda sac. In some nsances, e dssecng bood reeners e umen o e aora roug a second dsa nma ear, creang a vascuar canne wn e meda (doube-barreed aorta). Hsoogcay, cystc meda degeneraton, caracerzed by oss o smoo musce ces, easc ssue ragmenaon, and accumuaon o abnorma proeogycan-rc exraceuar marx, may be seen (Suppemena eFg. 7.2). In mos nsances, no specc deec s dened. Clncal Features. Pa ens  ypc a  y pres en w    e sud d en ons e  o excr uc a ng e ar  ng or s abb ng p a n , b e g  nn  ng n  e aner or ces and rad a ng o  e m d d e o  e b ack. R e rog rade d ss e c -  on no  e aor  c ro o may d s r up aor  c v a ve  u nc  on , c aus e myo c ard a  narc  on by compre ss  ng  e c oronar y ar er e s, or  e ad A B o massve emor rage  no  e p e r  c ard  a  sp a c e. O  er comp  c a- Fig. 7.8 Abdominal aortic aneurysm. (A) External view of a large aortic  ons are re ae d o exens  on o  e d ss e c   on o  e g re a ar e r  es aneurysm that ruptured at the site is indicated by the arrow. (B) Opened o  e ne ck or o  e rena , mes e ne r  c ,   ac, or sp na  ar e r  es, any view, with the location of the rupture tract indicated by a probe. The o w c may b e come obs r uc e d. R ap d d  ag nos s , an  yp e r ens ve wall of the aneurysm is attenuated, and the lumen is filled by a large, layered thrombus. * A B Fig. 7.9 Aortic dissection. (A) An opened aorta with a proximal dissection originating from a small, oblique intimal tear (identified by the probe) associated with an intramural hematoma. Note that the intimal tear occurred in a region largely free of atherosclerotic plaque. The distal edge of the intramural hematoma (black arrows) lies at the edge of a large area of atherosclerosis (white arrow), which arrested the propagation of the dissection. (B) Histologic preparation showing the dissection and intramural hematoma (asterisk). Aortic elastic layers are black, and blood is red in this section, stained with Movat stain.  CHAPTER 7 Diseases of Blood Vessels 111.e1 A B Supplemental eFig. 7.2 Cystic medial degeneration. (A) Cross section of aortic media from a patient with Marfan syndrome, showing elastin fragmentation and areas devoid of elastin that resemble cystic spaces but are actually filled with proteoglycans (asterisks). (B) Normal media for comparison, showing the regular layered pattern of elastic tissue. In both A and B, elastin is stained black.