Abdominal Ao and LE Aneurysms

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Abdominal Ao and LE Aneurysms Powered By Docstoc
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Abdominal Ao and LE Aneurysms                     yrs later (4.5% vs. almost 10%). It‘s very cost        Lancet (1998): pts w/ aneurysms of diam 4-5.5
                                                  efficient. Thus, we should screen for AAA in men.       cm were randomized to U/S surveillance vs
Definitions:                                                                                              early elective surgery.
 Aneurysms: permanent localized dilation, diam Expansion rate                                           At 6 yrs, both groups had comparable survival
    > 50% of expected nl                         About 10% diameter ↑ in diameter / yr                   rates (64%) (if died, from any cause, not just
 Ectasia: dilation < 50% above expected nl             o Widely variable                                 rupture)
 Arteriomegaly: diffuse enlrgmnt of several            o So routine surveillance is indicated           Thus, if aneurysm <5.5 cm diam, we don’t
    segments diameter > 50% of nl                       o Rapid growth  increased rupture risk           have to treat it
                                                 Median expansion rate = 3^(0.106t)                     RFs for rupture in pts kept under U/S
Epi:                                                                                                      surveillance as determined by this study
 M:F ratio 5-7:1 (so M>F)                      Rupture                                                       o If 4-5.5 cm diam, annual risk for
 Prevalence                                     Diameter is the primary determinant RF for                       rupture is 2.2% / yr
        o AAA > 3 cm : 3-10% for pts > 50 yo        rupture                                                   o But this rate is higher with the
        o AAA > 3 cm : 4-6% for VA pts bw 50-    LaPlace: T=(Pressure)(r) / (h)                                   following RFs
             79 yo                                  [personal notes: h = wall thickness. In this                        Female
        o AAA > 4 cm: 1.4%                          equation, T must refer to wall stress because                       Larger initial diam
 3.5 Caucasian: 1 AA                               tension is in units of N/m, and as it is above,                     Current smoking
 Seasonal: Fall, winter                            units come out to N/m2]                                             Lower FEV1 (COPD)
 Present in 6% of CAD pts, 9% PAD pts, 50%             o <4 cm diam              0% rupt/yr                            Higher BP
    of pts w/ femoral or popliteal aneurysms            o 4-5 cm                  0.5-5%
 Location: 95% of arterial aneurysms in Ao             o 5-6                     3-5%                Risk fo rupture of Larger (>5.5 cm) aneurysms
        o 95% of Ao aneurysms are infrarenal            o 6-7                     10-20%               Lancet (2002): 198 vets w/ AAA >5.5 cm who
        o Thrombosis, embolism can occur but            o 7-8                     20-40                   refused /unfit for surg
             rupture is more common                     o >8                      30-50                Mean f/u 1.52 yrs showed 112 deaths, 45 from
 Ruptured AAA: 13 leading cause of death
                        th                       RFs                                                     ―probable‖ AAA ruptures
    (USA)                                               o HTN                                          Found that diam was correlated w/ risk for
                                                        o COPD                                            rupture per yr
Diagnosis                                               o Smoking – strong RF                                 o 5.5-5.9 cm            9.4%
 directed PE is accurate if abd growth <100 cm         o FHx                                                 o 6-6.9                 10.2
 most aneurysms discovered during routine work         o Shape/wall tension: (saccular/bowing                o >7                    32.5
    up for another cause                                     out = high risk; fusisform lwr risk)      Anything >7 is considered very large
                                                        o Thrombus
 Imaging
        o plain abn x-rays                                                                            Criteria for Endovascular AAA grafting
        o U/S abd (first line)
                                                Intervention                                           Prox aueurysm neck
        o CT                                     1st performed 1950 in France                                 o Length >15 mm
        o MRI                                    Replace Ao w/ prosthetic graft                               o Diam: less than 32 mm
                                                 Good results: <5% death/comp                                 o No circumferential calcium
Screening: study of 60,000 men in England showed                                                               o Minimal mural thrombus
screening for aneurysm decreased risk for dying 10 UK Small Aneurysm Trial

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        o    Minimal funnel shape (a little bit helps           o    Open surg: 4.7%                                o Intraluminal thrombus
             hold graft but if goes from 2528 cm,              o    Endovasc: 1.7%                            Open surg can occur via medial or posterior
             that‘s too much)                                   o    Thus, if someone is a candidate for        approaches
   Tortuosity                                                       both procedures, we tell them their       Endovascualr stent grafting: usu for pts who are
         o Ao neck angle <30-50 deg                                  chance of dying is lower w/ endovasc       older and sicker
         o Iliac arter angle <90deg                        F/U 8 yrs later: chance of survival is very
   Iliac a access: 7-15 cm diam; calcification             similar in both groups. Also, endovasc repair  Summary
   Overall: 60% have suitable anatomy                      required much higher # of re-interventions.     <5.5 cm diam aneurysms: can be observed by
                                                            And cost for stent graft >> that of open surg     U/S
Endoleak – The Achilles Heel                                                                                Rate of rupture w/ observation of sm
 Endoleak = persistence of blood flow outside          Counseling your pts:                                  aneurysms: ~2%/yr
   the prosthesis but within the aneurysm sac            Open AAA surg is appropriate for fairly healthy  Endovasc aneurysm repair is an option for
 not an aneurysm                                          pts w/ AAA‘s >5.5 cm                               ~60% of pts
 Classification Types:                                  Not indicated in pts w/ chronic fatal dz: severe  Mortality lwr for endovasc repair than open
       o I: attachment site leak                           COPD, CHF, cancer                                  surg
                IA: prx end                             Problematic in ―healthy‖ elderly (>80 yo)         Long term outcomes for endovasc repair similar
                IB: distal end                          Most AAA are silent                                 to open surg
       o II: branch leak- retrograde blood               Primary role of AAA repair: prevent rupture       but endo vasc repair is more $$$ and requires
           comes from mesenteric a or collaterals        Poorer risk pts more likely to develop              indefinite monitoring due to higher re-
                IIA: simple (1 branch)                    functional impairment after open surg              intervention rate (10-20%)
                IIB: complx (2+ branches)
       o III: Device defect                     Popliteal aueurysms                                         Predisposing conditions
                IIIA: junction leak             Much less common                                           Marfans: fibrillin plays greater role in
                IIIB: fabric disruption                o 1% of 65-85 yo M pts                                  upper/thoracic Ao; collagen plays bigger role in
       o IV: Fabric porosity                            o present in 2-3% of AAA pts                            lower/abdominal Ao
                                                        o but 40-50% of pts w/ popliteal                            o so Marfan‘s pts have defects in
What connects IMA to SMA?                                   aueurysms also have Ao ones                                 ascending Ao
    1. Marginal artery of Drummond               Clinical pres                                              Ehlers Danlos
         (collection of arcades) and                    o Most silent                                               o Spont arterial rupture w/o necessarily
    2. Arc of Riolan (meandering mesenteric a)          o Thromboembolism – the knee bends a                            having aneurysms
         (more variable).                                   lot which can break off emboli                   Lowes Deeps (?) syndrome
Coils can be placed in these to prevent type II         o Large (4 cm) ones may cause                               o Defect assoc‘d w/ premature aneurysm
endoleaks                                                   compression                                                 formation
                                                        o Rarely rupture
Trial comparing conventional and endovascular                                                               Gallbladder and Pancreas
repair of AAAs                                  Repair of Popliteal aneurysm                                Gallbladder anatomy…tricky ones: Spiral valves of
 Lancet (2004) (EVAR Trial): For pts with >5.5  Indications                                               Heister and Triangle of Calot
    diam AAA, underwent open surgery or                 o Symptomatic
    endovascular repair                                 o 2 cm diam generally                               Bile formation:
 30 day mortality (all-cause)
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   liver excretes bile continuously, 500-1000 mL /      LFTs for Tbili, AST, ALT, AP                       Hepatobiliary Radionuclide Scanning (HIDA
    day                                                  ↑ WBC may indicate cholecystitis                    scan)
   w/ intact Sphincter of Oddi, bile flow is            ↑ TBili and AP suspicious for                       o Nuclear med study
    directed into gallbladder                             choledocholithiasis                                 o T-99 labeled protein injected IV, taken up
   bile composition: water, e-lytes, bile salts,        ↑ bili, AP, and transaminases in cholangitis            by Kupffer cells of liver, excreted by bile
    protein, lipid, pigments                                                                                  o Scarred/ inflamed GB (cholecystitis) will
   Enterohepatic circ:                               Ways to evaluate the GB                                     show the Technetium never taken up by the
    o 80% bile salts reabsorbed in terminal            U/S                                                       GB, never ends up in duodenum
         ileum                                          o Gen info                                           Magnetic Resonance
    o 15% reabsorbed by colon                                     Non-invasive, painless, no                 Cholangiopancreatography (MRCP)
    o 5% excreted by stool                                            radiation                               o Typically used for pts w/ GB/BD/head of
                                                                  Operator/technician dependent                  pancreas cancers to assess invasion of
Gallbladder (GB) fxn                                              Demonstrates gallstones w/ 90%                 vasculature
 GB stores 80% of bile secreted by the liver                         sens and spec                           o 95% sens, 89% spc for choledocholithiasis
 GB mucosa reabsorbs Na, Cl, water                    o Cholelithiasis: stones in GB                        o Single, non-invasive test for the dx of
   concentrating bile 10x                               o Choledocholithiasis: stones in CBD.                     biliary and pancreatic dz
 Releases bile in response to hormones:                     Secondary sign = Biliary ductal dilatation
   o (+) CCK, vagal stim‘n, distension of                    (proximal dilatation, distal stricture)      Gallstone Dz
        gastric antrum                                  o Acute cholecystitis: GB wall thickening,        Gallstone Formation
   o (-) VIP, splanchnic symp stim‘n,                        pericholecystic fluid (edema around GB),      Formed from solids settling out of bile soln in
        somatostatin                                         sonographic Murphy‘s sign (+ Murphy as a        the GB: bili, bile salts, phospholipids,
                                                             result of pressure from U/S probe)              cholesterol
Sphincter of Oddi                                       o Chronic cholecystitis: contracted, thin-         Cholesterol stones 80%, pigmented stones 15-
1. Regs flow of bile and pancreatic enzymes into             walled GB                                       20% (Western world)
   duod                                                Intraoperative Cholangiogram –
2. prevents regurg of duod‘l contents into biliary      o Gen info: to confirm there are no stones,       Epi and Nat Hx
   tree                                                      you need                                      Autopsy studies show prev of cholelithiasis 11-
3. diverts bile into the GB, resting pressure 13 torr             go through cystic duct                     36% so gallstones are common
4. CCK causes sphincter relax‘n and GB                            Filling of R and L hepatic ducts        RFs: Female, age, obesity, pregnancy, gastric
   contraction in response to acid, fat, amino acids              Absence of filling defects in CBD          bypass surg, term ilium resection, diet,
   in the duod                                                        tells you there are no stones           hereditary spherocytosis, sickle cell dz
5. morphine sulfate can cause Sphincter of Oddi                   Free flow of contrast into duod         Comps
   spasm (causes RUQ tenderness so don‘t give          Endoscopic Retrograde                                 o Acute cholecystitis
   someone with biliary colic morphine)                 Cholangiopancreatography (ERCP)                       o Choledocholithiasis (stone in CBD) +/-
6. Glucagon relaxes Oddi – can help when have           o Performed by gastroenterologist, use                    cholangitis (infxn of extrahepatic biliary
   trouble getting contrast through                          endoscope to cannulate the CBD                       ducts)
                                                        o Can perform retrograde sphincterotomy               o Gallstone pancreatitis
Labs                                                         (cut Oddi, let stones come out)                  o Cholecystoduodenal fistula +/- gallstone
 get CBC for wbc, hct, hbg, platelets                  o 5% complication rate-- Complications                    ileus (gallstone so big, size of golf ball,
                                                             include perforation and pancreatitis                 causes scaring and fistula through which it
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       goes through to duodenum, small intestine,      PE                                                 Rare, aggressive tumor w/ poor prognosis (5 yr
       gets trapped in ileocecal valve )                o Scleral icterus                                   survival = 5%)
   Symptomatic gallstone dz develops in 3% of          o Mild tenderness epigastrum, RUQ                  Calcified ―porcelain‖ GB (stiff, hard) = 20%
    asymptomatic pts / yr                              Dx                                                  malignancy. 80-90% of adenocarcinomas
   Complicated gallstone dz develops in 3-5% of        o RUQ u/s  choledocholithiasis, dilated           Corvoisier’s sign: enlarged, palpable GB
    symptomatic pts / yr                                    CBD (proximal to obstruction, >8 mm)           Found incidentally in 1% of pts undergoing
                                                        o MRCP / ERCP                                       cholecystectomy for gallstones
Chronic Cholecystitis                                   o Hi bili, AP (bile ducts are irritated; bile
Repeated inflammation of GB (biliary colic)                                                        Cholangiocarcinoma – cancer of extrahepatic
                                                            ductal tissue produces AP), transaminases
                                                       Tx – both these methods are done:          billiary ducts
Acute Cholecystitis                                     o ERCP  sphincterotomy, stone extraction   rare, most often at hepatic duct bifurcation
Obstruction (usu stone) causes cystic duct              o Laparoscopic cholecystectomy                  (Klatskin tumor)
inflamm‘n  GB distention, inflamm‘n, secondary                                                     Survival unresectable dz: 5-8 mo, 5-yr survival
bac infxn (due to stasis)                       Cholangitis – typical comp of stones stuck in CBD,      resected dz 10-30% (poor prognosis)
 Presentation                                  stasis  ascending bacterial infxn, usu gm (-) and  RFs: primary sclerosiing cholangitis,
     o RUQ/epigastric pain, lasting 1-2 days    anaerobes                                               choledochal cysts, UC, Clonarchis
     o Not hungry
     o N/V                                       Presentation                                     Three Rules of Surgery!
     o +/- Fever                                    o Charcot‘s triad: F, RUQ pain, jaundice            1. Eat when you can!
 PE                                                o Raynaud‘s pentad: above + septic shock +          2. Sleep when you can!
     o Focal tenderness in RUQ                          MS change                                       3. Don‘t mess w/ the pancreas
     o Palpable mass sometimes                   PE
     o + Murphy‘s                                   o Febrile, focal tenderness and guarding RUQ ANESTHESIA – Dr. Ken Abbey
 Dx                                             Dx
     o RUQ U/S  stones in GB, GB wall              o RUQ u/s  choledocholithiasis, dilated       Case: hernia repair for Al
        thickening, edema, sonographic Murphy‘s         biliary ducts                               Al = 46 yo shoe salesman married to Peg
        sign                                        o ERCP  gold standard visualization. Do        HPI: was squatting to fit a shoe, felt pop in
     o HIDA scan  non-visualization of GB              this right away – stones must be removed        groin
 Mild leukocytosis (12-15,000) +/- mildly ↑            quickly                                     PMH: low IQ, low self esteem
     LFTs                                           o Elevated bili, AP, LFTs; leukocytosis         PSH: removal of ‗will to live‘ by Peg
 Tx                                             Tx
     o IV fluids, pain control, IV Abx (3rd gen     o IV abx, fluids, ICU admission, vasopressor You speak to surgeon, Brett, who asks:
        cephs), remove GB w/in 24 hrs typically         support                                     what are the 4 goals of anesthesia?
                                                    o Emergent biliary decompression by ERCP,           o Amnestic - you don‘t remember
Choledocholithiasis – stuck in CBD, so no bile          eventual GB removal                             o Hypnotic – you‘re not aware
passes from liver to small bowel                                                                        o Analgesic - not in pain
                                                Laparoscopic Cholecystectomy (Lap Chole) video          o Paralyzed - not moving
 Pres                                                                                              What does MAC mean?
     o RUQ / epigastric pain                    Billiary neoplasms - rare                               o Minimum alveolar concentration
     o N/V                                      GB carcinoma
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    o   Amt of anesthetic necessary to prevent              If adult, then give muscle relaxant (ie
        movement in 50% of pts on incision                   pancuronium) before intubation (cords won‘t        Opiates:
    o   We aim for 1.3 MACs (95% of rats don‘t               slam together, helps give good view w/              Morphine
        move)                                                Laryngoscope)                                       Hydrocodone
                                                            Caution w/ morbidly obese pts: if give m            Methadone
So, why do we do anesthesia?                                 relaxant, may then be in a position where you       Fentanyl
 From 1821-46, MGH only did ~1 surgery per                  can‘t intubate and cannot ventilate either         Dilaudid
    month (no anesthesia)                                    disaster                                            Alfentanyl (short acting, quick onset)
 So a good surgeon back in those days was one              Pre-oxygenation buys you 6-7 mins in healthy        Remfentanyl – spontaneously metabolizes,
    who was fast (30 seconds chop off leg!)                  young pt                                              good when need quick pain relief that quickly
                                                             o Decreases oxygen demand                             goes away, ie head/neck cases
Gas is an anesthetic, meets all 4 goals.                     o When anesthetized, O2 demand goes down
Used sometimes in kids                                            to 200 cc/min                                 Work on mu receptors
                                                             o If you are not hooked up to O2 and you are       Reversible w/ Narcan
Midazolam (Versed) = benzo, anxiolytic, amnestic                  apneic, the O2 gets taken from the lung
 so don‘t talk to pt until 1 hr after surgery;                   reservoir (FRC, what passively stays in       Propofol
   otherwise they won‘t remember                                  lung after passive expiration)                 O/D killed Michael Jackson – they couldn‘t
                                                             o Pre-oxygenation causes FI02 increase from           manage his airway
Fentanyl = opioid, 100x more potent than                          0.21 to 1                                      MOA: GABA-A and Na channel
morphine, given in micrograms, initially acts like           o Thus when you are doing intubation, slow
                                                                                                                 Effects
short acting drug (lipophilic; sudden onset), then                down.                                            o Euphoria
redistributes to fat. Initial effects go away fast. If       o However, caution w/ obese pts, they                 o Hypnosis
give a lot, Vd fills up and acts like long-acting.                decompensate faster. With obese pts, after       o Amnesia
Cheap as dirt. Very little S/Es. Risky to use b/c of              giving benzo, fentanyl, and propofol,            o CV
sudden onset of action.                                           ventilate before intubation to determine if      o Resp
                                                                  ventilation is even possible. Then give          o V little analgesia
Propofol – common induction agent                                 muscle relaxant                                  o Not reversible
 other induction agents = gas induction (ceba-             Which pts do you give m relaxant right away?
   fluorine, least stinky), ketamine, penthol                o ―Rapid sequence induction‖ in ppl who            Suggestion: use Versed instead of Propofol. And
   (penafol, potent barbiturate, tastes like garlic d/t           are aspiration risk (full stomach, bad        have Narcan in your pocket.
   sulfa groups), midaz, other barbituates                        reflux)
   (methahexatol), ECT                                       o If try to ventilate while pushing air in         Vecuronium = non-depolarizing m relaxant.
 Propofol used a lot bc rapidly distributes and                  stomach, they may aspirate. Therefore they    Competitive inhibitor of NMJ. Won‘t cause
   causes least nausea                                            get propofol then m relaxant right away       fasiculations.
 Downside = burns upon injection
 Cheapish: $6 a vial                                   Are benzos reversible? Yes                              Succinocholine = depolarizing (2 Ach‘s stuck
                                                         Flumazenil = benzo antagonist.                        together), causes NMJ to be depolarized. All
Sequence: Benzo  Fentanyl  Propofol                       o If pt is a drinker, may cause pt to… wake         muscles fire, always wake up sore. After firing,
 Propofol will cause apnea                                    up? (not sure what he said)
                                                            o Works on NMDA receptors
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muscles have refractory period of 6-10 mins.                      Bacterial, fungal                        o   Lower specificity (detects only 60% of
Advantages = quick onset, short duration.                o   Inflammatory abdominal aortic                      AAAs)

Why doesn‘t heart stop?                               Pathophys                                          Abd U/S
 it‘s smooth muscle                                   Chronic transmural infamm‘n                       good screening tool (#1)
 gut, heart, vasculature—all smooth m, still          Destructive remodeling of extracell‘r matrix      v sens and spec
  work                                                 Depletion of vascular SM cells                    accuracy 80-90%
 ppl stop breathing bc diaphragm is skeletal m        Redistribution of hemodynamic stresses of         cost effective
                                                          vessel wall                                     can detect AAA in their earliest stages
How about BP and CO?                                   Reduction of collagen and elastin content from    reproducible to within 0.3 cm
 Propofol = potent vasodilator, so is gas                proximal to distal aorta                        Difficulties
 That‘s why BP goes down                                 o Loss of elastin  dilatation and aneurysm       o Bowel gas interference
   o Must give fluids bc capacitance has                  o Loss of collagen  rupture                      o Obese pts
        increased (due to vasodilation)                58% decrease in elastin from suprarenal to          o Suprarenal and iliacs not well visualized
   o This increases preload                               infrarenal aorta                                  o Operator dependent
   o Starling: fixing preload increases BP             Elastin T ½ 40-70 yrs, not synthesized
 Scopolamine can be used to reduce awareness          Genetics: 15% with +FHx                          CT Scan
   in trauma pts w/ less lowering of BP                                                                   Most accurate
                                                      RFs                                                 Gold standard as preop scanning tool
ANEURYSMAL DISEASE – Mitchell                          Number one: age (>65)                             Excludes rupture in symptomatic pts
                                                       Male                                              Defines anatomy and anomalies
   Def: ―a widening” 1.5x normal size                 Cig smoking                                       Reproducible to within 0.2 cm. Use 2 mm cuts
    o Ectasia= dilation <50%                           FHx of Ao aneurysm                                Use contrast to assess arteries
    o Arteriomegaly- diffuse enlargement,              HTN                                               Cons
        involving several arterial segments            COPD                                                o $$$
   True aneurysm: involves all artery walls
                                                       ASO                                                 o Ionizing radiation
   Pseudoaneurism/false aneuryism: involves one       PAD                                                 o Dye load
    layer of arterial wall, usually adventitia. Eg-
    femoral anastomotoc aneuryism                     Dx                                                 MRA
   Etiology                                           Hx and Pe                                         Avoids radiation and offers 3D images
    o Degenerative                                                                                        Generally speaking, not used for aneurysm
                                                         o Notoriously hard on hx and PE alone
              Nonspec (atherosclerotic- most
                                                         o Sensitivity high for AAA > 5-5.5 cm if          repair
                 common)                                                                                  Reproducible to within 0.2 cm
                                                           abdominal girth <40‖
              Fibromuscular dysplaysia                  o Ideally, pt lays on back w/ feet elevated      Able to differentiate ‗new‘ blood from ‗old‘
    o CT disorders
                                                       Abd x-ray                                          blood
              Marfans, Ehlers-Danlos, Cystic
                                                         o Findings                                       Does not require nephrotoxic dyes
                 medial necrosis
                                                                Calcified Ao wall
    o Arteritis: SLE, Kawasaki, PAN
                                                                Lrg soft tissue shadow                  Angiogram
    o Infxn
                                                         o Simple and cheap                               shows visceral and occlusive dz
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   helpful                                          o   Does not a/c for cylindrical shape or wall
    o visceral / extremity ischemia                      thickness                                       Rapidity of Growth
    o juxtarenal and suprarenal AAA                      [personal note: this is the form of LaPlace      If grows >0.5 cm in 6 mo then it should be
    o Horseshow kidney                                   as it applies w/ things like soap bubbles and      repaired
    o Renal insuf w/ uncomtrolled HTN                    alveoli, units are in N/m]                       No evidence to support regular medical mgt to
    o generally, not used often                     COPD: mechanism ↑ imbalance in protease                prevent expansion
                                                     activity
AAA Nat Hx                                          Eccentric saccular aneurysm—increases risk          Types of Repair
 Grows avg 0.4 cm / yr                             Rapid expansion                                      Endovasc aneurysm repair (EVAR)
 Risk of rupture exponentially related to          Inflammatory: no increase in risk                    Open aneurysmorrhaphy
  aneurysm of diam                                                                                          o Midline transabdominal incision
 5 cm diam  avg yrly rupture rate 3-5%         Screening                                                  o Retroperitoneal appraoach
 7 cm diam carries rupture rate of 19%/yr        Everyone agrees:
                                                     M >65 yo with hx of smoking                         EVAR Advantages
Complication of AAA                               More controversial:                                    Reduces operating time
 Rupture                                            o Men >65 yo, FHx of AAA, females w/ mult            Shorter LOS and ICU stay
   o only 40-50% reach hosp alive                        RFs                                              ↓ recovery time, post-op pain
   o 50% operative mortality                                                                              Blood transfusion
   o Overall >75% mortality rate for repair       Mgmt depends on:                                        Less chance graft infxn
   o Clinical pres                                 Size                                                  Return to work faster
            Severe back pain ~70%                  o Good risk pts w/ AAA > 5.5 cm should
            Palpable abdom mass – 85%                  undergo elective repair                          EVAR (endovasc repair) Disadvantages
            Hypotension – 50%                      o No survival advantage for <5.4 cm                   $$$
 Distal embolization                              UK Small Aneurysm Trial                               Not universally applicable
   o Most minor affecting distal extremities/toes   o pts randomly assigned for elective repair           Probs of endoleaks, graft failures
   o More common during repair                          (when >5.5 cm) or US surveillance every 6         Require life long graft surveillance
 Aortocaval fistula                                    mo                                                Long-term reports not available
   o Rare                                           o 4.9 yr f/u found surgery mortality 25%,
                                                                                                          No difference in mortality
   o Pres                                               surveillance mortality 21.5
            LE edema, hematuria, rectal bleed      o Most deaths d/t cardiovascular dz
                                                                                                         Based on avail evidence, EVAR is appropriate tx
            Hi output CHF                          o Median AAA growth rate 0.33 cm/yr
                                                                                                         for selected pts, esp those w/ hi risk for open surg
   o Repair fistula (ie bw inf vena cava and        o Bottom line: no level 1 evidence to repair
                                                                                                         repair
       aorta) from inside the aneurysm                  AAA <5.5 cm
                                                                                                         EVAR Indications
AAA Rupture Risk                                 Symptoms
                                                                                                          same as for open repair, for size threshold
 The bigger the aneurysm, the more likely to     if symptoms present, the AAA should be
                                                                                                          hi risk pts
  rupture                                           repaired
                                                                                                           o >75 yo
 Other RFs                                       back pain, tender, coexistent occlusive or
                                                                                                           o Disabling COPD, home O2, FEV1 <1 L
  o HTN: LaPlace  T = (P)(r)                       thrombotic dz
                                                                                                           o NYHC 3-4 or ASA IV
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                                                                                                                                                    A Tran
    o Hostile abdomen                                   Extent of aortic and iliac a involvement                    Type 5: endotension
   Life expectancy >2 yrs                              Neck:                                                o Management of endoleaks
   Young pts – good operative risk??                    o <25 mm diam                                               Type 1 and 3
                                                         o >15 mm length                                               - Require immediate repair:
EVAR: Preop imaging                                      o <45 degree angulation                                           use cuff or extension grafts;
Spiral CTA                                              Iliac aa                                                          induce thrombosis (coils,
 Hi quality contrast enhanced CTA is essential          o Minimal calcification and tortuosity                            glues); or open conversion if all
 Imaging technique of choice                            o Acceptable diam: 18-25 Fr catheter                              else fails
 Spiral CTA protocol                                    o >25 mm seal zone                                          Type 2:
    o +/- contrast                                      Extent of aortic and iliac a involvement                      - can be managed conservatively
    o Need lrg volume of iodinated contrast (100-        o Stent graft usu ends in common iliac a                          – no risk of rupture, only 30%
        150 cc)                                          o If diam of common iliac too large, the stent                    persist >6 mo
    o Narrow collimation, 3 mm cuts                           can be extended to the external iliac a                  - only worry about surg
    o Reformatting of axial slices 3D                    o You may exclude flow from mesenteric                            intervention if aneurism sac
        reconstruction                                        arteries which will cause sigmoid ischemia                   continues to grow – treat w/
 Pitfalls                                               o The hypogastric a should be coil-embolized                      embolization, lap clipping
    o As AAA expands and lengthens, the neck                  as retrograde flow from the internal iliac a    o Late comps
        deviates anteriorly and laterally  can               will cause an endoleak                                 Graft limb thrombosis – kinking in
        overestimate neck diam and                      Comps                                                         limb
        underestimate neck lengh                         o Perioperative                                             Stent-graft infxn: no published
                                                                   Injury to access vessels                           reports, only anecdotal reports
Angiography                                                        Embolization                                     Device failure
 not necessary for graft sizing                                       - Microembolization and death                 Dilatation ofproximal neck
                                                                                                                     Late rupture
 can provide add‘l info                                                  from renal failure
   o grade of stenosis of branches of Ao                               - Distal ischemia
                                                                   Post-implant syndrome                   EVAR results – a bunch of stuff she skipped
   o renal, accessory renal
   o patency of IMA                                                    - Febris eci (40 deg C)
                                                                          Personal note—stands for          EVAR: Post-op surveillance
   o lumbars
                                                                           “febris e causa ignota” or fever
                                                                                                              o What to look for in the post op period
                                                                          of unk origin                                Change in aneurysm size (ie
EVAR Anatomical Requirements
                                                                                                                           continued growth = bad)
 Visceral supply                                                      - Depression
                                                                       - Back pain from thrombosis                     Stent migration
  o Assess patency celiac and SMA before                                                                               Endoleak
      patent IMA overstented                                           - Incidence ↑50%
                                                                   Groin and wound comps                              Limb stenosis
 Diameter, length, angulation, and conical nature                                                                     Device integrity
  of prox neck                                           o Endoleak – failure to exclude aneurysm
                                                              sack from arterial blood flow                   o CTA
 Calcification and mural thrombus in prox neck                                                                        98% accurate in detecting
 Diam of iliac a                                                  Type 1: attachment to site leaks
                                                                   Type 2: branch leaks                                   endoleaks
 Length of distal sealing zone                                                                                        Accurate and reproducible diameter
                                                                   Type 3: structural failure
 Tortuosity of iliac aa                                                                                                   measurements
                                                                   Type 4: Graft wall porosity
                                                                             8
                                                                                                                                                    A Tran
                  Dense contrast bolus and delayed         sew aneurysm sack closed to prevent intestines
                   images                                    from sticking                                Early comps of AAA Repair
                Time course: 1, 6, 12 months, and          tube graft = a straight shaft of graft        bleeding – massive transfusion increases post
                   yearly thereafter                        bifurcated graft = aneurysm extends into iliac   op M&M
 2 kinds of open repair                                     aa                                            MI
Midline                       Retroperitoneal               to maintain perfusion to pelvis and sigmoid one  o #1 cause of periop mortality
- explore abdominal           - hostile abdomen              must maintain blood supply – may need to hook    o Renal failure
viscera                       - stromas                      up the IMA                                    Distal embolism
- expose distal common - morbid obesity                     Indications for renal a reconstruction        Severe acidosis – can be from prolonged aortic
iliac a: lrg right iliac a    - aneurysm requiring           o Renal a aneurysm >2 cm diam                    clamping, can get severe hypoTN w/ release of
aneurysm                      suprarenal clamping:           o Involvement of renal a ostia                   clamp
- right renal a dz not        complex aneurysm w/                                                          Graft infxn – rare, increased incidence after
                                                             o Renal failure w/ bilat pre-occlusive renal a
amenable to                   celiac and sma vessel dz       o Asymptomatic >80% renal a stenosis             assoc‘d ischemic colitis
endarterectomy                or juxta/suprarenal AAA        o Renovascular HTN                            Ischemic colitis – most dreaded complication
- L sided vena cava           - horseshoe kidney             o Best approached via retroperitoneal            o Occurs ~10%, more common in setting of
                              -inflammatory AAA                  approach                                         rupture
                                                                                                              o Only 2-3% clinically significant
 Retroperitoneal approach                            Ruptured AAA                                            o Usu 2-3 days post op
     o We are on the L side of the abd, sneak          If aneurysm freely ruptures anteriorly into           o Clinical manifestations
         behind peritoneum down to the Ao which          peritoneal cavity, rapid exsanguination                       Unexplained fluid sequestration
         lies over the lumbar spine                      occurs—pt usu doesn’t make it to hospital                        (BP unresponsive to resuscitation
     o Advantages:                                     If it ruptures posteriorly, the hemorrhage goes                   b/c their colon is dead)
               you can get higher up on the Aorta       into retroperitoneal space, may be contained, pt              Fever, leukocytosis, sepsis (L colon
                  than midline approach (in midline      makes it to the ER bc it’s a controlled bleed –                  dies bc insuff blood supply bc
                  approach, pancreas gets in the way)    there‘s no where for the blood to go                             you‘ve taken out the IMA)
               easier w/ morbidly obese pts           Achieve rapid proximal control by compression         o Prevention: reimplant IMA if
 Midline: the peritoneum is opened, make long           or clamping of supraceliac Ao through the                     Lrg IMA
     incision down to pelvis                             diaphragmatic crura                                           Good back bleeding
                                                       After establishing control, move clamp to                      Stump pressure <40 torr
Techniques of open repair: (she went through a           infrarenal position                                           h/o L hemicolectomy
bunch of diagrams w/ relatively little explanation,
this is what I could catch)                           Goals of AAA repair                                 Late comps
 move renal veins out of the way; give pt             Prevention of death from rupture                   Aortic graft infxns
     heparin; apply clips above and below the          Limb preservation by maintainance of adequate         o 1% aortoiliac
     aneurysm                                            arterial perfusion                                   o 2% aortofemoral
 ―oversew‖ lumbar arteries                            Maintaining quality of life – minimize comps,         o 70-80% late
 Cut a ―button‖ of tissue and sew it onto the           maximize durability of reconstruction,               o usu staph aureus, pseudoaneurysms in
     graft                                               preservation of sexual fxn (parasympathetic              anastomotic suture line ie almost always
                                                         plexus responsible for ejaculation)                      from graft infxn

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posted:4/18/2011
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