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Abstract remains the property of the author and should not be
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CardiothoracicAnaesthesia Newdevelopmentsandcurrentthinking.
Dr.JP.vanBesouw
St.George'sHealthcareNHSTrust.
London.
Tel: +442087253317
Fax:+442087253135
Email:[email protected]
Therehavebeenanumberofsignificantdevelopmentswithinthefieldsofcardiacsurgery
andinterventionalcardiologywhichhaveimpacteduponcardiacanaesthesiainthepast
yearorso.Someofthesedevelopmentswhichmayberelevanttothenoncardiac
anaesthetistaresummarisedbyotherlecturersatthissymposiume.g.ischaemicand
pharmacologicalmyocardialpreconditioningandadvancesincardiovascularmonitoringto
mentionbuttwo.Iwillthereforedealwiththefollowingspecificareas.
Advancesinvalvereplacementandpercutaneouscoronaryinterventions.
Advancesintransfusionmedicinelessonslearntfromcardiacsurgery.
Advancesincardiopulmonarybypass.
Advancesinpercutaneousvalveandcoronaryinterventions.
Bothpercutaneouscoronarystentingandvalvereplacementareexamplesofinnovations
thatchangelongestablishedpracticeandarecollectivelyknownasdisruptive
technologies.
Transcatheteraorticvalvereplacementisadevelopingmanagementstrategy1forhighrisk
elderlypatientswithaorticstenosisandhasdevelopedfromlessonslearntfromthe
percutaneouspulmonaryarteryreplacementprograminchildrenwithcongenitaldefects.A
numberofcommerciallyavailabledevicesareundergoingtrialsaroundtheworld.The
placementofsuchdevicescanbeachievedeitherbyatransfemoraloratransapical
approachthe
latter
being
favoured
in
individuals
with
extensive
aorto
iliac
disease
24.
Due
to
itsmorecomplexarchitecturethedevelopmentofapercutaneousapproachtosurgeryof
themitralvalvehasbeenmoreprotracted.Openmitralvalvotomyforseveremitralstenosis
wasacommonprocedurepriortotheadventofcardiopulmonarybypassthishasbeen
supersededbypercutaneousballoonvalvuloplasty.Morerecentlyapercutaneousapproach
tomitralvalverepairhasbeendescribedandanimalstudieshavebeenundertakenlooking
atavarietyofapproachestopercutaneousmitralvalvereplacementasaredoprocedure.In
manycasesthishasinvolvedavalveinvalveplacementinwhichthetranscathetervalveis
implantedwithinanexistingdeficientprostheticvalve.Therationalforthisapproachisthat
theexistingprostheticannulusactsasaframeworktosupportthenewvalveupon
deployment.Althoughtranscathetertechnologyisstillinearlydevelopmentthe
combinationof
these
technologies
with
advances
in
endovascular
stenting
of
the
thoracic
aortaandenhancedimaginge.g.intracardiacand3Dechocardiography,opensupnewvistas
fortheinvasivemanagementofintrathoraciccardiovascularproblems.
Therelativevalueofpercutaneousversussurgicalrevascularisationforcoronaryartery
diseaseremainscontentious5.Percutaneouscoronaryinterventionshavedevelopedfrom
simpleballoonangioplasty,followedbytheintroductionofasuccessionofstrategiesto
reducerestenosisratesstartingwithbaremetalstents,movingontodrugelutingstents
whichreducetheneointimalresponsebytheslowreleaseofantiproliferativedrugs
to
bioabsorbabledrugelutingcoronarystents.Thecontinuingpresenceoftheframeworkof
thestentfollowingdrugelutionpreventsadequaterepairofthearteryandisthoughttobe
themajorreasonbehindtheenhancedriskofstentthrombosis.Researchhasestablished
thatonce
an
artery
has
healed
there
is
no
further
requirement
for
this
neointimal
suppression,drugelutingbioabsorbablestentssupportavessel,preventingneointimal
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Abstract remains the property of the author and should not be
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proliferationduringthehealingphasefollowingangioplastybutaresubsequently
reabsorbedminimisingtheriskofstentthrombosis6.Otherpotentialadvantagesincludethe
abilitytoutilisenoninvasiveimagingmodalitiesofcoronaryarteriese.g.CTandMRIaswell
asimprovingsurgicalaccessshouldopenheartsurgeryberequiredatafuturedate.
Advancesintransfusionmedicinelessonslearntfromcardiacsurgery.
Cardiacsurgery
has
always
been
amajor
user
of
blood
and
blood
products,
the
requirementsforbothresultinginpartfromthephysiologicalupsetcausedbytheresponse
toextracorporealcirculationandthenecessityforsystemicanticoagulation.Haematological
managementoftheperioperativeperiodhasbeenalongtimeinterestofthecardiac
anaesthetist.Manyofthelessonslearnthavebeentransferredintothewiderworldof
anaestheticpracticee.g.pharmacologicalmanipulationofcoagulationsystems,cellsalvage
andtransfusiontriggersandpointofcaretestingforcoagulationdeficitsfacilitatingtargeted
productreplacement.
Inthefirsttwoofthesetherehavebeensignificantdevelopmentsin2008.Therehasalways
beenaconcernoverthesafetyprofileofAprotinin,particularlyinrespectofgraftocclusion
followingCABG.Amuchdebatedstudy7publishedin2006suggestedanadverseoutcome
forCABG
patients
treated
with
Aprotinin,
afurther
highly
damaging
study
in
2008
indicated
thatdeathratesinhighrisksurgicalcasetreatedwithAprotininweregreaterthanthoseina
cohortwherethedrugwasnotused8.Theadverseoutcomesfromthisandothertrials
publishedin2008ledthemanufacturerstowithdrawmarketingofthedrugandarenewed
interestinlysineanalogues9generatingmuchdebatewithintheworldofcardiac
anaesthesia.
Thestoragelesioneffectsresultingfromthestorageandsubsequentretransfusionofblood
componentsarewellknown.Thesignificanceoftheseeffectshasnotalwaysbeenfully
evaluated;howeverarecentstudy10
hasshownanenhancedpropensitytoadverse
outcomesinpatientsreceivingbloodtransfusionduringthecourseofcardiacsurgery.This
hasfurtherenhancedthedebateuponperioperativetransfusiontriggersincardiacsurgery.
Currentpractice
is
based
upon
absolute
values
e.g.
6g/dL,
however
logic
dictates
that
percentagefallsfrombaselineshouldbeconsideredtobeamoreappropriatetriggerand
thereisnowgoodoutcomeevidencetosupportthisrationale11.
Advancesincardiopulmonarybypass.
Traditionalcardiopulmonarybypass(CPB)islargelybasedupontechniquesdevelopedover
30yearsago.SimilarlytheadverseeffectsofCPBbothphysiologically,neurologicallyetc
havebeenwelldocumented.Thedesiretoreducethesesideeffectshasledtothe
developmentofoffpumpcardiacsurgery(OPCAB)forcoronaryarteryrevascularisationand
morerecentlyminibypasswhichallowsforintracardiacprocedurestobeundertaken.These
lowvolume
circuits
utilise
vacuum
venous
drainage,
low
volume
centrifugal
pumps
and
no
reservoir.Earlyexperiencewiththesesystemssuggestthatthereisalearningcurvetotheir
usewhichrequiresclosecooperationofperfusionist,anaesthetistandsurgeontoensure
minimalrisktothepatientinparticularfromarterialairembolisation.Thepotentialbenefits
oftheuseofsuchcircuitsincludeareductionofsheerforcesonbloodcellularcomponents,
reducedhaemodilutionandretransfusionofcardiotomyreservoirblood,improved
biocompatibilityandareductioninthesystemicinflammatoryresponsetobypass.Although
manyofthesephysiologicaloutcomeimprovementshavealreadybeendemonstrated
questionsstillremainastowhetherthiswilltranscendintoimprovedclinicaloutcomes12.
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Abstract remains the property of the author and should not be
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