Canadian Adult Obesity Clinical Practice Guidelines 1

KEY MESSAGES FOR HEALTHCARE PROVIDERS

• Bariatricsurgeryshouldbeconsideredforpatientswithsevereobesity(bodymassindex(BMI)≥35kg/m2)andobesity-relateddiseases,orBMI≥40kg/m2withoutobesity-relateddiseases.

• Bariatricsurgerycouldbeconsideredforpatientswithobesity(BMI≥30kg/m2)withsevereobesity-relateddiseasesnotrespondingtomedicalmanagement.

• Thechoiceofbariatricprocedure shouldbe tailored topa-tients’needs, in collaborationwithamultidisciplinary teamandbasedonthediscussionofrisks,benefitsandside-effects.

• SeveralproceduresarecurrentlyperformedinCanada(ad-justablegastricbanding,sleevegastrectomy,gastricbypass,duodenalswitchandothers)butvariationsexist.

• Forpatientswithsevereobesity,surgeryofferssuperiorout-comes compared tobestmedicalmanagement, in termsofqualityof life, long-termweight lossandresolutionofobesity-relateddiseases, especially type2diabetes, sleepapnea,fattyliverdiseaseandhypertension.

• Laparoscopicapproachshouldbestandardandisassociated,formostpatients,withalowmortalityrate(<0.1%)andlowseriouscomplicationrate(<5%).

• Bariatricsurgeryimproveslifeexpectancy.

• Novelsurgicalandendoscopicapproachesarebeingusedanddevelopedandcanrepresentanoptionforspecificpatients.

Bariatric Surgery: Surgical Options and Outcomes LaurentBierthoMDi,DennisHongMDMScii, and MichelGagnerMDiii

i) DepartmentofSurgery,LavalUniversityii) DivisionofGeneralSurgery,McMasterUniversityiii)HerbertWertheimSchoolofMedicine,FloridaInternational

University;HôpitalduSacreCoeurdeMontreal

Cite this Chapter

BierthoL,HongD,GagnerM.CanadianAdultObesityClinicalPracticeGuidelines:BariatricSurgery:SurgicalOptionsandOutcomes.Availablefrom:https://obesitycanada.ca/guidelines/surgeryoptions.Accessed[date].

Update History

Version1,August4,2020.AdultObesityClinicalPracticeGuidelinesarealivingdocument,withonlythelatestchapterspostedatobesitycanada.ca/guidelines.

RECOMMENDATIONS

1.BariatricsurgerycanbeconsideredforpeoplewithBMI≥40kg/m2orBMI≥35kg/m2withatleastoneadiposity-relateddiseaseto(Level4,GradeD,Consensus)to:

a. Reducelong-termoverallmortality(Level2b,GradeB);1,2

b. Induce significantly better long-term weight loss com-paredtomedicalmanagementalone(Level1a,GradeA);3

c. Inducecontrolandremissionoftype2diabetes,incom-binationwithbestmedicalmanagement,overbestmed-icalmanagementalone(Level2a,GradeB);4,5

d. Significantlyimprovequalityoflife(Level3,GradeC);6

e. Inducelong-termremissionofmostobesity-relateddiseases,includingdyslipidemia(Level3,GradeC),7hypertension(Level3,GradeC),8liversteatosisandnonalcoholicste-atohepatitis(Level3,GradeC).9

Canadian Adult Obesity Clinical Practice Guidelines 2

Introduction

Formost individualswithsevereobesity,healthbehaviour inter-ventions, perhaps effective in inducing short-lived weight loss,arefrequentlyineffectiveforlong-termweightlossmaintenanceand durablemetabolic recovery. For example, the vastmajority(74%)individualslivingwithsevereobesityundergoingintensivebehavioural intervention in the LookAHEAD (Action forHealthinDiabetes)trialdidnotmaintainaweightlossgreaterorequalto10%ofinitialbodyweightafterfouryears.14Accordingly,fewbenefitswereobservedinthisstudysubgroupfromthecardiovascu-larriskstandpoint.14Bariatricsurgeries,alsocalledmetabolicsurger-ies,nowclearlyrepresentareasonableoptionfortheseindividuals,especiallysincetheseminaldemonstrationsthatbariatricsurgeryismoreeffectivethanstandardmedicalapproaches,includinguseofmedicationanddietarycounselling,toimproveglycemiccontrol insevereobesityanduncontrolledtype2diabetesmellitus(T2DM).4,5

Which patients should be offered bariatric surgery?

Thefirst-linemanagementofobesity should includeamultidis-ciplinaryevaluationwithnutritionalandmedical counselling,as

wellasbehaviouralmodificationsandincreasedphysicalactivity.Unfortunately,themedium-termweightlossassociatedwiththebestmedicaltreatmentsismodest,andthechancesofremissionofT2DM,onceestablished,areanecdotal.15Weightloss(bariatric)surgeryhasthusbecomeanintegralpartforthemanagementofpatientswithsevereobesity.

Anumberofsurgicalprocedureshaveemergedoverthelast40years,includingRoux-en-Ygastricbypassin1971,adjustablegas-tricbandingin1980,duodenalswitchin1989andsleevegastrec-tomy in2000.16 Indications for the surgicalmanagementof se-vereobesitywereoutlinedbytheNationalInstituteofHealth(NIH)consensusdevelopmentpanelin1991andcontinuetorepresentgenerallyacceptedguidelines.17 Interestingly,eventhoughtheseguidelinesweredevelopedalmost30yearsago,andwerebasedonexpertopinions,theyhavenotyetbeenrevised.Potentialcan-didatesshouldbeagedbetween18and60yearsandwillingtoparticipateintheirtreatmentandlong-termfollow-up.

Patientswith a BMI between35 and40 kg/m²with at least onemajor obesity-related disease (e.g., T2DM, obesity-related cardiacdisease, sleepapnea),orpatientswithaBMI≥40kg/m²withorwithout associated diseases, are potential surgical candidates. Inaddition,bariatric surgerymaybeoffered topatientswithobesity

KEY MESSAGES FOR PEOPLE LIVING WITH SEVERE OBESITY

• Ifyouaresufferingfromsevereobesity,youshouldenquireaboutbariatricsurgery.Inyoursituation,behaviouralinter-ventionsandmedicaltherapiesareimportantbutusuallynoteffective enough to obtain significant long-term weightlossandremissionofobesity-relateddiseases.

• Bariatric surgery in combination with modifications tohealthbehaviourscanresultinsignificantlong-termweightloss(20%to40%ofyourbodyweight)andcontrol,or,insomecases,completeremission,ofobesity-relateddiseases,includingtype2diabetes,sleepapnea,fattyliverdiseaseandhypertension.

• Different surgical options exist (e.g., sleeve gastrectomy,gastricbypassandduodenalswitch),withdifferent levelsofeffectiveness.Youshouldhaveanextensivediscussionwiththesurgicalteambeforedecidingwhichsurgicaloptionseemstobethebestforyou.

• Allsurgerieshavesomeadverseeffectsandpotentialrisks,and require lifelong management to follow-up, mineralandvitaminsupplementations,andbehaviouralchanges.

2.Bariatric surgery should be considered in patients withpoorlycontrolledtype2diabetesandClassIobesity(BMIbetween30and35kg/m2) (Level1a;GradeA)10despiteoptimalmedicalmanagement.

3.Bariatric surgerymaybe considered forweight loss and/or to control adiposity-related diseases in persons withClass1obesity,inwhomoptimalmedicalandbehaviouralmanagementhavebeeninsufficienttoproducesignificantweightloss(Level2a,GradeB).11

4.Wesuggestthechoiceofbariatricprocedure(sleevegas-trectomy, gastric bypass or duodenal switch) be decided

accordingtothepatient’sneed,incollaborationwithanexpe-riencedinterprofessionalteam(Level4,GradeD,Consensus).

5.Wesuggestthatadjustablegastricbandingnotbeoffereddue tounacceptable complicationsand long-term failure(Level4,GradeD).12

6.Wesuggestthatsingle-anastomosisgastricbypassnotberou-tinelyoffered,duetolong-termcomplicationsincomparisonwithstandardRoux-en-Ygastricbypass(Level4,GradeD).13

Canadian Adult Obesity Clinical Practice Guidelines 3

(BMI ≥ 30 kg/m²) and significant obesity-associated disease(s),when psychological and behavioural interventions and medicalmanagementareinsufficienttoachieveoptimalweightlossandcontrolofcomorbidities.11Thesepatientsshouldbeevaluatedandcarefullyselectedbyamultidisciplinaryteamexperienced inthefieldofobesitysurgery.Teammembersshouldeducatepatientsregardingtherisks,benefitsandalternativestobariatricsurgery,includinguseofantiobesitymedications.Patientsshouldalsoun-derstandtheneedforlifelongmedicalsurveillancetopreventandcorrectpotential long-termnutritionaldeficienciesaftersurgery.Contraindications for bariatric surgery include recent substanceabuse (alcohol, drugs), non-stable psychiatric conditions (i.e.,changesinpsychiatricmedicationsinthelastsixmonths),adiag-nosisofcanceroranexpectedlifeexpectancylessthanfiveyears.

Even though an age limit of 60 years is considered in theNIHrecommendations,multiple studies have assessed the risks andbenefitsofbariatricsurgeryintheelderly.Thesearesummarizedin a systematic review that identified 26 articles encompassing8,149patients.18Pooled30-daymortalitywas0.01%andover-all complication ratewas 14.7%.At one-year follow-up,meanexcessweight losswas53.8%,diabetes resolutionwas54.5%,hypertensionresolutionwas42.5%andlipiddisorderresolutionwas41.2%.Theauthorsconcludethatoutcomesandcomplica-tionratesofbariatricsurgeryinpatientsolderthan60yearsarecomparabletothoseinayoungerpopulation,independentofthetypeofprocedureperformed.Patientsshouldnotbedeniedbar-iatricsurgerybecauseoftheiragealone.

Onthesametopic,theliteraturesupportingmetabolicsurgeryinadolescentshasbeensummarizedintherecentAmericanSocietyforMetabolicandBariatricSurgerypediatricmetabolicandbar-iatricsurgeryguidelines.19(NB:Thisreferenceisgivenforinforma-tiononlyandisoutsidethepurposeoftheseguidelines.)

Which bariatric surgery should be offered?

SurgicalproceduresaredescribedinFigure1.Historically,weight-losssurgerieswereclassifiedbasedontheirsupposedmechanismsofaction.Adjustablegastricbandingwasconsideredasapurelyrestrictivesurgery,butahighlong-termcomplicationrateassoci-atedwithweightregain,slippageanderosionshasledtoalossofinterestwiththisprocedureinfavourofsurgerieswithametabolicimpact.Hypoabsorptivesurgerieswere thought todecrease theabsorptionofnutrientsbybypassingportionsofthesmallintestine(i.e.,gastricbypassorduodenalswitch).However,mechanisticstud-ieshavedescribedmanymetabolicmodifications,includingchangesinincretins,guthormones,bileacidslevelsandmicrobiota,whichhasledtoreferringtothesesurgeriesas“metabolicoperations.”

Thedecisionforthetypeofsurgeryismadeincollaborationwithamultidisciplinaryteam,basedonthepatient’smedicalcondition,including weight, obesity-related diseases, expected adherencewith supplementation and follow-up, patients’ personal goalsandpreferences in termsofexpectedweight loss, resolutionofcomorbidities and side-effects. This team typicallymay include a

bariatric nurse, dietitian,mental health specialist, social workerandaninternist/bariatricphysician,inadditiontothebariatricsur-geon. Thegoal is tofindabalancebetween the complicationsand risk of mortality associated with the obesity itself, and toimprovethepatient’squalityoflife(QOL)andreduceobesity-re-lateddiseaseswhileaimingforacceptableshort-andlong-termcomplicationsandside-effectsrelatedtothesurgery itself.Asaruleofthumb,earlyandlong-termrisksandside-effects,butalsomaintenanceofweight lossand remissionofcomorbidities,areproportional to the intestinalbypass.Otherbariatricproceduressuchassingle-anastomosisduodeno-ileostomyandsingle-anasto-mosisgastricbypassarebecomingmorepopular,butarestilllack-ingsubstantialscientificrationale.Theyarediscussedinthe“Newsurgicalandendoscopicapproaches”sectionofthischapter.

Adjustable gastric banding isoneoftheproceduresthathasevolved themostover the last20years, fromanon-adjustablegastric band performed by laparotomy to laparoscopically per-formed adjustable gastric banding. Iterations of the techniquehave always aimed to reduce the complications that appearedovertime.Theprocedureconsistsinplacinganadjustablesiliconebandatthe levelofthecardia,creatingasmallstomachpouchabovetheband,withtherestofthestomachbelowtheband.Thegastricband is connectedbya silicone tube toa subcutaneousreservoir.Thereservoircanbeinflatedordeflatedtocontroltheopeningbetweenthepouchandtheremainderofthestomach.Eventhoughthisprocedure isassociatedwiththe lowestshort-term complication rate, it is associated with a high long-termcomplicationrateandweightregain,whichhasledtoitsprogres-sivereplacementbysleevegastrectomy.

Sleeve gastrectomywasfirstusedby laparoscopyasastagedapproachinordertoreduceperioperativecomplications inhighriskpatients.20Interestingly,somepatientsexperiencedapprecia-bleweightlosswithsleevegastrectomyaloneanddidnotrequiresecond-stagesurgery,thusavoidingtheside-effectsofmalabsorp-tion.Itsrelativetechnicalsimplicityandgoodoutcomesledtoaworldwidesurgeinpopularityasastand-aloneprocedure,start-ingaround2008.Thisprocedureinvolvesresectionofthelateralpart of the stomach to create a narrowgastric tube along thelesser curvature. Itpromotesweight loss through reducedmealvolumeand reducedappetite. It hasbecome themost frequentlyperformed surgical approach, representing 45.9% and 58.3%ofallsurgeriesintheworldandinNorthAmericarespectively.21 Thesenumbersarelikelytobemaintainedgiventherecentcon-firmationof thefive-year efficacyof sleevegastrectomy in tworandomizedcontrolledtrials.22,23Inaddition,sleevegastrectomyistypicallyeasiertoreviseincaseofweightregaincomparedwithRoux-en-Ygastricbypass.

Roux-en-Y gastric bypass involvesthecreationofasmallgas-tricpouchatthelevelofthecardia.Thispouchisconnectedtotheproximal smallbowelbybypassing thefirst75cm–150cmand bringing a 100 cm–150 cm alimentary limb onto the gas-tricpouch.Short-termmetabolicandhormonaleffectshavebeenstudiedextensivelyinnumerousstudies.24Ithasbeenconsideredas the gold standard in bariatric surgery until recently,when it

Canadian Adult Obesity Clinical Practice Guidelines 4

wassupplantedbysleevegastrectomy.Long-termdatahavebeenreportedinnumerousstudies,12andaresummarizedbelow.

Duodenal switch combines moderate restrictive and hypoab-sorptive mechanisms by creating a wider sleeve gastrectomy,whiletheduodenumistransecteddistaltothepylorusandanas-tomosedtoa250cmalimentarylimb,leavinga100-cmcommonchannel for nutrient absorption.Duodenal switch reducesmor-bidityandmortality,improvesT2DMandcorrectsmanyfeaturesofthemetabolicsyndromeinlong-termstudies.25Thisoperationcompares very advantageously with the other surgical optionsavailable,offeringthemostpronouncedanddurableweightlossand 80%–90% remission rates for T2DM.26 Yet, the technicalcomplexityandtheriskforlong-termnutritionaldeficiencieshashindereditswidespreaduse.Accordingtothemostrecentdata,duodenalswitchrepresented1.1%ofthetotalnumberofsurger-iesworldwideand5%–6%ofallbariatricoperationsinCanada.21

Risks

Eventhoughbariatricsurgeryprovidessubstantialandsustainedeffectsonweightlossandamelioratesobesity-attributablecomor-biditiesinthemajorityofbariatricpatients,risksofcomplication,reoperationanddeathexist.Inasystematicreviewandmeta-anal-ysispublishedin2014,atotalof164studies,randomizedcontroltrialsand127observationalstudieswereidentified.27 Analyses in-cluded161,756patients,withameanageof44.6yearsandBMIof45.6.Inrandomizedcontroltrials,themortalityratewithin30dayswas0.08%(95%CI,0.01%–0.24%);themortalityrateaf-ter30dayswas0.31%(95%CI,0.01%–0.75%).BMIlossatfiveyearspost-surgerywas12to17.Thecomplicationratewas17%(95%CI,11%–23%),andthereoperationratewas7%(95%CI,3%–12%).Gastricbypasswasmoreeffectiveinweightlossbutassociatedwithmore complications.Adjustablegastricbandinghadlowermortalityandcomplicationrates;yet,thereoperation

ratewas higher andweight losswas less substantial thangas-tricbypass.InalargeanalysisofUnitedStatesbariatricregistries(n=134,142), sleeve gastrectomy was associated with half therisk-adjustedoddsofdeath(0.1%versus0.2%),seriousmorbidity(5.8%versus11.7%)andleak(0.8%versus1.6%)inthefirst30dayscomparedtoRoux-en-Ygastricbypass.Sleevegastrectomyappearedtobemoreeffectiveinweightlossthanadjustablegas-tricbandingandcomparablewithgastricbypass.Table1summa-rizestherisksandbenefitsofthefourdifferentsurgeries.

Metabolic effects of bariatric surgery

What Is the quality of life after bariatric surgery?

PatientslivingwithsevereobesityhavelowerperceivedhealthacrossalldimensionsofQOL.28Moreover,theimpactonfunctioningissoimportantthatsevereobesitycanbedescribedasacauseofdisability.Formostpatients,bariatricsurgeryhasasignificantpositiveinfluenceonQOL.Theimpactvariesconsiderablyacrossstudies,withbariatricsurgeryshowingasignificantlygreaterpositiveinfluenceonphysicalQOLcomparedwithmentalQOL.Also,improvementinhealth-relat-edqualityoflife(HRQOL)istypicallyassociatedwiththeamountofweightloss.Meta-analysesofshort-term(oneyear)andlong-term(≥5years)HRQOLfollowingbariatricsurgeryversusnonsurgicalmanagement inpatientswithClass IIor IIIobesity, showedevi-dence for a substantial and significant improvement inphysicalandmentalhealth favouring the surgicalgroupcomparedwithcontrols,spanningfiveto25yearsaftersurgery.29,30Inasystematicreviewcomparingbariatricsurgerytomedicaltreatmentinadultswithobesity(BMI>30kg/m2),31bariatricsurgeryresultedingreat-erimprovementsinQOLthanotherobesitytreatments.However,significantdifferencesinQOLimprovementswerefoundbetweendifferenttypesofbariatricsurgery,andgreaterimprovementsinphysicalQOLthanmentalQOLwerefound.Similarly,Lindekilke

Figure 1

Fromlefttoright:Adjustablegastricbanding,Roux-en-Ygastricbypass,sleevegastrectomyandbiliopancreaticdiversionwithduodenalswitch.Copyright:Graphicdepartment,QuebecHeartandLungInstitute,LavalUniversity.Reprintedwithpermission.

Canadian Adult Obesity Clinical Practice Guidelines 5

etal.,6inameta-analysisoftheimpactofbariatricsurgeryonQOLinadults receivingsurgeryforobesity, reportedapositiveeffectonqualityQOL, especiallywhen lookingatphysicalwell-being.Inanotherseriesof139patientswithsevereobesityrandomizedtoRoux-en-Ygastricbypass (n=76)versus intensivebehaviouralintervention (n=63), Karlsen et al.32 reported a significant im-provement inHRQOLafteroneyear,withaweakerresponse inthe behavioural group. Significant association between weightreductioninpercentofbaselineweightandHRQOLwasfound,explainingtheweakerresponseofintensivebehaviouralchangescomparedtoRoux-en-Ygastricbypass.

What is the impact on weight?

Manystudieshaveconfirmedthe long-termsuperiorweight lossfollowingsurgery,comparedtononsurgicalinterventions.Asaruleofthumb,weightlossandremissionofcomorbiditiesisproportion-altointestinalbypass,whichisasurrogateofthemetaboliceffectofthesurgery(e.g.,adjustablegastricbanding<sleevegastrectomy<Roux-en-Ygastricbypass<duodenalswitch).Thereis,however,nodirectcomparisonofthesefoursurgeriesinasingleprospectivetrial.Table1summarizestheaverageweightlossfollowingsurgery.

Oneofthelargestprospectivetrialsinbariatricsurgery,calledtheSwedish Obese Subjects (SOS) Study,1,33 involved 4047 subjectslivingwithobesitywhounderwentbariatric surgery (n=2010)orconventionaltreatment(n=2037)inamatchedcontrolgroup.Theaverageweightchangeincontrolsubjectswaslessthan2%duringtheperiodoffollow-upto15years.After10years,thetotalweightlosswas25%aftergastricbypass,16%afterverticalbandedgas-troplastyand14%afterbanding.Colquittetal.3didameta-analysisofstudiescomparingsurgerywithnonsurgicalinterventions.Atotalof22randomizedcontrolledtrialswereidentified,representingal-together1496patientsallocatedtosurgeryand302tononsurgicalinterventions.Outcomeswere similar betweenRoux-en-Ygastricbypassandsleevegastrectomy,andbothoftheseprocedureshadbetteroutcomesthanadjustablegastricbanding.ForpeoplewithveryhighBMI,biliopancreaticdiversionwithduodenal switch re-sultedingreaterweightlossthanRoux-en-Ygastricbypass.

Aseriesof250patientswithaninitialBMIof45to60kg/m2wererandomized toRoux-en-Ygastricbypassor laparoscopicadjust-ablegastricbanding.12At10-yearfollow-up,themeantotalbodyweightlosswas-42±20kgforgastricbypassversus-27±15kgfor gastric banding (p<0.05). Late reoperationwas significantlyhigher after gastric banding compared with the gastric bypassgroup(31%vs.8%,respectively,p<0.01).At10yearsandcom-paredwith gastric banding, gastric bypasswas associatedwithbetterlong-termweightloss,lowerrateoflatereoperationandimprovedremissionofcomorbidities.

Five-yearoutcomesoflaparoscopicRoux-en-Ygastricbypassandlaparoscopicbiliopancreaticdiversion-duodenalswitchwerealsocomparedinarandomizedcontroltrialinvolving60patientswithaninitialBMIof50to60kg/m2.26Atfiveyears,duodenalswitchsurgeryresultedingreaterweightlossandgreaterimprovementsinLDL-cholesterol,triglycerideandglucoselevelscomparedwith

gastricbypass,whileimprovementsinQOLweresimilar.However,duodenal switchwas associatedwithmore surgical, nutritionalandgastrointestinaladverseeffects.Excessweightlosswasassessedaftersleevegastrectomyinasystematicreview.34

SleevegastrectomywasalsocomparedtoRoux-en-Ygastricby-passintworandomizedcontroltrialswithfive-yearoutcomes.22,23 Roux-en-Ygastricbypassandsleevegastrectomyresultedinequiv-alent,long-standingQOLimprovement.Roux-en-Ygastricbypassresulted in more stable weight loss (75% versus 65% excessweightlossatfiveyears,p=0.017)butwasassociatedwithhigherreadmissionrates.SimilarimprovementsinQOLwerefoundinthesecondrandomizedcontroltrial;excessweightlosswas49%inthesleevegastrectomygroupversus57%intheRoux-en-Ygas-tricbypassgroup,but thedifferencedidnot reachsignificance.Overallmorbiditywas19%forsleevegastrectomyand26%forRoux-en-Ygastricbypass(p=0.19).

What are the effects on type 2 diabetes?

OverthelasttwodecadeswehavewitnessedadramaticincreaseintheincidenceofT2DM,nowaffecting10%oftheadultpopu-lation.Most(80%)isduetoexcessweightorobesityandT2DMhasbecome the leadingcauseofchronickidneydisease,blind-ness, and non-traumatic amputation. Overall, bariatric surgeryprocedureshavebeenconsistentlymoreeffectivethanstandardmedical approaches, including intensivemedical treatment andpsychological/behaviouralinterventionstoinducedurablecontrolandremissionofT2DM.35

TheSOSstudyisaprospectivecontrolledtrialwithoneofthelon-gestperiodsoffollow-upinthebariatricliterature.Thisstudyhasshown impressive resultswith respect to sustained remissionofT2DM.35Attwo(n=1762)and10years(n=1216),remissionrateswere72%and36%,respectively, inthepooledsurgicalgroup.Reductionsinglucose,insulinandhomeostaticmodelassessmentfor insulin resistance increasedwith increasingweight loss,andchanges were typically related to weight change within eachsurgerygroup.Several randomizedcontrol trialshavespecifical-lystudiedT2DMresponsetodifferentsurgicalproceduresversusmedicaltreatment.Mingroneetal.4reportedratesofremissionofdiabetesatthreeyearstobe75%and95%inRoux-en-Ygastricbypassandduodenalswitchgroups,comparedtonoresponsewithmedicalinterventionalone.Atfiveyears,remissionwasmaintainedin37%of theRoux-en-Ygastricbypasspatientsand63%of thebiliopancreatic diversionpatients.4 Further, Schauer et al.5 stud-ied the impactofRoux-en-Ygastricbypass, sleevegastrectomyandbestmedicalmanagementforpatientswithpoorlycontrolledT2DMandsevereobesity (BMI27to43kg/m2).At threeyears,Roux-en-Ygastricbypass (n=50)andsleevegastrectomy (n=50)resulted in improved diabetes outcomes and remission in 42%and 37%of patients, respectively, compared to 12% achievedwithmedicaltherapy(n=50).Atfiveyears,5thecriterionfortheprimaryendpointwasmetby5%ofpatientswhoreceivedmed-icaltherapyalone,comparedto29%whounderwentRoux-en-Ygastricbypassand23%whounderwentsleevegastrectomy.Meanreductioninglycatedhemoglobinwas2.1%vs.0.3%(p=0.003)in

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thesurgeryversusmedicalcroup.ChangesfrombaselineobservedintheRoux-en-Ygastricbypassandsleevegastrectomygroupswerealsosuperiortothechangesseeninthemedicaltherapygroupwithrespect to body weight. These changes were −23%, −19% and−5%intheRoux-en-Ygastricbypass,sleevegastrectomyandmed-icaltherapygroups,respectively;thetriglyceridelevelswere−40%,−29% and −8%; high density lipoprotein cholesterol levels were32%,30%and7%;useofinsulinwas−35%,−34%and−13%;andQOLmeasureswerep<0.05forallcomparisons.Five-to20-yearremissionratesafterduodenalswitchareevenhigher,withobserva-tionalstudiesshowingcompleteremissionintherangeof93%anddiscontinuationofinsulintherapyin97%.25

In general,metabolic outcomes of adjustable gastric banding arelessimpressivecomparedwithbypassprocedures.Inarandomizedcontroltrialcomparingadjustablegastricbandingtointensivemed-icaldiabetesandobesitymanagement inpatientswithT2DMandBMIof30–45kg/m2,36laparoscopicadjustablegastricbandingandmedicalprogramshadsimilarone-yearbenefitsondiabetescontrol,cardiometabolicriskandpatientsatisfaction.Theproportionmeetingtheprimaryglycemicendpointwasachievedin33%ofthelaparo-scopicadjustablegastricbandingpatientsand23%oftheintensivemedicaldiabetesandweightmanagementpatients(p=.457).Gly-catedhemoglobin(HbA1c)reductionwassimilarbetweengroupsatboththreeand12months(-1.2+/-0.3vs-1.0+/-0.3%;p=.496).Weightlosswassimilaratthreemonthsbutgreaterat12monthsafter laparoscopicadjustablegastricbanding.TheseoutcomesandothersfavourmetabolicsurgeriesincasesofT2DM.

An abundant literature, including prospective and randomizedtrialscomparingdifferentmetabolicprocedurestomedicaltreat-ment, have been identified by our literature search. All studiesconsistently showed superior control and remissionofT2DM inthe surgical arms37–39, including superiorweight loss and lowerHbA1cthreeyearsafterduodenalswitchcomparedwithRoux-en-Ygastricbypass.40Variationsinreportedoutcomesaremultifacto-rial and include differences in study design, surgical technique,durationoffollow-upandpatientcharacteristics,suchashigherpre-surgical BMI and shorter durationof T2DM (bothofwhichconferhigherlikelihoodofremission).41

Also, continuedmonitoringofglycemic control iswarrantedbe-cause theeffectof surgery tends todiminishover timewithpo-tentialrelapseofhyperglycemia.38TheplaceofmetabolicsurgeryinthemanagementofT2DMwasultimatelyrecognizedbytheIn-ternationalFederationonDiabetesin201142andtheCanadianDi-abetesAssociationin2013.43BothstatedthatsurgeryrepresentsavalidoptionforT2DMmanagementinpatientswithsevereobesitywhohavefailedinitialmedicalandnutritionalmanagement.

What is the impact on other comorbidities?

Hypertension

Ameta-analysisoftheeffectofbariatricsurgeryonhypertensionwasperformedbyWilhelmetal.8Ofthe57studies,32report-

ed improvement of hypertension in 32,628 of 51,241 patients(OR=13.24;95%CI7.7,22.7;p<0.00001);46studiesreport-ed the resolutionofhypertension in24,902of49,844patients(OR=1.7; 95%CI 1.1, 2.6; p=0.01).Another systematic reviewand meta-analysis on the early impact of bariatric surgery onT2DM,hypertensionandhyperlipidemiawasperformedbyRiccietal.44Therewasanoverallreductionofcardiovascularriskafterbariatricsurgery.Accordingtotheiranalysis,aBMIreductionoffive after surgery corresponds to a T2DM reduction of 33%, ahypertension reductionof27%andahyperlipidemia reductionof20%.Theimpactofsleevegastrectomyonhypertensionwasassessedinasystematicreview.45Atotalof33studieswereiden-tified,involvingatotalof3997patients.Laparoscopicsleevegas-trectomyresultedinresolutionofhypertensionin58%ofpatientsandimprovementorresolutionin75%.Basedonthesereviews,bariatricsurgeryhasasignificanteffectonhypertension,inducingresolutionorimprovementinthemajorityofcases.

Sleep apnea

Thereislimitedhigh-levelevidenceregardingtheimpactofbariatricsurgeryonsleepapnea.Weidentifiedthreerandomizedclinicaltrials assessing the impact of adjustable gastric banding versusclinicalmanagementonsleepapnea.46–48ForAguiaretal.47, bar-iatric surgerywas effective in reducing neck andwaist circum-ference,inincreasingmaximumventilatorypressures,enhancingsleeparchitectureandreducingrespiratorysleepdisorders,specif-icallyobstructivesleepapnea.Ontheotherhand,Feigel-Guilleretal.48didnotfindsignificantdifferenceintherateofweaningfrom non-invasive ventilation between laparoscopic adjustablegastricbandingandmedicaltreatmentatoneyear(35%vs13%)orthreeyears(14versus21%).DecreasesintheApnea-HypopneaIndexwereobservedinthelaparoscopicadjustablegastricband-inggroupfrombaseline toyearone (44%,p=0.001)and frombaselinetoyearthree(-26%,p=0.04).

TheAmericanThoracicSocietyrecentlyreleasedaclinicalpracticeguidelineonthemanagementofsleepapnea.49TheirconditionalrecommendationforpatientswithsleepapneaandaBMIof35kg/m2,whoseweighthasnot improveddespiteparticipating ina comprehensiveweight-loss lifestyle intervention program andwhohaveno contraindications, is to referpatients forbariatricsurgery evaluation. They, however, assessed certainty in the es-timatedeffectasvery low.Morerandomizedcontrol trials,par-ticularlyincludingothertypesofsurgeriesthanadjustablegastricbanding,arethusneededtoconfirmthesefindingsgiventhehighdegreeofheterogeneityusingrespiratoryeventsscoring.

Lipid metabolism

Improvementsinlipidmetabolismhavebeenreportedconsistentlyin various prospective and retrospective studies. Contemporarybariatric surgical techniques produce significant improvementsinserumlipids,butchangesvarywidely, likelyduetoanatomicalterationsuniquetoeachprocedure.AliteraturereviewbyHef-fronetal.7 identified178studies,with25,189subjects, report-ingchanges in lipidsfrombaselinetooneyearaftersurgery. In

Canadian Adult Obesity Clinical Practice Guidelines 7

patientsundergoinganybariatricsurgerycomparedtobaseline,therewere significant reductions in total cholesterol (TC, -28.5mg/dL), lowdensity lipoproteincholesterol(LDL-C,-22.0mg/dL)andtriglycerides(-61.6mg/dL),andasignificantincreaseinhighdensitylipoproteincholesterol(6.9mg/dL)atoneyear(p<0.00001for all). Themagnitudeof this changewas significantly greaterthanthatseeninnon-surgicalcontrolpatients(e.g.LDL-C;-22.0mg/dLvs.-4.3mg/dL).Whenassessedseparately,themagnitudeofchangesvariedgreatlybysurgicaltype(pinteraction<0.00001;e.g.LDL-C:DS-42.5mg/dL,Roux-en-Ygastricbypass-24.7mg/dL, adjustable gastric banding -8.8 mg/dL, sleeve gastrectomy-7.9mg/dL). In thecasesofadjustablegastricbanding (TCandLDL-C)andsleevegastrectomy(LDL-C),theresponseatoneyearfollowingsurgerywasnotsignificantlydifferentfromnon-surgicalcontrolpatients.Thesedifferencesmayberelevantindecidingthemostappropriatetechniqueforagivenpatient.

Urinary incontinence

Urinary incontinence is extremely frequent in patients seekingbariatricsurgery.Inaseriesof470patientsundergoingbariatricsurgery,theprevalenceofurinaryincontinencewas66%.50Otherpelvicfloordisordersarealsofrequentand,ingeneral,surgicallyinducedweight-lossisveryefficientinimprovingtheseconditions.Lianetal.51performedameta-analysisoftheeffectsofbariatricsurgeryonpelvicfloordisorders.Elevencohortstudieswereidentified,involving784participantsassessedforpelvicfloordisorderswithavarietyofquestionnaires,beforeandafterbariatricsurgery.Bar-iatric surgerywas associatedwith a significant improvement inpelvicfloordisordersonthewhole,andwithsignificantimprove-ments in urinary incontinence andpelvic organprolapse. Therewasnosignificantimprovementinfecalincontinenceandsexualfunction.Inaprospectiveanalysisof140patientsundergoingbar-iatricsurgery,Saidandcolleagues52reportedthatsurgery-inducedweightlosswasassociatedwithanimprovementinstressurinaryincontinence (40%atbaselineversus15.5%atoneyear),urgeincontinence(37%atbaselinevs.8%),dysuria(20%atbaselinevs.3.4%)andQOLrelatedtourinarysymptoms(allP<.0001).Inaddition,reductioninprevalenceofurinaryincontinencewassig-nificantlyassociatedwithdecreasesinBMI(p=.01).53

Steatosis and steato-hepatitis

The non-alcoholic fatty liver disease (NAFLD) spectrum rangesfromhepatic steatosis tomore severenon-alcoholic steato-hep-atitis(NASH)andfibrosisthatcanprogresstocirrhosis,end-stageliverdisease,andhepatocellularcarcinoma.TheprevalenceofNA-FLDisestimatedtobearound70%inpeoplelivingwithobesityand85%to95%inpatientswithsevereobesity.Theprevalenceofnonalcoholicsteatohepatitisisashighas18.5%inpeoplelivingwithobesityand33%inthoselivingwithsevereobesity.Atpres-ent, interventionsforNAFLDfocusonweight lossandimprove-ment in insulinresistanceandassociatedcomorbidities.Medicaltreatmentforweightlosswithdrugs,nutrition,exerciseandotherpsychological/behaviouralinterventionshaslimitedefficacy,espe-ciallyinthoselivingwithsevereobesity.Ontheotherhand,liversteatosis,steatohepatitisandevenliverfibrosisappeartoimprove

orcompletelyresolveinthemajorityofpatientsafterbariatricsur-gery-inducedweightloss.54Inasystematicreviewoftheliterature(15 studieswith 766 paired liver biopsies),9 the pooled propor-tionofpatientswithimprovementorresolutioninsteatosiswas91.6%(95%CI,82.4%–97.6%),81.3%insteatohepatitis(95%CI,61.9%–94.9%),65.5%infibrosis(95%CI,38.2%–88.1%),and69.5%forcompleteresolutionofnonalcoholicsteatohepa-titis (95%CI,42.4%–90.8%).Lassaillyetal.55prospectively fol-lowed109patientswithbiopsy-provennonalcoholic steatohep-atitis who underwent bariatric surgery. One year after surgery,nonalcoholic steatohepatitis had disappeared from 85%of thepatients (95%CI, 75.8%–92.2%). Nonalcoholic steatohepatitisdisappearedfromahigherproportionofpatientswithmildnon-alcoholicsteatohepatitisbeforesurgery(94%)thanseverenonal-coholicsteatohepatitis(70%)(p<.05),accordingtoBruntscore.

Renal function

Obesityisanindependentriskfactorforthedevelopmentandpro-gressionofchronickidneydisease.However,dataonthebenefitsofbariatricsurgeryinpatientslivingwithobesitywhohaveimpairedkidney function are limited.A recent systematic review andme-ta-analysis56assessedtheimpactofbariatricsurgeryonglomerularfiltrationrate,proteinuriaoralbuminuria.Theauthorsincluded30observational studies and founda significant reduction inhyper-filtration,albuminuriaandproteinuriaafterbariatricsurgery.Mainlimitationswerethelackofrandomizedcontroltrialsandlong-termfollow-up. In another systematic review of the impact of bariat-ricsurgeryonrenal function inpatientswithT2DM,Zhouetal57 identified29studies(fourrandomizedcontrolledtrials,fivecohortstudies,20beforeand-afterstudies;allatmoderatetohighriskofbias)involving18,172patients.Analysesofchangesbeforeandaf-tersurgeriessuggestedasignificantlylowerproportionofalbumin-uria(difference-21.2%,95%CI-28.8%to-13.5%),24-hoururinealbumin excretion rate (weightedmeandifference -48.78mg/24heartrate,95%CI-75.32to-22.24)andurinealbumin-to-creat-inineratio (uACR) (weightedmeandifference-16.10mg/g,95%CI –-22.26 to –-9.94) after surgery. Compared with nonsurgicaltreatment,bariatricsurgerywasassociatedwithastatisticallylow-erlevelofuACRandlowerriskofnewonsetalbuminuria(OR.18,95% CI.03-.99 from randomized controlled trials). Even thoughlow-quality evidence suggests that bariatric surgery possibly im-proves albuminuria and uACR in patientswith T2DM, its effectsonotheroutcomesareuncertain. Large, randomizedprospectivestudieswithalongerfollow-upareneeded.

Does bariatric surgery decrease long-term mortality risk?

Anobservationaltwo-cohortstudycomparingthemorbidityandmortalityof1035patientswithsevereobesitytreatedwithbariatricsurgery to5746controlsubjectswithsevereobesityhasshownthat bariatric surgery significantly decreases overallmortality aswellasreducesriskofchronicconditionsinsubjectswithsevereobesity.Thebariatric surgerysubjectshadsignificant risk reduc-tionsfordevelopingcardiovascular,cancer,endocrineconditions

Canadian Adult Obesity Clinical Practice Guidelines 8

(includingT2DM),aswellasinfectious,psychiatricandmentaldis-orderscomparedwiththecontrolgroup.58Themortalityrateinthebariatricsurgerycohortwas0.68%comparedwith6.17%incon-trols,translatingtoareductionintherelativeriskofdeathby89%.

IntheSOSstudy,1surgicaltreatmentswereshowntodecreasetheincidenceof total and fatal cardiovascular eventsover20yearscomparedtocontemporaneouslymatchedcontrolsofthoselivingwithobesityreceivingusualcare.Therewere129deaths inthecontrolgroupand101deathsinthesurgerygroup.Thehazardratioadjustedforage,sexandriskfactorswas0.71inthesurgerygroup (p=0.01) as comparedwith the control group. Themostcommoncausesofdeathweremyocardialinfarctionandcancer.Analyses of the SOS data failed to demonstrate an associationbetween initialBMIandpostoperativehealthbenefits.Eventhemagnitudeofsurgery-inducedweightlossdidnotpredictcardio-vasculareventsinthatcohort,indirectlypointingtowardweightloss-independentbeneficialmechanisms.

Inameta-analysisofthepublishedliteratureonlong-term(>2years)mortality after bariatric surgery, Cardoso et al.2 identified 12 ob-servationalstudies involving27,258operatedpatientsand97,154non-operatedcontrolsofthoselivingwithobesity.Eightstudieswereeligibleforthemeta-analysis,whichshowedareductionof41%inall-causemortality(hazardratio,0.59;95%CI0.52-0.67;p<.001).

Indeed, surgical weight loss seems to reduce the incidence ofsomecancerformsandcancer-relatedmortality.IntheSOStrial,59 thenumberoffirst-timecancersafterinclusionwaslowerinthesurgerygroup (n=117) than in thecontrolgroup (n=169;heartrate 0.67, 95%CI 0.53-0.85, p=0.0009). Bariatric surgerywasassociatedwithreducedcancerincidenceinwomenwithobesitybutnotinmenlivingwithobesity.

Is bariatric surgery indicated in patients with Class I obesity (BMI 30–35)?

With the improved understanding of hormonal and metabol-icchanges relatedto the intestinalbypass,bariatric surgeryhasevolvedconceptuallyfrombariatricsurgerytometabolicsurgery,particularlyforpatientswithametaboliccomplication(especiallyT2DM),thatismoreofaproblemthanweightitself.AnumberofrandomizedtrialshavelookedattheimpactofsuchsurgeriesonT2DM, compared to thebestmedicalmanagement.5,60–62 Thesestudies were summarized in a meta-analysis by Cohen et al.10 lookingatpatientswithBMIof30–40kg/m2undergoingRoux-en-Ygastricbypassvs.medical treatment.10A totaloffive ran-domizedcontroltrialswereidentified,with43.3%ofthepatientswithaBMIbelow35kg/m2.Roux-en-Ygastricbypasssignificantlyimprovedtotalandpartial remissionofT2DM(OR17.48; (95%CI4.28-71.35)andOR20.71(95%CI5.16–83.12),respectively).HbA1cwasalsoreducedatlongestfollow-upinthesurgerygroup(−1.83[95%CI−2.14;−1.51]).Thismeta-analysisreinforcedtheviewthataddingmetabolicsurgery,particularlyRoux-en-Ygastricbypass,tothebestmedicaltreatmentisagoodoptionfortheman-agementofuncontrolledT2DMinpatientswithaBMI30kg/m2.

TheplaceofmetabolicsurgeryinthemanagementofT2DMwasrec-ognizedbytheInternationalFederationonDiabetesin2011.42Thispo-sitionstatementcalledforbariatricsurgerytobeconsideredearlierineligiblepatients,tohelpstemtheseriouscomplicationsthatcanresultfromdiabetes.InadditiontoconsideringsurgeryinpeoplewithT2DMandaBMI≥35kg/m2,theInternationalFederationonDiabetestaskforcestatedthatsurgeryshouldbeconsideredasanalternativetreat-mentoptioninpatientswithaBMIbetween30and35kg/m2whendi-abetescannotbeadequatelycontrolledbyoptimalmedicalregimens,especially in thepresenceofothermajorcardiovasculardisease riskfactors.In2016,over50internationalmedicalsocietiesendorsednewguidelineswheremetabolicsurgerywasincludedinthetreatmental-gorithmforpatientswithuncontrolledT2DMandBMIabove30kg/m2.63Othermetabolicoutcomeswerealsoimprovedinpatientswithmildtomoderateobesity.Ikramuddinetalrandomized120patientswithBMIbetween30and40kg/m2toRoux-en-Ygastricbypassver-susintensivemanagementandlookedatacompositemainendpointofhyperglycemia,hypertensionanddyslipidemiaresolution.11At12months,theprimaryendpointwasreachedin49%(95%CI,36%–63%)versus19%(95%CI10%–32%)ofthesurgicalversusmedicalpatients,respectively(OR,4.8;95%CI,1.9–11.7).Participantsinthegastricbypassgrouprequired3.0fewermedications(mean,1.7vs4.8;95%CIforthedifference,2.3-3.6)andlost26.1%vs.7.9%oftheirinitialbodyweightcomparedwiththelifestyle-medicalmanagementgroup(difference,17.5%;95%CI,14.2%–20.7%).Regressionanal-ysesindicatedthatachievingthecompositeendpointwasprimarilyattributabletoweightloss.

New surgical and endoscopic approaches

Bariatricsurgeryisoneofthefastestevolvingfieldsofgeneralsur-gery.Surgicalproceduresarebeingmodifiedandnewconceptsemergeovertime;onlysomewithstandthetestoftimeandsci-entificevaluation.Themostcommonsurgicalmodificationsper-formedaroundtheworldaredescribedbelow.

Single-anastomosis duodenal switch

ThissimplifiedduodenalswitchtechniquehasbeenputforwardbySánchez-Pernaute.64 Much like the duodenal switch developed byMarceau65,66 andfirstperformed laparoscopicallybyGagner,65 it in-volvesthecreationofasleevegastrectomy,buttheduodenumistran-sectedandconnectedtoanomega-shapedloopofsmallbowel(Fig-ure1)Thisnewprocedurehastheadvantageofbeingsimplerthantheduodenalswitchbecauseonlyone intestinalanastomosis isneededinsteadoftwo.Theotherpotentialbenefitsaretodecreasetherateofperioperativecomplicationsandincreaseaccesstothistypeofsurgery.Inaddition,thelengthofthecommonintestinalchannelallowingdi-gestionandabsorption(250cm)ismorethandoubledcomparedtostandardduodenalswitch (100cm),whichcouldattenuateside-ef-fects related to dietary fat- and fat-soluble vitamin malabsorption.ThisprocedurewasrecentlyendorsedbytheInternationalFederationfor theSurgeryofObesityandAmericanSocietyforMetabolicandBariatricSurgery,67basedon its similaritiesandcommonlyaccepteddecreasedriskcomparedtostandardduodenalswitch.Single-anasto-mosisduodeno-ileostomyisemergingasapotentialoptionforsleeve

Canadian Adult Obesity Clinical Practice Guidelines 9

gastrectomyweightregainorT2DMrecurrences.Asinglesmallseriesof16patientswhohadtwo-stagesingle-anastomosisduodeno-ileos-tomyexperiencedan increase inexcessweight loss from39.5%to72%twoyearsafterthesecondstage(n=5).RemissionrateforT2DMwas88%,60%forhypertension,and40%fordyslipidemia.

Gastric plication

LaparoscopicgastricplicationwasfirstdescribedbyTalebpouretal.68 Thisprocedureconsists in imbricating thegreater curvatureof thestomachwithtwolayersofnon-absorbablesutures.Theoverallgoalistoduplicatetheeffectsofasleevegastrectomy,whileavoidinganygastricstaplingor resection.Theprocedure is,however,associatedwithsignificantpostoperativenauseaandfoodintoleranceanddoesnotseemtoreducetheriskofgastricleak.Asystematicreviewidenti-fied14studiesinvolving1450patientswhounderwentgastricplica-tion.69Excessweightlossrangedfrom32%to74%withfollow-upfromsixto24months.Nomortalitywasreportedinthesestudiesandtherateofmajorcomplicationsrequiringreoperationrangedfromnilto15.4%(average3.7%).However,itremainsunclearifweightlossfollowing laparoscopicgastricplication isdurable inthe long-term.Two-yearoutcomeswereassessedinarandomizedcontroltrialcom-paringsleevegastrectomytogastricplication.Attwoyears,thetotalweight loss and complication rateswerenot significantly differentbetweenthetwogroups.68Additionalcomparativetrialsandlong-termfollow-upareneededtofurtherdefinetheroleoflaparoscopicgastricplicationinthesurgicalmanagementofobesity.

Single-anastomosis gastric bypass

Roux-en-Ygastricbypasshas longbeen consideredas thegoldstandard in bariatric surgery, offering a good compromise be-tweenbenefits(weightloss,QOL,remissionofcomorbidities)andsurgical risksandsideeffects. Itwas recently replacedbysleevegastrectomyasthemostcommonbariatricprocedure.However,sometechnicallimitations(difficultyincreatingagastrojejunosto-my)andtheriskofweightandcomorbiditiesrecidivismhaveledtothedevelopmentofsingle-anastomosisgastricbypass(SAGB).Thisprocedurewas initiallydescribed in2001byRutledge, andconsistsofcreatingalongandnarrowgastricreservoir(+/-10cm,vs.5cm longforstandardRoux-en-Ygastricbypass)associatedwithasingle-looptypicallylonger(biliopancreaticlimbof200cm).ThistechniqueisincreasinglypopularinEuropeandAsiaandhasbeenendorsedbytheInternationalFederationfortheSurgeryofObesity.70 It is,however,notcurrentlyapprovedoutsideof Insti-tutional Review Board protocols in the U.S. Long-term benefitsofSAGBcomparedtostandardRoux-en-Ygastricbypassarestillquestionedregardingtheriskofbilerefluxandlong-termriskofesophagealandgastriccancerassociatedwithchronicexposureto bile acids. A recent randomized control trial compared sin-gle-anastomosis gastric bypass to Roux-en-Ygastric bypass andsleeve gastrectomy (200 patients in each groups). The authorsreportedsuperiorweightloss(98%vs.76%vs.77%inthesin-gle-anastomosisgastricbypass,sleevegastrectomyandRoux-en-Ygastricbypassgroups, respectively)andsimilar remission rateofmetabolicsyndrome,includingremissionofT2DMin94%versus87%versus90%afterSAGB,sleevegastrectomyandRoux-en-Y

gastricbypass.71However,thelong-termriskassociatedwithbileacidexposurehasnotyetbeenclearlyaddressed.

Current endoscopic therapies

Itisconservativelyestimatedthatapproximately600,000to1,200,000CanadiansmightbeeligibleforbariatricsurgeryassumingthattwotofourpercentoftheCanadianadultpopulationislivingwithsevereobesity.72OnlyafractionofCanadiansseeksurgicalinterventionforobesity. Approximately 10,000 bariatric surgeries were performedin2017.Manypatientsareinterestedinlessinvasiveproceduresinorder to decrease postoperative complication rates, hospitalizationandrisksofmicronutrientdeficienciestypicallyassociatedwithstan-dard surgical therapies.Anumberofendoscopicapproacheshaveemergedovertimeandaretypicallyplacedbetweenmedicaltherapyandsurgicaltherapy,intermsofeffectiveness,risks,andside-effects.

Intra-gastric balloons

Intra-gastricballoonswerefirstdescribedin1982byNiebenetal.73 and represent theoldest endoscopic procedure forweight loss.Multiplemodificationshavebeenrealizedtoimprovethetolera-bility,riskofperforationandeaseofplacementandretrieval.Mostballoonsstillrequireuppergastrointestinalendoscopywithseda-tionorgeneralanesthesia,andneedtoberetrievedafterthreetosixmonthsusing the same technique.Mostpatientsexperiencesomesideeffects,likenausea(24%),vomiting(2.7%),abdominalfullness (6.3%) or pain (14%), deflation (6%) and gastric ulcer(12.5%).74Rarecomplicationscanalsooccur,includinggastricoresophagealperforation, smallbowelobstructionandhypoxiaatthetimeofextraction.Inameta-analysisof20randomizedcontroltrialsinvolving1195patients,Saberetal.calculatedthefollowingsignificanteffect sizes:1.6and1.3kg/m2 foroveralland three-monthsBMI loss, and4.6 kg and4.8 kg for overall and three-monthweight loss.74 In anothermeta-analysis by Zhenget al.75

effectsizewas8.9kgforweightloss,3.1kg/m2forBMIreductionand21%forexcessweightlossaftersixmonths.However,mostpatientswill regainweightafterballoonextraction,andthere isinsufficientevidencesupportingitslong-termeffectiveness.74Thelastmodificationsofthistechniqueallowtheballoontobeswal-lowed76andevenself-excreted.77Initialstudieshavedemonstrateditssafetyandshort-termefficacy.

Endoscopic bypass

AnumberofendoscopicprocedureshavebeendevelopedrecentlythatattempttomimicthemetaboliceffectofRoux-en-Ygastricbypass.Themostadvancedendoscopicbypass (EndoBarrier,®orduodeno-jejunalendoscopicbypass)consistsinplacinga1mmplasticsleeve in thefirstduodenum toprevent contactof foodwithbileacidsandtobringundigestedfoodintotheproximaljejunum.Thesleeveisplaced,undersedation,withagastroscope.Itneedstoberetrievedaftersixmonths.Smallrandomizedcontroltrialsshowedanexcessweightlossof32.0%(22.0%–46.7%)versus16.4%(4.1%–34.6%)inthecontrolgroup(p<0.05)withimprovementinglucosemetabolism.78Meta-analysisidentified151patientswhounderwentanendoscopicbypass,withaweightlossof-5.1kg(95%CI-7.3,

Canadian Adult Obesity Clinical Practice Guidelines 10

-3.0)andexcessweightlossof12.6%(95%CI9.0,16.2),respec-tively.79However,itisassociatedwithariskofseriousadverseevents,likeacutepancreatitisin3%ofpatients,devicemigration,earlyexplant,gastrointestinalbleedingandliverabscess.80–82

Endoscopic sleeve gastroplasty

Differentendoscopicprocedureshavebeendevelopedtoendoscop-icallyreducegastricvolume.Themostcommon(thePoseprocedure)involvesendoluminalplacementoffull-thicknesssuturetoplicatethefundusanddistalbodyof thestomach.Largerandomizedcontroltrialshaveassessedthetechniqueandshownacceptableshort-termweightlosswithlowperioperativecomplications.Sullivanetal.83per-formedarandomizedcontroltrialoftheprocedureversus lifestylemodifications(332patients).At12months,weightlosswas4.9±7%inactiveversus1.4±5.6%intheshamgroup(p<0.0001).Theproportionofpatientsachieving≥5%weight losswas41.5% inactiveand22.1%inshamgroups,respectively(p<0.0001);meanresponderresultwas11.5%totalbodyweightloss.Procedurerelat-edseriousadverseeventrateswere5.0%(active)and0.9%(sham,p=0.068),andmostwereprocedurerelated.

Aspiration therapy

Percutaneousgastrostomydevice(AspireAssist®)hasbeenrecentlydescribedforthetreatmentofpatientssufferingfromClassIIandIIIobesity.Theprocedure isperformedundersedationandcon-

sistsofplacementofagastrostomytubeandanexternaldevicetofacilitatedrainageofabout30%ofthecaloriesconsumedinameal,inconjunctionwithlifestylemodifications.Thompsonetal.84 randomized 207 patients in a 2:1 ratio to treatmentwithAspireAssist® plus lifestyle counselling (n=137; mean BMI was42.2+/-5.1kg/m2)orlifestylecounsellingalone(n=70;meanBMIwas40.9+/-3.9kg/m2).At52weeks,participants intheAspi-reAssist® grouphad lost amean (+/-s.d.) of 12.1+/- 9.6% to-talbodyweight,whereasthoseinthelifestylecounsellinggrouphad lostameanof3.5+/-6.0%totalbodyweight, (p<0.001).Most adverse events were those known to be associatedwithpercutaneousendoscopicgastrostomytubes (abdominalpain in38%,nausea/vomiting in17%,peristomalbacterial infection in13.5%).Seriousadverseeventswerereportedin3.6%ofpartic-ipants,includingsevereabdominalpain,peritonitis,gastriculcerand tube replacement.Medium-term results are starting to ap-pear,withstudiesconfirmingmaintenanceofweightloss,at19+/-13%weightloss,uptofouryears.85Eventhoughtheseresultsseem to be promising, patients and physicians’ acceptability oftheprocedure,theneedforlong-termnutritionalsurveillanceandlackoflong-termdataandcostitselfareamongfactorslimitingtheadoptionofthisprocedure.

Table 1: Weight Loss Surgeries3

Adjustable gastric banding Sleeve gastrectomy Roux-en-Y gastric bypass Duodenal switch

Totalweightloss(%)

ResolutionrateofT2DM(%)

Resolutionrateofhypertension(%)

Resolutionrateofsleepapnoea/hypopnoea syndrome(%)

Mortalityrate(%)

Seriousadverseevents(%)

Commonsideeffects

Long-termrisks

20

20

20

30

0.01

2

Dysphagia,vomiting

Banderosion,Band intolerance,weightregain

25

30

30

40

0.01

3

Vomiting,constipation

Gastro-esophagealreflux,Barrett’sesophagus,weightregain

30

40

40

50

0.01

3

Dumpingsyndrome

Anastomoticulcer, internalhernia,smallbowelobstruction,nesidioblastosis(uncommon)

40

80

60

70

0.02

5

Increasedbowel movements,bloating

Proteinmalnutrition,vitamindeficiency,smallbowelobstruction, internalhernia

Canadian Adult Obesity Clinical Practice Guidelines 11

Correspondence:guidelines@obesitynetwork.ca

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