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Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_2804_Библиотеки_им_академика_М_И_Перельмана

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☆
Assess EF in patients with severe MR but with an inadequate assessment of EF by
echocardiography.
AssessquantitativemeasureofMRseveritywhenechocardiographyisnondiagnostic.
ViabilityassessmentmayplayaroleinconsideringtherapeuticstrategyinischemicMR.
TREATMENT
AcuteMitralRegurgitation
Whileawaitingsurgery,aggressiveafterloadreductionwithIVnitroprussideoranIABPcandiminish theamountofMRandstabilizethepatientbypromotingforwardflowandreducingpulmonaryedema. Thesepatientsare usuallytachycardic,butattemptstoslow downtheir heartrateshouldbe avoided becausetheyareoftenheartratedependentforanadequateforwardCO.
ChronicMitralRegurgitation
ChronicprimaryMR
Medical therapyis reasonable inpatientswith chronic primary MRand LVEF less than 60% not
undergoingsurgery.
Angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers have been
showntoreducetheregurgitantfractionandaidwithventricularremodeling.β-Blockershavealso
beenshowntoreduceseverityofMRinasymptomaticpatients.
ThereisnobenefitofvasodilatortherapyintheasymptomaticpatientwithnormalLVfunctionand
chronicsevereMR.
ChronicsecondaryMR
TreatsymptomsrelatedtoLVdysfunction.
Guideline-directedmedicaltherapy(GDMT)forLVsystolicdysfunction,includingACEinhibitors
andβ-blockers,isindicatedandhasbeenshowntoreducemortalityandtheseverityofMR.
Somepatientsmayalsoqualifyforcardiacresynchronizationtherapy,whichcanfavorablyremodel
theLVandreducetheseverityofMR.
PercutaneousIntervention
2
Transcatheteredgetoedgerepair(TEER)(i.e.,MitraClip)pinchestheleafletstogetherinanattemptto enhance coaptation (a percutaneous treatment analogous to the surgical Alfieri stitch), creating a double-orificevalve.
This procedure is performed via femoral venous access, and a transseptal puncture is used to
positionthedeliverysystemintheLA.
UsingfluoroscopyandTEEguidance,theclipisadvancedandattemptsaremadetograsptheleaflet
tipsoftheanteriorandposteriorMVleafletsandclipthemtogether.
Indicated for chronic severe secondaryMRwith LVEF between 20% and 50% for patients with
persistentsymptomsdespiteGDMTandappropriateanatomy(ClassIIa).
This recommendation comes from results of the COAPT trial demonstrating improvement in survival,symptoms,andqualityoflifeinselectedpatientswithmoderatetoseveresecondaryMR whounderwentTEERascomparedtomedicaltherapyalone.
7,8
TEERisalsoanoptionforpatientswithseverelysymptomaticwith primarysevereMRathighor prohibitivesurgicalriskwhohavefavorableanatomy(ClassIIa).
Transcatheter mitral valve replacement is an emerging structural intervention and currently being
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investigatedinanumberofclinicaltrials.Currently,thistechnologyisonlyreservedfordegenerative MR.
SurgicalManagement
PrimaryMR
2
SymptomaticwithchronicsevereprimaryMR(stageD)(ClassI). Asymptomatic withchronic severe primaryMRwithEF≤60% or LV end-systolicdimension≥40 mm(stageC2;ClassI). ChronicsevereprimaryMRundergoingcardiacsurgeryforotherindications(ClassI). Repairisrecommendedoverreplacement(ClassI). AsymptomaticpatientswithchronicsevereprimaryMR(stageC1)inwhomrepairishighlylikely (>95%)andoperativemortalityislow(<1%)(ClassIIa).
SecondaryMR
2
ClassIIa:chronicseveresecondaryMRundergoingcardiacsurgeryforotherindications. ClassIIb
SeverelysymptomaticpatientsdespiteGDMT(NYHAIII/IV)withchronicseveresecondaryMR
(stageD)andLVEF≥50%.
PatientswithpersistentsymptomswithchronicseveresecondaryMR(stageD)andLVEF<50%
whodonothavefavorableanatomyforTEER. NotethatthebenefitsofsurgeryarenotwellestablishedforsecondaryMR.
AorticRegurgitation
ARmayresultfrompathologyoftheaorticvalve,theaorticroot,orboth;itisimportantthatboththe aorticvalveandtheaorticrootareevaluatedtodeterminetheappropriatemanagementandtreatment. ARusuallyprogresses insidiouslywitha longasymptomatic period;whenitoccursacutely, patients areoftenverysickandmustbemanagedaggressively.
Etiology
Morecommon
Bicuspid aortic valve, rheumatic disease, calcific degeneration, infective endocarditis, idiopathic dilatationoftheaorta,myxomatousdegeneration,systemichypertension,dissectionoftheascending aorta,Marfansyndrome.
Lesscommon
Traumaticinjurytotheaorticvalve,collagenvasculardiseases(ankylosingspondylitis,rheumatoid arthritis, reactive arthritis, giant cell aortitis, and Whipple disease), syphilitic aortitis, discrete subaorticstenosis,ventricularseptaldefectwithprolapseofanaorticcusp.
AcuteAR
Infectiveendocarditis,dissectionoftheascendingaorta,trauma.
Pathophysiology
AcuteAR(Figure6-4)
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Figure 6-4  Acute aortic regurgitation.CO, cardiac output; HR, heart rate; LAP, left atrial pressure; LV, left ventricle;
LVEDP,leftventricularend-diastolicpressure;SV,strokevolume.
ChronicAR(Figure6-5)
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Figure 6-5  Chronic aortic regurgitation.CHF, congestive heart failure; CO, cardiac output; EF, ejection fraction; LV, left
ventricle;LVED,leftventricularend-diastolic;LVEDP,leftventricularend-diastolicpressure;LVH,leftventricularhypertrophy;
SV,strokevolume.
DIAGNOSIS
History
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Acute AR: patients with acute ARmay presentwith symptoms of cardiogenic shock and severe dyspnea.OtherpresentingsymptomsmayberelatedtothecauseofacuteAR. Chronic AR: symptoms dependonthepresence of LVdysfunction andwhether the patientis in the compensated versus decompensated stage. Compensated patients are typically asymptomatic,
whereas those inthe decompensated stage maynotedecreased exercise tolerance, dyspnea, fatigue, and/orangina.
PhysicalExamination
AcuteAR
Widened pulse pressure may be present, but it is often not present because forward SV (and thereforesystolicbloodpressure)isreduced. Mayhearbriefsoftdiastolicmurmurorsystolicflowmurmur. Look for evidenceofaortic dissection, infective endocarditis, andcharacteristics associated with Marfandisease.
ChronicAR
LVheave;pointofmaximalimpulseislaterallydisplaced. Diastolic decrescendomurmur heard best at leftsternal border leaning forward at end-expiration (severityofARcorrelateswithduration,notintensity,ofthemurmur). Systolicflowmurmur(mostlybecauseofvolumeoverload;concomitantASmayalsobepresent). Widenedpulse pressure (often >100 mm Hg)with a low diastolic pressure;there are numerous eponymsforthecharacteristicsignsrelatedtoawidepulsepressure.
DiagnosticTesting
ECG:tachycardia,LVH,andLAE(morecommoninchronicAR). CXR:pulmonaryedema,widenedmediastinum,andcardiomegaly. TTE
Assess LV systolic function, LV dimensions at end systole and diastole, leaflet number and morphology,assessmentoftheseverityofAR. Lookforevidenceofendocarditisoraorticdissection,dimensionofaorticroot.
TEE
ClarifywhetherthereisabicuspidvalveifunclearonTTE. BettersensitivityandspecificityforaorticdissectionthanTTE. ClarifywhetherthereisendocarditiswithorwithoutrootabscessifunclearonTTE. Bettervisualizationofaorticvalveinpatientswithaprostheticaorticvalve.
Cardiaccatheterization:assessmentofLVpressure,LVfunction,andseverityofAR(viaaorticroot angiography) is indicated in symptomatic patients in whom the severity of AR is unclear on noninvasiveimagingordiscordantwithclinicalfindings.
MRI/CT
Either ofthesemaybe the imagingmodalityofchoice for evaluating aortic dimensionsand/or for evaluationofaorticdissection. IfechocardiographyassessmentoftheseverityofARisinadequate,MRIisusefulforassessingthe severityofAR.
TREATMENT
TheroleofmedicaltherapyinpatientswithARislimited.
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Vasodilator therapy (i.e., nifedipine, ACE inhibitor, hydralazine) is indicated to reduce systolic bloodpressureinhypertensivepatientswithAR. Whenendocarditisissuspectedorconfirmed,appropriateantibioticcoverageiscritical.
SurgicalManagement
AHA/ACCrecommendationsforintervention
2
SymptomaticpatientswithsevereAR(stageD)regardlessofLVsystolicfunction(ClassI). Asymptomatic patientswith chronic severeARandLVsystolic dysfunction(EF≤55%) (stageC2; ClassI). PatientswithsevereAR(stageCorD)undergoingcardiacsurgeryforotherindications(ClassI). AsymptomaticpatientswithsevereARandnormalLVsystolicfunction(EF>55%)butwithsevere LVdilation(LVend-systolicdimension>50mm)(stageC2;ClassIIa).
Acute,severeARisalmostuniversallysymptomaticandistreatedsurgically.
If the aortic rootis dilated, itmay be repaired or replaced atthe time of AVR. For patients witha bicuspid valve, Marfan syndrome, or a related genetically triggered aortopathy, surgeryonthe aorta shouldbeconsideredatthetimeofAVR.
Outcome/Prognosis
Asymptomatic patients with normal LV systolic function (LVEF ≥55%): progression to symptoms and/orLVdysfunctionapproximately6%peryear.
9
AsymptomaticpatientswithLVdysfunction(LVEF<50%):progressiontocardiacsymptoms>25%per year.
9,10
Symptomaticpatients:mortalityrateapproximately9.4%peryear.
9
ProstheticHeartValves
The choice ofvalve prosthesis dependsonmany factors including thepatient,surgeon, cardiologist, andclinicalscenario. Withimprovementsinbioprostheticvalves,therecommendationforamechanicalvalveinpatients<65 yearsofageisnolongerasfirm,andbioprostheticvalveusehasincreasedinyoungerpatients.
Mechanicalvalves
Ball-and-cage(Starr–Edwards):rarely,ifever,usedtoday. Bileaflet(i.e.,St.Jude,Carbomedics):mostcommonlyused. Singletiltingdisk(i.e.,Björk–Shiley,MedtronicHall,Omnicarbon). Advantages of mechanical valve: structurally stable, long-lasting, relatively hemodynamically efficient(particularlybileaflet). Disadvantages of mechanical valve: need for anticoagulation/risk of bleeding, risk of thrombosis/embolismdespiteanticoagulation,severehemodynamiccompromise ifdiskthrombosis or immobility occurs(single tilting disk),riskofendocarditis, anticoagulationissuesinwomen of child-bearingage.
Bioprostheticvalves
Porcineaorticvalvetissue(i.e.,Hancock,Carpentier-Edwards) Bovinepericardialtissue(i.e.,Carpentier-EdwardsPerimount) Advantagesofbioprostheticvalve: noneedfor anticoagulation,low thromboembolismrisk,low
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riskofcatastrophicvalvefailure Disadvantages of bioprosthetic valve: structural valve deterioration, riskofendocarditis, still a small risk (approximately 0.04%–0.34% per year in meta-analysis) of thromboembolism without anticoagulation
11
Homograft(cadaveric):rarelyused;mostcommonlyusedtoreplacethepulmonicvalve
TREATMENT
Anticoagulation with a vitamin K antagonist (VKA) and international normalized ratio (INR) monitoringisrecommendedinpatientswithamechanicalprostheticvalve(ClassI).
2
Goal INR of 2.5 is recommended in patients with a mechanical AVR and no risk factors for thromboembolism.GoalINR3.0inpatientswithamechanical AVRandadditionalriskfactorsfor thromboembolic events (AF, previous thromboembolism, LV dysfunction, or hypercoagulable conditions)oranoldergenerationmechanicalAVR(suchasball-in-cage)(ClassI). GoalINR3.0inpatientswithamechanicalMVreplacement(ClassI). Aspirin in addition to VKA therapy for mechanical prosthetic valves is no longer routinely recommendedintheabsenceofotherindicationsforaspirintherapy. Aspirin 75–100 mg dailyis reasonable in all patients witha bioprosthetic aortic or mitral valve (ClassIIa).
Anticoagulanttherapywithoraldirectthrombininhibitorsoranti-Xaagentsshouldnotbeused inpatientswithmechanicalvalveprostheses(ClassIII).
Bridgingtherapyforprostheticvalves2:
Continuation of VKA anticoagulation with a therapeutic INR is recommended in patients with mechanical heart valves undergoing minor procedures (i.e., dental extractions) where bleedingis easilycontrolled(ClassI). Temporary interruption of VKA anticoagulation, without bridging agents while the INR is subtherapeutic,isrecommendedinpatientswithbileafletmechanicalAVRandnootherriskfactors forthrombosiswhoareundergoinginvasiveorsurgicalprocedures(ClassI). Bridging anticoagulation is reasonable for patients who are undergoing invasive procedures and have mechanical AVR with thromboembolic riskfactors, an older generation mechanical AVR, or mechanicalMVR(ClassIIa).
InfectiveEndocarditisinNativeorProstheticValves
Patientsatriskorwithsuspectedendocarditisshouldreceiveantibiotictherapyaftertwosetsofblood cultures(ClassI).
2
These patients should be evaluated for need and timing of surgery: early surgery is recommended (Class I) for those with valve dysfunction causing heart failure, resistant organisms (fungi, staphylococcus),heartblock/abscess,persistentinfection. Surgeryisalsorecommendedforrelapsingprostheticvalveendocarditis(ClassI).
2
Those with large mobile vegetations of the native valve and recurrent emboli canbe evaluated for earlysurgery(ClassII).
2
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ManagementofPregnantPatientswithProstheticHeart Valves(Figure6-6)
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Figure 6-6  Anticoagulation management in pregnant patients with prosthetic valves.INR, international normalized ratio;
LMWH,lowmolecular weightheparin.(ModifiedfromNishimuraRA,OttoCM,BonowRO,et al.2014AHA/ACC guideline
for the management of patients with valvular heart disease: executive summary. A report of the American College of
Cardiology/AmericanHeartAssociationtaskforceonpractice guidelines. JAmCollCardiol. 2014;63:2438-2488.Copyright©
2014AmericanHeartAssociation,Inc.,andtheAmericanCollegeofCardiologyFoundation.Withpermission.)
REFERENCES
1. ImazioM,BobbioM,CecchiE,etal.Colchicineinadditiontoconventionaltherapyforacute pericarditis.Circulation.2005;112:2012-2016.
2. OttoCM,NishimuraRA,BonowRO,etal.2020ACC/AHAguidelineforthemanagementof patientswithvalvularheartdisease:areportoftheAmericanCollegeofCardiology/American HeartAssociationJointCommitteeonclinicalpracticeguidelines.Circulation.2021;143:e72­e227.
3. LeonMB,SmithCR,MackM,etal.Transcatheteraortic-valveimplantationforaorticstenosisin patientswhoCannotundergosurgery.NEnglJMed.2010;363:1597-1607.
4. LeonMB,SmithCR,MackMJ,etal.Transcatheterorsurgicalaortic-valvereplacementin intermediate-riskpatients.NEnglJMed.2016;374:1609-1620.
5. SmithCR,LeonMB,MackMJ,etal.Transcatheterversussurgicalaortic-valvereplacementin high-riskpatients.NEnglJMed.2011;364:2187-2198.
6. ReardonMJ,MieghemNMV,PopmaJJ,etal.Surgicalortranscatheteraortic-valvereplacementin intermediate-riskpatients.NEnglJMed.2017;376:1321-1331.
7. StoneGW,LindenfeldJ,AbrahamWT,etal.Transcathetermitral-valverepairinpatientswith heartfailure.NEnglJMed.2018;379:2307-2318.
8. MackMJ,AbrahamWT,LindenfeldJ,etal.CardiovascularoutcomesassessmentoftheMitraClip inpatientswithheartfailureandsecondarymitralregurgitation:Designandrationaleofthe COAPTtrial.AmHeartJ.2018;205:1-11.
9. DujardinKS,Enriquez-SaranoM,SchaffHV,BaileyKR,SewardJB,TajikAJ.Mortalityand morbidityofaorticregurgitationinclinicalpractice.Circulation.1999;99:1851-1857.
10. MaurerG.Aorticregurgitation.Heart.2006;92:994.
11. PuriR,AuffretV,Rodés-CabauJ.Bioprostheticvalvethrombosis.JAmCollCardiol. 2017;69:2193-2211.
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7
CardiacArrhythmias
SandeepS.Sodhi,DanielH.Cooper,MitchellN.Faddis
Tachyarrhythmias
ApproachtoTachyarrhythmias
GENERALPRINCIPLES
Tachyarrhythmiasareencounteredinbothinpatientandoutpatientsettings. Recognitionandstepwiseanalysisoftheserhythmsfacilitateappropriatemanagement. Clinicaldecision-makingisguidedbypatientsymptomsandsignsofhemodynamicstability.
Definition
Cardiacrhythmswhoseventricularrateexceeds100beatsperminute(bpm).
Classification
BroadlyclassifiedintothefollowingbasedonthewidthoftheQRScomplexontheECG:
Narrow-complex tachyarrhythmia (QRS <120 ms): Arrhythmia originates within the atria (supraventriculartachycardia[SVT])andrapidlyactivatestheventriclesviaHis–Purkinjesystem. Wide-complex tachyarrhythmia (WCT) (QRS ≥120 ms): Arrhythmia originates withinthe ventricles anddoes notdependon the His–Purkinje system (ventricular tachycardia [VT]) or originatesin the atriaandtravelstotheventricleseitherviaanabnormalHis–Purkinjesystem(SVTwithaberrancy)or throughanaccessorypathway.
Etiology
Mechanismdividedintodisordersofimpulseconductionandimpulseformation
Disorders of impulse conduction: Reentry is the most common mechanism of tachyarrhythmias.
Reentrantmechanismcanoccurwhen differentialrefractoryperiods andconductionvelocitiesallow for propagation of an activation wavefront in a unidirectional manner around a zone of scar or refractorycardiactissue.Reentryoftheactivationwavefrontaroundamyocardialcircuitsustainsthe arrhythmia(e.g.,VT). Disordersofimpulseformation:Enhancedautomaticity(e.g.,acceleratedjunctionalandaccelerated idioventricularrhythm)andtriggeredactivity(e.g.,longQTsyndrome[LQTS]anddigitalistoxicity) areother,lesscommonmechanismsoftachyarrhythmias.
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