The (R)evolution of Mechanical Circulatory Support

Extracorporeal Membrane Oxygenation (ECMO): Indications and Management StrategyDavid Spielvogel, MDSurgical Director, Cardiac Transplant and Mechanical Circulatory SupportGilbert Tang, MD, MSc, MBACardiothoracic Surgeon, Transcatheter Heart Program

On behalf of the Cardiac Transplant and Mechanical Circulatory Support TeamWestchester Medical Center, Valhalla, New York

OBJECTIVESUnderstand the clinical indications for ECMO therapyIdentify procedural strategies and techniques of ECMO therapyDiscuss management strategy of ECMO in the ICUDescribe the ECMO experience at Westchester Medical CenterPHYSIOLOGY of ECMOBasic principle: De-saturated blood is drained via a venous cannula, CO2 is removed, O2 added through an extracorporeal device (an oxygenator), and the blood is then returned to systemic circulation via another vein (VV ECMO) or artery (VA ECMO) VV ECMOPerfusate blood returned to systemic circulation via venous cannula travels into right ventricle and next pulmonary vasculature and is returned to the systemic circulation

Volume removed = volume returned; therefore no net effect on CVP, ventricular filling, or hemodynamics

CO2/O2 content in arterial blood supply is that of the blood arriving to right ventricle + any effects from gas exchange from remaining pulmonary function VA ECMOReplaces/augments both pulmonary and cardiac functionPerfusate mixes in the aorta with blood from left ventricle (arriving from compromised lungs); thus O2/CO2 content = content of blood returning from the circuit + that of pulmonary source;Systemic blood flow = ECMO flow + pts own CORole of ECMO in Cardiogenic ShockBridge to recovery (BTR)Bridge to decision (BTD)Bridge to surgeryBridge to long-term VADBridge to transplant (BTT)IABP in Cardiogenic ShockCan initially stabilize patientMay not provide enough supportRequires a certain level of LV functionLimited by persistent tachycardia / arrhythmiasDoes not unload the RV

Provides some pulsatile flow with ECMO BRIDGE TO RECOVERYIndicationsAcute MIAcute decompensated HFPost-cardiotomy syndromeAcute myocarditisSevere rejection in transplantTakotsubosMassive PERespiratory failure and ARDS88 BRIDGE TO SURGERYIndicationsMechanical complications of AMIVSDSevere MR from papillary muscle ruptureCAD requiring CABGMassive PE with heparin failure

99 BRIDGE TO Long-term VADIndicationsUnable to wean off ECMODifficult donor match for transplantNot a transplant candidate => LVAD as Destination Therapy1010 BRIDGE TO TRANSPLANTIndicationsUnable to wean off ECMOTransplant candidateEasy donor match for transplant1111Predictors of Poor OutcomesMultiorgan dysfunctionARDS with sepsisSevere neurological injuryLong time interval between shock and initiating ECMO1212CONTRAINDICATIONSMajor CNS injurySevere anoxiaEmbolic or hemorrhagic strokeIntracerebral hemorrhageMultiorgan failureMetastatic diseaseOverwhelming sepsisECMO: How to do itTWO TYPES OF ECMO:Veno-arterial bypass - supports the heart and lungsVeno-venous bypass supports the lungs only

ECMO The Recent Past

Centrimag-ECMO

Equipment: CannulasVV ECMO:Jugular vein, femoral vein

VA ECMOVein: femoralArtery:FemoralAxillaryAorta

Equipment: Pump, OxygenatorThoratec Centrimag pump & motorCentrimag consoleMaquet Quadrox oxygenator

CENTRIMAG QUADROXOXYGENATORIABPPA CatheterVenous: percutaneousArterial:Femoral percutaneousAxillary graftAorta direct

R axillary arteryR femoral veinAxillary vs Femoral CannulationAXILLARYFEMORALSide-arm graft sewn onAntegrade perfusion better for cerebral and aortic root oxygenation, especially when lungs not oxygenatingIncreased afterloadRisk of arm hyper-perfusionPercutaneousNeed antegrade stick for forward perfusionRetrograde perfusion increases atheroembolic riskAd-mixing with cardiopulmonary circulation => indequate cerebral and aortic root oxygenation if lungs not oxygenatingCheck arterial line pressure!High line pressure risks hyperperfusion and bleeding at axillary siteNeed to Y the arterial outflow:Bi-axillaryAxillary + femoralIndicationsPatients with large BSASmall axillary artery

ECMO ManagementAnticoagulationIV Heparin, target ACT of 200-240 seconds to prevent clotting upon interference of blood with prosthetic surfaces and in stagnant areas.

If high bleeding risk, ACT 180-220 s

Watch for platelet drop and heparin induced thrombocytopenia (HIT)Monitoring an ECMO patientContinuous cerebral SaO2CVP, PAP, COCXR assess pulmonary edemaSvO2: 75% in VA ECMO and 85-90% on VV ECMO considered adequate as long as CO normalEtCO2 measures return of native lung functionaBG, lactate tissue perfusionUrine output, fluid balance renal functionLabs: renal, hepatic functionPlatelet count

POTENTIAL RISKSInfectionBleedingBrainSurgical siteNon-pulsatile flowRenal insufficiencyPeripheral ischemiaLimb complicationsArm hyperperfusionLeg ischemiaAir in circuitPump malfunctionClots in the circuitsHeat exchanger malfunctionCannula dislodgementCriteria for Weaning ECMOPulmonary edema resolvedMinimal inotropes / pressorsEnd-organ dysfunction nearly recoveredECMO Weaning ProtocolICUECMO flow down to 1-1.5 L/min for 5 minAssess CVP, PAP, COTTE to assess LV, RV functionOR3000-5000 U heparinECMO flow down to 1 L/minAssess CVP, PAP, COTEE to assess LV, RV function, septal positionExplant ECMO if appropriateSpecial Note on ECMO & LVADPts with LVAD need to balance flow with both LVAD and ECMO to optimize end-organ perfusionTEE to check septal position, need to unload RVAfter ECMO explant, LVAD flow needs to increase b/c of LV preload increasesWestchester ECMO Experience

Patient CharacteristicsN = 21 (%)Age (mean +/- SD)61 +/- 14 yearsFemale7 (33%)Renal failure1 (5%)COPD2 (10%)PVD4 (19%)TIA / Stroke2 (10%)History of MI16 (76%)History of CHF8 (38%)Cardiogenic shock21 (100%)Prior PCI11 (52%)Prior CABG4 (19%)Ventricular tachycardiac/fibrillation11 (52%)Cardiac arrest requiring resuscitation10 (48%)IABP or Impella support prior to ECMO21 (100%)Predicted mortality from APACHE 4 score (mean +/- SD)38 +/- 16% - Catheterization laboratory45 +/- 16% - Operating room36 +/- 16% ACS Shock on ECMO at WMCImplant DataN = 21 (%)Location of ECMO implant: - Catheterization laboratory7 (33%) - Operating room14 (67%)Site of arterial outflow: - Percutaneous femoral (all placed in cath lab)7 (33%) - Axillary (all placed in OR)14 (67%)Duration of support (mean +/- SD)9.0 +/- 7.5 daysOUTCOMES30-day all-cause mortality5 (24%)30-day mortality by location of ECMO implant: - Catheterization laboratory4/7 (57%) - Operating room1/14 (7%)ECMO as bridge to: - Recovery9 (43%) - CABG5 (24%) - LVAD / Transplantation2 (10%)Prolonged ventilation10 (48%)Pneumonia3 (14%)Renal failure1 (5%)Stroke1 (5%)Irreversible neurological injury2 (10%)Multiorgan failure1 (5%)Bleeding2 (10%)Vascular injury0 (0%)CONCLUSIONSRapidly evolving technologyIncreasing array of indicationsExcellent tool for ACS with cardiogenic shockShifting the paradigm of bridge to recoveryPresently investigating the science behind the clinical results