Ventricular Assist DevicesVentricular Assist Devices

Brian Schwartz, CCPBrian Schwartz, CCP

February 25, 2003February 25, 2003

Criteria for Ventricular Assist Criteria for Ventricular Assist DevicesDevices

• Cardiac Index < 2.0 L/m2/minCardiac Index < 2.0 L/m2/min

• SVR > 2,100 dyn/sec/cm2SVR > 2,100 dyn/sec/cm2

• Systolic Pressure < 80 mmHgSystolic Pressure < 80 mmHg

• Atrial Pressure > 20 mmHgAtrial Pressure > 20 mmHg

• Assisted (diuretics) Urine Output < Assisted (diuretics) Urine Output < 20 ml/hr20 ml/hr

• Metabolic AcidosisMetabolic Acidosis

Criteria for Ventricular Assist Criteria for Ventricular Assist DevicesDevices

• Failure to separate from CPBFailure to separate from CPB

• Irreversible cardiac injuryIrreversible cardiac injury

Short Term SupportShort Term Support

• Cardiopulmonary bypass Cardiopulmonary bypass Resuscitation Resuscitation – 15 % survival rate15 % survival rate– Immediately able to support patientImmediately able to support patient– Need to fully heparinize patientNeed to fully heparinize patient

• CPRCPR– Provides support temporarily Provides support temporarily

Devices Used to Assist the Devices Used to Assist the VentricleVentricle

(Moderate Setting)(Moderate Setting)• Intra-aortic balloon pumpIntra-aortic balloon pump

• Cardiopulmonary Support (CPS)Cardiopulmonary Support (CPS)

• Centrifugal Pump “Bio-Head”Centrifugal Pump “Bio-Head”

• Abiomed (BVS-5000) Bi-VadAbiomed (BVS-5000) Bi-Vad

Intra-aortic Balloon PumpsIntra-aortic Balloon Pumps

• The least complicated means of The least complicated means of circulatory assistancecirculatory assistance

• Effects of IABPEffects of IABP– Augmentation of Diastolic PressureAugmentation of Diastolic Pressure– Decrease AfterloadDecrease Afterload– Decrease myocardial oxygen Decrease myocardial oxygen

consumptionconsumption– Augments C.O. by 10% (500-800 cc/min)Augments C.O. by 10% (500-800 cc/min)

• Relatively inexpensive Relatively inexpensive

Intra-aortic Balloon PumpsIntra-aortic Balloon Pumps(Indications) (Indications)

• Cardiogenic shock following MICardiogenic shock following MI

• Unstable AnginaUnstable Angina

• Left Main Disease Left Main Disease

• Ventricular Dysrhythmias Ventricular Dysrhythmias

• Septic ShockSeptic Shock

Intra-aortic Balloon PumpsIntra-aortic Balloon Pumps(Contraindications) (Contraindications)

• AIAI

• Aortic AneurysmAortic Aneurysm

• Severe Femoral DiseaseSevere Femoral Disease

Cardiopulmonary Support Cardiopulmonary Support (CPS)(CPS)• Percutaneous insertionPercutaneous insertion

• Need oxygenator and heat exchangerNeed oxygenator and heat exchanger

• Cannulate both femoral artery and Cannulate both femoral artery and femoral veinfemoral vein

• Needs continuous monitoring, Needs continuous monitoring, therefore very labor intensivetherefore very labor intensive

• Maximum support…48 hoursMaximum support…48 hours

Centrifugal PumpCentrifugal Pump

• Easy to prime and set upEasy to prime and set up

• Requires continuous monitoringRequires continuous monitoring

• Kinetic assisted venous drainage Kinetic assisted venous drainage

• ACT’s around 180-200 secondsACT’s around 180-200 seconds

• Moderate costModerate cost

Abiomed Abiomed

• Quick set-upQuick set-up

• Minimal bedside monitoring Minimal bedside monitoring

• Supports large children and adultsSupports large children and adults

• Flow rates up to 5 L/MinFlow rates up to 5 L/Min

• Maximum use….1 weekMaximum use….1 week

• Patients are not mobilePatients are not mobile

• High costHigh cost

Long Term Devices for Long Term Devices for Ventricular SupportVentricular Support

• TCI ( Heartmate IP 1000) Pneumatic TCI ( Heartmate IP 1000) Pneumatic – LVAD onlyLVAD only

• TCI (VE) Vented Electric TCI (VE) Vented Electric – LVAD onlyLVAD only

• Novacor (N 100P) Electric Novacor (N 100P) Electric – LVAD onlyLVAD only

• Thoratec PneumaticThoratec Pneumatic– LVAD, RVAD, Bi-VADLVAD, RVAD, Bi-VAD

Heartmate Pneumatic LVADHeartmate Pneumatic LVAD

• Allows blood flows to exceed 10 liters Allows blood flows to exceed 10 liters per minuteper minute

• Inserted during CPBInserted during CPB

• Minimum BSA required…1.7Minimum BSA required…1.7

• Very costly to insertVery costly to insert

Heartmate Vented Electric Heartmate Vented Electric LVADLVAD

• Allows flows exceeding 10 litersAllows flows exceeding 10 liters

• Need CPB for placementNeed CPB for placement

• BSA requirement…greater than 1.7BSA requirement…greater than 1.7

• Patients are able to go homePatients are able to go home

• Minimal anti-coagulation Minimal anti-coagulation

• High costHigh cost

Total Artificial HeartTotal Artificial Heart

• CardioWest ( C-70 ) Pneumatic total CardioWest ( C-70 ) Pneumatic total artificial heartartificial heart– C.O. is approximately 7.0 L/MC.O. is approximately 7.0 L/M– BSA>1.7 BSA>1.7 – Need CPB for implantNeed CPB for implant– Native heart not excisedNative heart not excised– Need Anti-coagulation Need Anti-coagulation – Patient in-house but mobilePatient in-house but mobile

Total Artificial HeartTotal Artificial Heart

• Abiomed’s total artificial heartAbiomed’s total artificial heart– Still in clinical trialsStill in clinical trials– First patient lasted several months on First patient lasted several months on

devicedevice– If successful, will save hundreds of If successful, will save hundreds of

thousands of live because there will be thousands of live because there will be no waiting like the transplant listno waiting like the transplant list

Signs indicating Left Signs indicating Left Ventricular FailureVentricular Failure

• Decreased contractility Decreased contractility

• Elevated left ventricular filling Elevated left ventricular filling pressurespressures

• Elevated pulmonary capillary wedge Elevated pulmonary capillary wedge pressurespressures

• Decrease pulmonary oxygenation Decrease pulmonary oxygenation

Signs of Right Ventricular Signs of Right Ventricular FailureFailure

• Cardiac Index less than 1.8 L/min/m2Cardiac Index less than 1.8 L/min/m2

• Aortic pressure less than 90 mmHgAortic pressure less than 90 mmHg

• Atrial pressure greater than 20 Atrial pressure greater than 20 mmHgmmHg

• Pulmonary capillary wedge pressure Pulmonary capillary wedge pressure less than 10 mmHgless than 10 mmHg

Cannulation sites for LVAD’sCannulation sites for LVAD’s

• InletInlet– Left atrium Left atrium – Left ventricle Left ventricle – Left superior pulmonary veinLeft superior pulmonary vein

• OutletOutlet– AortaAorta

Cannulation sites for RVAD’sCannulation sites for RVAD’s

• InletInlet– Right atriumRight atrium

• OutletOutlet– Pulmonary arteryPulmonary artery

Heparin Management in Heparin Management in Patients with VAD’sPatients with VAD’s

• ACT’s are maintained around 180-ACT’s are maintained around 180-200 seconds…as long as the cardiac 200 seconds…as long as the cardiac output is above three liters per output is above three liters per minuteminute

• ACT’s are maintained above 300 ACT’s are maintained above 300 seconds while the cardiac output is seconds while the cardiac output is below three liters per minutebelow three liters per minute– WHEN IS THIS IMPORTANT???????WHEN IS THIS IMPORTANT???????

Discontinuing a VADDiscontinuing a VAD

• If possible, the heart is allowed to rest for If possible, the heart is allowed to rest for 48-72 hours48-72 hours

• Weaning the patient off the assist devices Weaning the patient off the assist devices is then performed. ( Patient needs to have is then performed. ( Patient needs to have a native C.I. of at least 2.2 L/min/m2)a native C.I. of at least 2.2 L/min/m2)

• ACT’s are increased to compensate for the ACT’s are increased to compensate for the low flowslow flows

• If the patient tolerates the low flows, If the patient tolerates the low flows, he/she is separated from the assist he/she is separated from the assist devices and the cannulae are removeddevices and the cannulae are removed

VAD Protocol for Your VAD Protocol for Your Institution Institution

• Know your protocolKnow your protocol

• Know your equipmentKnow your equipment

• Be able to predict those patients at riskBe able to predict those patients at risk

• Be able to prime in an orderly fashionBe able to prime in an orderly fashion

• Be prepared to assist the surgeons Be prepared to assist the surgeons

• Help educate all staff working with the Help educate all staff working with the patientpatient