Ventricular Assist Devices Brian Schwartz, CCP February 25, 2003

Criteria for Ventricular Assist Devices Cardiac Index < 2.0 L/m2/min Cardiac Index < 2.0 L/m2/min SVR > 2,100 dyn/sec/cm2 SVR > 2,100 dyn/sec/cm2 Systolic Pressure < 80 mmHg Systolic Pressure < 80 mmHg Atrial Pressure > 20 mmHg Atrial Pressure > 20 mmHg Assisted (diuretics) Urine Output < 20 ml/hr Assisted (diuretics) Urine Output < 20 ml/hr Metabolic Acidosis Metabolic Acidosis

Criteria for Ventricular Assist Devices Failure to separate from CPB Failure to separate from CPB Irreversible cardiac injury Irreversible cardiac injury

Short Term Support Cardiopulmonary bypass Resuscitation Cardiopulmonary bypass Resuscitation –15 % survival rate –Immediately able to support patient –Need to fully heparinize patient CPR CPR –Provides support temporarily

Devices Used to Assist the Ventricle (Moderate Setting) Intra-aortic balloon pump Intra-aortic balloon pump Cardiopulmonary Support (CPS) Cardiopulmonary Support (CPS) Centrifugal Pump “Bio-Head” Centrifugal Pump “Bio-Head” Abiomed (BVS-5000) Bi-Vad Abiomed (BVS-5000) Bi-Vad

Intra-aortic Balloon Pumps The least complicated means of circulatory assistance The least complicated means of circulatory assistance Effects of IABP Effects of IABP –Augmentation of Diastolic Pressure –Decrease Afterload –Decrease myocardial oxygen consumption –Augments C.O. by 10% ( cc/min) Relatively inexpensive Relatively inexpensive

Intra-aortic Balloon Pumps (Indications) Cardiogenic shock following MI Cardiogenic shock following MI Unstable Angina Unstable Angina Left Main Disease Left Main Disease Ventricular Dysrhythmias Ventricular Dysrhythmias Septic Shock Septic Shock

Intra-aortic Balloon Pumps (Contraindications) AI AI Aortic Aneurysm Aortic Aneurysm Severe Femoral Disease Severe Femoral Disease

Cardiopulmonary Support (CPS) Percutaneous insertion Percutaneous insertion Need oxygenator and heat exchanger Need oxygenator and heat exchanger Cannulate both femoral artery and femoral vein Cannulate both femoral artery and femoral vein Needs continuous monitoring, therefore very labor intensive Needs continuous monitoring, therefore very labor intensive Maximum support…48 hours Maximum support…48 hours

Centrifugal Pump Easy to prime and set up Easy to prime and set up Requires continuous monitoring Requires continuous monitoring Kinetic assisted venous drainage Kinetic assisted venous drainage ACT’s around seconds ACT’s around seconds Moderate cost Moderate cost

Abiomed Quick set-up Quick set-up Minimal bedside monitoring Minimal bedside monitoring Supports large children and adults Supports large children and adults Flow rates up to 5 L/Min Flow rates up to 5 L/Min Maximum use….1 week Maximum use….1 week Patients are not mobile Patients are not mobile High cost High cost

Long Term Devices for Ventricular Support TCI ( Heartmate IP 1000) Pneumatic TCI ( Heartmate IP 1000) Pneumatic –LVAD only TCI (VE) Vented Electric TCI (VE) Vented Electric –LVAD only Novacor (N 100P) Electric Novacor (N 100P) Electric –LVAD only Thoratec Pneumatic Thoratec Pneumatic –LVAD, RVAD, Bi-VAD

Heartmate Pneumatic LVAD Allows blood flows to exceed 10 liters per minute Allows blood flows to exceed 10 liters per minute Inserted during CPB Inserted during CPB Minimum BSA required…1.7 Minimum BSA required…1.7 Very costly to insert Very costly to insert

Heartmate Vented Electric LVAD Allows flows exceeding 10 liters Allows flows exceeding 10 liters Need CPB for placement Need CPB for placement BSA requirement…greater than 1.7 BSA requirement…greater than 1.7 Patients are able to go home Patients are able to go home Minimal anti-coagulation Minimal anti-coagulation High cost High cost

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

Total Artificial Heart Abiomed’s total artificial heart Abiomed’s total artificial heart –Still in clinical trials –First patient lasted several months on device –If successful, will save hundreds of thousands of live because there will be no waiting like the transplant list

Signs indicating Left Ventricular Failure Decreased contractility Decreased contractility Elevated left ventricular filling pressures Elevated left ventricular filling pressures Elevated pulmonary capillary wedge pressures Elevated pulmonary capillary wedge pressures Decrease pulmonary oxygenation Decrease pulmonary oxygenation

Signs of Right Ventricular Failure Cardiac Index less than 1.8 L/min/m2 Cardiac Index less than 1.8 L/min/m2 Aortic pressure less than 90 mmHg Aortic pressure less than 90 mmHg Atrial pressure greater than 20 mmHg Atrial pressure greater than 20 mmHg Pulmonary capillary wedge pressure less than 10 mmHg Pulmonary capillary wedge pressure less than 10 mmHg

Cannulation sites for LVAD’s Inlet Inlet –Left atrium –Left ventricle –Left superior pulmonary vein Outlet Outlet –Aorta

Cannulation sites for RVAD’s Inlet Inlet –Right atrium Outlet Outlet –Pulmonary artery

Heparin Management in Patients with VAD’s ACT’s are maintained around seconds…as long as the cardiac output is above three liters per minute ACT’s are maintained around seconds…as long as the cardiac output is above three liters per minute ACT’s are maintained above 300 seconds while the cardiac output is below three liters per minute ACT’s are maintained above 300 seconds while the cardiac output is below three liters per minute –WHEN IS THIS IMPORTANT???????

Discontinuing a VAD If possible, the heart is allowed to rest for hours If possible, the heart is allowed to rest for hours Weaning the patient off the assist devices is then performed. ( Patient needs to have a native C.I. of at least 2.2 L/min/m2) Weaning the patient off the assist devices is then performed. ( Patient needs to have a native C.I. of at least 2.2 L/min/m2) ACT’s are increased to compensate for the low flows ACT’s are increased to compensate for the low flows If the patient tolerates the low flows, he/she is separated from the assist devices and the cannulae are removed If the patient tolerates the low flows, he/she is separated from the assist devices and the cannulae are removed

VAD Protocol for Your Institution Know your protocol Know your protocol Know your equipment Know your equipment Be able to predict those patients at risk Be able to predict those patients at risk Be able to prime in an orderly fashion Be 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 patient Help educate all staff working with the patient