Mechanics of Cath Lab Support Devices Issam D. Moussa, MD Professor of Medicine Mayo Clinic College of Medicine Chair, Division of Cardiovascular Diseases Mayo Clinic Jacksonville, Florida
DISCLOSURE Presenter: ISSAM D. MOUSSA, M.D. Grant/Research: Medtronic, Baxter, Gilead
Percutaneous Circulatory Support Percutaneous circulatory support Objectives Mechanics Devices
Percutaneous Circulatory Support Objectives Augmentation of the cardiac output to support end organ perfusion Reduce the work of the native LV to provide rest as a therapy
Measuring Performance in Circulatory Support Pressure and volume inside the left ventricle can be measured during the cardiac cycle with a conductance catheter These measurements are then plotted against one another to form a loop
Measuring Performance in Circulatory Support The area inside the resulting PV loop is equal to the work being done by the heart in a single cardiac cycle Smaller area inside the PV loop means less work being done by the LV
Cardiac Power The Most Important Predictor of Mortality in the SHOCK Trial
Measuring Performance in Circulatory Support The Pressure Volume Area Represents the total mechanical energy generated by ventricular contraction PVA = Stroke Work (SW) + Potential Energy (PE)
Calculating Total Pressure Volume Area The PV loop can be used to calculate PVA SW + PE = PVA
Calculating Total Pressure Volume Area Stroke Work (SW) is equal to the area inside the PV Loop SW + PE = PVA
Calculating Total Pressure Volume Area To calculate Potential Energy (PE), we use Pressure Volume Relationships: ESPVR = End Systolic Pressure Volume Relationship An index of myocardial contractility EDPVR = End Diastolic Pressure Volume Relationship An index of ventricular compliance SW + PE = PVA
Calculating Total Pressure Volume Area The area of the resulting triangle is equal to Potential Energy (PE) SW + PE = PVA
Calculating Total Pressure Volume Area The combined areas of SW and PE is equal to Pressure Volume Area (PVA) Larger PVA = More Myocardial Oxygen Consumption (MVO 2 ) Smaller PVA = Less Myocardial Oxygen Consumption (MVO 2 ) SW + PE = PVA
Calculating Total Pressure Volume Area A rightward shift of the PV Loop, or an increase in End Systolic Volume, will cause an increase in PE, even if the size of the PV loop remains the same. SW + PE = PVA
Percutaneous Circulatory Support Devices Intra aortic balloon pump (IABP) Volume displacement Intracorporeal transvalvular ventricular-to-aortic pumping (e.g., Impella, Abiomed). Axial pump Left atrial-to-arterial pumping (e.g., TandemHeart, Cardiac Assist) Centrifugal pump
IABP Augmentation of diastolic pressure Increase coronary perfusion Increase myocardial oxygen supply Inflation Diastole Deflation Systole Decrease cardiac work Decrease afterload Increase cardiac output
Impella 2.5 System
Impella CP TM 17 Increased Cardiac Power Speed of the Cath Lab Percutaneous implant 9 Fr catheter / 14 Fr pump Compatible with 14 Fr sheath Abiomed peel-away (Oscor) Cook 30cm, 14Fr
Impella CP TM Impella 2.5 Comparison Impella 2.5 Impella CP Mean Flow Rate 2.3 to 2.5 3.3. to 3.5 (at P9) (L/min, max) Catheter Size 9 Fr 9 Fr Pump Size 12 Fr 14 Fr Insertion Method Percutaneous via 13 Fr Introducer Sheath Percutaneous via 14 Fr Introducer Sheath Guidewire Placement Measurement Cannula Geometry 0.018 Silicone Wire Fluid filled Pressure Lumen Curved, Pigtail RPM 51,000 46,000 P-level P1 P9 (Boost P1 P9 Mode) 0.018 PTFE Wire Fluid filled Pressure Lumen Curved, Pigtail
How the System Works: The TandemHeart Transseptal Cannula Withdraws oxygenated blood from the left atrium via a transseptal cannula; returns to the femoral artery. Creates an extracorporeal circuit that completely bypasses the left ventricle, our target for work reduction.
How the System Works: The TandemHeart Centrifugal Pump Centrifugal pump provides up to 5 liters per minute of forward flow in a percutaneous configuration. Provides uniform flow and full pressure rise support across a wide range of operating conditions.
TandemHeart PV Loop Performance The combination of left atrial cannulation with a high flow centrifugal pump enables up to 80% work reduction On File, Cardiac Assist, Inc.
Work Capability of Circulatory Support Devices On File, Cardiac Assist, Inc.
Percutaneous Circulatory Support Devices Device Mechanism Hemodynamic Impact IABP Pressure Augmentation Increased diastolic, decreased systolic aortic pressure, decreased PCWP, no active flow Tandem Heart LA -------- Aorta Indirectly unloads LV by decompressing LA, Up to 4 L/Min flow (retrograde) Impella LV----------Aorta Directly unloads LV, up to 2.5 L/Min flow (antegrade)