Update on Long-term Ventricular Assist Devices Basel Ramlawi,MD, MMSc, FACS, FACC, FRCSC Co-Director, Methodist Aortic Network Cardiothoracic Surgery & Transplantation Methodist DeBakey Heart Center The Methodist Hospital Houston, TX
Basel Ramlawi, MD Bramlawi@TMHS.ORG
Heart Failure – Incidence / Stats • US Figures: – – – – –
400,000 new cases/year 5 Million living with HF diagnosis Most common diagnosis in patients > 65yrs. Annual cost $60 billion. Incidence increasing.
• In the last 20 years: – Death by MI has decreased by 30% – Death by heart failure has doubled
• Prognosis – 50% mortality within 5 years – NYHA III or IV 40% survival at 1 year.
First Ventricular Assist Device
• Product of Total Artificial Heart Program (Est. 1963) • Temporizing Measure Only
Heart Replacement Need
NUMBER OF HEART TRANSPLANTS REPORTED BY YEAR
2005 J Heart Lung Transplant 2005;24: 945-982
Ventricular Assist Devices
Surgical Intervention: VADs
Post-Cardiotomy Recovery Mechanical support for patients who are unable to be weaned from the cardio/pulmonary by-pass pump
Bridge-to-Transplantation Mechanical support of the heart for patients awaiting transplant Improve post-transplant outcomes
Bridge-to-Recovery Mechanical support allowing patients to recover sufficient myocardial function to allow device explantation
Destination Therapy (DT) Mechanical support for patients who are ineligible for cardiac transplantation due to age, malignancy or co-morbidities
Early Generation LVADs • Thoratec HeartMate(I) XVE
– REMATCH Study Group( N Engl J Med, 2001)
• Novacor LVAD
– InTrEPID Trial (J Am Coll Cardio,2007)
• Thoratec (Implantable Ventricular Assist Device) – IVAD Study Group (J Thorac Cardiovasc Surg,2007)
HeartMate XVE Pneumatic Displacement Pump
HeartMate II Axial Flow Pump
NEJM 2009
Improvement in Quality of Life
Patient Selection for LVAD Therapy Inotrope dependent? Hemodynamic criteria? “Optimal”
“Too Late”
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“Too Early” Disease progression
Death
Non-inotrope dependent? Acute, Catastrophic Event
Basel Ramlawi, MD Bramlawi@TMHS.ORG
Basel Ramlawi, MD Bramlawi@TMHS.ORG
Basel Ramlawi, MD Bramlawi@TMHS.ORG
Basel Ramlawi, MD Bramlawi@TMHS.ORG
Basel Ramlawi, MD Bramlawi@TMHS.ORG
Basel Ramlawi, MD Bramlawi@TMHS.ORG
Surgical Implant Procedure Pump Pocket
HM II Surgical Implant Procedure – Aortic Anastomosis
HM II Surgical Implant Procedure Aortic Anastomosis
Surgical Implant Procedure Inflow Conduit Placement • Point posteriorly toward mitral valve • Should not point toward septum or free wall – Partial occlusion of inflow conduit, leading to poor filling of the LVAD and possible thromboembolic complications
HM II Surgical Implant Procedure - LV Coring
HM II Surgical Implant Procedure - Apical Sewing Ring
HM II Surgical Implant Procedure Percutaneous Lead Placement
HM II Surgical Implant Procedure - De-airing
Continuous Flow, Rotary Pumps Smaller size – – – –
60% Smaller than XVE 35 mm diameter 70 mm long 400 grams
No requirement for venting ― 40% reduction in the size of percutaneous driveline
Patient comfort Quiet Ease of surgical implantation ― Standard sternotomy ― Smaller pre-peritoneal pocket
HeartMate II LVAS • Design – Valveless – Only one moving part, the rotor – Blood immersed bearings designed for minimization of blood damage – All motor drive and control electronics are outside of the implanted blood pump
• Two piece outflow conduit • Speed range: 6,000 to 15,000 rpm • Flow range: 3 – 10 L/min
Pump Rotor and Stators Flow
Outflow Stator
Inflow Stator
Rotor Outflow Bearing
Inflow Bearings
VAD Complications Bleeding
Embolism
Infection
MOF
Right-Heart Support w/ CentriMag RVAD
Driveline Infections
NEJM 2009
3rd Generation VADs Centrifugal Flow
The HeartWare Ventricular Assist System (3rd generation) ®
HVAD™ miniaturized implantable blood pump • 50cc, 140g, 2” outside diameter • Full circulatory support device designed for patients with a BSA >1.2m2 • Advanced Impeller is the only moving part Hybrid magnetic / hydrodynamic suspension Contact-less system
• Two motors designed to provide power redundancy • Thin (4.2 mm), flexible driveline constructed with pacemakers conductor wires
Pericardial Placement of HVAD™ Pump
• Ischemic Stroke 8% Hemorrhagic stroke 3%
Heartware DT Trial Primary Endpoint: The primary endpoint is stroke-free survival at 2 years.
Secondary endpoints:
1. Incidence of bleeding, per INTERMACS definition 2. Incidence of major infections, per INTERMACS definition 3. Time to death 4. Incidence of all device failures and device malfunctions per INTERMACS definition 5. Health Status improvement, as measured by KCCQ and EuroQol EQ-5D 6. Functional status improvement, as measured by NYHA and 6-minute walk
Jarvik 2000 Blood Pump Motor
Outflow Impeller
Inflow
EvaHeart LVAS
Options for Biventricular Failure •Heart Transplantation •LVAD and temporary RVAD •Long term BiVAD (extracorporeal) •Syncardia Total Artificial Heart
Thoratec pVADs biventricular solution
The SynCardia Total Artificial Heart • 79% bridge-to-human-heart transplant rate (Highest of any heart device) •
Over 900 implants account for more than 210 patient years on the Total Artificial Heart
•
Pneumatically powered through drivelines that connect to a driver
The SynCardia Total Artificial Heart replaces both Human Ventricles
Creatinine (mg/dL) Total Bilirubin (mg/dL)
3.0 2.5 2.0 1.5 1.0 0.5 0
5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0
Recovery Kidney
Out of Bed
100% 80% 60% 40% 20%
-1
2
5
8
11 14 35 56 77
0%
2
Time (days)
4
7
14
21
Days on Study
100%
Walking > 100 Feet
80%
Liver
60% 40% 20%
-1
2
5
8
11 14 35 56 77
Time (days)
0%
2
4
7
14
Days on Study
21
Circulite Synergy – Partial Support Device 4 L/min flow
Conclusions •
Long Term LVAD support (DT) rapidly gaining acceptance
•
Patient referral often “too late”
•
HMII LVAD still “gold standard” for BTT and DT
•
Investigational devices and future pump designs look promising
•
Syncardia TAH option for biventricular failure as bridge to transplant
What is coming? • Minimally-invasive implantation refinements • Apical anastomotic devices • Improved peripherals and monitoring
VAD Wish list • Infection Totally Implantable – Trans-cutaneous Energy Conduction
• Bleeding No anti-coagulation • Stroke Minimal Thrombo-embolism • Malfunction Durable / No friction • Small Size Potential for BiV Support Comfort Minimally Invasive
Thank you