Advances in LVAD Design

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Advances in LVAD Design

• Improving Reliability and Minimizing Risk of
  Stroke Thrombosis

Steve Reichenbach, PhD Senior Director,
Technology Development Thoratec Corporation
J100-1111
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Key Objectives In LVAD DesignImplications For
HeartMate II

• Maximize reliability
• Minimize stroke complications and thrombus
  formation
• Minimize infection risk
• Reduce device size
• Reduce anticoagulation requirements
• Enable return to highly active lifestyle

HeartMate II LVAS 6,000 Implants Worldwide
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HeartMate IIDesigned For Extended Reliability

• Elegant design and configuration
• Precision engineering
• Design targeting more than 10 years of support
• 30 years of clinical experience reflected in the
  design
• More than 6,000 HeartMate II patients implanted
  worldwide
• Longest ongoing patient supported more than 6
  years and 60 patients more than 4 years

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HeartMate IIDesigned For Extended Reliability

• Redundant circuitry of the percutaneous lead and
  system controller provides backup if there is a
  problem with the primary source
• Lithium-ion batteries provide a full work day of
  support (1014 hours) on a single charge and are
  designed to last up to 3 years before replacement
• Reliability of percutaneous lead design
  continuously refined through extensive clinical
  trial data and feedback over thousands of implants

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HeartMate IIDesigned For Highly Washed Flow Path
And Low Rates Of Stroke Pump Thrombosis

• Rotor speed typically set between 8,000 and
  10,000 RPM and capable of pumping up to 10 liters
  of blood per minute.
• A single moving part combined with open flow
  paths help to optimize the blood flow.
• Flow dynamics designed to maximize washing and
  minimize the risk of thrombus stasis formation
  and stroke.
• Flow design maintains integrity of blood cells.

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HeartMate IIDesigned For Low Rates Of Stroke And
Pump Thrombosis Over Extended Periods

• Blood-immersed ruby bearings designed for ultra
  long-lifeanalysis of explanted pumps indicates
  an excess of 17 years with an average expected
  life of 60 years.
• No bearing failures in the 6,000 worldwide
  patient experience.
• High-precision bearing / cup design enables
  plasma to serve as lubricant while dissipating
  heat, avoiding damage to red blood cells and
  preventing thrombus formation.

Reichenbach SH. Negligible bearing wear in
explanted HeartMate II LVADs following clinical
support for up to 4 years. Paper presented at
Annual Meeting of the International Society for
Rotary Blood Pumps 2010 October 1416, 2010
Berlin, Germany.
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Benefits Of Textured Surfaces

• Most LVADs have been designed with smooth
  interior surfaces in an effort to minimize sites
  for thrombus nucleation yet the frequency of
  thromboembolic complications associated with
  LVADs has been reported to be as high as 29.
• Thoratec began evaluating textured surfaces for
  LVAD applications more than 3 decades ago and
  refined its application over that period.
• Textured surfaces in select areas of the device
  encourage a dense, adherent pseudo-neointima,
  thereby eliminating the direct interface between
  prosthetic material and blood elements, reducing
  the risk of thromboembolic complications.

Textured Surfaces
Rose EA, Lewis HR, Oz MC, et al. Artificial
circulatory support with textured interior
surfaces a counterintuitive approach to
minimizing thromboembolism. Circulation.
19949087-91. Zapanta CM, Griffith JW, Hess
GD, et al. Microtextured materials for
circulatory support devices preliminary studies.
ASAIO J. 200652(1)17-23.
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HeartMate IIDesigned For Low Rates Of Stroke And
Pump Thrombosis Over Extended Periods
HeartMate II uses customized texturing that has
been refined and proven throughout decades of
clinical experience.

• Rose et al. found that despite the low levels in
  anticoagulation (including patients with no
  anticoagulation regimen), only 3.5 of patients
  had thromboembolic complications with the
  first-generation HeartMate that incorporated
  Thoratecs customized texturing process.
• The study concluded that this specific
  application of sintered titanium surfaces can be
  used for prolonged periods with limited TE
  complications despite minimal anticoagulation.
• Due to the benefits observed with the use of
  textured surfaces in the first-generation
  HeartMate, they have been incorporated into the
  HeartMate II design.

HeartMate II Inflow Conduit
Rose EA, Lewis HR, Oz MC, et al. Artificial
circulatory support with textured interior
surfaces a counterintuitive approach to
minimizing thromboembolism. Circulation.
19949087-91.
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HeartMate IIDesigned For Low Rates Of Stroke
Pump Thrombosis Over Extended Periods

• Flex section consists of a knitted polyester
  graft that is reinforced and covered with a
  silicone sleeve.
• Flexibility allows for relative movement between
  the native left ventricle and the LVAD
• Maintains an open flow path
• Accommodates reverse remodeling of the heart over
  time while maintaining cannula position inside
  left ventricle
• Prevents misalignment against ventricular wall
• Helps avoid suckdown events
• Suction detection algorithm
• Detects suction events and automatically adjusts
  pump speed
• Intended to prevent suckdown events which
  subsequently might cause ventricular arrhythmias,
  flow interruption, or damage to the left ventricle

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Low Rates of Stroke and Pump Thrombosis With The
HeartMate II
Boyle AJ, Russell SD, Teuteberg JJ, et al. Low
thromboembolism and pump thrombosis with the
HeartMate II left ventricular assist device
analysis of outpatient anticoagulation. J Heart
Lung Transplant. 200928881-7.
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Low Rates Of Stroke Pump Thrombosis With The
HeartMate II
HeartMate II Bridge-to-Transplantation Clinical
Trial Experience

• In 331 patients discharged on support
• 2.4 had ischemic stroke
• 0.9 had pump thrombosis
• 2.1 suffered from hemorrhagic stroke

This study also concluded that the INR range
should target between 1.5 to 2.5 to minimize the
risk of hemorrhagic events.
Boyle AJ, Russell SD, Teuteberg JJ, et al. Low
thromboembolism and pump thrombosis with the
HeartMate II left ventricular assist device
analysis of outpatient anticoagulation. J Heart
Lung Transplant. 200928881-7.
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Low Rates Of Stroke Pump Thrombosis With The
HeartMate II

• No pump replacements through the first 6 months
  of HeartMate II support
• Low ischemic and hemorrhagic stroke rates

HeartMate II Bridge-to-Transplantation Commercial
Study Experience
HeartMate II Left Ventricular Assist System
instructions for use 105747. Pleasanton,
Calif. Thoratec Corp October, 2010.
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HeartMate IIProven Technology

• HeartMate II provides efficacy and reliability
  through simplicity of design with a single moving
  part, open blood flow paths, durable bearings and
  compliant inflow conduit to accommodate reverse
  remodeling of the heart.
• HeartMate II has the lowest published rates of
  stroke and pump thrombosis of any continuous-flow
  LVAD.
• HeartMate II has the lowest published
  anticoagulation regimen for continuous-flow
  LVAD therapy.
• HeartMate II offers excellent reliability, proven
  in more than 6,000 implanted patients worldwide.

Based on published data from multicenter
experience and separate studies, which may
involve different patient populations and other
variables. Please refer to the HeartMate II
Instructions for Use about indications,
contraindications, adverse events, warnings, and
precautions (http//www.thoratec.com/medical-profe
ssionals/resource-library/ifus-manuals/heartmate-l
l-lvad.aspxlevelFour).
Boyle AJ, Russell SD, Teuteberg JJ, et al. Low
thromboembolism and pump thrombosis with the
HeartMate II left ventricular assist device
analysis of outpatient anticoagulation. J Heart
Lung Transplant. 200928881-7. Slaughter MS,
Pagani FD, Rogers JG, et al. Clinical management
of continuous-flow left ventricular assist
devices in advanced heart failure. J Heart Lung
Transplant. 201029S1-39.