Influence of Slippery Pacemaker Leads on Eccentric lead ...€¦ · Influence of Slippery Pacemaker...
Transcript of Influence of Slippery Pacemaker Leads on Eccentric lead ...€¦ · Influence of Slippery Pacemaker...
Influence of Slippery Pacemaker Leads on Lead-Induced Venous Occlusion
Introduction
Introduction
! Pacemakers are used to treat arrhythmias.! Pacemaker implantation: between 1993-2009, 2.9 M patients in US! Complications: Infection, haemothorax, lead dislodgement, lead
failure, venous occlusion...! Venous occlusion: 15-30% for adults and 20% for children
! Symptomatic: 1-3%! Challenges arise with system revision or upgrade.
http://www.nhlbi.nih.gov
Stanford University Introduction 2 / 9
Introduction
! Does lead size matter? Maybe.
! Small-diameter lead: increased rate of lead failure
! Simulations show flow stasis is concentrated around leads.! What if slippery?
! Pitcher plant inspired omniphobic surface coating (SLIPS)
Leslie et al., Nature Biotechnology, 2014
Stanford University Introduction 3 / 9
Computational Approach
r · u = 0
uk = �n · � · (I� nn)/µ
@⌧
@t+ u ·r⌧ �r · r⌧ = H
⇢
✓@u
@t+ u ·ru
◆= r · �
Methods
! Navier-Stokes equations:
ρ(u,t + u · ∇u) − ∇ · σ = 0, (1)
∇ · u = 0, (2)
where σ = −pI + µ(∇u + ∇(u)T ).! Slip boundary conditions:
n · u = 0 on Γslip, (3)
t · σ(u, p) · n = βt · u on Γslip, (4)
b · σ(u, p) · n = βb · u on Γslip (5)
! Slip length: Lslip = µβ .
! Implemented in Simvascular package! Stabilized finite element formulation (SUPG),! Linear finite element for space discretization! Generalized α method for time integration
Stanford University Methods 4 / 9
Validation
Eccentric Cylinders
Eccentric lead
! Three positions are simulated: h = 0.55, 0.41 and 0.26 cm.
! Slippery coating reduces flow stasis between lead and vessel wall.
h
Stanford University Results 7 / 9
Eccentric lead
! Three positions are simulated: h = 0.55, 0.41 and 0.26 cm.
! Slippery coating reduces flow stasis between lead and vessel wall.
h
Stanford University Results 7 / 9
Eccentric lead
! Three positions are simulated: h = 0.55, 0.41 and 0.26 cm.
! Slippery coating reduces flow stasis between lead and vessel wall.
h
Stanford University Results 7 / 9
Eccentric lead
! Three positions are simulated: h = 0.55, 0.41 and 0.26 cm.
! Slippery coating reduces flow stasis between lead and vessel wall.
h
Stanford University Results 7 / 9
Eccentric lead
! Three positions are simulated: h = 0.55, 0.41 and 0.26 cm.
! Slippery coating reduces flow stasis between lead and vessel wall.
h
Stanford University Results 7 / 9
Patient-specific Simulation
Conclusions �
�
Leslie et al., Nature Biotechnology, 2014
1. Slippery surfaces 2. Lead-induced occulsions
3. Simulation and comparison 4. Patient specific modeling
Stanford University Conclusions 9 / 9
Conclusions �
�
Leslie et al., Nature Biotechnology, 2014
1. Slippery surfaces 2. Lead-induced occulsions
3. Simulation and comparison 4. Patient specific modeling
Stanford University Conclusions 9 / 9
Anatomy realistic cases
! A 3-4 year old patient (pulsatile inflow, resistance outlet)! Residence time: ∂τ
∂t + u · ∇τ − ∇ · κ∇τ = H (Esmaily Moghadamet al.,Phys Fluids, 2013)
AB
C
noslip slip
noslip slipnoslip slip
Vel
RT
Vel
RT
Vel
RT
Stanford University Results 8 / 9
Anatomy realistic cases
! A 3-4 year old patient (pulsatile inflow, resistance outlet)! Residence time: ∂τ
∂t + u · ∇τ − ∇ · κ∇τ = H (Esmaily Moghadamet al.,Phys Fluids, 2013)
AB
C
noslip slip
noslip slipnoslip slip
Vel
RT
Vel
RT
Vel
RT
Stanford University Results 8 / 9
Anatomy realistic cases
! A 3-4 year old patient (pulsatile inflow, resistance outlet)! Residence time: ∂τ
∂t + u · ∇τ − ∇ · κ∇τ = H (Esmaily Moghadamet al.,Phys Fluids, 2013)
AB
C
noslip slip
noslip slipnoslip slip
Vel
RT
Vel
RT
Vel
RT
Stanford University Results 8 / 9
Concentric lead
! Analytical solution is given by
v(r) = Q(R2
0−R2
i)π
×1+4c ln(r/R0)−(r/R0)2
1−4c[1/2+b2 ln b/(1−b2)]−(1+b2)/2 , where
b = Ri/Ro, c = b(1−b2+2bλ)4(λ−b ln b) , λ =
Lslip
Ro.
! Simulation setting: Q = 16cc/s, Ro = 0.55cm, Ri = 0.117cm
Stanford University Results 6 / 9
Concentric lead
! Analytical solution is given by
v(r) = Q(R2
0−R2
i)π
×1+4c ln(r/R0)−(r/R0)2
1−4c[1/2+b2 ln b/(1−b2)]−(1+b2)/2 , where
b = Ri/Ro, c = b(1−b2+2bλ)4(λ−b ln b) , λ =
Lslip
Ro.
! Simulation setting: Q = 16cc/s, Ro = 0.55cm, Ri = 0.117cm
Stanford University Results 6 / 9
Concentric lead
! Analytical solution is given by
v(r) = Q(R2
0−R2
i)π
×1+4c ln(r/R0)−(r/R0)2
1−4c[1/2+b2 ln b/(1−b2)]−(1+b2)/2 , where
b = Ri/Ro, c = b(1−b2+2bλ)4(λ−b ln b) , λ =
Lslip
Ro.
! Simulation setting: Q = 16cc/s, Ro = 0.55cm, Ri = 0.117cm
Stanford University Results 6 / 9
�/R0 = 10
�/R0 = 1
�/R0 = 0.1�/R0 = 0
V [cm/s]
S. Bhatia, D. Obenauf, O. S. Pak Department of Mechanical Engineering
Santa Clara University
W. Yang, M. Esmaily-Moghadam, J. Feinstein Department of Pediatric Cardiology and Mechanical Engineering
Stanford University
Introduction
! Pacemakers are used to treat arrhythmias.! Pacemaker implantation: between 1993-2009, 2.9 M patients in US! Complications: Infection, haemothorax, lead dislodgement, lead
failure, venous occlusion...! Venous occlusion: 15-30% for adults and 20% for children
! Symptomatic: 1-3%! Challenges arise with system revision or upgrade.
http://www.nhlbi.nih.gov
Stanford University Introduction 2 / 9
Introduction
! Pacemakers are used to treat arrhythmias.! Pacemaker implantation: between 1993-2009, 2.9 M patients in US! Complications: Infection, haemothorax, lead dislodgement, lead
failure, venous occlusion...! Venous occlusion: 15-30% for adults and 20% for children
! Symptomatic: 1-3%! Challenges arise with system revision or upgrade.
http://www.nhlbi.nih.gov
Stanford University Introduction 2 / 9
Introduction
! Pacemakers are used to treat arrhythmias.! Pacemaker implantation: between 1993-2009, 2.9 M patients in US! Complications: Infection, haemothorax, lead dislodgement, lead
failure, venous occlusion...! Venous occlusion: 15-30% for adults and 20% for children
! Symptomatic: 1-3%! Challenges arise with system revision or upgrade.
http://www.nhlbi.nih.gov
Stanford University Introduction 2 / 9
Introduction
! Pacemakers are used to treat arrhythmias.! Pacemaker implantation: between 1993-2009, 2.9 M patients in US! Complications: Infection, haemothorax, lead dislodgement, lead
failure, venous occlusion...! Venous occlusion: 15-30% for adults and 20% for children
! Symptomatic: 1-3%! Challenges arise with system revision or upgrade.
http://www.nhlbi.nih.gov
Stanford University Introduction 2 / 9
Introduction
! Pacemakers are used to treat arrhythmias.! Pacemaker implantation: between 1993-2009, 2.9 M patients in US! Complications: Infection, haemothorax, lead dislodgement, lead
failure, venous occlusion...! Venous occlusion: 15-30% for adults and 20% for children
! Symptomatic: 1-3%! Challenges arise with system revision or upgrade.
http://www.nhlbi.nih.gov
Stanford University Introduction 2 / 9
Methods
! Navier-Stokes equations:
ρ(u,t + u · ∇u) − ∇ · σ = 0, (1)
∇ · u = 0, (2)
where σ = −pI + µ(∇u + ∇(u)T ).! Slip boundary conditions:
n · u = 0 on Γslip, (3)
t · σ(u, p) · n = βt · u on Γslip, (4)
b · σ(u, p) · n = βb · u on Γslip (5)
! Slip length: Lslip = µβ .
! Implemented in Simvascular package! Stabilized finite element formulation (SUPG),! Linear finite element for space discretization! Generalized α method for time integration
Stanford University Methods 4 / 9
Methods
! Navier-Stokes equations:
ρ(u,t + u · ∇u) − ∇ · σ = 0, (1)
∇ · u = 0, (2)
where σ = −pI + µ(∇u + ∇(u)T ).! Slip boundary conditions:
n · u = 0 on Γslip, (3)
t · σ(u, p) · n = βt · u on Γslip, (4)
b · σ(u, p) · n = βb · u on Γslip (5)
! Slip length: Lslip = µβ .
! Implemented in Simvascular package! Stabilized finite element formulation (SUPG),! Linear finite element for space discretization! Generalized α method for time integration
Stanford University Methods 4 / 9
Methods
! Navier-Stokes equations:
ρ(u,t + u · ∇u) − ∇ · σ = 0, (1)
∇ · u = 0, (2)
where σ = −pI + µ(∇u + ∇(u)T ).! Slip boundary conditions:
n · u = 0 on Γslip, (3)
t · σ(u, p) · n = βt · u on Γslip, (4)
b · σ(u, p) · n = βb · u on Γslip (5)
! Slip length: Lslip = µβ .
! Implemented in Simvascular package! Stabilized finite element formulation (SUPG),! Linear finite element for space discretization! Generalized α method for time integration
Stanford University Methods 4 / 9
Anatomy realistic cases
! A 3-4 year old patient (pulsatile inflow, resistance outlet)! Residence time: ∂τ
∂t + u · ∇τ − ∇ · κ∇τ = H (Esmaily Moghadamet al.,Phys Fluids, 2013)
AB
C
noslip slip
noslip slipnoslip slip
Vel
RT
Vel
RT
Vel
RT
Stanford University Results 8 / 9
Concentric lead
! Analytical solution is given by
v(r) = Q(R2
0−R2
i)π
×1+4c ln(r/R0)−(r/R0)2
1−4c[1/2+b2 ln b/(1−b2)]−(1+b2)/2 , where
b = Ri/Ro, c = b(1−b2+2bλ)4(λ−b ln b) , λ =
Lslip
Ro.
! Simulation setting: Q = 16cc/s, Ro = 0.55cm, Ri = 0.117cm
Stanford University Results 6 / 9
�/R0 = 0
�/R0 = 0.2
�/R0 = 1
No-slip Slippery
Anatomy realistic cases
! A 3-4 year old patient (pulsatile inflow, resistance outlet)! Residence time: ∂τ
∂t + u · ∇τ − ∇ · κ∇τ = H (Esmaily Moghadamet al.,Phys Fluids, 2013)
AB
C
noslip slip
noslip slipnoslip slip
Vel
RT
Vel
RT
Vel
RT
Stanford University Results 8 / 9
Anatomy realistic cases
! A 3-4 year old patient (pulsatile inflow, resistance outlet)! Residence time: ∂τ
∂t + u · ∇τ − ∇ · κ∇τ = H (Esmaily Moghadamet al.,Phys Fluids, 2013)
AB
C
noslip slip
noslip slipnoslip slip
Vel
RT
Vel
RT
Vel
RT
Stanford University Results 8 / 9
The influence of a slippery hydrodynamic condition on pacemaker lead surface is evaluated in idealized and patient-specific scenarios.
The slippery surface condition reduces the residence time in close proximity of the lead, suggesting its possibility of mitigating risks of lead-induced thrombosis.
References:
Introduction
! Does lead size matter? Maybe.
! Small-diameter lead: increased rate of lead failure
! Simulations show flow stasis is concentrated around leads.! What if slippery?
! Pitcher plant inspired omniphobic surface coating (SLIPS)
Leslie et al., Nature Biotechnology, 2014
Stanford University Introduction 3 / 9
1. National Heart, Lung, and Blood Institute, NIH2 Leslie et al. (2014).Nature Biotechnol. 32,1134-1140.
Image: NHLB, NIH
Leslie et al. (2014).Nature Biotechnol.
[cm/s]