Improving Patient Outcomes Neil K Sanghvi MD FACC FHRS Cardiac Electrophysiology Jacksonville FL Office 9044230010 Disclosures Received honoraria and travel expenses from ID: 552380
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Slide1
MRI-Conditional Pacemakers: Improving Patient Outcomes
Neil K. Sanghvi, M.D., F.A.C.C.,
F.H.R.S.
Cardiac Electrophysiology
Jacksonville, FL
Office: 904-423-0010Slide2
DisclosuresReceived honoraria and travel expenses from Boehringer Ingelheim, Medtronic, Boston Scientific, St. Jude Medical. Consulted for St. Jude Medical.Slide3
Discussion GoalsGrowing need for MRI access for patientsSociety guidelines for performing MRIs in patients with CIEDSHazards of placing non-MR conditional CIEDs in a MRI machineMRI conditional PPM – data and device designSlide4
MRI: Powerful Diagnostic ToolNon-ionizing radiationExcellent differentiation between soft tissues without the need for iodinated contrastUtilization increasing as more applications become validatedSlide5
1
Magnetic
Resonance Imaging (MRI) Equipment – A Global Strategic Business Report, Global Industry Analysts, Inc.
, San
Jose, CA. 2002
.
2
Roguin A.
Europace
2008;10:336-346
> 65yo
2x as likely to require
MRI1 80% pacemaker patients > 65yo
MRI Access Is a Growing NeedSlide6Slide7
MRI Access Is a Growing Need2.9 million patients received pacemakers in the US between 1993 - 20091Approximately 3 of 4 pacemaker patients indicated for MRI over lifetime of their device2Pacemaker patients previously subjected to risk/benefit analysisIf risk high, MRI is deferred for less optimal studiesIf risk low, MRI performed on devices not approved for MRI with known risk of device complications
1
Greenspon AJ. JACC 2012;60(16):1540-45.
2
Kalin R. PACE 2005;28:326-328Slide8
Computed Tomography vs. MRIMRI
Image sources: Dr.
Torsten
Sommer
. University of Bonn.
CT
Potential Risks:
Delayed
diagnosis
Missed diagnosis
Increased risk from alternative imaging modalitiesSlide9
Unexpected programming changes, inhibition of pacemaker output, failure to pace, transient asynchronous pacing, rapid cardiac pacing, the induction of ventricular fibrillation, heating of the tissue adjacent to the pacing or ICD system, early battery depletion, and outright device failure requiring replacement may all occur during MRI of patients with pacemakers or ICDs.
ACR Guidance Document 2007
Patients who have a pacemaker or ICD should not undergo an MR study if an alternative diagnostic test is available, and
MR imaging should only be considered in cases in which the potential benefit to the patient clearly outweighs the risks to the patient.
AHA Scientific Statement 2007
Society StatementsSlide10
Nazarian S.: http://crm.cardiosource.org/Learn-from-the-Experts/2012/10/MRI-in-Patients-with-ICDs-and-Pacemakers.aspx
A 2-second pause was noted…
…diminished battery voltage was noted immediately after MRI…
Significant changes were reported in 9.4% of leads…
1.9% required a change in programmed output.
…increased capture threshold was noted post MRI.
…4 out 114 examinations resulted in an
TnI
levelSlide11
MRI: Three Powerful FieldsStatic Field
Gradient Field
RF FieldSlide12
Multiple Potential Interactions
Roguin
A.
Europace
2008;10:336-346
Santini
L. PACE 2013;36:270-78Slide13
Multiple Potential Interactions
Static
Gradient
RF
Vibration
Case Heating
Force & Torque
Lead Heating
Stimulation
Device InteractionsSlide14
Hazards of MRI
Gimbel
JR.
Europace
2009;11(9):1241-42Slide15
Roguin
A.
Europace
2008;10:336-346
Inappropriate sensing of VF
Hazards
of MRISlide16
http://
www.medscape.org
/
viewarticle
/738347_3Slide17
MRI Conditional Labeling
MR Safe
MR Conditional
MR Unsafe
*
ASTM standard F2503: Standard Practice for Marking Medical Devices and Other Items for Safety in the
Magnetic Resonance Environment
ASTM Standard F2503
*
Defines Three Terms:Slide18
Santini
L. PACE 2013;36:270-78Slide19
Pacemaker Design SolutionsMinimize ferromagnetic contentIsolated circuit board Hall sensorOptimize input circuitryCircuit component change
Unintended cardiac stimulation
Device interactions
Force and Torque
Slide courtesy of
MedtronicConnect.comSlide20
5076
5086MRI
Medtronic Lead Heating Solution
Lead inner conductor coil design mitigates lead heating
4
filar
to 2
filar
increases inductance and reduces heating
0
10
20
30
40
50
60
70
80
90
100
0
5
10
15
20
25
30
35
40
45
50
Percent of Maximum
Lead Path
5076 vs. 5086MRI Comparison
5076
-
52
5086
-
52
Slide courtesy of
MedtronicConnect.comSlide21
SJM Lead Heating SolutionSlide22
X-rays identify the system via unique radiopaque MRI symbol
Positive System ID:
Radiographic Studies
Slide courtesy of
MedtronicConnect.comSlide23
Positive System ID:Radiographic StudiesSlide24
Prospective, randomized, multi-center trial
464 implanted patients
42 international centers
Randomization (MR scan: Control/no MR scan); 1.5T MRI
Enrollment
February 2007 through July 2008
Follow-up: November 2008
11.2 ± 5.2 months (range 0.1-21.5 months)Slide25
Medtronic Revo MRI™ ConclusionsAll 5 primary endpoints were met Safety MRI procedure-related complication-free rate
Effectiveness
Atrial pacing capture thresholds
Ventricular pacing capture thresholds
Atrial sensed amplitudes
Ventricular sensed amplitudes
●
●
Wilkoff
BL. Heart Rhythm 2011;8:65-73Slide26
MedtronicSt. JudeBiotronikImplant TimePPM + Leads > 6 monthsStable pacing thresholdsPPM + Leads > 6 monthsPectoral Implant+++
No other CEIDs or leads implanted
+
+
+
N
o abandoned leads, lead extenders or adaptors
+
+
+
Capture threshold <2V
@ 0.4ms
++Capture threshold <2.5V @ 0.5ms+200 ≥ Impedance ≥1500 Ohms+++
No diaphragmatic stimulation at 5V @ 1ms+
+
Battery charge ≥ 30%
+
MRI conditional
programming
+
+
+
Santini
L. PACE 2013;36:270-78Slide27
Should I Insist on a MRI – conditional PPM for my patient?
ANSWER
: Probably
Downsides of MRI – compatible devices:
Cost – more expensive than traditional PPM
Unknown
battery
longevitySlide28
Proposed Indications for Implantation
Santini
L. PACE 2013;36:270-78Slide29
Summary75% of patients with CIEDs will likely require an MRI at some pointDenying MRIs in clinically indicated situations may result in sub-optimal outcomes for patientsMRI-conditional pacemakers allow for safe performance of MRIsFuture devices should all strive for MRI-conditional status