Transcript MRI safe pacemaker: waarom niet?

Dr. A.F.M. Kuijper
Spaarneziekenhuis, Hoofddorp
Amersfoort 28 september 2012
2010 ACCF/ACR/AHA/NASCI/SCMR Expert Consensus Permanent
Cardiac Pacemakers and ICD (1)
 damage or movement of the device
 inhibition of pacing output
 activation of tachyarrhythmia therapy of the device
 cardiac stimulation
 heating of the electrode tips
 -> changes in pacing/defibrillation thresholds,
pacemaker ICD dysfunction or damage (including
battery depletion), arrhythmia, or death.
2010 ACCF/ACR/AHA/NASCI/SCMR Expert Consensus Permanent
Cardiac Pacemakers and ICD(2)
 Few small clinical trials under which MR examination with these
devices could be conducted safely.
 Pacemaker-dependent patients were excluded from
these studies, no episodes of pacing above the upper rate limit or arrhythmias were
noted, though 1 patient had a change in device programming.
after the year 2000
 ICDs and pacemakers manufactured
are more resistant
to the electrical and magnetic fields associated with MR examination at 1.5-T.
 no deaths have been reported under conditions in which patients were
deliberately scanned and monitored during MRI , although changes in pacing threshold,
programming changes, need for device reprogramming, and possibly battery depletion
have been reported.
2010 ACCF/ACR/AHA/NASCI/SCMR Expert Consensus Permanent
Cardiac Pacemakers and ICD(3)
 2010 pacemakers in the USA MR unsafe
 MRI examination of patients with pacemaker
 - is discouraged
 - only at highly experienced centers
 - strong clin. indication, benefits outweigh risk
 - ICD pts in highly experienced ICD/MRI center
2010 ACCF/ACR/AHA/NASCI/SCMR Expert Consensus Permanent
Cardiac Pacemakers and ICD(4)
Retained Transvenous Pacemaker and Defibrillator Leads
 No studies in MRI with retained pacemaker or ICD
leads (either functioning or fractured). Significant
heating of the lead tips may occur. Discouraged.
 MRI in EP center when no alternatives to MRI under
compelling clinical circumstances.
J Am Coll Cardiol 2009;54:549–55
MRI at 1.5-T in pts With ICD Naehle et al. J Am Coll Cardiol 2009;54: 549–55
 18 Non–pacemaker-dependent ICD patients
 Specific Absorption Rate (SAR) was limited to 2 W/kg.
 ICDs reprogrammed to avoid competitive pacing and
potential pro-arrhythmia:
 1) the lower rate limit as low as reasonably achievable; and
 2) arrhythmia detection on, therapy delivery off, (detection
off programming consumes less battery current).
 ECG+ pulse oximetry. All ICDs were interrogated before
and after the MRI examination and after 3 months,
including measurement of pacing capture threshold, lead
impedance, battery voltage, and serum troponin I.
MRI at 1.5-T in pts With ICD Naehle et al. J Am Coll Cardiol 2009;54: 549–55
 All 18 examinations were completed safely.
 All ICDs interrogated and reprogrammed post-MRI.
 No changes of pacing capture threshold, lead impedance,
and serum troponin I were observed.
 Battery voltage decreased significantly from pre- to postMRI. (4 complete, 9 partial recovery, 3 no recov, 2 missing).
 Mean battery voltage decreased from pre-MRI 3.86 ± 1.48 V,
to post-MRI 3.83 ± 1.48 V but was 3.90 ± 1.52 V at FU.
 In 2 MRI examinations, oversensing of radiofrequency
noise as ventricular fibrillation occurred. However, no
attempt at therapy delivery was made.
Editorial Roguin JACC 2009
 FDA : “for some patients, risks of MRI under specific, characterized






scanning and monitoring conditions may be acceptable given the
diagnostic benefit.”
Risks of MR scanning should be discussed with the patient, with
written informed consent.
In ICD patients the MR study should be performed at centers with
expertise in MRI and electrophysiology.
The MR scan should be optimally planned in order to minimize time
and energy.
A physician who is knowledgeable in device therapy and programming
should be present during the MR scan.
Pre-MR reprogramming, careful patient monitoring during MR
scanning, and thorough follow-up after MR scanning must be
performed.
Full resuscitation facilities should be available should any adverse event
occur during MR scanning.
Am Heart J 2011;161:1096-105
Safety, feasibility, and diagnostic value of cardiac MRI in patients
with cardiac pacemakers and implantable cardioverters
defibrillators at 1.5 T Am Heart J 2011;161:1096- Naehle et al
Patients and Methods






PM/ICD systems > 3 months after implant
stable physical parameters
EOL> 6 months
pacing lead impedances 200-2000 Ω
shock lead impedance, 10-80 Ω
stable functional parameters (pacing capture
threshold <2.5 V at a pulse duration of 0.4
milliseconds, sensing > .5 mV).
 No abandoned leads or presence of other MR
imaging–incompatible devices.
Device en onderzoeksindicatie
Resultaten procedure safety (1)
 No unexpected changes in heart rate or rhythm,





indicating inhibition of ICD output, shock delivery, or
sustained atrial or ventricular arrhythmias.
No torque or heating sensation during MR imaging.
No changes programmed parameters.
No change of pacing threshold
No change of pacing lead impedance to >2,000 or <200
Ω
No change of highvoltage lead impedance to >80 or
<10 Ω was observed.
Resultaten procedure safety (2)
 Troponin I. In 6 (6/32, 19%) patients, baseline
troponin I level was elevated because of the underlying
cardiac condition.
 In the residual 26 patients, troponin I level was normal
pre-MRI and did not increase above the upper normal
limit post-MRI (0/26, 0%).
Pacing capture threshold
 Because CMR is performed during 8- to 15-second
breath-holds, duration of RF exposure is limited, and
cooling off of the lead tip is possible between breathholds.
 In vivo blood flow provides an additional cooling effect
and thus reduces RF-related heating.
 SAR was limited to a maximum of 1.5 W/kg in this
study.
Concluderend
 Cardiac MR may be performed safely when limiting
specific absorption rate, appropriately monitoring
patients, and following device reprogramming.
 Cardiac MR delivers good image quality and diagnostic
value in patients with right sided device.
 Cardiac MR in patients with right sided device may be
performed with an acceptable risk/benefit ratio,
whereas the risk/benefit ratio is rather unfavorable in
patients with LSD.
SAFETY OUTCOMES IN PTS WITH ICD AND PERMANENT
PACEMAKERS UNDERGOING MRI AT 1.5-TESLA ACC 2010 Vatthyam et al.
Prystowsky,Indianapolis, IN




Retrospectief bij non-pacing dependent pts
N=86, 2005-2009 (ICD = 47, PM = 39)
Results: no adverse clinical sequelae after MRI
Conclusions: MRI in non-pacemaker-dependent
patients with PPMs or ICDs showed no adverse clinical
sequelae during initial testing and over a mean followup period of 6.4 months. There was no oversensing of
electromagnetic interference with any device.
 The absence of negative outcomes was found despite
occasional threshold differences between subject
groups.
Nazarian Ann Intern Med. 2011;155:415-424.
Baltimore USA, Haifa Israel
555 MRI bij 458 patienten
In/exclusie
 Inclusie februari 2003-april 2010
 Exclusie:
 < 6 weken implantatie
 abandoned or epicardial leads
 pacemaker-dependent pts with ICD: lack of
asynchronous pacing capability
Assessment of Device and Lead Variable Changes
 Because of considerable expected variability,
 lead impedance variations exceeding 30% capture
 threshold variations exceeding 50%, and
 sensing variations exceeding 40% indicate clinically
significant changes in lead performance.
 Eerste 55 patienten max 2 w/kg MRI, nadien full 1.5 T
MRI
 Medtronic, St. Jude, Boston Scientific
 Pacemakers van na 1998 implantatie
 ICD’s van na 2000 implantatie
patienten
 438 patienten, 555 MRI
 237 (54%) pacemaker, 201 (46%) ICD
 Pacemaker 78% brady, 22% CHB
 MRI 40% brain, 22% spine, 16% heart
 13% abdomen/pelvis, 9% extremiteit
 15% repeat MRI
 6% > 3 MRI
Acute resultaten
 Power on reset bij 3/438 (0.7%), 1 MRI stop, 2
uneventfull MRI
 No device revision, programming, or interventions at
MRI examination were otherwise required.
 In pacemakers without magnet-mode programming
capability, reed switch activation by MRI led to
transient, asymptomatic asynchronous pacing at the
pacemaker-specific magnet rate.
 No unexpected or rapid activation of pacing was
observed during MRI.
Lead Sensing, Impedance, and Capture Thresholds at Immediate
and Long-Term Follow-up
 No immediate or long-term change in variables in any
patient was large enough to require lead or system
revision or device reprogramming.
Overall, MRI was performed safely in all patients.
 When the device was located in the MRI field of view,
image distortion, signal voids or bright areas, and poor
fat suppression were noted.
 Selecting imaging planes perpendicular to the plane
of the device generator, shortening the echo time, and
using spin echo and fast spin echo sequences reduced
the qualitative extent of artifact.
 Artifacts, were limited to thoracic examinations, and
the great majority of examinations yielded clinically
useful information.
 Thoracic MRI may pose more risk owing to greater
power deposition over the region containing the
device.
 The association between thoracic imaging and longterm right ventricular sensing in our study supports
this hypothesis.
MRI bij pacemaker afhankelijke pt
(1)
 53 pacemaker-dependent patients without ICD
underwent MRI without safety issues.
 It is vital, however, to emphasize the need for
appropriate programming of the device to an
asynchronous mode, monitoring by qualified
personnel, and availability of external pacing backup
for such patients
MRI bij pacemaker afhankelijke pt
(2)
 If a power-on-reset event occurs, the device reverts to
an inhibited pacing mode.
 Therefore, in pacemaker-dependent patients, the
device may transiently cease pacing owing to EMI, and
electrocardiographic monitoring and pulse oximetry
are necessary so that the scan can be stopped if
inhibition of pacing is noted.
Conclusie 1
 Using a protocol based on device selection and
programming, MRI can be performed safely in patients
with certain pacemaker and ICD systems.
 Given the potential for changes in device variables and
programming, monitoring by device experts is
necessary.
Conclusie 2
 The decision to perform MRI in each patient with an
implantable device should be made by balancing the
potential benefit of MRI against the attendant risks.
 Because thoracic MRI sequences have a greater effect
on device variables and are more likely to result in
artifacts, these sequences should be reserved for
patients with an absolute clinical need.
Magnasafe Registry (Russo ACC 2012)
 multicenter, prospective study designed to determine
the frequency of major adverse clinical events and
device parameter changes for 1500 patients with
standard implantable cardiac electronic devices who
undergo clinically-indicated, non-thoracic MRI at 1.5T.
Magnasafe pts en methods
 Device interrogation pre- and post-MRI.
 Pacemaker-dependent subjects were programmed to an
asynchronous pacing mode, and non-dependent subjects
had pacing functions deactivated.
 For ICD patients, all therapies were programmed to off for
those not pacing-dependent;
 ICD pacing-dependent ICD subjects were excluded.
 Primary study endpoints were device failure,
generator/lead replacement, induced arrhythmia, loss of
capture, or electrical reset. Secondary endpoints were
clinically-relevant device parameter changes. No limits
were placed on the number of repeat scans performed
Magnasafe Results (1)
 April 2009-November 2011, 431 MRI studies (324
pacemakers, 107 ICDs)
 88% 1 MRI, 12 meer dan 1 MRI
 No deaths, device failures, generator/lead
replacements, losses of capture, or ventricular
arrhythmias occurred in either the Initial scan or
Repeat scan groups.
Magnasafe Results (2)
 Decrease in battery voltage ≥0.04V in 4 % of the Initial
scan group and 0% of the Repeat scan group.
 Pacing lead impedance change ≥ 50Ω in 7 % of the
Initial scan group, and 2% of the Repeat scan group.
 No decrease of ≥ 50% in R-wave or P-wave amplitude
occurred.
 A pacing threshold increase ≥ 0.5V at 0.4 ms occurred
in 2% in each group.
Magnasafe Conclusion
 No association between number of MRI scans and rate
of clinical events or device parameter changes.
 No deaths, device failures, generator/lead
replacements, or losses of capture were noted after
clinically-indicated non-thoracic MRI at 1.5T
Is de huidige MRI-unsafe
pacemaker/ICD MRI-safe?
 > 1000 patienten MRI
 ICD zowel als pacemakers
 Pacemaker afhankelijk
 Thoracic MRI/extra thoracic MRI
 Protocol volgens Nazarian is veilig
Waarom geen MRI safe device (1)?
 Hoeveel mag een nieuwe feature kosten?
 Boston Scientific: fineline draden sinds 2000
geimplanteerd hebben MRI approval
 Boston Scientific rekent niets extra’s voor MRI safe
pacemaker/ICD
 Medtronic: onhandige MRI safe draden (mijn mening)
 SSIR bestaat bij mijn weten niet, MRI safe is 2
kamersysteem met 2 draden, ook bij AAI/VVI pacing
indicatie
Waarom geen MRI safe device (2)?
 Biotronik pacing draden: dik en onhandig (mijn
mening).
 Onderlinge uitwisselbaarheid: geen firma is bereid te
garanderen dat andere draden op eigen device ook
MRI safe combinatie is (persoonlijke ervaring met
Biotronik draden en Medtronic Surescan PG)
 Nieuwe technologie/nieuwe lead: weer een Riata?
Waarom geen MRI safe device (3)?
 Oude leads: alleen BSc Fineline retrograde CE




markering
Biotronik, listprijs A en V lead + 100-150 euro, nog
alleen MR-conditional devices?
Medtronic?
St Jude SR +5%, DR + 3.5%, lead + 53%, geen
CRTD/ICD
Boston SR +6,6% DR +5,8% lead Fineline retrogr CE