Steroid eluting, bipolar, implantable, screw-in, ventricular/atrial, transvenous lead
Technical Manual
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CapSureFix, Medtronic
Contents
1 Description3
2 Drug component description3
3 Indications3
4 Contraindications4
5 Warnings and precautions4
6 Drug information5
7 Adverse events6
8 Clinical trials6
Dispose of all single-use accessories according to local
environmental requirements.
Anchoring sleeve – An anchoring sleeve secures the lead to
prevent it from moving and protects the lead insulation and
conductors from damage caused by tight sutures.
Fixation tool – A fixation tool facilitates connector pin rotation.
Stylet – A stylet provides additional stiffness and controlled
flexibility for maneuvering the lead into position. Each stylet knob
is labeled with the stylet diameter and corresponding lead length.
Stylet guide – A stylet guide facilitates stylet insertion into the
lead.
Vein lifter – A vein lifter facilitates lead insertion into a vein.
1 Description
The Medtronic CapSureFix Novus 4076 steroid eluting, bipolar,
implantable, screw-in, ventricular/atrial, transvenous lead is
designed for pacing and sensing applications in either the atrium
or ventricle. The platinum alloy tip and ring electrodes feature a
high-active surface area of titanium nitride microstructure. This
electrode configuration contributes to low polarization.
The helical tip electrode on the lead can be actively fixed in the
endocardium. The helix electrode can be extended or retracted by
rotating the lead connector pin with a fixation tool. An active
fixation lead is particularly beneficial for patients who have smooth
or hypertrophic hearts where lead dislodgment may be a potential
problem. The lead also has a second, larger electrode proximal to
the helical tip electrode and an IS-11 Bipolar (BI) connector with 1
terminal pin. The lead features MP35N nickel alloy conductors, an
outer insulation of 55D polyurethane, and an inner insulation of
silicone rubber.
The distal tip of the lead contains a target nominal dosage of
680 µg of dexamethasone acetate. Upon exposure to body fluids,
the steroid elutes from the lead tip. The steroid is known to
suppress the inflammatory response that is believed to cause
threshold rises typically associated with implanted pacing
electrodes.
1.1 Contents of package
The lead and accessories are supplied sterile. Each package
contains:
●
1 lead with 1 radiopaque anchoring sleeve, stylet, and stylet
guide
●
1 vein lifter
●
2 fixation tools
2 Drug component description
The active ingredient in the Model 4076 lead is dexamethasone
acetate. Dexamethasone acetate is 9-Fluoro-11β,
17,21-trihydroxy-16α-methylpregna-1,4-diene-3,20-dione
21-acetate. Dexamethasone acetate has a molecular formula of
C24H31FO6 and a molecular weight of 434.50. The MCRD
(Monolithic controlled release device) excipient is silicone. See
Figure 1 for the structural formula.
Figure 1.
The target dosage of dexamethasone acetate is 680 µg per lead.
3 Indications
The Model 4076 lead is designed to be used with a compatible
implantable pulse generator as part of a chronic cardiac pacing
system. The lead has application where implantable atrial or
ventricular, single chamber or dual chamber pacing systems are
indicated.
1
IS-1 refers to an International Connector Standard (ISO 5841-3) whereby pulse generators and leads so designated are assured of a basic mechanical fit.
3
4 Contraindications
●
Use of a ventricular transvenous lead is contraindicated in
patients with tricuspid valvular disease.
●
Use of a ventricular transvenous lead is contraindicated in
patients with mechanical tricuspid heart valves.
●
Use of a steroid eluting lead is contraindicated in patients for
whom a single dose of 1.0 mg of dexamethasone acetate may
be contraindicated.
5 Warnings and precautions
Note: Medical procedure warnings and precautions that pertain to
the Medtronic implanted system are provided in the manual that is
packaged with the device or on the Medtronic Manual Library
website (www.medtronic.com/manuals).
Magnetic resonance imaging (MRI) – An MRI is a type of
medical imaging that uses magnetic fields to create an internal
view of the body. Do not conduct MRI scans on patients who have
this device or lead implanted. MRI scans may result in serious
injury, induction of tachyarrhythmias, or implanted system
malfunction or damage.
Line-powered and battery-powered equipment – An
implanted lead forms a direct current path to the myocardium.
During lead implant and testing, use only battery-powered
equipment or line-powered equipment specifically designed for
this purpose to protect against fibrillation that may be caused by
alternating currents. Line-powered equipment used in the vicinity
of the patient must be properly grounded. Lead connector pins
must be insulated from any leakage currents that may arise from
line-powered equipment.
Diathermy is a treatment that involves the therapeutic heating of
body tissues. Diathermy treatments include high frequency, short
wave, microwave, and therapeutic ultrasound. Except for
therapeutic ultrasound, do not use diathermy treatments on
cardiac device patients. Diathermy treatments may result in
serious injury or damage to an implanted device and lead system.
Therapeutic ultrasound (including physiotherapy, high intensity
therapeutic ultrasound, and high intensity focused ultrasound), is
the use of ultrasound at higher energies than diagnostic
ultrasound to bring heat or agitation into the body. Therapeutic
ultrasound is acceptable if treatment is performed with a minimum
separation distance of 15 cm (6 in) between the applicator and the
implanted device and lead system, as long as the ultrasonic beam
is pointing away from the device and lead system.
Single use – The lead and accessories are for single use only.
Sterilization – Medtronic has sterilized the package contents
with ethylene oxide before shipment. This lead is for single use
only and is not intended to be resterilized.
Necessary hospital equipment – Keep external defibrillation
equipment nearby for immediate use during acute lead system
testing, the implant procedure, or whenever arrhythmias are
possible or intentionally induced during post-implant testing.
Inspecting the sterile package – Inspect the sterile package
with care before opening it.
●
If the seal or package is damaged, contact a Medtronic
representative.
●
Store at 25 °C (77 °F). Excursions from this storage
temperature are permitted in the range of 15 to 30 °C (59 to
86 °F). (See USP Controlled Room Temperature.) According
to USP excursion conditions, transient spikes up to 40 °C
(104 °F) are permitted as long as they do not exceed 24 hours.
●
Do not use the product after its expiration date.
Concurrent devices – Output pulses, especially from unipolar
devices, may adversely affect device sensing capabilities. If a
patient requires a separate stimulation device, either permanent
or temporary, allow enough space between the leads of the
separate systems to avoid interference in the sensing capabilities
of the devices. Previously implanted pulse generators and
implantable cardioverter defibrillators should generally be
explanted.
Steroid use – It has not been determined whether the warnings,
precautions, or complications usually associated with injectable
dexamethasone acetate apply to the use of this highly localized,
controlled-release lead. For a listing of potential adverse effects,
refer to the dexamethasone acetate manufacturer prescribing
information or the Physicians’ Desk Reference.
Steroid elution and exit block – Although the addition of steroid
to passive fixation leads has been shown to reduce pacing
thresholds in patients with a history of exit block, the frequency of
redevelopment of exit block was not statistically different between
the steroid eluting and the non-steroid eluting, active fixation,
screw-in leads in the Medtronic Model 4068 clinical trial.
Handling the steroid tip – Avoid reducing the amount of steroid
available before implanting the lead. Reducing the available
amount of steroid may adversely affect low-threshold
performance.
●
Do not allow the electrode surface to come in contact with
surface contaminants.
●
Do not wipe or immerse the electrode in fluid, except blood, at
the time of implant.
Handling the stylet – Handle the stylet with care at all times.
●
Curve the stylet before inserting it into the lead to achieve a
curvature at the lead’s distal end. Do not use a sharp object to
impart a curve to the distal end of the stylet.
●
Do not use excessive force or surgical instruments when
inserting the stylet into the lead.
●
Avoid overbending or kinking the stylet.
●
Use a new stylet when blood or other fluids accumulate on the
stylet. Accumulated blood or other fluids may damage the
lead or cause difficulty in passing the stylet into the lead.
Before inserting the lead – Use an anchoring sleeve with all
leads. Ensure that the anchoring sleeve is positioned close to the
lead connector pin. This will prevent inadvertent passage of the
sleeve into the vein. If wiping the lead is necessary prior to
insertion, ensure that the anchoring sleeve remains in position.
4
Vessel and tissue damage – Use care when positioning the
lead. Avoid known infarcted or thin ventricular wall areas to
minimize the occurrence of perforation and dissection.
Handling a lead – Handle the lead with care at all times.
●
Do not implant the lead if it is damaged. Return the lead to a
Medtronic representative.
●
Protect the lead from materials that shed small particles such
as lint and dust. Lead insulators attract these particles.
●
Handle the lead with sterile surgical gloves that have been
rinsed in sterile water or a comparable substance.
●
Do not severely bend, kink, or stretch the lead.
●
Do not immerse the lead in mineral oil, silicone oil, or any other
liquid, except blood, at the time of implant.
●
Do not use surgical instruments to grasp the lead.
●
Do not force the lead if resistance is encountered during lead
passage.
Chronic repositioning or removal of a screw-in lead –
Proceed with extreme caution if a lead must be removed or
repositioned. Chronic repositioning or removal of screw-in
transvenous leads may not be possible because of blood or
fibrotic tissue development into the helix mechanism on the lead.
In most clinical situations, it is preferable to abandon unused leads
in place. Return all removed leads, unused leads, or lead sections
to Medtronic for analysis.
Note: If a helix electrode does not disengage from the
endocardium by rotating the connector pin, rotating the lead body
counterclockwise may withdraw the helix electrode and decrease
the possibility of damage to cardiovascular structures during
removal.
●
Lead removal may result in avulsion of the endocardium,
valve, or vein.
●
Lead junctions may separate, leaving the lead tip and bare
wire in the heart or vein.
●
Chronic repositioning of a lead may adversely affect the
low-threshold performance of a steroid lead.
●
An abandoned lead should be capped so that the lead does
not transmit electrical signals.
●
Severed leads should have the remaining lead end sealed
and the lead body sutured to adjacent tissue.
Connector compatibility – Although the lead conforms to the
IS-1 International Connector Standard, do not attempt to use the
lead with any device other than a commercially available
implantable pacing system with which it has been tested and
demonstrated to be safe and effective. The potential adverse
consequences of using such a combination may include, but are
not limited to, undersensing cardiac activity and failure to deliver
necessary therapy.
6 Drug information
6.1 Mechanism of action
Steroid suppresses the inflammatory response that is believed to
cause threshold rises typically associated with implanted pacing
electrodes. Dexamethasone acetate is a synthetic steroid of the
glucocorticoid family. Glucocorticoids have potent
anti-inflammatory actions via direct and indirect effects on major
inflammatory cells. Glucocorticosteroids bind to a cytoplasmic
glucocorticoid receptor as well as a membrane-bound receptor.
Binding to the cytoplasmic receptor leads to receptor activation
and translocation to the nucleus. The receptor interacts with
specific DNA sequences within the regulatory regions of affected
genes. Thus, glucocorticoids inhibit the production of multiple cell
factors that are critical in generating the inflammatory response.
6.2 Pharmacokinetics and metabolism
Pharmacokinetics – The pharmacokinetics (local drug levels
and systemic levels) of dexamethasone acetate and its
metabolites following implant were not evaluated in human clinical
trials. When delivered intra-muscularly, the lipid-soluble
dexamethasone acetate is slowly absorbed throughout the tissue.
Metabolism – The conversion of dexamethasone acetate to
dexamethasone occurs within hours. The dexamethasone
alcohol (dexamethasone) is the active glucocorticoid used in this
Medtronic lead. Steroid is applied via MCRD (Monolithic
controlled release device) and eluted to the tissue interface where
it will be used. The form of the steroid, whether it is a prodrug or the
pharmacologically active dexamethasone, is irrelevant, as the
steroid is directly present at the injury site to treat the
inflammation. Dexamethasone acetate is hydrolyzed into
dexamethasone, which is readily absorbed by the surrounding
tissue and body fluids. Glucocorticoids, when given systemically,
are eliminated primarily by renal excretion of inactive metabolites.
6.3 Mutagenesis, carcinogenicity, and reproductive
toxicity
Mutagenesis, carcinogenicity, and reproductive toxicity –
The mutagenesis, carcinogenicity, and reproductive toxicity of the
CapSureFix Novus 4076 lead have not been evaluated. However,
the mutagenesis, carcinogenicity, and reproductive toxicity of
dexamethasone acetate have been evaluated previously.
Carcinogenesis, mutagenesis, and impairment of fertility –
No adequate studies have been conducted in animals to
determine whether corticosteroids have a potential for
carcinogenesis (tumor initiation or promotion). Dexamethasone
was genotoxic in assays for clastogenicity (including sister
chromatid exchange in human lymphocytes) but not in an assay
for mutagenicity in salmonella (Ames test). Adrenocorticoids have
been reported to increase or decrease the number and mobility of
spermatozoa in some patients.
6.4 Pregnancy
Pregnancy – Dexamethasone acetate has been shown to be
teratogenic in many species when given in doses equivalent to the
human dose. There are no adequate and well-controlled studies
in pregnant women. Dexamethasone acetate should be used
during pregnancy only if the potential benefit justifies the potential
risk to the fetus. Studies in mice, rats, and rabbits have shown that
adrenocorticoids increase the incidence of cleft palate, placental
insufficiency, and spontaneous abortions, and can decrease the
intrauterine growth rate.
5
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