Title: Percutaneous Lead Extraction in Patients with Large Vegetations:
Limiting our Aspirations.
Robert D. Schaller, DO1
1The Section of Cardiac Electrophysiology,
Cardiovascular Division, Department of Medicine, Hospital of the
University of Pennsylvania, Philadelphia, Pennsylvania
Funding: This work was supported in part by the Mark Marchlinski EP
Research & Education Fund
Key words: Lead extraction, vegetation, pulmonary embolism, thrombus,
aspiration
Disclosures: None
Word count: 1547
Transvenous lead extraction (TLE) in the 1960’s involved
orthopedic-style pulley systems that joined the exposed portion of the
lead to progressively heavier weights hanging from the bed. Sustained
tension on the lead was maintained until the patient experienced
discomfort, ventricular arrhythmias, or noticeable resistance developed,
and was maintained for minutes to days. The location of the lead within
the chest was monitored with daily chest radiographs and the ensuingbang of the weight hitting the floor of the intensive care unit
signified case conclusion; at which point the patient was assessed.
Complications were erratic and included lead laceration and possible
migration, injury to the tricuspid valve (TV), myocardial avulsion,
tamponade, and death.1 Due to the immature nature of
the procedure at that time, it was relegated to infectious indications
including lead-related endocarditis, at that time referred to as
“catheter fever”.
Contemporary TLE has evolved into a highly refined practice with a
multitude of tools and predictable results, and procedural indications
that now span infection, venous occlusion, management of redundant
leads, and access to magnetic resonance imaging.2Procedural imaging with computed tomography (CT) and real-time
ultrasound-based tools have similarly changed the TLE experience with
identification of adhesions, thrombi, vegetations, and
complications.3 Large lead-related masses have
historically caused angst due to the possibility of being sheared off by
the extraction sheath and embolizing to the lung, and still represent a
relative contraindication to percutaneous TLE.2
In this issue of the Journal of Cardiovascular Electrophysiology ,
Giacopelli, et al.4 present the outcomes of 25
consecutive patients (mean age 64 years, 68% male) including 5 with
pacemakers, 10 with implantable cardioverter-defibrillators, and 10 with
cardiac resynchronization therapy devices, who underwent TLE with
vegetations ≥10 mm on transesophageal echocardiography (TEE).
Contrast-enhanced CT was performed before and after TLE with 18 (72%)
patients showing subclinical pulmonary embolism (PE). Vegetation size
(median of 17.5 mm and maximum of 30 mm) did not differ in those with
and without PE (20.0 mm vs. 14.0 mm, p=0.116). Complete TLE success was
achieved in all patients with 76% requiring advanced tools and 2
needing femoral snaring, and there were no significant procedural
complications. In the group with pre-TLE PE, a post-TLE scan confirmed
the presence of PE in only 14/18 (78%) and there were no patients with
new PE formation. During a median follow-up period of 19.4 months, no
re-infection of the new implanted systems was reported and there were 5
deaths (20%); with no differences between the groups. The authors
concluded that subclinical PE was common in this clinical scenario but
did not influence the complexity or safety of the procedure.
Several aspects of this paper warrant comment. No data are reported on
the size or location of the PEs nor the time between the first and
second CT. It is possible that small PEs would not be identified on
subsequent studies days after antibiotics had already been started.
Patients also received acute and chronic anticoagulation if PE was
identified, which in the setting of vegetations, is generally not
indicated and could potentially lead to bleeding. The authors did not
provide information regarding infectious pathogens or the timing of
culture clearance, which could influence treatment. Additionally, it is
unclear which patients received new CIED systems including the type and
timing of reimplantation, which might influence subsequent infectious
risk. A vascular occlusion balloon was not used in any patients in this
report. While this tool is associated with a reduced risk of death in
the setting of a superior vena cava laceration when used properly, it
has also been shown to be thrombogenic during long dwell
times,5 and use could impact post-operative CTs in
future studies. Despite utilizing transthoracic echocardiography during
TLE, neither TEE nor intracardiac echocardiography were used
intraoperatively and thus no information regarding the precise location
of the vegetations within the heart is known. Importantly, no
information regarding the characteristics of the vegetations other than
size was reported.
Not all lead-related masses are created equal with two distinct
sub-types previously described.6 The first is composed
of thickened endocardium and fibrous tissue covering the leads and
ultimately forming into connective tissue. These masses, commonly found
on leads behind the TV, are caused by a vortical flow pattern leading to
low shear stress on the lead surface and provoking neointimal
hyperplasia,7 and range from small fibrous strands to
large, smooth organized thrombus (Figure, left column). Despite their
sterile nature, TLE in the setting of a large, mature thrombus could
result in embolization and obstruction of the pulmonary artery resulting
in symptomatic PE. The second type, frequently seen in the setting of
infective endocarditis, is composed of inflammatory cells, platelets,
adhesion molecules, fresh fibrin, and bacteria binding to coagulum and
forming vegetations. They are typically longer, more likely to be
multi-lobular, and commonly span several chambers of the heart (Figure,
right column). These vegetations that are typically acute, with friable
finger-like projections, characteristically break apart upon being
sheared off during TLE, with reports showing low risk of symptomatic
PE.8 Vegetations that are lobular, however, have been
associated with worse outcomes.9
Despite acute procedural success in the setting of lead-related
vegetations, mortality rates at 1 year approach
25%.10 Indeed, despite successful TLE in this report,
20% of patients were dead at 1.5 years. Although complete understanding
of the mechanism of these poor outcomes remains unknown, septic emboli,
lung abscesses, and infected lead “ghosts” have been
implicated.11 Vegetation removal prior to TLE has thus
represented an appealing therapeutic option with reports of successful
percutaneous aspiration prior to TLE showing promising results, albeit
with unknown long-term benefit.12,13 Although the lack
of new PEs after TLE in this report does not directly support the
effort, cost, and added risk of such a strategy, “debulking” of
infectious burden remains a tempting complementary treatment.
Importantly, the acute safety of TLE with large vegetations in this
study should not be extrapolated to chronic, large lead-related masses,
which are more like to cause acute PE if embolized. While aspiration of
these sterile masses prior to TLE is appealing from a procedural outcome
perspective, their morphologic characteristics, and the imperfect, but
evolving, aspiration sheaths currently available are limiting, and
requires consideration of surgical extraction. Further advancements in
aspiration catheter technology and the development of right ventricular
outflow track filters might influence future management.
TLE continues to represent the gold standard for the management of
lead-related infection.2 Due to the extensive work of
the pathfinders in the vanguard of procedural development, the sound of
crashing weights has been supplanted by those that power advancing
sheaths. Yet despite the safe and predictable nature of modern-day TLE,
the sobering long-term mortality of patients with infectious indications
remains out of proportion to acute procedural success. While infectious
“debulking” continues to represent the most attractive and practical
complementary option to address this incongruity, future studies should
concentrate both on identification of mass characteristics that suggest
success, as well as determining if long-term benefits exist above and
beyond lead removal. However, if improvement in clinical outcomes that
warrant this added cost and effort are not identified, we should likely
limit our aspirations.