Figure 3
Build-up around an ICD lead visualized on TEE and fluoroscopy and its
consequences during TLE
- TEE (2D, ME- bicaval) Segmental thickening of the ICD lead with three
binding sites in the RA wall (arrows), additionally a blue arrow
points to the binding site and conductor externalization
- TEE (2D and 3D, ME - bicaval ) The thickened ICD lead attached to the
IAS (arrows)
- TEE (2D, ME RV - Inflow) The ICD lead, hyperechoic, thickened, over
the TV bound to the lateral atrial wall at the site of externalization
(blue arrow)
- D1- Evaluation of ICD lead position and venous patency before TLE. D1
– Imaging during TLE – well visible site of externalization (blue
arrow), the tip of Byrd’s dilator marked with a black arrow. D3 –
significant pulling on the ICD lead during TLE
- TEE (2D, bicaval) The moment of pulling on the thickened ICD lead (red
arrow) seen on fluoroscopy. D3 – significant pulling on the RA wall
and the separation of pericardial layers
- The extracted lead with multiple fragments of the connective tissue,
the site of externalization and a dilator (black arrow)
The connective tissue on the leads (scar tissue build-up around the
lead, fibrous tissue binding sites, accretions) is visible on TEE as
lead thickening resulting in the formation of sites at which the leads
are bound to one another after being in direct contact over an extended
period of time. The imaging of this phenomenon has important
implications for the course of the TLE procedure. During the extraction
procedure the direct pulling on the wall at the binding site may be too
strong and cause inadvertent pulling on and uncontrolled removal of the
other lead, risking a tear of the heart wall with cardiac tamponade or
hemopericardium as the end result.
The originality of this study is that it explores the impact of TEE
assessment before TLE on the course of the procedure. Multivariate
analysis showed that lead-to-lead binding sites were the strongest
predictive factor which caused a 3-fold increase in the probability of
major complications during TLE. The presence of fibrous tissue binding
the lead to the atrial wall and tricuspid valve approached the
borderline of significance. The presence of binding sites in the RV wall
caused a nearly 2-fold increase in the risk of technical difficulties,
thus increasing the degree of procedure complexity. The probability of
technical difficulty increased also in the presence of excess lead
loops, fibrous tissue binding the lead to the RA wall and lead-to-lead
binding sites. The presence of binding sites in the tricuspid apparatus
and lead-to-lead adhesion on the borderline of statistical significance
reduced the chances of complete clinical success. The chances of
procedural success were also reduced in relation with the presence of
binding sites in the SVC, RA and lead-to-lead adhesions, whereas
lead-dependent tricuspid dysfunction approached the borderline of
significance.
There are numerous studies [4-7] which on the basis of demographic
data (age, sex), clinical information (indications, accompanying
diseases, heart sufficiency), information about PM/ICD/CRT devices
(number and type of leads) and history of pacemaker therapy (age of
leads and route of implantation) show that initial patient assessment
may identify the individuals in whom TLE may be more difficult or
associated with the occurrence of major complications. Only few studies
using scoring systems provide a more precise prediction of the level of
procedure difficulty or estimate the true risk [6,7]. A review of
the literature shows that so far echocardiographic findings have not
been analyzed with respect to prediction of technical difficulties
associated with TLE and complications of the procedure. Only one paper
demonstrated that low LVEF was a predictor of major complications
[6], another paper documented an eventful postoperative course in
patients with right ventricular dysfunction [4]. The evidence from
another study suggests that information from CT examination may be
useful for estimating procedure difficulty [8]. Yet another study
implies that accurate Doppler blood flow measurements in the SVC may
identify patients with significant lead fibrosis requiring powered
sheaths for successful removal. Although numerous papers have emphasized
the role of the connective tissue (scar tissue binding the lead to the
SVC and heart wall) in estimating procedure complexity and its
complications [3,6,7], to the best of our knowledge we are the first
to use the information about the degree of connective tissue build-up to
predict technical difficulties and risk of major complications
associated with TLE.
When developing a risk calculator for prediction of complications
(SAFeTy TLE) [7] we found out that lead-to-lead binding site was an
extremely important prognostic factor, however other information (S =
sum of lead dwell times, A = anemia, Fe = female, T == treatment
(previous procedures), Y = young patients) appeared more significant in
multivariate analysis. We are of the opinion that all forms of
connective tissue response (scar tissue binding the lead to the vein and
heart structures, lead-to-lead adhesion) are extremely significant
factors that increase procedure complexity and its radiological
efficacy, however they do not necessarily translate into major
complications at an experienced high volume center. Nevertheless TEE
before TLE should become a tool that provides additional information
about procedure-related risk.