Eur J Vasc Endovasc Surg (2018) 56, 94e100
Pre-operative Color Doppler Ultrasonography Predicts Endovenous Heat
Induced Thrombosis after Endovenous Radiofrequency Ablation5
Chiara Lomazzi
a
b
a,*
, Viviana Grassi a, Sara Segreti a, Marta Cova a, Daniele Bissacco a, Ruth L. Bush b, Santi Trimarchi
a
Vascular Surgery II and Thoracic Aortic Research Centre, IRCCS Policlinico San Donato Teaching Hospital, University of Milan School of Medicine, Milan, Italy
Baylor College of Medicine and the Centre for Innovations in Quality, Effectiveness, and Safety, Houston, TX, USA
WHAT THIS PAPER ADDS
This cohort study offers a specific analysis of endovenous heat induced thrombosis (EHIT), occurring after radiofrequency ablation (RFA) of the great and small saphenous veins. In particular, it was found that the distance
between the superficial epigastric vein and the sapheno-femoral junction (dSEVeSFJ) introduced a novel measurement variable to be included during the pre-operative color Doppler ultrasound of the great saphenous vein
(GSV). In this study, this variable reliably predicted the occurrence of EHIT. This new measurement will assist vein
surgeons in identifying which patients may be at higher risk of EHIT after RFA of the GSV. Accordingly, these higher
risk patients would benefit from meticulous follow up after their ablation procedure to assess for EHIT.
Objectives: The aim was to identify pre-operative color Doppler ultrasound (CDUS) variables predictive of postoperative endovenous heat induced thrombosis (EHIT) after radiofrequency ablation (RFA) of the saphenous
veins.
Design: This was a single centre, observational study with retrospective analysis of consecutive patients treated
from December 2010 to February 2017.
Materials and methods: Pre-operatively, the diameter of the sapheno-femoral junction (dSFJ), distance between
superficial epigastric vein and SFJ (dSEVeSFJ), maximum great saphenous vein (GSV) diameter (mdGSV),
diameter of the saphenousepopliteal junction (dSPJ), and maximun small saphenous vein (SSV) diameter
(mdSSV) were measured. All patients received low molecular weight heparin (LWMH) at a prophylactic dose for a
week. Post-operatively, CDUS was performed after 72 h, 1 week, and 3 months.
Results: Venous interventions on 512 patients were performed: 449 (87.7%) underwent RFA of the GSV (Group
1), and 63 (12.3%) of the SSV (Group 2). At Day 3 post-operatively, CDUS documented 100% complete closure of
the treated saphenous vein segment. Overall, 40 (7.8%) cases of post-operative EHIT were identified: 29 in Group
1, and 11 in Group 2 (6.4% vs. 17.5%, p ¼ .005). Deep venous thrombosis or pulmonary embolism did not occur
in either group. At the 1 month follow up, all cases of EHIT regressed. In Group 1, on multivariate analysis, dSEVe
SFJ (OR, 1.13, p ¼ .036; 95% CI 1.01e1.27) was the only statistically significant predictor for EHIT. A dSEVeSFJ
distance of 4.5 mm yielded an 84% of sensitivity for EHIT prediction with a 72.4% positive predictive value. In
Group 2, univariate analysis did not identify independent risk factors for EHIT occurrence.
Conclusions: EHIT was higher than previously reported. The dSEVeSFJ was the most significant predictor for EHIT
in the GSV group.
Ó 2018 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.
Article history: Received 2 July 2017, Accepted 19 February 2018, Available online 23 May 2018
Keywords: Endovenous heat induced thrombosis, Radiofrequency ablation
INTRODUCTION
5
Presented at the Twenty-eighth Annual Meeting of the American
Venous Forum, Orlando, FL, February 24e26, 2016.
* Corresponding author. Vascular Surgery II and Thoracic Aortic Research
Centre, IRCCS Policlinico San Donato Teaching Hospital, University of Milan
School of Medicine, Piazza “E. Malan” 2, 20097 San Donato Milanese,
Milan, Italy.
E-mail address: doc.chiara@libero.it (Chiara Lomazzi).
1078-5884/Ó 2018 European Society for Vascular Surgery. Published by
Elsevier Ltd. All rights reserved.
https://doi.org/10.1016/j.ejvs.2018.02.025
In the past 15 years, endovenous ablation techniques have
drastically revolutionised the treatment of chronic superficial venous insufficiency, providing a minimally invasive
approach with excellent post-operative outcomes, patient
satisfaction, and quality of life.1e6 New techniques bring
new types of complications: endovenous heat induced
thrombosis (EHIT), which is defined as the extension of
thrombosis at the sapheno-femoral junction (SFJ), is a recognised unique complication secondary to radiofrequency
ablation (RFA).2,3 Both endothelial modifications and local
DUS predictors for EHIT
injury triggered by endovenous thermal ablation may
generate the formation of thrombosis beyond the target
treatment area, potentially leading to deep venous thrombosis (DVT) and/or pulmonary embolism (PE).6e8 Although
there are studies that describe EHIT management and
treatment, there are few data regarding the risk factors of
this potentially dangerous complication.9e12 The aim of this
study was to evaluate both clinical and color Doppler ultrasound (CDUS) parameters to identify potential risk factors associated with EHIT after RFA of either the great
saphenous vein (GSV), or the small saphenous vein (SSV).
MATERIALS AND METHODS
Patient cohorts
This was a single centre, observational study. The patients
were maintained in a prospectively created database which
was analyzed retrospectively. It included consecutive patients treated with RFA for chronic superficial venous
insufficiency. Patients treated from December 2010 to
February 2017 were included; for the final analysis, the end
of study was March 1, 2017. During the study period,
venous interventions were performed on 512 patients: 449
(87.7%) underwent RFA of the GSV (Group 1), and 63
(12.3%) of the SSV (Group 2). All patients were identified
from a computerised database registry that remained
consistent over the study period. Information about demographics, comorbidities, medical and surgical history,
operative details, and post-operative events during the
hospital stay and follow up were all registered.
Pre-operative venous assessment
All patients considered for endovenous thermal ablation
underwent clinical and CDUS evaluation. Pre- and postoperative ultrasound assessments were performed by
vascular surgeons who were certified in the examination of
the deep and superficial venous circulation, with more
than 10 years experience with CDUS examinations for both
venous and arterial disease detection and follow up. A set
protocol for the CDUS examination was used: it was
consistent for all assessments with the same scanner
(MyLab 50; Esaote, Genova, Italy). The technique of venous
duplex scanning complies with the technique accepted by
the Society for Vascular Surgery (SVS) and the American
Venous Forum (AVF).3 Briefly, pulsed wave Doppler with a
4e7 MHz linear array transducer was used. Evaluation with
duplex scanning was performed with the patient upright,
started below the inguinal ligament, and the veins were
examined at 3e5 cm intervals. In every examination both
the deep and superficial systems, as well as tributaries/
accessories and perforating veins were evaluated. The
following features were evaluated: visibility, compressibility, venous flow, measurement of the duration of reflux,
and augmentation. Flow characteristics and waveform
patterns were evaluated using respiratory variations (e.g.,
Valsalva manoeuvre, or manual compression of the limb
distal to the point of examination). The cut off value for
95
abnormally reversed venous flow (reflux) in the saphenous,
tibial, and deep femoral veins was 0.5 s. Pre-operatively,
the following parameters during CDUS of the GSV were
collected:
diameter of the sapheno-femoral junction (dSFJ);
distance between superficial epigastric vein and SFJ
(dSEVeSFJ);
maximum GSV diameter (mdGSV);
mean GSV diameter (adGSV) obtained from the mean of
three measurements taken at the proximal, middle, and
distal thirds of the thigh.
For the SSV, the following parameters were collected
during CDUS:
diameter of the saphenoepopliteal junction (dSPJ);
maximum SSV diameter (mdSSV).
Indication for operative intervention with RFA were as
follows:
classification 2e6, accordingly to the Clinical, Etiology,
Anatomy and Pathophysiology (CEAP) grading system2;
venous incompetence with reflux time > 0.5 s over a
segment length of at least 10 cm (both GSV and SSV);
failure of conservative medical therapy (e.g., persistence
or worsening of venous symptoms despite lifestyle
changes including exercise, leg elevation, management
of weight and diet, the use of compression hosiery, and
venotonic agents).
Exclusion criteria for RFA for chronic superficial venous
insufficiency included:
deep or superficial vein thrombosis of the lower limbs, or
previous ones with endoluminal thrombotic remnant;
pregnancy.
The superficial vein to be ablated was mapped and
marked on the skin at the end of examination. Informed
consent was signed by each patient; approval for the study
was obtained from the local Institutional Review Board,
accordingly to the National Policy in the matter of the Privacy Act on retrospective analysis of anonymised data. Also,
each patient received adjunctive treatment in the form of
elastic compression stockings, and venotonic agents, or
periodic evaluation with complex wound dressings in case
of ulcers.2
Operative management
All procedures were performed by one of four trained
vascular surgeons (C.L., V.G., S.S., M.C.) in the operating
theatre in compliance with the national health system rules.
A standard protocol was used for tumescent anaesthesia
(lidocaine 2%, 20 mL; sodium bicarbonate 8.4%, 5 mL),
made easier with the use of an infiltration pump (roller
pump), and mild sedation (intravenous remifentanyl,
96
Chiara Lomazzi et al.
months post-operatively. In the event of EHIT, a clinical visit
and CDUS evaluation were performed on a weekly basis;
LWMH as well as elastic compression stockings were
continued until thrombosis regression, but the dose was
increased to a therapeutic level in the event of a DVT.13
Definitions
Figure 1. Day 3 endovenous heat induced thrombosis of the great
saphenous vein: Level 5 according to Lawrence level of classification. CFV ¼ common femoral vein; EHIT ¼ endovenous heat
induced thrombosis; EV ¼ superficial epigastric vein; GSV ¼ great
saphenous vein; SFJ ¼ sapheno-femoral junction.
infusion rate 0.02 mg/kg - 0.15 mg/kg/min). Tumescent
anesthesia was used by all surgeons at the recommend
infusion rates of 10 mL/cm vein treated. Saphenous vein
ablation was performed with the same radiofrequency
catheter (ClosureFAST; Medtronic Inc., Santa Rosa, CA, USA)
technique. Duplex ultrasound was used to position the tip
of the catheter 2 cm caudal to the SFJ, and 2e3 cm caudal
to the SPJ prior to treatment. Concomitant phlebectomies
were performed as needed. Post-operatively, the operated
limb was wrapped with a single layer elastic bandage from
the ankle to the thigh, which remained in place for 24 h.
Each patient received a prophylactic dose (4000 IU for patients with body mass index (BMI) 30 kg/m2, 6000 IU for
those with BMI > 30 kg/m2) of low molecular weight
heparin (LWMH) with sodium enoxaparin (Clexane; Sanofi,
Milan, Italy). Following the procedure, the patients became
ambulatory and were discharged home within 2 h of the
intervention. A week of prophylactic dose of LMWH was
prescribed. The bandage applied intra-operatively was
replaced by an elastic stocking (18 mmHg) on Day 1 postoperatively, which was then continued for 1 month. In
the event of extensive superficial ecchymosis, the patients
were prescribed glycosaminoglycan polysulfide gel. All patients were evaluated with CDUS 72 h, 1 week, and 3
Endovenous heat induced thrombosis was defined as the
extension of the thrombosis from the saphenous vein
beyond the most proximal aspect of intended thermal
ablation, and was classified by the closure level (Fig. 1). The
closure level of the GSV was classified according to Harlander et al.10: Level 1 represented closure with thrombus
below the level of the SEV. Level 2 represented closure with
thrombus extension flush with the orifice of the SEV. Level 3
represented closure with thrombus extension flush with the
SFJ. Level 4 represented closure with thrombus bulging into
the common femoral vein (CFV). Level 5 represented
closure with proximal thrombus extension adherent to the
adjacent wall of the CFV past the SFJ. Level 6 represented
closure with proximal thrombus extension into the CFV,
consistent with a DVT. The closure level of the SSV was
classified according to Harlander-Lock et al.10: Level A closures defined thrombus extending 1 mm caudal to the
SPJ, Level B was characterised by flush thrombus or < 1 mm
with the popliteal vein, Level C included patient with
thrombus extending beyond the SPJ, and Level D defined a
DVT caused by the extension of the thrombosis to
completely occlude the popliteal vein.
Degree and symptoms of chronic superficial venous disease were classified accordingly to the CEAP grading system, and the Revised Venous Clinical Severity Score
(RVCSS).14,15 Morphologic characteristics and outcomes
were defined according to the clinical practice venous
guidelines of the European Society for Vascular Surgery
(ESVS) and the American Venous Forum (AVF).2,3
Statistical analysis
Clinical data were recorded prospectively in Microsoft Excel
(Microsoft Corp, Redmond, WA, USA), and statistical analysis was performed with SPSS, release 23.0 for Windows
(IBM SPSS Inc.; Chicago, IL, USA). Categorical variables were
presented using frequencies and percentages, continuous
variables were presented with mean standard deviation
(SD). For categorical variables, the Pearson’s chi-square test
was used; the independent samples Student t-test was used
for continuous variables. A paired t-test was used to evaluate the difference of adGSV and mdSSV before and at 1
week after RFA. A stepwise logistic regression model was
developed to identify variables associated with EHIT
development. The stepwise approach was confirmed by
backward and forward methods. The significance within the
models was evaluated with the Wald test, whereas the
strength of the association of variables with post-operative
EHIT was estimated by calculating the odds ratio (OR) and
95% confidence intervals (CI). The model was built using
variables that demonstrated p < .25 in univariate mode.
DUS predictors for EHIT
Table 1. Demographic characteristics and risk factors
N (%)
Group 1 (GSV)
Group 2 (SSV)
(n ¼ 449)
(n ¼ 63)
Age, mean SD (IQR)
53 12 (44e63) 54 12 (45e64)
M:F
136:313
17:46
Active smoking
54 (10.5)
55 (10.5)
Obesity (BMI > 30)
20 (4.4)
8 (12.7)
Hypertension
5 (1.1)
2 (3.2)
Autoimmunity
2 (0.4)
2 (3.2)
Anticoagulant Tx
0 (0)
3 (4.8)
Ischemic heart disease
0 (0)
2 (3.2
RVCSS, mean SD (IQR) 6 3 (3e7)
6 4 (3e7)
N ¼ number; SD ¼ standard deviation; IQR ¼ interquartile range;
M ¼ male; F ¼ female; BMI ¼ body mass index; Tx ¼ treatment;
CEAP ¼ Clinical, Etiology, Anatomy, and Pathophysiology;
RVCSS ¼ revised venous clinical severity score.
The model was calibrated by the HosmereLemeshow
goodness of fit test, and residual diagnostics (deviance
and degree of freedom of b). The discrimination of the
model was obtained by calculating the area under the
receiver operating characteristic (AUROC) curve. A p
value < .05 was considered significant.
RESULTS
Cohort and operative data
Demographic data and risk factors of the two groups are
summarised in Table 1. Primary technical success was obtained in all but one (99.8%) patient: in this case, the
catheter was unable to pass the most proximal aspect of
the GSV, and an open SFJ ligation was performed. Neither
operative/in hospital mortality nor major morbidity were
observed. On day 3 post-operatively, CDUS documented
100% of complete closure of the treated saphenous vein
segment. At 1 week, the mean adGSV diameter decreased
significantly in Group 1 (10.1 3.4 vs. 6.1 2.4; p < .001)
as well as mdSSV in Group 2 (8.9 3.2 vs. 7.4 2.8;
p ¼ .002).
Post-operative complications are reported in Table 2.
EHIT occurrence
Overall, 40 (7.8%) cases of post-operative EHIT were identified, a finding which was significantly different between
the two groups: 29 developed in Group 1 and 11 in Group 2
(6.4% vs. 17.5%, p ¼ 0.005). Classification and closure
extent in both groups are represented in Table 3. The
prevalence of EHIT did not change among operating surgeons. When EHIT cases were evaluated, Group 1 patients
were significantly older (56 12 vs. 48 8 years, p ¼ .049,
and had a higher RVCSS (7 3 vs. 5 2, p ¼ .049) than
Group 2 patients. Thrombus progression did not occur. Also,
no patient in either cohort had a DVT or PE. At the 1 month
follow up, all cases of EHIT had regressed.
EHIT predictor analysis
Univariate analysis in Group 1 identified statistically significant variables (Table 4). In particular, when stratified for
97
Table 2. Post-operative complications
N (%)
Type of complication
Wound hematoma
Access hematoma
At phlebectomy
surgical incision
Bruising
Thrombophlebitis
Skin pigmentation
0
5 (0.9)
3
2
9 (1.7)
7 (1.4)
Treatment (N)
Surgical revision (1)
Spontaneous
resolution (4)
Spontaneous
resolution
Spontaneous
resolution
Paresthesia
7 (1.4)
Lymphangitis
5 (0.9)
Antibiotics (3)
DVT
0
N ¼ number; DVT ¼ deep venous thrombosis.
tertiles ( 44 vs. 45e64 vs. 65), age was not statistically
associated with the incidence of EHIT (8.9% vs. 7.7% vs.
6.6%, p ¼ .812). The combination of RFA and adjunctive
phlebectomies (n ¼ 484, 94.3%) was not significantly
associated with the development of EHIT (8.9% vs. 0%,
p ¼ 0.246). On multivariate analysis, dSEVeSFJ (OR per
1 mm increase, 1.13, p ¼ 0.036; 95% CI 1.01e1.27) was the
only statistically significant predictor for EHIT; a CEAP
Class 3 showed a trend without reaching statistical significance (OR per class increase, 0.35, p ¼ .052; 95% CI
0.12e1.01). The HosmereLemeshow goodness of fit test
(chi-square [8 d.f.] ¼ 10.5, p ¼ 0.232) and ROC analysis
(AUROC, 0.674; 95% CI 0.557e0.791) revealed a reasonable
calibration, and discrimination for the multivariate model
(Fig. 2). Fig. 3 shows the distribution of dSEVeSFJ in Group
1. dSEVeSFJ of 4.5 mm yielded a 84% sensitivity, 57%
specificity, and 72.4% positive predictive value for EHIT
prediction (AUROC, 0.731; 95% CI 0.634e0.828). In Group
2, univariate analysis did not identify significant risk factors
for EHIT occurrence.
DISCUSSION
In this study the dSEVeSFJ distance, as measured on preoperative CDUS, was significantly associated with the
occurrence of EHIT after RFA of the GSV.
Table 3. Classification of EHIT and closure level
Group 1
(N ¼ 449)
Lawrence
Level 1
Level 2
Level 3
Level 4
Level 5
Locke
Class A
Class B
Class C
Total
N ¼ number.
Group 2
(N ¼ 63)
Total
(N ¼ 512)
1 (1.6%)
6 (9.5%)
4 (6.3%)
11 (17.5%)
40 (7.8%)
0
20 (4.5%)
6 (1.3%)
2 (0.4%)
1 (0.2%)
29 (6.4%)
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Chiara Lomazzi et al.
Table 4. Univariate analysis after RFA of the GSV
Variable
EHIT
No EHIT
p
(n ¼ 29)
(n ¼ 420)
Obesity (BMI > 30), (%) 15 (3.6)
5 (17.2)
.006
CEAP 3, (%)
21 (13.2)
8 (4.7)
.016
RVCSSa
6.92 2.8
5.45 2.8 .012
dSFJb
10.7 2.9
8.9 2.8
.002
adGSVb
11.85 4.1 9.5 3.5
.001
dSEVeSFJb
8.4 5.3
5.5 3.3
<.001
RFA ¼ radiofrequency ablation; GSV ¼ great saphenous vein;
n ¼ number; OR ¼ odds ratio; CI ¼ confidence interval;
BMI ¼ body mass index; CEAP ¼ Clinical, Etiology, Anatomy, and
Pathophysiology; RVCSS ¼ revised venous clinical severity score;
dSFJ ¼ diameter of the sapheno-femoral junction;
adGSV ¼ mean diameter of the great saphenous vein; dSEVe
SFJ ¼ distance between superficial epigastric vein and
saphenofemoral junction.
a
Per 1 point increase.
b
Per 1 mm increase.
The occurrence of endovenous heat induced thrombosis
has been reported uncommonly after endovenous thermal
ablation therapy for GSV and SSV insufficiency. Although
the reported incidence is < 3% in large series and most
patients remain asymptomatic, some papers have reported
pulmonary embolism as a potential alarming complication.8,9,16e18 Therefore, being able to identify pre-operative
factors that may increase the occurrence of EHIT would be
beneficial in the post-operative monitoring of these higher
risk patients. In this series, there are several explanations of
the overall high incidence of EHIT: first, the aim was to
describe all types of EHIT, independently of the related
clinical concern and consequence. Secondly, post-operative
follow up surveillance was performed meticulously, an
Figure 2. Receiver operating characteristic curve analysis of the cut
off levels for predicting endovenous heat induced thrombosis
based on the distance between the superficial epigastric vein and
the sapheno-femoral junction.
Figure 3. Distribution of the distance between superficial epigastric
vein and the sapheno-femoral junction in the cohort of the radiofrequency ablation for great saphenous vein insufficiency.
approach which is supported by the literature.14 The follow
up protocol enabled identification of the highest number of
EHIT possible, which otherwise, with a less meticulous
follow up would have been lost.18
Thromboprophylaxis of EHIT is described with variability
in randomised trials and single centre studies. Although
EHIT occurred despite the systematic use of LWMH during
the peri-operative period, it remained asymptomatic and
dissolved in the weeks after the procedure.14,16 In particular, Lawrence et al.13 developed an algorithm for management of different levels of closure and reported no case
of extension of thrombus into the femoral vein with use of
either close observation or LMWH. Routine use of LMWH
for DVT prevention after RFA of the GSV has not been reported or recommended by the ESVS venous guidelines.
Thromboprophylaxis was routinely used for different reasons: firstly, there are no current or definitive data supporting the absence of potential clinical sequelae after type
1 EHIT development and, secondly prevention of EHIT was
not targeted, rather the progression of this thrombotic
complication was limited in the event it might have
occurred before CDUS detection. Thirdly, the vast majority
of patients underwent adjunctive stab phlebectomies,
which alone have been identified as a risk factor for DVT
formation. Finally, taking into account all these factors, a
DVT or PE would be a more serious event if compared with
the anecdotal occurrence of a complication due to LWMH.
The prevalence of EHIT was higher than previously reported,
despite the use of chemoprophylaxis in all patients. This
finding may suggest that the use of LMWH does not protect
against EHIT development; however, previous studies did
not compare patients treated with LWMH after RFA versus
non-chemoprophylaxis. Chemoprophylaxis was used to
prevent thrombus extension or DVT-PE in the patients,
DUS predictors for EHIT
primarily in those treated with RFA and stab phlebectomies,
who have been reported to be at higher risk.2,19 Nevertheless, the aim of this study was not to assess chemoprophylaxis, and from the findings a definitive conclusion
cannot be reached in support of the use of chemoprophylaxis in such cases. Further studies may potentially clarify
this topic. Previous studies have shown that pre-operative
activation of the hemostatic system plays an important
role in the development of thrombotic complications after
thermal ablation of the GSV. Thus use of biomarkers has
been suggested to identify patients at high risk of EHIT in
order to optimise the antithrombotic regimen.20 Although
biomarkers are currently used to detect and follow patients
with suspected or documented primary DVT or PE, they
were not routinely evaluated in this group of patients.
Endothermal ablation of the SSV has been reported less
frequently than for GSV insufficiency, with no meticulous
follow up; in addition studies have rarely analysed potential
predictors of EHIT after RFA of the SSV.12,18e23 Despite the
marked numerical difference between the two groups, EHIT
prevalence was considerably higher after treatment of the
SSV. This finding is supported by a recent series of Doerler
et al.,24 who showed significant differences in outcomes
between GSV and SSV cases. Considering pre-operative
CDUS evaluation, there were no variables identified to be
predictive of post-operative EHIT in this group. This event
may be correlated with the different anatomy of the SFJ and
SPJ. The SPJ does not have large branches as does the superficial epigastric vein which, at the proximal GSV contributes to the avoidance of thrombosis development with a
“wash out” phenomenon. Specific to this study, EHIT was
more likely to occur with increased distance between the
SEV and SFJ. Variability in the anatomy of the SEV has been
described including the possibility of the SEV being a tributary of an anterior accessory GSV. There are no existing
data supporting this hypothetical effect from a haemodynamic point of view. In this study, the SEV was always
identified as a tributary vessel of the GSV. However, even in
the case of that anatomical variation, the protective haemodynamic concept would have been maintained.
Previous studies have uniformly reported that GSV
diameter played a key role in the development of EHIT after
RFA.12,13 In particular, Sufian et al.16 noted that, in their
cases of EHIT, a significantly increased GSV or SSV diameter
has been found. Similar findings could not be reproduced in
this study. In contrast, a new, single parameter was found
which was a significant predictor for EHIT after RFA of the
GSV: the distance between the superficial epigastric vein
and the SFJ. These data find a reasonable justification based
on the interaction between anatomy and haemodynamics
in this region. The longer the dSEVeSFJ the greater the
probability of developing an EHIT possibly due to a protective “wash out” effect played by the SEV which is more
rapid when it is nearer to the SFJ.25
Age is a known marker of potential post-operative complications in several vascular settings, but in endothermal
ablation of superficial venous insufficiency this is not constant finding.12,26 Age was not a significant predictor
99
overall; however, among those who experienced EHIT, age
was significantly higher in the GSV group. In this latter
group, patients with EHIT were characterised by a significantly higher RVCSS score: these two findings may find
justification in the fact that older patients are potentially
those with a disease of longer duration and thus a worse
clinical scenario.
Limitation and future perspectives
The present study has obvious limitations: it is retrospective
in nature, and both sample size and the number of events
were low, particularly in Group 2. Thus the statistical significance may be affected by Type II error. Furthermore, the
pattern of termination of the SSV was not correlated with
the occurrence of EHIT. Despite these limitations, the cohort
is homogeneous in terms of clinical data, and outcomes
adhered systematically to the proposed guidelines which
allows for comparison with other published studies.
Recognizing all these limitations, the finding of the significant association between EHIT and this new anatomical
parameter (e.g., dSEVeSFJ) may be integrated into future
ESVS venous guidelines, in order to optimise both the preoperative stratification risk, and also to refine the technique
of RFA in these selected cases.
CONCLUSIONS
The following are clinically relevant findings: first, close
post-operative CDUS surveillance has revealed that EHIT
prevalence was higher than previously reported, and seems
to be more frequently associated with RFA of the SSV;
secondly, a predictive factor associated with post-operative
EHIT in patients treated with RFA of the GSV was identified.
The distance between the SEV and the SFJ was significantly
related to the development of post-operative EHIT.
CONFLICT OF INTEREST
Prof. Santi Trimarchi and Dr. Chiara Lomazzi are consultants
and speakers for Medtronic Vascular (Santa Rosa, CA, USA),
but do not declare conflict of interests for this specific
study.
FUNDING
None.
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