WHAT ROLE DOES ENDOVASCULAR INTERVENTION PLAY IN MANAGING PSS?
Once the diagnosis of PSS is confirmed via history, physical exam, and
imaging (such as X-ray of the thoracic inlet, duplex ultrasonography, or
venography), holistic treatment typically proceeds in several stages,
beginning with thrombolysis, followed by surgical decompression, and
finally adjunctive angioplasty or venous bypass in certain
cases.4
At this juncture, it is worth noting that a hybrid endovascular/open
decompression approach is not always taken. Depending on local
guidelines, patient characteristics, and myriad factors, the managing
clinician may opt to proceed with only endovascular intervention or only
open decompression. An approach employing both endovascular techniques
alongside open decompression is associated with 100% technical success
rates, and high rates of event-free survival.6 Zurkiya
et al. emphasise that timely endovascular lysis or debulking of the
thrombus is a well-documented contributing factor to the preservation of
long-term luminal patency, and to the mitigation of re-occlusion,
scarring, and intimal fibrosis.7 Further, Koury et al.
suggests that surgical decompression may not be required if complete
lysis is achieved via thrombolysis and there remains no evidence of
residual stenosis or re-thrombosis.8
The endovascular management of PSS is chiefly centred on either CDTL or
endovascular thrombectomy. Koury et al. describe the surgical technique
for CDTL in upper extremity DVT (UEDVT) as beginning with gaining venous
access in the ipsilateral upper extremity.8 Venography
is carried out to determine the extent of thrombosis. The guidewire is
then crossed over the lesion, to allow the infusion catheter to be
introduced as near the lesion as possible. Thrombolytic agents such as
tissue plasminogen activator or urokinase is then infused for a duration
of at least 8 hours, or in some cases up to 72 hours. Patient fibrinogen
levels and subclavian vein patency are monitored continuously.
Catheter-related thrombosis can be prevented via infusion of a
subtherapeutic dose of heparin. Koury et al. further note that CDTL is
often augmented with mechanical thrombectomy, angioplasty, or
endovascular stent placement to correct factors such as underlying
stenosis.8
Intriguingly, Landry et al. note that CDTL is often associated with
prolonged treatment durations and adverse events including cerebral
haemorrhage, pulmonary embolism, and access site bleeding. As a result,
mechanical thrombectomy using devices such as the AngioJet used with the
power pulse spray technique are being increasingly employed to tackle
PSS (as opposed to iliofemoral DVTs).4
The AngioJet utilises a perforated catheter tip through which
high-velocity, high-pressure streams of saline are projected. The
resulting local region of low pressure allows entrapment and retrieval
of bulky thrombi via the Venturi-Bernoulli effect.9,
10 Though this system has historically been used more extensively for
thrombus debulking in acute coronary syndromes and iliofemoral DVTs,
Schneider and colleagues suggest the use of the AngioJet system in the
setting of PSS is promising - they report an average treatment time of
12 hours overall, a significant reduction in comparison to that of
CDTL.11
Completion of thrombolysis via endovascular intervention is then
typically followed by surgical decompression of surrounding anatomical
structures, before further adjunctive endovascular measures are
implemented. Aggressive angioplasty prior to surgical decompression is
generally discouraged, to prevent inflicting barotrauma to the wall of
the SV while under anatomical compression.