DISCUSSION
Optimum surgical treatment of PSS arguably requires both endovascular
intervention and adequate surgical decompression of the SV surrounding
extrinsic structures. This is often further augmented via
post-decompression secondary endovascular intervention or vascular
reconstruction to ensure long term patency of the venous wall and lumen.
Endovascular treatments such as mechanical thrombectomy performed in
conjunction with CDTL, when combined with decompression and
reconstruction as needed, seems to be particularly promising.
The clinical data from the series included in this literature review has
shown that most patients undergoing thrombolysis and decompression had a
definite venous wall stenosis secondary to the longstanding extrinsic
compression: 42.3% (n=11) underwent venoplasty at some point. The
durability of open surgery is impressive where adequate venolysis or
early venoplasty seems to maintain patency of the SV and reduce rates of
recurrent stenosis. Three developed SV occlusion post surgery of which
one occurred on the first post operative day (symptomatic) and the
second on routine venography four months later (asymptomatic). The third
developed symptoms of arm swelling and pain thirty-six months post
initial TA decompression which was lysed and underwent a further
venoplasty successfully. The majority of patients in the series also had
underlying SV stenosis following thrombolysis and decompression –
possibly due to longstanding extrinsic compression of the SV leading to
transmural fibrosis and ultimately thrombosis.
It must be highlighted that all patients in the cohort underwent
thrombolysis via CDTL only. As outlined previously, CDTL is associated
with several clinical limitations, such prolonged treatment time and key
adverse events including pulmonary and cerebral embolism and entry site
bleeding.4 Our review of current literature suggests
that there exist viable alternatives to CDTL for the management of PSS.
Schneider et al reported an average thrombolysis time of 12 hours
overall (compared to 22 hours in the included series) when the AngioJet
mechanical thrombolysis system was used for thrombus debulking prior to
CDTL.11 Similarly, Shah et al. reported that use of
the AngioJet system yielded successful thrombolysis in 2-3 hours for
three patients.14 Results from Hileman et al. also
seem to suggest the viability of mechanical thrombectomy as an
alternative to CDTL in PSS: 93% of patients included had more than a
50% clot reduction when treated with mechanical thrombectomy, compared
to 79% of patients treated with CDTL only.15Furthermore, O’Sullivan and colleagues reported an average thrombolysis
time of 91 minutes in using the Trellis thrombolysis
catheter.16 This alternative to traditional CDTL, also
conventionally used for treating LEDVT, was associated with 50-95% clot
removal in 82% of patients, and > 95% removal in 3
patients. It was also associated with no major
complications.16 The extent to which the residual SV
stenosis experienced by the patients in the included series can be
attributed to CDTL being performed over other thrombolysis methods is
unclear. Though more research into the use of such endovascular devices
would be prudent, it seems that approaches typically used to tackle
lower-limb DVTs offer a promising step forward in the endovascular
management of PSS.
Data from Wooster et al. also seems to suggest that endovascular
intervention can help improve overall clinical outcome in patients with
upper extremity DVT in general. Sixty seven percent of patients in their
cohort underwent endovascular intervention, which included procedures
such as PTA, patch PTA, and stenting. A 100% surgical success rate with
symptomatic relief was observed in patients that underwent endovascular
intervention in conjunction with decompression. Moreover, this approach
was associated with low rates of SV reocclusion and symptom recurrence
(9.4% and 11.3% respectively).6 The clinical
outcomes reviewed from available literature are summarised in Table 2.
Other contributory factors for re-thrombosis were incomplete resection
of the costoclavicular ligament (CCL) and/or tendon of the subclavius
muscle. The CCL is a rigid structure medial to the SV which can be seen
by the TA and PC routes and causes SV compression particularly when the
insertion into clavicle is lateral (figure 2). Similarly, the anteriorly
lying subclavius muscle may be a further source of external compression
on the SV and is easily identified by the IC route requiring excision to
expose the vein. Recent series comparing the SC to the IC route for SV
decompression have shown improved patency rates with fewer postsurgery
symptoms for the IC approach17. Additionally, Molina
et al. emphasise the importance of surgical access to the medial aspect
of SV to adequately decompress the vessel
surgically.18-21 The importance of carrying out
decompression conjunction with endovascular interventions is therefore
clear – as emphasised by Zurkiya et al., the degree of SV stenosis
immediately post-decompression is usually comparable to that of
pre-decompression because anatomical resection does not deal with
intrinsic lesions to the SV.7 This also suggests that
prolonging the interval between thrombolysis and decompression, and
indeed between decompression and adjunctive intervention, would prove
only detrimental to clinical outcome: time from presentation to
decompression > 14 days is a documented factor associated
with worse clinical outcome, as it may lead to early re-thrombosis
warranting re-intervention down the line.22
There is little current data concerning the approach surgeons use to
manage PSS, both in terms of open decompression and endovascular
intervention. A survey of 60 United Kingdom (UK) members of the Vascular
Surgical Society showed 4% performed surgery for PSS by a PC incision
with 55% opting for a TA approach and 28% for SC23.
Hence, at least in the UK, there appears to be considerable variation in
approaches adopted. This report dates to 2004 and clinical practice may
have significantly changed since then.
Not a single randomised controlled trial has been conducted to determine
the optimum surgical approach for PSS, perhaps due to its low incidence.
Hence, it may not be feasible for a prospective randomised trial to be
performed with sufficient power to gain a definitive answer as to even
the optimum surgical approach to treat acute PSS - particularly if the
TA and PC/IC outcome differences are minimal. What seems increasing
clear, however, are the added benefits of undertaking endovascular
intervention alongside surgical decompression, both in terms of
preoperative thrombolysis and postoperative adjunctive venous repair.
A prospective randomised trial investigating the relative efficacies of
the various approaches to preoperative endovascular intervention, for
example mechanical thrombectomy and CDTL techniques, would therefore be
prudent. Such a trial would help to elucidate whether the management of
PSS, and indeed UEDVT in general, would benefit from treatment
strategies traditionally employed to tackle LEDVT or even intraarterial
pathologies. Indeed, the shift towards endovascular approaches has
gained great popularity amongst surgeons managing complex cardiac and
aortic pathologies – one needs only to look towards the advent of
thoracic endovascular aortic repair as an example of the potential for
endovascular procedures to successfully resolve complex cardiovascular
surgical pathologies, without the need for large incisions and surgical
trauma.24