CASE IMAGE
A 80-year-old woman with chronic atrial fibrillation on long-term
anticoagulation was diagnosed with normal pressure hydrocephalus and
referred for ventriculoperitoneal shunt placement. Due to heightened
bleeding (HAS-BLED score=4) and stroke (CHA2DS2-VASc score=4) risks,
left atrial appendage occlusion with Watchman device was recommended
prior to neurosurgical intervention.
Baseline transesophageal echocardiography (Panel A-D )
demonstrated a left atrial septal pouch (ASP), formed by two distinct
parallel inter-atrial septal layers, creating a tunnel-like inter-atrial
chamber that communicated with the left atrium (LA; broken line) and
which contained a thrombus (arrowhead) within its cavity
(Video-1; asterix marks mouth of the ASP; RA, right
atrium) . Recognizing this, a SENTINELTMcerebral embolic protection device was placed prior to transseptal
puncture. A slight shift in thrombus position was noted during septal
tenting (Panel E ) and, unfortunately, transseptal puncture
resulted in thrombus extrusion from the tunnel into the left atrium
before embolizing systemically (Panel F-H; Video-2 ). Following
the Watchman device placement, assessment of the ASP showed development
of spontaneous echo-contrast (yellow star) within the pouch cavity
despite the newly created left-to-right shunt at the transseptal
puncture site (Panel I ). A decision was made to obliterate the
body of the ASP cavity to prevent future thrombus formation, utilizing a
Cardioform septal occluder (Panel J-K ). The remainder of
post-procedural course was uncomplicated. No thrombus was identified on
examination of the SENTINELTM device post-procedure.
Intraprocedural cerebral angiography performed at case conclusion was
also negative for intracranial embolism (Panel L ). The patient
was admitted overnight for observation and was discharged home the next
day without clinical evidence of systemic embolization.
Atrial septal pouch is a common anatomic variant of the interatrial
septum and a nidus for thrombus formation, which may be associated with
thromboembolic complications.1 Left-sided atrial
septal pouch has been associated with an increased risk of cryptogenic
stroke.2 Left-sided atrial septal pouch thrombus
should be considered a relative contraindication to transseptal
puncture. This case highlights the importance of a thorough
echocardiographic evaluation of the atrial septum prior to transseptal
access and recognition of this anatomic septal variant as a potential
cardiac source of embolism.