<div>Large paradoxical embolus through a patent foramen ovale following
arteriovenous graft thrombectomy</div><div>Running head: Large thrombus through a patent foramen ovale</div><div>Chadi Allam<sup>1,2</sup>, Zeina Kadri<sup>1,2</sup>,
Rabih Azar<sup>1,2</sup></div><div><sup>1</sup> Faculty of Medicine, Saint-Joseph University,
Beirut, Lebanon.</div><div><sup>2</sup> Division of Cardiology, Hôtel-Dieu de France
Hospital, Beirut, Lebanon.</div><div>First author: Chadi Allam, MD</div><div>Corresponding author: Rabih Azar, MD, MPH, FACC</div><div>Division of Cardiology, Hôtel-Dieu de France Hospital, Alfred Naccache
Blvd, Beirut, Lebanon.</div><div>Tel: +9613590999</div><div>Fax: none</div><div>Email: razar@usj.edu.lb</div><div>Chadi Allam: chadiallammd@gmail.com</div><div>Zeina Kadri: zkadri@hotmail.com</div><div>Key words: echocardiography, ultrasound, thrombosis, paradoxical
embolism, patent foramen ovale</div><div>Conflict of interest: none</div><div>Abstract</div><div>An 86-year-old man with end-stage renal disease on hemodialysis with an
arteriovenous fistula in his left upper extremity presented to his
hemodialysis session with thrombosis of his arteriovenous fistula. The
patient underwent surgical thrombectomy. The patient later showed
evidence of peripheral embolization and livedo reticularis.
Transthoracic and transesophageal echocardiograms revealed a large
thrombus (5x2 cm) in the left atrium prolapsing to the right atrium via
a patent foramen ovale and another thrombus (white arrow) adherent to
the apical wall of the right ventricle. The thrombus in the left atrium
was intermittently crossing the mitral valve and entering the left
ventricle.</div><div>An 86-year-old man with end-stage renal disease on hemodialysis with an
arteriovenous (AV) graft in his left upper extremity presented to his
hemodialysis session with orthostatic hypotension and orthopnea.
Clinical examination revealed thrombosis of his AV fistula. A
transthoracic echocardiogram (TTE) showed global hypokinesia of the left
ventricle (LV) with an estimated ejection fraction of 25% and no
significant valvular disease. The patient underwent surgical
thrombectomy and was admitted to the intensive care unit (ICU), where he
underwent hemodialysis. We initiated anticoagulation with unfractionated
heparin.</div><div>Following his admission to the ICU, the patient showed evidence of
peripheral embolization and livedo reticularis. Ultrasound revealed
occlusion of the left tibial artery. A chest CT-angiogram ruled out
pulmonary embolism. Brain MRI showed multiple small infarcts. A second
TTE and a transesophageal echocardiogram revealed a large thrombus (red
arrow) (5x2 cm) in the left atrium (LA) prolapsing to the right atrium
(RA) via a patent foramen ovale (FO) and another thrombus (white arrow)
adherent to the apical wall of the right ventricle (RV) (Figure panels
A, B and C, Videos 1 and 2). The thrombus in the LA was intermittently
crossing the mitral valve and entering the LV (Figure panel A, Video 1).
Due to high surgical risk, we adopted a noninvasive approach consisting
of anticoagulation with unfractionated heparin.</div><div>Follow-up TTE three weeks later showed a decrease in thrombus size
(Figure panels D and E, Videos 3 and 4).</div><div>This is a rare documentation of a large thrombus crossing a patent
foramen ovale and causing paradoxical embolization.</div><div>Figure legend:</div><div>A, Baseline echocardiography, apical four chamber view, showing a large
thrombus in the left atrium crossing the mitral valve and entering the
left ventricle and also prolapsing to the right atrium via the foramen
ovale (red arrows). Another thrombus appears adherent to the apical wall
of the right ventricle (white arrow). B and C, Transesophageal
echocardiogram with 3D reconstruction showing a thrombus (red arrows) in
the left atrium crossing the foramen ovale and prolapsing in the right
atrium. D and E, Follow-up transthoracic echocardiography three weeks
later showing a decrease in thrombus size (red arrows). LV = left
ventricle; RV = right ventricle; LA = left atrium ; RA = right atrium;
FO = foramen ovale.</div><div>Video 1: Transthoracic echocardiography apical four chamber view showing
a large thrombus in the left atrium crossing the mitral valve and
entering the left ventricle and also prolapsing to the right atrium via
the foramen ovale. Another thrombus appears adherent to the apical wall
of the right ventricle.</div><div>Video 2: Transesophageal echocardiogram showing a thrombus in the left
atrium crossing the foramen ovale and prolapsing in the right atrium.</div><div>Video 3: Follow-up echocardiography (long axis view) three weeks later
showing a decrease in thrombus size.</div><div>Video 4: Follow-up echocardiography (apical 5-chamber view) three weeks
later showing a decrease in thrombus size.</div>