Keywords: Aneurysm. Colitis. thromboembolism
Key clinical massage
The atrial septal aneurysm is a rare cardiac abnormality with
thromboembolic potential and should be considered in a patient with
ischemic colitis with no obvious risk factors.
Abstract
The atrial septal aneurysm is a rare cardiac abnormality that is usually
detected during routine echocardiography or evaluation of cases with
thromboembolism. It may be isolated or associated with other cardiac
defects i.e. most often patent foramen ovale. Atrial arrhythmias and
arterial embolisms are associated with complications that must be
treated with anticoagulants. We report a 62 years old male who presented
with abdominal pain and bleeding per rectum found to have ischemic
colitis and atrial septal aneurysm on transesophageal echocardiogram,
systemic thromboembolism is one of the complications of atrial septal
aneurysm most of the reported cases are associated with stroke, TIA and
renal emboli. our patient treated with anticoagulation, Rivaroxaban.
Introduction
An atrial septal aneurysm is defined as “redundant and mobile
interatrial septal tissue in the region of the fossa ovalis with a
phasic excursion of at least 10 to 15 mm during the cardiorespiratory
cycle “(1).it can be classified according to their intrusion into the
left or right atrium and according to their motion during the
respiratory cycle (1).the aneurysm may either protrude preeminently into
the right or left atrium or produce striking oscillation into the atrial
cavities during the respiration according to variation in the pressure
differences between the atria (1)(2). atrial septal aneurysm is most
commonly discovered incidentally during a routine evaluation, but in
some populations, it can be associated with systemic thromboembolism
(1)(3)(4) and intracardiac shunt if it is associated with one or more
atrial septal defects, the commonest association is patent foramen ovale
(5).
Diagnosis of atrial septal aneurysm usually through a transthoracic
echocardiogram, a however transesophageal echocardiogram is more
sensitive as the interatrial septum can be visualized more consistently
(6).
Case presentation
we report 62 years old male who presented to our facility with one-day
history of severe lower abdominal pain associated with fresh bleeding
per rectum. the patient had a history of hypertension and diabetes for a
long time controlled with medications. upon presentation, the patient
was in pain but conscious, alert, oriented, afebrile, and vitally
stable. The abdominal exam was soft, lax with mild lower abdominal
tenderness, the digital rectal examination was positive for blood. The
cardiac exam was normal. his blood works showed mild neutrophilic
leukocytosis and normal hemoglobin level. other labs with normal limits.
Autoimmune and thrombophilia workup were both negative, viral serology
for hepatitis B, C and HIV were negative.
CT scan of abdomen and pelvis with contrast showed diffused colitis
involving entire descending colon with peri-colonic fat stranding and
possible reduced bowel wall perfusion with poor contrast filling of
distal branches of the left colic artery but without major vascular
occlusions or stenosis which goes with the possibility of ischemic
colitis (pictures 1 and 2). Colonoscopy was done and showed blushed
mucosa goes with ischemia. biopsy result confirmed the diagnosis of
ischemic colitis which showed necrotic bowel mucosa with fibrin thrombi
and fibrinous material (pictures 3 and 4). Patient underwent 12 leads
Electrocardiogram which was sinus and no arrhythmias, transthoracic
Echocardiogram showed mild mitral valve regurgitation, mild to moderate
tricuspid valve regurgitation, and suspicion of an atrial septal
aneurysm with no obvious shunt across it. Bubble contrast Echocardiogram
was negative for shunt across the atrial septum and the left atrium was
clear with no thrombus.
Transesophageal echocardiogram showed atrial septal aneurysm, but was no
patent foramen ovale or any other atrial septal defects (pictures 5 and
6). bilateral lower limb doppler both were negative for deep veins
thrombosis. 48 hours Holter was negative for atrial fibrillations. The
patient was counseled about the conventional anticoagulation Vs DOAC
(direct oral anticoagulation), pros and cons were explained to him and
he chose to be in DOAC. he was started on Rivaroxaban 15 mg twice per
day for 21 days then 20 mg daily and discharge on the same regimen. he
was followed after 1-week form the date of discharge and there were no
complications and he was compliant with his medication. till writing
this case there was no documented complications or emergency visit for
any reason.
Discussion
Our patient suffered from ischemic colitis which was proven by
colonoscopy and tissue biopsy. His CT scan finding goes more with the
embolic nature of disease rather than diffused atherosclerosis, and the
only risk factor was atrial septal aneurysm which is a potential risk
factor for cardiogenic embolism. After a discussion with cardiology and
gastroenterology, our patient was labeled as arterial embolization with
ischemic colitis secondary to an atrial septal aneurysm and was started
on anticoagulation with Rivaroxaban (off label).
Atrial septal aneurysm manifestations can be either atrial arrhythmias
or arterial embolisms. It can act as a source of arrhythmic focus
leading to atrial tachycardias (6)(7). Arterial embolism is a well-known
complication, different studies had shown a significant association
between the atrial septal aneurysm and arterial embolism(1)(3)(4).
The echocardiogram is a gold stander diagnostic tool for an atrial
septal aneurysm which is usually discovered during routine tests or
during the evaluation of cardioembolic stroke or arterial embolisms.
comparing transthoracic echocardiogram with transesophageal, the last
one showed to be more sensitive in picking up atrial septal
aneurysm(1)(6). other modalities like cardiac tomography and cardiac
magmatic resonance showed to be useful as well for the diagnosis(8)(9).
Treatment lines for this pathology vary according to the presentation
and associated structural cardiac anomalies, in an asymptomatic patient
with isolated atrial septal aneurysm no specific treatment is required
after ruling out intracardiac thrombus. In other hands, in a patient
with cryptogenic stroke and presence of isolated atrial septal aneurysm
options including medical therapy with antiplatelets or anticoagulation
as in case of recurrent stroke while taking antiplatelets. rarely
surgical excision of the defect is considered in a patient with a
recurrent stroke whom antiplatelet or warfarin fail to prevent stroke
recurrence or in patients with a large left to right shunt leading to
right heart enlargement. Percutaneous device closure is also rarely
performed as well(10).
Furthermore, in patients with atrial arrhythmias and embolic episodes,
the preferable treatment is oral anticoagulation for secondary
prevention. Most the authorities recommend traditional anticoagulation
like in the case of renal artery emboli limited to one of the renal
arteries or segmental branches (11). Embolectomy is another option in
case of bilateral renal artery embolism if the patient suitable for the
procedure. Lastly, intra-abdominal thrombolysis is also a valid option
in such cases(12). In the patient with stroke or TIA American heart
association/ American stroke association has recommended to use aspirin
for secondary prevention and warfarin can be used in high-risk
patients(13). And in other case reports of stroke associate with atrial
septal aneurysm anticoagulation was employed as well(3)(14).
Moreover, in one case report a patient with paroxysmal atrial
fibrillation developed intracardiac thrombus after found to had an
atrial septal aneurysm and followed for 3 years. The patient started on
warfarin, six months later no thrombus was found in repeated
echocardiogram but the defect persists despite adequate anticoagulation
later patient offer surgery (15). Till now there is no reported case in
literature of ischemic colitis associated with an atrial septal aneurysm
and the uses of DOAC on such cases and on systemic arterial embolization
secondary to atrial septal aneurysm has not been studied as well.
Conclusion
It is concluded that in a patient with ischemic colitis and no obvious
risk factors atrial septal aneurysm is a cardiac abnormality with
thromboembolic potential and should be considered.
Acknowledgment
The authors would like to acknowledge the internal medicine residency
program for their support.
Statement of Ethics
The patient consented to the publication of his case.
Disclosure statement
The authors have no conflict of interest.
Authors contributions
Dr. Eihab A. Subahi and Dr. Mohamed A. Yassin wrote and edited the
manuscript.
Dr. Narinder Kumar performed the Echocardiogram and provided us with
labeled pictures of the cardiac lesion. Dr Abdulwahab M. Hamid perform
the colonoscopy and provided us with labeled pictures of the
colonoscopy. Dr. Mohamed S. Elmahadi was in charge of the clinical care.