DISCUSSION
Although described in the 1950s by Dr, Edward Heyde, as the combination
of calcific aortic stenosis and iron deficiency anemia resulting from
gastrointestinal bleeding. Heyde syndrome now refers to a triad of
aortic stenosis, acquired coagulopathy (von Willebrand syndrome type 2A,
abbreviated here vWS-2A) and anemia due to bleeding from intestinal
angiodysplasia or an idiopathic site4. The definitive
pathophysiology of Heyde Syndrome has yet to be agreed upon. Currently,
the most widely accepted one is the acquired deficiency of von
Willebrand factor due to high shearing stress due to the flow of blood
through the narrowed valve as in conditions such as aortic
Stenosis5. The high shearing force leads to a
significant conformational change in the high- molecular-weight (HMW)
von Willebrand factors (vWF) which enables the A2 domain of vWF to be
degraded by ADAMST13, a well-known plasma protease. The resulting HMW
vWF multimers are less effective in coagulation and are cleared away
easily which leads to the development of acquired Von Willebrand factor
deficiency.5,6 Even though the pathophysiology of the
development of Acquired VWF deficiency (AVWS) is well laid out, a study
of case reports has found that almost 65 % of the cases didn’t develop
AVWS. Thus, other modalities of pathophysiology should be
explored1.
Angiodysplasia in the Gastrointestinal tract as described in the
original triad should also be taken into consideration as a potential
source of bleeding in adjunction to the acquired VWF deficiency. The
available literature on Heyde syndrome suggests that the site most
common for the development of angiodysplasia was the small intestine
with jejunum in particular whereas the site most common for development
of isolated angiodysplasias is caecum. This may hint towards different
pathogenesis of angiodysplasia in Heyde syndrome and also highlights the
importance of examining the jejunum and small
intestine.1 AVWS may potentially be a factor in the
development of angiodysplasias.7
In an elderly patient with established aortic stenosis, if there is
development of iron deficiency anemia, Heyde syndrome should be kept in
consideration4. One of the challenges of diagnosing a
case such as Heyde syndrome is establishing the connection between
arteriovenous malformation (AVM) and aortic stenoses. The evidence that
aortic stenosis is the root cause of coagulopathy is much stronger than
the evidence for a causal association with
angiodysplasia8. However, one study demonstrates that
AS is substantially more common in individuals with concurrent AVMs and
that the stenoses are more severe, which may have an impact on how both
AVMs and AS are managed. Since there may be changes in how patients with
a recognized Heyde syndrome are managed, current studies likely
underestimate the true prevalence of the Heyde
syndrome9.
Our patient had a history of recurrent GI bleeds requiring blood
transfusions. Similar findings have been reported from other studies
indicating Heyde disease as having a high risk of bleeding and
subsequent mortality requiring urgent interventions.10Patients with Heyde syndrome who are treated by intestinal resection
generally continue to bleed from other sites, while AVR usually cures
clotting disorder and anemia. Although aortic valve replacement is the
mainstay of treatment in Heyde syndrome, newer interventions such as
TAVI (Transcatheter Aortic Valve Implantation) have been found to
durably reduce the events of Gastrointestinal bleeds in Heyde
syndrome11. As the recurrence rate was significant
during follow-up, a possible association with residual PVL (Paravalvular
Leakage) requires further investigation to improve treatment options and
outcomes in patients with HS12. Episodes of severe
bleeding may necessitate blood transfusions and emergency bowel
resections.
In our case, aorto-atrial fistula was noted on TTE with a paravalvular
leak from the previous repair of aortic stenosis. Aorto-atrial fistulas
are infrequent but have the potential to be life-threatening by creating
excessive burden on the heart’s volume. They occur when an abnormal
connection develops between the structures of the aorta and the cardiac
atria. The diagnosis of AAFs is frequently delayed due to the
non-specific nature of the symptoms presented, and the sensitivity of
trans-thoracic echocardiography (TTE) is only around
50%.13 The aorto-atrial fistula usually is caused as
a sequela of endocarditis, congenital causes and rarely as a
complication of cardiac surgery13. In recent years,
there has been an increasing utilization of percutaneous closure for
Atrial-Arterial Fistulae (AAF). Although there are no dedicated devices
designed exclusively for transcatheter closure of fistulas, devices that
are primarily intended for closing atrial septal defects, have shown its
effectiveness for this application. The overall success rates for the
treatment are at least 70%, albeit with a mortality rate of
approximately 15%14.