Heyde’s syndrome (HS) is a syndrome of gastrointestinal bleeding from angiodysplasia in the presence of aortic stenosis.
HS also known as Heyde’s phenomenon, is a rare condition that involves the combination of aortic stenosis and gastrointestinal bleeding due to acquired von Willebrand syndrome.
It has a deficiency in von Willebrand factor activity.
Normally, von Willebrand factor helps in the clotting process by promoting the adhesion and aggregation of platelets.
In HS the presence of aortic stenosis causes high shear stress on the blood vessels, which leads to the destruction of von Willebrand factor.
It can result in a decreased level or activity of von Willebrand factor, leading to impaired clotting function and increased risk of gastrointestinal bleeding.
The symptoms of Heyde’s syndrome typically include a combination of symptoms related to aortic stenosis as well as signs of gastrointestinal bleeding.
The optimal treatment involves addressing both the aortic stenosis and the acquired von Willebrand syndrome.
It results in Von Willebrand disease type IIA, acquired.
Aortic stenosis is associated with acquired from Willebrand syndrome, a static disorder that results from excessive cleavage of high molecular weight multimers of von Willebrand factor caused by high shear stress at the stenotic valve.
Typically the bleeding originates from gastrointestinal angiodysplasia, a conditioncharacterized by the presence of fragile, abnormal vessels just underneath the mucosa of the gut.
Treatment for aortic stenosis can range from medication management to surgical intervention, such as aortic valve replacement.
The acquired von Willebrand syndrome can be managed with medications that promote clotting, such as desmopressin or factor replacement therapy.
Prognosis is excellent in patients who undergo aortic valve replacement, which is both effective and often curative.
Frequency- 7.5% of persons 75 years of age or older.
Pathophysiology of Heyde’s syndrome:
von Willebrand Factor (vWF) passes through a normal aortic valve and remains in its coiled form.
vWF passes through a stenotic aortic valve and uncoils.
Coiled vWF is unaffected by the catabolic enzyme ADAMTS13.
Uncoiled vWF is cleaved in two by ADAMTS13.
In damaged arterioles vWF uncoils and becomes active.
Unfoiled vWF binds collagen, platelets bind to vWF, and a clot forms.
Inactive vWF cannot bind to the collagen, no clot forms.
Von Willebrand factor is synthesized in the walls of the blood vessels and circulates freely in the blood in a folded form.
When it encounters damage to the wall of a blood vessel, particularly in situations of high velocity blood flow, it binds to the collagen beneath the damaged endothelium and uncoils into its active form.
Platelets are attracted to this activated form of von Willebrand factor and they accumulate and block the damaged area, preventing bleeding.
As the stenotic aortic valve becomes increasingly narrowed there is an increase in speed of the blood through the valve in order to maintain cardiac output.
This narrow opening and a higher flow rate results in an increased shear stress on the blood causes von Willebrand factor to unravel in the same way it would on encountering an injury site.
Normally, when von Willebrand factor changes conformation into its active state, it is degraded by its natural catabolic enzyme ADAMTS13, rendering it incapable of binding the collagen at an injury site.
As the quantity of von Willebrand factor in the blood decreases, the rate of bleeding dramatically increases.
The unraveling of high molecular weight von Willebrand factor in conditions of high shear stress is essential in the prevention of bleeding in the vasculature of the gastrointestinal system where small arterioles are common, as platelets cannot bind to damaged blood vessel walls well in such conditions.
In the presence of intestinal angiodysplasia, arteriovenous malformations lead to very high blood flow, and so the loss of von Willebrand factor can lead to much more extensive bleeding from these lesions.
In individuals with aortic stenosis and gastrointestinal bleeding, it is invariably from angiodysplasia.
Heyde’s syndrome: gastrointestinal bleeding from angiodysplasic lesions due to acquired vWD-2A deficiency secondary to aortic stenosis, and the diagnosis is made by confirming the presence of those three things.
Gastrointestinal bleeding, the presence of angiodysplasia, and aortic stenosis.
Heyde’s syndrome can be confirmed using blood tests for vWD-2A.
The definitive treatment for Heyde’s syndrome is surgical replacement of the aortic valve.
Transcatheter aortic valve implantation (TAVI) can also be used for definitive management.
Direct surgical treatment of the bleeding is rarely beneficial.
In severe bleeding, blood transfusions, and desmopressin (DDAVP) are known to be effective in people with von Willebrand’s disease, including people with valvular heart disease.
Desmopressin stimulates release of von Willebrand factor from blood vessel endothelial cells by acting on the V2 receptor, which leads to decreased breakdown of Factor VIII.
Desmopressin is thus sometimes used directly to treat mild to moderate acquired von Willebrand’s disease and is an effective prophylactic agent for the reduction of bleeding during heart valve replacement surgery.
The exact prevalence of the syndrome is unknown.
Both aortic stenosis and angiodysplasia are common diseases in the elderly.