Acute aortic syndrome covers a spectrum of potentially life-threatening aortic diseases and often requires immediate medical attention. This article outlines their clinical presentations, diagnosis and available treatments – including thoracic endovascular aortic repair (TEVAR), an emerging alternative to conventional open surgery.
Acute aortic syndrome describes a myriad of life-threatening aortic diseases. Their presentations can be similar and clinical features are generally
comparable in terms of symptoms, signs as well as
epidemiological and imaging features.
The conditions include aortic dissection, aortic intramural
haematoma, leaking aortic aneurysms and
penetrating atherosclerotic ulcers.
Aortic dissection occurs when an injury to the innermost layer of the aorta allows blood to flow
between the layers of aortic wall, forcing the layers apart. In this disease process, there is reduced or absent blood supply to the various vital organs at
Intramural haematoma is defined as blood within the aortic media without the presence of an intimal tear. Its causes range from the rupture of vasa vasorum of
the media or haemorrhage within an atherosclerotic
plaque, to progression from a penetrating aortic ulcer.
It may progress and increase in size, and is at a greater
risk of rupture than dissection.
Penetrating aortic ulcers
Penetrating aortic ulcers are defined as focal intimal defects occurring at the site of atherosclerotic plaques. Progressive intimal erosion eventually results in pulsatile blood entering the media. This can lead to
intramural haematomas, dissections and ruptures, as
well as pseudoaneurysm and aneurysm formation.
Figure 1 Acute aortic syndrome
Aortovascular diseases have been increasing in
incidence over the years. This can be attributed to the
ageing population and use of surveillance scans.
These patients are usually elderly, smokers and male
with a past medical history of hypertension. A lot of
them are non-compliant to medications and in some
Rare cases that general practitioners (GPs) may
encounter in the community include:
A classical symptom is an acute tearing chest pain
radiating to the back.
The location of the pain correlates with the location
of pathology. Pain located anteriorly in the chest
or in the neck and jaw typically denotes ascending
aortic involvement. In contrast, pain in the back and
abdomen suggests descending aortic pathology.
Patients are usually severely hypertensive. If a patient
is hypotensive, this is a bad sign and the risk of death
can be imminent.
Chest X-ray usually shows widened mediastinum.
Computed tomography (CT) imaging is readily
available in most centres, and has high sensitivity and
specificity. Most importantly, it is a quick scan.
Alternatives include magnetic resonance imaging (MRI)
and transoesophageal echocardiography; however,
these may not be readily available.
In many emergency departments, transthoracic
echocardiography is readily available which can give
a clue to the diagnosis.
Figure 2 CT angiography obtained in a patient with dissection of the aortic arch is clearly demonstrated on axial
imaging (left panel). Involvement of the brachiocephalic (B) and left subclavian (S) ostia is apparent on a more cranial
axial image (middle panel), whereas the origin of the left common carotid artery (C) is spared.
A multiplanar image reformatted in an oblique sagittal plane (right panel) nicely renders false lumen in the brachiocephalic (long arrow) and left subclavian (short arrow) arteries.
The diagnosis of the aortic pathology determines its
Not all conditions require immediate or early
interventions. In mild cases, patients are serially
monitored with the use of scans.
Blood pressure control helps slow the disease
process, and stopping smoking further helps the
For acute aortic syndrome involving
the ascending aorta
Aortic pathology involving the ascending aorta is
treated with emergency high-risk open surgery.
Emergency surgery includes the replacement of the
ascending aorta under deep hypothermic circulatory
Deep hypothermic circulatory arrest is a surgical
technique that induces deep medical hypothermia. It
involves cooling the body to temperatures between
16-25°C and stopping blood circulation and brain
function for 45-60 minutes.
During this time, the ascending aorta is excised, and
synthetic graft is sutured to the proximal aortic arch.
After which, circulation is resumed and rest of the
At the normal body temperature of 37°C, only several
minutes of stopped blood circulation causes changes
within the brain leading to permanent damage.
Lowering the body temperature extends the time
interval in which such stoppage can be survived.
At a brain temperature of 16-18°C, blood circulation
can be safely stopped for 45-60 minutes. There is an
increased incidence of brain injury at time intervals
longer than 45-60 minutes.
For acute aortic syndrome sparing
the ascending aorta
More distal disease sparing the ascending aorta is
treated with medical therapy.
Patients with acute aortic syndrome sparing the
ascending aorta were usually offered high-risk
conventional open surgeries in the past. Today, a
selected group of patients are suitable for thoracic
endovascular aortic repair (TEVAR).
Benefits of TEVAR
TEVAR has emerged as an alternative to conventional open surgery.
Many of the patients who suffer from aortovascular conditions are elderly, frail and have a number of medical conditions – including patients who previously would not have qualified for any intervention. TEVAR thus increases the population of patients who can be treated.
The TEVAR procedure
Patients are typically under general anaesthesia, and the TEVAR procedure is performed in a hybrid operating theatre under X-ray guidance.
During the procedure, a tube or catheter is inserted into the femoral artery in the groin. A wire is guided through the artery into the aorta. A stent graft is delivered in a collapsed state through the catheter, positioned accurately using X-ray guidance.
The stent graft is then expanded to span and cover the site of aortic injury. As a result, the stent graft lines and reinforces the torn aortic wall to ensure continuity of blood flow and prevent further bleeding.
This procedure usually takes about one to three hours.
Post-procedure recovery and care
Patients typically stay in the hospital for three to four days and can resume all regular activities within a month. Complex cases may require a longer procedure time and hospital stay. Follow-up is lifelong with serial scans.
TEVAR vs open surgery
The main procedural risks of TEVAR include catastrophic paraplegia which can be mitigated with spinal drain insertion and permissive hypertension. Other risks include bleeding, infection and stroke.
Overall, despite these risks, it provides the advantage of being less invasive than open surgery and requiring a shorter recovery time. It also gives hope to patients who are at high or prohibitive surgical risk.
In the past, the femoral artery in the groin was accessed using a surgical incision and subsequently repaired post-procedure. However, in recent times, percutaneous closure devices have had success in furthering the procedure.
Today, the painful surgical incision in the groin has been replaced by percutaneous closure devices. The TEVAR procedure is evolving into a truly minimally invasive surgery.
In the last few years, TEVAR technology has had further enhancements. Stents can be custom-built for each patient’s vascular anatomy. However, the time needed to build each customised stent is about four to six weeks.
Up to 30% of these acute aortic syndrome cases may
have serious complications at the time of presentation.
These can include:
The National Heart Centre Singapore cardiovascular
team evaluates and follows up with these patients
to determine the timing and type of intervention.
Those with extensive aortic disease may require a
combination of both open and endovascular surgery.
Dr Sivaraj Pillai Govindasamy is a Consultant at the Department of Cardiothoracic Surgery,
National Heart Centre Singapore. His interests include coronary artery bypass grafting
surgery, extracorporeal membrane oxygenator implantation, valvular heart disease and
GPs can call the SingHealth Duke-NUS Vascular Centre for appointments at the following hotlines:
Singapore General Hospital: 6326 6060Changi General Hospital: 6788 3003Sengkang General Hospital: 6930 6000KK Women’s and Children’s Hospital: 6294 4050National Heart Centre Singapore: 6704 2222