Our aorta is the biggest artery in our body which carries oxygenated blood from our heart to the rest of our body. Disease in the aorta can cause narrowing or, more commonly, abnormal dilation of the artery. Aortovascular diseases have been increasing in incidence over the years. This can be attributed to ageing population and increasing use of scans especially for screening. Two main conditions, which can be life-threatening, include aortic dissection and aortic aneurysms.

By Dr Sivaraj Pillai Govindasamy, Associate Consultant, Department of Cardiothoracic Surgery

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. During this disruption of the aortic wall, blood supply to the various vital organs may be affected, compromising blood flow. Patients usually present with a sudden onset of severe tearing chest or back pain and this is an emergency condition. Depending on the location of the tears, patients need to undergo either emergency surgery or delayed intervention. Common causes include uncontrolled hypertension or genetic disorders like Marfan’s Syndrome (conditions that weaken the wall of the blood vessel). 

Aortic aneurysms is an abnormal dilatation of blood vessel that carries blood away from our heart to our organs. Aneurysms can potentially dissect or rupture and the risks increase with the size of the enlarged blood vessel. The causes of aortic aneurysm may be due to hypertension, smoking and genetics, and symptoms present are chest pain or shortness of breath. At times, the condition can be picked up on routine pre-employment chest x-ray test. Generally, intervention is recommended for aortic aneurysms that are larger than 5.5cm or growing at a fast rate.

aortic aneurysm vs aortic dissection
Aortic aneurysm (left) and aortic dissection (right)

In the past, patients with aortic dissection or aneurysms are usually offered high risk conventional open-heart surgeries. With the emergence of Thoracic Endovascular Aortic Repair (TEVAR) procedure, there is now an alternative to conventional open-heart surgery for selected groups of patients such as those with aortovascular conditions who are elderly, frail and have a number of medical conditions, as well as those who were previously not recommended for any intervention due to health conditions.

The TEVAR Procedure

The TEVAR procedure is performed in a hybrid operating theatre under x-ray guidance. Patients are typically under general anaesthesia. During the TEVAR 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 or disease. As a result, the stent graft lines and reinforces the torn or diseased aortic wall to ensure continuity of blood flow and prevent further bleeding. The procedure usually takes about one to three hours. 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.

In the past, the femoral artery in the groin is accessed using a surgical incision for the procedure and subsequently repaired after the procedure. This incision can be painful and at times, limits the mobility of many patients. This further attributes to an extended length of time required for recovery. In recent times, percutaneous closure devices have been a success in improving the TEVAR procedure. Now, the painful surgical incision in the groin has been replaced by percutaneous closure devices. A big painful surgical incision is replaced by a mere prick on the skin. The TEVAR procedure has evolved into a truly minimally invasive surgery.

In recent years, there were further enhancements to TEVAR technology. Stents can now be customised for each patient’s vascular anatomy, which previously cannot be achieved with standard available stents. Thus, allowing a broader population of patients to benefit from TEVAR procedures. 

As in any procedure, the TEVAR procedure carries risks too but the main advantage is that it is less invasive than open-heart surgery and requires a shorter recovery time. It gives hope to patients who are at high or prohibitive surgical risk.

TEVAR procedure illustration
TEVAR procedure – close-up of an aortic aneurysm where a catheter is inserted and a stent graft is delivered through the catheter to cover the site of the aortic injury

Not all aortovascular conditions require immediate or early interventions. In the mild cases, patients are serially monitored with use of scans. Blood pressure control helps slow the disease process. Stopping smoking further helps the patient’s cause. Those with extensive aortic disease may require a combination of both open-heart and endovascular surgery.

The NHCS cardiovascular team has more than 10 years’ experience in the TEVAR procedure. With the enhanced TEVAR technology, the outcomes achieved now are much better.

This article is from Murmurs Issue 35 (September – December 2019). Click here to read the full issue.