A normal functioning aortic valve allows blood to flow from the heart into the aorta when the heart contracts and prevents blood from leaking backwards when the heart relaxes.

Aortic stenosis is where the aortic valve cannot open sufficiently and this is due to thickened and calcified valve leaflets.

Aortic Valve and
Aneurysm Surgery

The aorta is the main artery which transports all of the blood from the heart and distributes it throughout the body. The aortic valve is situated at the base of the aorta and controls the flow of blood out of the heart. Surgery is required if the aortic valve fails to open (aortic stenosis) or close properly (aortic regurgitation), or if the aorta is enlarged (aortic aneurysm).

The Aortic Valve

The aortic valve allows blood to flow out of the heart into the aorta, to supply the entire body with the oxygen and nutrients contained in the blood. The valve itself is constructed of 3 leaflets which open and close like door flaps. The aortic valve can fail if it doesn’t open sufficiently (aortic stenosis) or doesn’t close causing the blood to leak back into the heart (aortic regurgitation). The most common reason why a patient would need a valve replacement is aortic stenosis. This commonly occurs with ageing as the valve leaflets become thickened and immobile with calcium. Some people are born with a bicuspid valve; a congenital malformation where the valve has only two leaflets. Bicuspid valves are more prone to failure due to the suboptimal function and is also associated with enlargement of the aorta (aortic aneurysm).

Once a patient starts experiencing symptoms such as shortness of breath or dizzy spells, they would be referred to a surgeon for consideration of valve replacement.

There are three broad categories for aortic valve replacement:

  • Open heart valve surgery where the breastbone is split open
  • Minimally invasive valve surgery through a small skin incision
  • Transcatheter aortic valve implantation (TAVI) where no surgery is required and the valve can be replaced via a needle in the leg artery

Diagnosis

Aortic valve disease may be picked up incidentally with a routine check-up when a doctor hears a ‘murmur’ in the heart with their stethoscope. Aortic stenosis is more common in patients over the age of 70 and this can often be monitored for years before surgery is required. Patients with bicuspid aortic valves (two leaflets) may develop aortic stenosis in their 40s or 50s as the abnormal valve is more prone to failure.

In other situations, patients may present to their general practitioner with shortness of breath on exertion and a new heart murmur is discovered. They will be referred to a cardiologist who will perform an ultrasound of the heart – an echocardiogram. This will provide a detailed look of the interior of the heart – its function and the degree of aortic regurgitation or stenosis.

If someone has severe aortic regurgitation or stenosis they may be referred to a cardiothoracic surgeon for consideration of valve replacement.

 

The faulty aortic valve is replaced with a new valve. This is an example of a bioprosthetic or tissue valve which is constructed from the lining of a cow heart (bovine pericardium).

Who needs this procedure?

Patients with aortic valve dysfunction who are experiencing symptoms of shortness of breath, dizzy spells or chest discomfort (angina) should undergo valve replacement to improve their survival and to alleviate their symptoms. Some patients may be candidates for this procedure to be performed minimally invasively which can offer less pain and a faster recovery for the patient.

TAVI is reserved for patients that are too high risk for open or minimally invasive surgery and this is because we don’t yet know the long-term results of this relatively new procedure.

The patient would need an open valve replacement if:

  • The patient requires double or triple valve surgery
  • The patient requires coronary bypass surgery
  • The patient has undergone previous heart surgery
  • The patient presents with a dilated aorta (aneurysm)

What is involved?

Open aortic valve surgery is performed under general anaesthetic through a vertical incision down the middle of the breastbone (sternum) to expose the heart. The patient is connected to a heart-lung machine which pumps blood through the body whilst the heart is stopped to operate on it.

The operation takes approximately 3-4 hours. The aorta is opened and the diseased aortic valve is removed taking care not to injure important nearby structures. A new valve is then sewn in place and the aorta is closed. The heart is restarted and the function of the new valve is assessed using an ultrasound (echocardiogram) to ensure that it is opening and closing appropriately. Once the surgeon is satisfied that the new valve and the heart are working well, the heart-lung machine is stopped and the sternum and skin can be closed. The patient is then transferred to the intensive care unit for close monitoring once they are stable.

Aortic Valve Replacement

The faulty valve is replaced with an artificial valve from these two broad categories: tissue valves and mechanical valves.

Generally, patients under the age of 60 will choose a mechanical valve and patients older than 65 will choose a tissue valve due to the differences in longevity of the valves and the need to be on blood thinners. In younger patients, tissue valves are found to be less durable for reasons that aren’t completely clear but may relate to their stronger immune system. When the valve fails a repeat surgery is generally required to place a new valve.

With newer technologies emerging we can now replace the deteriorated valve via catheter techniques and avoid surgery completely, however not all patients are suited to this new technology and each patient has to be assessed individually for suitability.

TAVI – TRANSCATHETER AORTIC VALVE IMPLANTATION

A mechanical valve will essentially last forever mechanically but requires the blood thinner warfarin for life. This is because the natural blood clotting system ‘sees’ the mechanical valve as foreign and will form a clot. If there is clot formation on a valve it can cause a catastrophic failure. Warfarin is a strong blood thinner that requires regular blood testing to monitor its effect and increases the risk of bleeding with trauma and surgery.

Ultimately, the choice of valve is individual and Dr Bassin will discuss this with each patient in detail.

Tissue Valve

  • Is made from cow or pig material
  • Is more usually suitable for patients over 65
  • Will usually last for 10 years before needing a replacement
  • No long-term requirements to take blood thinners

Mechanical Valve

  • Is sometimes referred to as a metal valve, but is actually constructed from pyrolytic carbon
  • Is more usually suitable for patients under 60
  • Will last mechanically forever
  • Requires the patient to take the blood thinner ‘warfarin’

What is the recovery like?

The operation takes approximately 3-4 hours and you will wake up in intensive care later that day or the next morning.  Small tubes to drain any residual fluid from around the heart will be placed in your neck, as well as intravenous lines, to sample blood and administer medications. These tubes and lines will be removed after 1-2 days and then you will be transferred to the ward to continue your recovery.

Once on the ward, the goal is to monitor your blood pressure and heart rate and ensure adequate mobilisation. We work very closely with our nurses, physiotherapists and occupational therapists to work on breathing exercises and functional mobilisation. Every patient is different and the assistance is tailored to your needs. Many patients are discharged home after a week but there is a significant number of patients, particularly the elderly who find it easier to transition home after a short stay in a rehabilitation hospital.

Once at home, patients are encourgaed to take plenty of walks and to generally take it easy.  Your body will let you know what it is capable of and there is no need to push it during this recovery period.

For the first 6 weeks there are precautions to be taken whilst the bone is healing. Lifting should be limited to 3kg and patients are encouraged to sleep on their back. Any activity that requires heavy use of the arms is generally discouraged.

Patients generally go back to work after 4-6 weeks and complete recovery is achieved by 3 months.

The aortic valve opens and
closes 100,000 times a day.

What are the benefits and risks of this procedure?

Open heart aortic valve surgery has been performed since the 1960s with excellent results. We have continued to improve the safety of surgery but there are still risks. For patients who are otherwise well the risks of surgery include: death (1%), stroke (1%), significant wound infection (1%), kidney injury (2%), requirement for a permanent pacemaker (3%) and blood transfusion (25%). The risk can be higher if patients have other co-morbidities including advanced age, previous heart disease or stroke, lung disease or having undergone cardiac surgery previously.

Dr Bassin will explain these risks to you in person as they pertain to your condition.

When can I drive?

You may drive 4 weeks following surgery, according to the national guidelines.

YOUR PATIENT JOURNEY

An enlarged or dilated aorta (aortic aneurysm) is shown in red compared with the normal aorta shown in the dashed line.

The abnormal section of the aorta is replaced with an artificial tube constructed from Dacron, a resilient woven fabric.

Aortic Aneurysm Surgery

The aorta is the main artery coming out of the heart and it distributes the blood and oxygen throughout the body. If the aorta is sufficiently enlarged it is termed an aneurysm and may require surgery. This is because as the aorta grows in size there is a risk of rupture with catastrophic consequences. Aortic aneurysms are often picked up as incidental findings on CT scans or in someone who is being assessed for other cardiac surgery.

Who needs this procedure?

Patients generally require surgery if the aorta in the chest has reached 5.5cm in diameter. Additionally, if patients require an aortic valve replacement, then the aorta should be replaced if it has reached 4.5cm in diameter. This is measured on ultrasound (echocardiogram) or CT scans. These are guidelines and not clear-cut rules as it will depend on the individual patient circumstances – for instance, an aorta of 5.5cm is not as much of a problem for a patient who is very tall as opposed to a patient who is shorter – we expect the taller patient to have a larger aorta.

What is involved?

The aim of the operation is to remove the aortic aneurysm and replace it with an artificial aorta usually constructed from a woven fabric called Dacron. It is major open heart surgery and is performed under general anaesthetic through a vertical incision down the middle of the breastbone (sternum) to expose the heart. The patient is connected to a heart-lung machine which pumps blood through the body whilst the heart is stopped to operate on it.   In many cases the body is cooled down to allow for a decrease in blood flow to the brain whilst the aorta is replaced. This is because it is impossible to replace the arteries to the brain whilst they have a continuous flow of blood.

Bentall Procedure

A Bentall Procedure is an operation for an aortic aneurysm where the first portion of the aorta is replaced. This entails replacing the aortic valve, the aorta itself and reimplanting the coronary arteries. This is reserved for patients with an aortic root aneurysm.

Aortic Dissection

An aortic dissection occurs when the aortic wall splits, which creates two passages for blood to flow – the true lumen and the false lumen. This can be a complication of an aortic aneurysm or of genetic diseases which result in a weaker aorta.

This is a major emergency and if it occurs in the first part of the aorta after it emerges from the heart (ascending aorta), requires urgent surgery, usually within the first few hours following diagnosis. Surgery for aortic dissection involves replacing the affected section of the aorta and it carries significant risks that would be explained in detail.

What is the recovery like?

The operation can take between 5 and 12 hours depending on the extent of the aneurysm. Aortic aneurysm surgery is major open heart surgery. The hospital stay and recovery period are usually similar to other open heart surgeries. After experiencing an aortic aneurysm patients will be monitored life-long with CT or MRI scans to ensure that any remaining aorta is not enlarging.

What are the benefits and risks of this procedure?

Aortic aneurysm surgery has been performed since the 1960s with excellent results. The risks depend on the extent of the aneurysm with replacement of the ascending aorta being lower risk and replacement of the aortic arch being higher risk. For patients who are otherwise well the risks of surgery on the ascending aorta include: death (3%), stroke (3%), significant wound infection (1%), kidney injury (5%), requirement for a permanent pacemaker (3%) and blood transfusion (50%). The risk is higher for more extensive aortic aneurysms and if the patient has other co-morbidities including advanced age, previous heart disease or stroke, lung disease or having undergone previous cardiac surgery.

Dr Bassin will explain these risks to you in person as they pertain to your condition.