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Heart Treatments

Background

Aortic stenosis is a common cardiological

condition in the elderly. Once patients

develop symptoms, aortic stenosis carries

a poor prognosis. In patients with aortic

stenosis, mortality rates at 3 years are 25-

50% and in the elderly, this increases to a

2-year mortality from 50% to 60%.

The condition also substantially interferes

in quality of life, resulting in a reduced

exercise tolerance due to shortness of

breath and chest pain, along with pre-

syncopal or syncopal episodes.

The standard treatment for this condition

is surgical Aortic Valve Replacement (AVR).

This is a highly successful operation in

patients with no co-morbidities. However,

in the elderly patient with co-morbidities,

cardiac surgery can carry a very high

risk, often resulting in withholding of this

therapy. It is estimated that up to one-

third of patients with symptomatic aortic

stenosis are never referred for cardiac

surgery because the referring doctor

considers the risk too high.There is no

effective medical therapy for severe aortic

stenosis, and thus these patients will

continue with a poor quality of life with

a high mortality.

This new technique is catheter based and

a balloon expandable valve mounted on

a stent is delivered either ante-gradely

(through a small incision at the apex)

or retro-gradely via the femoral artery.

Suitable Patients

At present, the procedure is restricted

to patients at high surgical risk, or who

have been turned down for conventional

AVR. Patients will have severe aortic

stenosis (valve area < 0.8 sq cm) and at

least moderate left ventricular function

(ejection fraction >20%).The decision to

perform the procedure via the femoral

artery or apex is largely down to the

presence of peripheral vascular disease –

if the ilio-femoral vessels are <7mm

and/or significantly calcified, the

procedure may need to be performed

apically.The screening process includes

risk assessment, echocardiography, CT

of aorta and peripheral vessels and

coronary and peripheral angiography.

The Procedure

The procedure is performed under

general anaesthesia by a team including

Cardiologists, Cardiac Surgeons,

Echocardiographers and Anaesthetists.

It is performed either ante-gradely, via

a 4-5cm incision at the apex to gain

direct access to the left ventricle, or

retro-gradely via the femoral artery.

In both approaches, a valvuloplasty is

performed prior to introducing the

valve mounted on a balloon. After

careful positioning with angiography

and trans-oesophageal echo guidance,

the balloon is inflated thus deploying

the valve in the aortic root.

Results

Worldwide implants currently total

greater than 3,000 using the Edwards

Sapien valve.The predicted surgical

mortality in these patients is >20% and

the current trial data demonstrates that a

30-day mortality of <10% can be achieved.

Haemodynamic improvements include

a reduction in aortic valve gradient to

<10mm Hg associated with an increase

in aortic valve area. Clinically, a marked

improvement in symptoms and quality

of life has been demonstrated.

Although this is still a very new procedure,

these preliminary results are highly

encouraging and it is likely that, over time,

this therapy will become more widely

available to less high-risk patients.

Trans-femoral approach – This figure shows the balloon

catheter passing up the aorta from the femoral artery

with the balloon inflated when deploying the valve.

0

0

40

50

Age (Years)

Latent Period

(Increasing Obstruction,

Myocardial Overload)

Onset

Severe Symptoms

Avg. Survival (Yrs)

Angina

0

Syncope

Failure

% Survival

60

70

80

20

40

60

80

100

2 4 6

New Procedure

Transcatheter Aortic Valve Implantation (TAVI)

Dr Simon Redwood

MD FRCP FACC FSCAI

Reader and Consultant Interventional Cardiologist at St Thomas’ Hospital and London

Bridge Hospital. He is also Director of the Cardiac Cath labs at St Thomas’ Hospital,

and Treasurer and a Council Member of BCIS. He has extensive experience in high-

risk and complex interventional procedures including rotablation, laser, chronic total

occlusions and mitral valvuloplasty.

For further information, please contact Suzanne Pattinson on

:

020 7188 0955

.

This is a very exciting innovation where the aortic valve is replaced without the

requirement for open heart surgery or heart bypass. Although it is currently only

performed in high-risk surgical patients, it is likely that in the near future this will

start to be performed on lower risk patients. At present, the procedure requires

a multidisciplinary team involving interventional cardiology, echocardiography,

cardiothoracic surgery and cardiac anaesthesia.

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