Heart Diseases-IX-Heart Diseases-operations.

Operations available to treat heart disease and stroke range from relatively minor procedures such as angioplasties and the fitting of pacemakers, to heart transplants.
Pacemakers – Implantable defibrillators
An artificial pacemaker may be needed by patients with heart block or who have irregular heart rates or heart rhythms.
A pacemaking system has a pulse generator and one (single chamber) or two (dual chamber) electrode leads.
The pacemaker has a power supply or batteries and electronic circuitry, weighs about 20 to 50g and is almost completely hidden.
They last on average between six and 10 years.
Electrical impulses are conducted down the electrode lead to the heart, stimulating heartbeats.
Some pacemakers discharge electrical impulses at a fixed rate, but most work on demand.
The pacemaker may be fitted under local anaesthetic when an electrode lead is inserted into a vein at the shoulder or the base of the neck and guided into the correct chamber of the heart using an X-ray screen.
The electrode may alternatively be attached directly onto the outer surface of the heart. The pacemaker box is positioned under the skin of the abdomen.
There is a small danger of infection where the pacemaker is fitted.
Heart transplants
There are around 300 heart transplants carried out in the UK each year.
Heart transplants are usually carried out on people with severe heart failure caused by coronary heart disease or cardiomyopathy.
They can also be carried out for patients with severe abnormalities of the heart valves, congenital heart defects or an uncontrollable fast heart rhythm.
The average wait for a transplant once on the waiting list in the UK is six months. About 15% of patients die while on the waiting list.
The heart is stopped and a machine takes over the function of the heart and lungs. The diseased heart is removed and the donor organ sewn in and connected to the main blood vessels.
After the operation, immunosuppressant drugs are given to ensure the body does not try to reject the new heart. They must be taken for the rest of the patient’s life.
Rehabilitation programmes, including physiotherapy, begin shortly after the operation. Life should return to normal within six to eight weeks.
Between 50% and 60% of heart transplant patients are alive after 10 years.
Coronary angioplasty, and stents
There are 23,500 angioplasties performed on patients with angina in the UK each year. Nine out of 10 operations are successful.
Fatty tissue – atheroma – responsible for narrowing arteries, is squashed, allowing blood to flow more easily.
A catheter is inserted into an artery under local anaesthetic in either the groin or the arm and guided using an X-ray screen to a coronary artery until its tip reaches the narrowed or blocked section.
A balloon mounted on the end of the catheter is then gently inflated to a diameter of about 3mm, flattening the atheroma.
A short tube of stainless steel mesh – a stent – may be inserted into the part of the artery to be widened to prevent re-narrowing after angioplasty.
Ultrasound and laser angioplasty can also be used but are rare.
Coronary bypass surgery
Coronary bypass surgery is used to bypass the narrowed sections of coronary arteries by grafting a blood vessel between the aorta – the main artery leaving the heart – and a point in the coronary artery beyond the narrowed or blocked area.
More than 21,000 patients have coronary artery surgery in the UK each year. The risk of death within a month of the operation is 2%.
The graft to be used comes from another blood vessel within the patient’s body.
An incision is usually made in the middle of the chest and the breastbone split lengthways.
Keyhole surgery, which involves less opening of the chest, remains rare and is currently being evaluated.
During the operation, a heart lung bypass machine takes over the pumping of blood and breathing.
Around eight in 10 patients experience immediate and lasting relief from angina. Most of the others find the bypass improves their angina, says the British Heart Foundation.
Atherectomy
Atherectomy uses a rotating shaver on the end of a catheter, introduced through a blood vessel in the leg or arm, which is fed through to the blocked coronary artery.
The high-speed rotating device at the tip of the catheter grinds the plaque into minute particles, clearing the artery. Balloon angioplasty may then be used on the artery.
Heart valve replacement
Heart valve surgery may be required if drugs are unable to control the problem.
Valve replacement – Diseased valves are usually replaced by manufactured valves (artificial/mechanical valves), or animal valves (tissue valves/biological valves).
The valves open and close around 40m times a year. They can make a clicking sound.
Anticoagulants are taken with artificial valves because there is a risk of blood clots developing on the surface, but are not usually necessary with tissue valves.
Long-term survival rates for patients with either type of valve are similar. Eight out of 10 tissue valves are still working after 10 to 12 years.
Valve repair – Usually done only for the mitral valve – between the left atrium and left ventricle.
Congenital heart disease treatments
Arterial Switch – Where babies are born with the major arteries switched round, an operation is carried out to reverse the defect.
Balloon atrial sepostomy – The atrial opening is enlarged using a catheter to improve the oxygen supply in babies whose major arteries are transposed.
Balloon valvuloplasty – A catheter is inserted into the opening of a narrowed heart valve and a balloon opened to stretch the valve.
Fontan procedure or operation – The right atrium is connected to the pulmonary artery directly or with a conduit, allowing blood to bypass an incomplete or under-developed right ventricle.
The atrial defect is also closed to relieve blueness – cyanosis.
Pulmonary artery banding – A band is placed around the pulmonary artery to narrow it and reduce blood flow and high pressure in the lungs.
Band can later be removed and the defect fixed with open heart surgery.
Shunt or shunting procedure – A passage is formed between blood vessels to divert blood from one part of the body to another and reduce blueness in infants with severe Tetralogy of Fallot.
Venous switch or intra-atrial baffle – A tunnel is created inside the atria to help correct transposition of the major arteries.
Carotid endarterectomy
Build up of plaque in the carotid arteries – major blood vessels in the neck, taking blood from the heart to the brain – can be surgically removed by carotid endareterctomy to prevent a stroke.
http://news.bbc.co.uk/2/hi/health/medical_notes/g-i/764043.stm