A simple technique that involves squeezing the arm three times before surgery could speed up recovery from heart bypass operations and even improve patients’ long-term survival. Using the same type of blood pressure device found in GPs’ surgeries, doctors squeeze the upper arm three times, for five minutes at a time, restricting blood flow to the heart.
According to conventional medical thinking, this should be a bad thing, because depriving the heart of oxygen-rich blood is exactly what happens when someone suffers a heart attack.
But the latest therapy, which has been developed by Professor Derek Yellon and a team at the Hatter Cardiovascular Institute at University College London, taps into a recent strange discovery.
Studies suggest that when the heart is partially deprived of oxygenrich blood for short periods, it seems to go into survival mode.
Protective enzymes are immediately released into the blood and make their way to the heart, where they shield cardiac muscle against injury.
During a heart attack, when blood supply is almost completely cut off, this survival mechanism is not powerful enough to prevent often fatal muscle damage.
Yet scientists believe it is powerful enough to protect the heart from the trauma of major surgery. Nearly 30,000 people a year in Britain undergo a coronary artery bypass, mostly men over the age of 60.
The procedure is carried out when arteries supplying the heart with blood become so clogged they cannot be cleared with drugs or stents – tiny implants used to prop open blocked vessels.
Surgeons take a blood vessel from elsewhere, usually the chest or leg, and attach it to the diseased artery above and below the area that is clogged.
Blood is then diverted away from the blockage and through the healthy new blood vessel.
Bypass surgery has been used for decades and has saved thousands of lives. But 2 to 3 per cent of patients die during surgery and a full recovery can take six months to a year.
To perform the operation, surgeons must stop the heart from beating and switch to a machine that carries on pumping blood while the bypass is carried out. The problem is that stopping the heart can cause damage by killing off muscle cells.
And restarting it can make things even worse – for reasons that remain unclear, blood rushing back into heart tissue causes even more cell death, a common problem known as reperfusion injury.
Such damage can affect the heart’s ability to recover from major surgery.
But the arm-squeezing technique could be a brilliantly simple solution. The UCL team carried out a trial involving 45 patients.
Once under anaesthetic, 23 had a blood pressure cuff placed on either arm and inflated for five minutes, followed by a five-minute break. This was repeated three times.
The remaining 22 patients also had the cuff on their arm but it was not inflated.
When the researchers compared the two groups after surgery, they found those who had their arms squeezed had lower levels of a protein, troponin, in their bloodstream. Troponin leaks out of heart muscle when cells have been killed and is a ‘marker’ for damage to the organ.
Those who had the armsqueezing treatment had 42 per cent less troponin.
‘It was a huge reduction,’ says Professor Yellon. ‘The heart seems to have a short-term survival mechanism that can reduce the severity of injury.’
A larger study is under way to measure the benefit of the therapy in terms of patients’ recovery and survival.
The British Heart Foundation, which is partly funding the research, says it is confident the new technique will transform bypass surgery.
‘I am hopeful it will help patients recover more quickly,’ says associate medical director Professor Jeremy Pearson.
‘There’s good evidence from studies that it can have a significant advantage in protecting the heart.’
Via Daily Mail