A team of doctors have identified a ‘second heart’ that has been hiding in the body in plain sight.
They’ve found the aorta, the body’s largest artery, acts like a second heart by stretching and recoiling to help push blood, easing the heart’s workload.
For decades the bodypart was thought to just passively carry oxygenated blood from the heart to rest of body.
But for the first time, the team from the University of Southern California have found the aorta physicall stretches when the heart beats and then recoils to push blood forward in a process called ‘wave-pumping.’
The recoiling action is in sync with the heartbeat, which sends a surge of blood into the aorta. When the the heart relaxes and the aorta recoils, it pushes blood forward, keeping blood flowing continuously to help with circulation, especially in people with heart failure.
Now that scientists know the aorta helps the heart pump blood, they can start working on medicines for heart failure patients that make the aorta more flexible.
A more flexible aorta can stretch and bounce back better, which helps push blood forward and takes away some of the strain on the heart.
Researchers said: ‘This [wave-like pattern of pumping] may provide a supplementary pumping mechanism to the heart that helps reduce its workload and can have a significant impact on individuals who suffer from cardiac dysfunction such as heart failure.’
The aorta is the body’s largest artery, responsible for carrying oxygenated blood from the heart to the rest of the body. Blockages increase the risk of suffering a heart attack or stroke
The aortas in people with heart failure have a weaker stretching and recoiling action, inhibiting the artery’s ability to move blood forward and throughout the rest of the body.
And when the aorta stiffens, the weakened heart must compensate by working harder just to maintain circulation. This can lead to trouble breathing and fatigue.
In the study, 35 subjects had heart failure, while 124 were healthy.
They ranged in age from 20 to 92.
MRI scans captured detailed videos of their hearts and aortas in action, while software tracking measured how much the aorta stretched and recoiled with each heartbeat.
The healthy aortas, typically in young, otherwise healthy people, stretched about three times farther than the stiffened aortas seen in heart failure patients.
Researchers then crafted an artificial aorta model made of flexible latex to match the actual aorta’s elasticity.
The model was perfectly scaled to the size of the human aorta, and the stiffness could be adjusted based on each subject.
A motorized heart stretched the aorta while sensors measured its pumping effects.
The scientists measured whether the aorta’s motion gave blood an extra push to send oxygen to the brain, the arms, and the rest of the body, or backward into the heart.
The wave-like pressure pulses in the artificial aorta were measured, and researchers found that faster waves meant stiffer arteries in heart failure patients.
Heart failure patients’ aortas had significantly less stretch than those of healthy people. They also recoiled weakly and too quickly, creating a similarly weak forward push, stalling blood flow.
Their results, published in the Journal of the Royal Society Interface, prove that the aorta isn’t just a pipe that transfers oxygenated blood from the heart. Instead, it actively boosts blood flow beyond what the heart alone can provide.
While doctors have known for years that stiff arteries are connected to heart disease, they did not fully understand why: they disrupt the aorta’s ability to assist circulation via wave pumping. This forces the heart to compensate, increasing workload and accelerating dysfunction.
The study’s results also open new treatment opportunities, demonstrating the importance of developing treatments targeting the aorta’s elasticity.
When cholesterol builds up in the wall of the aorta, the deposits reduce elasticity and impede the stretching and recoiling action that keeps oxygen-rich blood moving.
When a blockage obstructs blood flowing from the heart, the heart then has to work harder to force the blood through, raising the risk of a heart attack or stroke.
