"You have high turbulence inside the pumps, and that can cause clots to form inside", Wieselthalers told The Atlantic.
An unnamed 36-year-old male patient who had been admitted to ICU for aggressive end-stage heart failure spontaneously coughed up the medical marvel, according to Georg Wieselthaler, a transplant and pulmonary surgeon at the University of California at San Francisco who spoke to The Atlantic.
"After a ventricular assist device was placed and anticoagulation therapy initiated, haemoptysis developed, and he expectorated a cast of the right bronchial tree", the journal wrote.
Spanning about 15 cm by 17 cm, it was such a ideal cast of airways that they knew precisely where the blot had come from, the right bronchial tree of the patient's lung. The patient was already dying from heart failure. His medical history included heart failure with an ejection fraction of 20%, bioprosthetic aortic-valve replacement for bicuspid aortic stenosis, endovascular stenting of an aortic aneurysm, and placement of a permanent pacemaker for complete heart block.
Human lungs are too large to fit through the trachea, so it is not possible to cough up an entire lung. But because these machines can also increase the risk of blood clots, he was prescribed a blood-thinner medication.
But blood eventually broke into his lungs and after days of coughing up smaller clots, the patient hawked up the famous one, giving new meaning to the phrase "coughed up a lung".
In 2012, it was reported a 40-year-old in the United Kingdom literally coughed out her lung through her ribs.
According to doctors, the clot was a near ideal cast of the man's right bronchial tree.
"Blood clots may develop, which can travel through your blood vessels and block the blood flow to other organs, including your lungs making breathing hard", according to the Impella website.
The man died from heart complications a week after coughing up the clot.