Doctors placed an Impella ventricular assist device into his heart through an artery, which is a heart pump that temporarily supports a patient by moving blood through the heart to the rest of the organs in the body. Blood and mucus came out during intense coughing in the first week but this was followed by tubes meant to distribute air to the lungs.
The clot shows the three segmental branches in the upper lobe (white arrows), two segmental branches of the middle lobe (black arrows) and five segmental branches of the lower lobe (blue arrows), the NEJM said.
In 2005, a heavily pregnant woman coughed up a similar but smaller bronchial tree clot.
The patient had a violent coughing fit in hospital a week after surgery to fit him with a pacemaker in case his heart became blocked.
Blood clots are a known possible side effect of the pump.
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Various media reports have twisted the science of the thing, presenting it as a patient literally coughing up a lung, a common expression for what it feels like to cough profusely. In other words, it was a mold (cast) made of clotted blood in the shape of the lung's branched airway passages known as bronchi.
But it wasn't a piece of coral, or even something doctors had removed themselves - it was an intact, perfectly formed blood clot cast that a patient had spat up after "an extreme bout of coughing".
To reduce clotting, doctors use a blood thinner called heparin.
He also had to be supplied with oxygen due to breathing problems.
On Monday, The Journal tweeted a picture of a completely intact blood clot, shaped just like the right bronchial tree in the lung. Nope, it was coughed up in one piece by a patient in San Francisco.
The man was reportedly "extubated" two days after the incident and suffered no further instances of coughing up blood.