Entertainment manager Jordan Feldstein died from blood clots that originated in his legs.
Actor Jonah Hill's brother died on December 22, aged only 40.
According to a report from Los Angeles County Medical Examiner, Feldstein's main causes of death were pulmonary thromboembolism and deep leg vein thrombosis.
A pulmonary embolism is a blockage in one of the pulmonary arteries in the lung usually caused by clots that travel from the leg.
The report also lists other significant causes as acute bronchopneumonia and obesity.
He did have a history of heart issues, but was not being treated for anything specific at his time of death.
Feldman suffered a sudden cardiac arrest at his home in Los Angeles.
His family representative claimed that he called 911, the emergency helpline for shortness of breath.
The paramedics arrived soon, but he passed away leaving hus his family, friends, and fans in shock.
A full toxicology report is not yet available.
Feldstein, who was the longtime manager of Maroon 5, as well as other musicians Miguel, Elle King and Robin Thicke'.
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