‘Buffy the Vampire Slayer’ Alum Nicholas Brendon’s Cause of Death Revealed

A cause of death for Buffy the Vampire Slayer alum Nicholas Brendon has been revealed.

The actor died of atherosclerotic and hypertensive cardiovascular disease, with acute pneumonia and previous myocardial infarction (heart attack) being contributing factors, according to autopsy results obtained by Page Six. Arteriosclerosis occurs when the arteries become thick and stiff while acute pneumonia is an intense, sudden-onset infection that causes inflammation in the lungs.

The outlet noted that the mechanism of Brendon’s death — which was determined to be natural — was 90 percent blockage of his right coronary artery.

According to People, the Putnam County Coroner’s office is still awaiting the results of a toxicology report. Coroner Todd Zeiner noted in a statement that there “were no signs of foul play, and nothing at the scene indicated the death was anything other than natural,” adding that “family members reported a history of cardiac issues.”

‘Buffy’ Cast Share Tributes to Costar Nicholas Brendon After His Death at 54

Us Weekly confirmed on March 20 that Brendon died at the age of 54.

“We are heartbroken to share the passing of our brother and son, Nicholas Brendon,” the actor’s family told Us in a statement, noting that Brendon died in his sleep of “natural causes.”

“Most people know Nicky for his work as an actor and for the characters he brought to life over the years. In recent years, Nicky has found his passion in painting and art,” the statement continued. “Nicky loved to share his enthusiastic talent with his family, friends and fans. He was passionate, sensitive, and endlessly driven to create. Those who truly knew him understood that his art was one of the purest reflections of who he was.”

His family concluded, “Our family asks for privacy during this time as we grieve his loss and celebrate the life of a man who lived with intensity, imagination, and heart. Thank you to everyone who has shown love and support.”

Brendon was best known for playing Xander Harris on all seven seasons of Buffy alongside the likes of Sarah Michelle Gellar, Alyson Hannigan and David Boreanaz, all of whom offered their condolences following Brendon’s death.

“I saw you Nicky. I know you are at peace, in that big rocking chair in the sky,” Gellar, 48, wrote via Instagram on March 21, also quoting one of Xander’s famous lines, “They’ll never know how tough it is to be the one who isn’t chosen. To live so near to the spotlight, and never step in it. But I know. I see more than anybody realizes, because nobody’s watching me.”

‘Buffy the Vampire Slayer’ Cast: Where Are They Now?

Buffy aired from 1997 to 2003, following a teenage vampire slayer named Buffy Summers (Gellar) as she navigated the ups and downs of high school life and monster-slaying.

“There are people you work with and then there are people you share time with, Nick was the latter,” Boreanaz, 56, who played Angel, recalled of working with Brendon in a social media tribute. “Some moments stay small on paper, a laugh between takes, a look that says we got this, the quiet understanding of showing up and doing the work together. But those are the things that last. He carried something real, not perfect, not polished, just real.”

He continued, “In this business that matters more than most things. We don’t always get to choose how long someone stays in the story, only that they were here. And he was … Rest easy, Brother. Some people leave a mark without trying.”