The New York native is best known for his work with the bands Ministry and Rigor Mortis.
Lead singer Al Jourgensen confirmed his death in Fort Worth on the Ministery website Sunday.
"I just lost my lil' brother and my best friend," he wrote. "Mikey was not only the best guitar player in the history of music, but he was a close, close, close part of our family -- and I just lost a huge chunk of my heart today. Our lives are forever changed. Life without Mikey is like orange juice without pulp -- kind of bland."
In a Facebook posting, Rigor Mortis vocalist Bruce Corbitt described Scaccia as "the greatest guitar player I ever knew."
"My brother is gone," Corbitt said. "The only reason I am who I am is because of this man. If it wasn't for him I wouldn't even be in a band."
The BBC said he was performing at Corbitt's birthday gig Sunday when he collapsed and died of a heart attack brought on by heart disease.