Lamar Odom Had 12 Strokes, 6 Heart Attacks ... During Coma

Lamar Odom says it's a miracle he's alive -- revealing he had 12 strokes and 6 heart attacks while he was in a coma from his 2015 drug overdose.

Th ex-NBA spilled his guts about the incident to Kevin Hart while sitting in an ice bath for KH's YouTube show, "Cold as Balls."

"All my doctors that see me say I'm a walking miracle," Odom said while shivering in the ice tub next to Hart.

TMZ Sports broke the story ... Odom was rushed to a hospital on October 13, 2015 after he was found unconscious at Dennis Hof's Love Ranch South in Pahrump, Nevada.

Blood tests showed Odom had cocaine in his system at the time of his overdose. There were times doctors didn't think Odom would survive -- but somehow,…