"It was extremely dangerous, like a time bomb in her heart," Mehra said. "We don't have a crystal ball, but it could have led to a big heart attack in the near future."
Similar artery blockages were responsible for her late husband's first heart attack in 1993, which led to triple bypass surgery. He died of another heart attack nine years later while exercising on a treadmill at a physical therapy center in Timonium.
But she was in denial at first, she told her audience, and was reluctant to upset her children.
"I saw what they went through losing their father, and I didn't want them to go through this again."
She also wished her late husband was there to help her face the difficult decisions she had to make. "I felt so alone," she said.
The urgency of the situation eventually registered, and she called her son, Chad Unitas, to tell him what was happening. On hearing the news, he and other family members rushed to the hospital.
A few hours after walking into Mehra's office, and several weeks after receiving the invitation to speak at the Sister to Sister breakfast, Unitas went into heart surgery.
During the operation, Mehra used a long catheter to insert stents into the blocked portion of the artery. The mesh tubes hold the artery open, returning regular blood flow to her starved heart and greatly reducing the risk posed by the blockage.
Afterward, she spent a couple of days in the hospital recuperating.
Her prognosis is good, Mehra said. "We got it in time, before there was damage to her heart," he said.
At yesterday's breakfast, Unitas urged the women - who applauded loudly at the end of her story - to take care of themselves and to get screened for heart disease.
"Without that screening," she said, "I might not be here to share my story."