Paula Rojeski, 55, died Sept. 8 following her procedure at the Valley Surgical Center in West Hills, also known as Woodlake Medical Center.
Rojeski, a Ladera Ranch resident, is the second Lap-Band patient to die after being treated there, according to the Los Angeles Times.
Since 2009, five people have died following Lap-Band surgeries at Los Angeles-area clinics.
The other three patients were treated at a clinic on Wilshire Boulevard in Beverly Hills.
Both clinics, each of which has used more than one name, receive patients referred via the 1-800-GET-THIN advertising campaign.
The Lap-Band, made by Irvine-based Allergan Inc., is a silicone ring that is surgically implanted around the stomach to discourage overeating. The surgeries cost from $12,000 to about $20,000 and often are covered by insurance.
Friends said Rojeski had high hopes for her Lap-Ban surgery.
"She just wasn't someone I think needed that so I was surprised she was even having it and then just shocked that she could pass away from something like this," said Rojeski's friend, Marni Rader.
Brian Oxman, an attorney representing the company behind 1-800-GET-THIN, says the company has nothing to do with the deaths.
In an interview with Eyewitness News, Oxman said, "1-800-GET-THIN does not treat patients. It does not care for patients. It is a marketing firm and we are not involved in patient care."
City News Service contributed to this report.