Mark Landau, the husband in the first married couple believed to have had heart transplants, has died. He was 59.

Landau died May 2 at Fountain Valley Regional Hospital and Medical Center, his widow, Sandra, told the Los Angeles Times. He'd undergone a second heart transplant on Dec. 17, 2007, and had never recovered, she said.

Mark Landau, of Ladera Ranch, received his first heart transplant on April 15, 1997, after doctors told him he needed a new heart while treating him for the flu.

Six and a half years later, Sandra Landau received a heart transplant, making the Landaus the first known couple to undergo the procedure, according to Dr. Lawrence Czer, director of the heart transplant program at Cedars-Sinai Medical Center in Los Angeles.

Czer, who treated the Landaus, said they cared for each other through the operations, keeping track of medications and appointments.

Mark Landau also frequently volunteered at the hospital, offering counsel to patients waiting for a transplant, Czer said.

Czer also praised him for helping set up a fund at the hospital to defray costs of medications needed for heart transplant patients.

Czer told The Associated Press that Sandra Landau is "doing extremely well."

Mark Landau is also survived by his son, Larry Landau of Mission Viejo, and his daughter, Sarah Chapman of Kodiak, Alaska.

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