The precise costs are hard to say. In this region, Medicare pays an average of $40,000 to $60,000, depending on the open-heart procedure, but many elderly suffer complications that can inflate the total. DeBakey's care, for example, reportedly cost more than $1 million.

The risks of open-heart surgery, while still substantial, have steadily declined.

Consider that in 1988, University of Pennsylvania researchers published what was then the largest series of open-heart surgeries on the oldest patients in medical history. Not one of those 100 patients was over 89. Yet 29 of them - almost a third - died within three months.

Fast-forward to 2003, when Bridges led an analysis of a national database of open-heart procedures, including almost 60,000 octogenarians, 1,092 nonagenarians, and five centenarians. Surgery-related mortality had fallen to 12 percent - and that was for the oldest old, those in their 90s and 100s.

For octogenarians, mortality ranged from 7 percent to 11 percent, depending on the procedure.

"Surgery has gotten better," noted Sharon Kaufman, a medical anthropologist at the University of California, San Francisco. "Even old people who are frail and have chronic conditions can withstand surgery better than ever."

The odds of death for those 80 and over are two to three times greater than for patients ages 50 to 79, Bridges' study found. But again, it's relative.

"If you have a 20 percent chance of dying, that means you have an 80 percent chance of surviving," Bridges said. "And without surgery, there might be an 80 percent chance of death."

Complicating this calculus is the issue of quality of life. Even with advances, surgery and its aftermath are traumatic, especially for elderly with chronic conditions such as diabetes or kidney failure.

"A lot of patients spend months in the hospital, in pain and suffering, and then they die anyway," said Muriel Glick, a physician specializing in geriatrics at Harvard University. She advocates better nursing-home and hospice care rather than "using ever more technology to try to eke out a little more life."

Callahan, the bioethicist, added: "I believe it's gotten harder for doctors to find a bright line between living and dying. Physicians feel compelled to offer heroic measures. They say, 'Let's not give up hope.' "

Limits on care, access

That attitude may be uniquely American. In Western countries with government-sponsored health care, both the amount of care and access to it are limited.

Alan Maynard, a health-economics professor at England's University of York, wryly contrasted American and British perspectives in a 2005 article in the journal Health Affairs.

"Dying is an un-American activity!" he wrote. "This accounts in part for Americans' spending twice as much per capita on health care as the British do. The British reluctantly accept two facts of life. First, they are all suffering from a terminal, sexually transmitted disease called life. Second, with death inevitable and resources finite, health-care rationing is inevitable."

Last month, the latest report on Medicare projected it would run out of money in about seven years.

"The trend is negative and not very encouraging," said Olivia Mitchell, an expert on insurance and risk management at Penn's Wharton School.

She noted that the cost of the program had long been rising faster than the cost of living. What's more, she said, about $88 billion - 27 percent of Medicare's annual budget - is spent on care in the last year of life.

"I suspect there will have to be some form of rationing," she said. "The question is whether age is the only - or even one of many - factors that should be used."

Callahan has been answering that question affirmatively since 1987, when he published a book titled Setting Limits: Medical Goals in an Aging Society. He's been calling for age-related rationing for so long, in fact, that he has reached the age at which he would qualify for a dose of his own medicine.