Armed with a survey that showed doctors are limiting the number of older patients they are seeing and cutting office expenses, the American Medical Association on Thursday launched a national ad campaign to pressure Senators to reverse cuts in Medicare physician payments.

The doctors group is running a multimillion-dollar media campaign that includes television, radio and newspaper ads that urge people to lobby Congress to rescind a 21 percent cut to Medicare payments that went into effect on June 1. The ads will run in 17 states and in the New York Times, USA Today and the Wall Street Journal.

While the House approved a 19-month reprieve from the cuts, the Senate failed to act on the measure before it left town for the weeklong Memorial Day recess.

In a conference call with reporters, AMA President J. James Rohack, a doctor, accused Senators of turning their backs on seniors and “leaving for vacation” without dealing with the payment issue. He also said military families will be affected because physician rates for TRICARE, the military health insurance plan, are tied to Medicare.

To bolster its argument, the AMA released a survey of 9,000 physicians who treat Medicare patients. The survey showed that 17 percent of the doctors, including almost a third of primary care physicians, say they are restricting the number of Medicare patients they see, citing low payment rates and the threat of future cuts.

In response to the two delays by Congress in dealing with the physician payment cuts this year, the survey found that 60 percent of physicians are considering opting out of Medicare and that 39 percent had delayed payments for supplies, rent and other expenses. It found that 17 percent had held up paychecks or laid off or furloughed staff.

Rohack blamed both parties for failing to fix the Medicare formula. Responding to concerns by lawmakers that fixing the formula will increase the deficit, Rohack said the physicians were saving Medicare money by keeping patients from more expensive hospital stays.

Rohack also said he doesn’t regret the AMA’s throwing its support behind the massive health care overhaul signed earlier this year by President Barack Obama. He said the problems with the Medicare formula predated the latest move to reform health care.