I recently recommended an operation for a 72-year-old man with atrial fibrillation, an irregular heart rhythm that leads to an increased risk of having a stroke. A tiny blood clot the size of a pin head can break off from the top chamber of the heart (the atrium) and travel the short distance to the brain, resulting in a devastating stroke. This patient had several complicating issues that placed him at risk, with hypertension, diabetes, and a prior stroke a year ago.

The common treatment for this condition is usually a blood thinner to prevent clots. Popular blood thinners such as Eliquis, Xarelto and Pradaxa are effective, though expensive ways to reduce this risk. Coumadin is less expensive, but means frequent blood tests for monitoring. Aspirin alone or other blood thinners such as Plavix are not adequate to reduce the risk of stroke.

But this man had a recent episode of bleeding from his intestine, which required multiple blood transfusions, so he could not take blood thinners. My suggestion, instead, was that he consider a new medical device, called a Watchman, to reduce his risk of stroke.

As I made this recommendation, I reflected on the subtle influence of pharmaceutical companies and device manufacturers on my daily practice. This is especially pronounced in cardiology, as heart disease is responsible for more than 23 percent of deaths in this country, and more than 12 percent of health-care expenditures.

The Watchman device is a good example of the double-edged sword that is modern medicine.

It is a medical implant placed by cardiologists into the heart via a small catheter. Because up to 90 percent of the blood clots that cause stroke come from a part of the heart called the left atrial appendage, this device is designed to close off this source of blood clots, without the need for blood thinners.

The atrial appendage is like our vestigial appendix, sitting on top of the left atrium and not really doing anything except potentially causing problems. Closing it off should not result in harm, but reaching the spot is not easy. It involves threading a catheter from a vein in the leg into the right atrium. There is a wall between the right atrium and the left atrium, so to reach the left atrium a tiny puncture hole is made, and the tube placed into the appendage. At this point, the Watchman is still deflated, but it is then positioned carefully under X-ray guidance, and expanded as it leaves the catheter so it fits snugly in the atrial appendage.

Invasive cardiologists love putting these in, as they are challenging and help people. The device is FDA-approved and research suggests it is effective in reducing stroke in people who cannot take blood thinners.

The downside: expense, potential complications, and spiraling use as the device begins to be implanted for questionable indications. There have already been well more than 50,000 placed worldwide. Questions have been raised about validity of studies, many of which have been sponsored by the device manufacturer.

Boston Scientific, the manufacturer, charges a hospital an upfront fee to start a program to put in the devices. The hospital even gets a discount if it puts in more devices, a potential incentive.

Concerns have been raised about an increased risk of blood clots occurring on these devices in the months after they are implanted. Not a surprise — they are foreign bodies in the heart. The patient would then need a blood thinner for life, but remember that avoiding blood thinners was the whole point of the operation.

In an analysis by researchers at the University of Alabama-Birmingham, almost 60,000 patients treated for atrial fibrillation were compared, and it was found that medications were safer than the Watchman device. Apixaban (Eliquis) was the safest, followed by edoxaban (Savaysa), dabigatran (Pradaxa), warfarin (Coumadin) and then rivaroxaban (Xarelto); the Watchman device ranked last.

The Watchman device has been advertised heavily, both to the public, in medical journals, and at medical conferences. Cardiologists who are trained to put the device in often speak on behalf of the company to tout how patients can be helped, so doctors refer patients to them. Like many other devices and new medications, after some initial caution, they get expanded use. Many cardiologists are now suggesting it as an initial way to avoid being on blood thinners. One study suggested it might be cost effective as initial therapy, as the expense of anticoagulants can be avoided, a not subtle way to push someone into a procedure to cut monthly high copays for expensive non-generic blood thinners.

Despite these misgivings, I did feel obligated to recommend the Watchman to my patient that day, because I was worried about his risk of another stroke. He had no interest in having it done, despite a careful discussion of the risks and benefits, saying simply, “Not for me.” Other than isolated cases like this, I would not recommend it for my patients. Most people with atrial fibrillation will unfortunately continue to need powerful blood thinners to reduce their risk of stroke.

David Becker, M.D., is a frequent Inquirer contributor and a board-certified cardiologist with Chestnut Hill Temple Cardiology in Flourtown, Pa. He has been in practice for 25 years.