Just like the phrase “take two aspirin and call me in the morning” implies, acetylsalicylic acid is a medical mainstay, one of the world’s most frequently prescribed and least expensive drugs. In fact, 100 billion aspirin tablets are produced worldwide each year. That said, there’s still a lot we don’t know about aspirin, particular when it comes to heart-attack prevention.

“I think aspirin is still a fascinating topic because it’s a commonly used medication, both in terms of doctors recommending it and also patients sometimes just taking it over the counter for a variety of indications. However, given how widespread its use is, it’s actually amazing that in 2012 there are still a lot of unanswered questions about aspirin,” said Deepak L. Bhatt, MD, chief of cardiology at the VA Boston Healthcare System and director of the Integrated Interventional Cardiovascular Program at Brigham and Women’s Hospital.

Nonetheless, some things are certain. For secondary prevention, when patients have already suffered a heart attack or certain types of strokes or have undergone a heart bypass or other procedure, aspirin is a proven therapy. “Taking aspirin is the right thing to do for the vast majority of those patients unless they have some serious bleeding problems. They really should be on aspirin, and it’s unfortunate that a proportion of such patients aren’t,” Bhatt said. “Typically, as is the case with all medicines, patients don’t always adhere to what’s recommended, especially once they’re feeling well and once time has passed from the index event.”

Echoing that notion is Stephen L. Kopecky, MD, professor of cardiology at the Mayo Clinic and president-elect of the American Society for Preventive Cardiology. “For people who have heart disease, aspirin clearly is beneficial, and it lowers their risk for having a recurrent heart attack, and if they do have a heart attack, it lowers their chance of dying,” he said. Yet Kopecky bemoaned the fact that patients don’t loyally adhere to aspirin regimens – or regimes of any medication, for that matter.

To underscore his point, Kopecky referenced a study published in late 2011 in the New England Journal of Medicine that examined patients’ adherence to a drug therapy after a heart attack. Even when the patients in the study received free of charge the drug that may prevent a recurrent heart attack, only about half the patients stuck with the therapy for three years. “You would think that those patients would be the most motivated,” he said.

Then there’s the problem of ensuring that those patients who should be taking aspirin for secondary prevention are indeed informed. Bhatt was on the research team of the international REACH study, which wrapped up its findings in 2010 and documented the underutilization of aspirin. It concluded that about 14 percent of patients who had strong indications to be on aspirin for secondary prevention weren’t. “Some proportion of that might have been side effects or problems with bleeding, but I don’t think that explains that whole percentage,” Bhatt said.

Yet, when it comes to aspirin for primary prevention, the jury is still out, even for patients with multiple risk factors such as advancing age, diabetes, smoking, high blood pressure and high cholesterol. While some physicians believe a low-dose daily aspirin for such patients is appropriate, provided those patients don’t have a history of problems taking aspirin, other physicians are shying away until more concrete, evidence-based data are available.

“There are certainly are some studies that show reductions in nonfatal heart attacks, but it’s not been absolutely shown with certainty in any large, contemporary, randomized, clinical trial that aspirin for primary prevention (in high-risk patients) does reduce events like death and heart attack,” Bhatt said. And the downside, he added, can be devastating. Gastrointestinal bleeding increases with an aspirin regimen, and there’s also a very small, but very real, risk of bleeding into the brain. “That’s why it creates a dilemma,” Bhatt said.

As for Kopecky, he said he does recommend aspirin for primary prevention if a patient presents with more than two risk factors and especially if there’s evidence of narrowing of arteries to the heart or anywhere in the body. He said he sometimes orders a CT scan to pinpoint whether there’s calcium in the arteries to the heart. “Then we know those patients have a process that is damaging the lining of their arteries, so we get those people on aspirin,” he said.

There are a number of large, randomized, clinical trials ongoing that should be reporting in the next few years and should nail down the role of aspirin in primary prevention.

Meanwhile, both Kopecky and Bhatt said physicians should consider each patient’s particular circumstances when deciding whether to recommend an aspirin therapy. “It’s a complex decision, and it really should be individualized,” Bhatt said, adding, “I think it’s actually an error for patients to just start taking aspirin on their own for primary prevention without consulting with their doctor, even though it’s cheap, over the counter and is a familiar medicine.”

Could patients become immune to aspirin? Such a phenomenon hasn’t been demonstrated, and Kopecky said patients don’t become immune in the same way that they would develop a tolerance for an antibiotic. “However, we do know that if you take aspirin and you still have a heart attack, then you’re higher risk and you probably need something more than aspirin next time,” he said.

Yet, there’s something about aspirin that Kopecky would really like to know, and it’s something research has yet to tell him. “Aspirin is the most used drug, most prescribed drug for the most common disease that is the biggest killer in the world – coronary artery disease. Yet we’ve never had a study that has told us what dose to use,” he said. “Is it 81 milligrams, which used to be called a baby aspirin but now is called the adult low dose? Is it 160 milligrams? Or is it the regular adult aspirin, which is 325? We know it’s probably not more than 325, and it actually looks like 81 is enough for just about everybody.” He routinely prescribes the 81.

Tags:

Bookmark:

Digg

Facebook

Technorati

Newsvine

Google

Related: