Bypass Patients Less Likely to Take Meds

Coronary bypass patients less likely to fill prescriptions than angioplasty recipients

(RxWiki News) Medication after heart surgery is often a key part of recovery. Interestingly, individuals who receive more invasive cardiac surgery may be the least likely to follow up with preventative medication.

Researchers found that bypass surgery patients were less likely to take preventive medication or refill prescriptions within the initial year after an operation as compared to those who received angioplasty.

"Fill and take medication as prescribed by your physician."

Both operations treat blocked coronary arteries. During angioplasty, a catheter is inserted into the groin, then threaded to the heart to open a clogged artery. Coronary artery bypass surgery involves taking veins from another part of the body, usually the legs, to divert blood flow around a section of blocked artery in the heart. 

Mark A. Hlatky, MD, a lead researcher from Stanford University School of Medicine, found that bypass patients were less likely to be consistent in refilling heart protecting medications.

During the cohort study, researchers reviewed the files of 8,837 bypass patients with new onset coronary disease and 14,516 angioplasty patients with coronary disease between 2000 and 2007.

Investigators identified patients who never filled prescriptions for a variety of heart protecting medications including statins, beta blockers, ACE inhibitors and angiotensin receptor blockers (ARBs). They also calculated the ratio of patients who possessed medication if they had filled at least one medication.

Researchers found that bypass patients were more likely to skip refills for statins during the first year after surgery. About 7 percent did not refill statins compared to almost 5 percent of angioplasty patients.

Bypass patients failed to refill 29 percent of prescriptions for ACE inhibitors or ARBs versus 22 percent who received the less-invasive heart surgery. About 6 percent did not refill beta blockers regardless of the type of cardiovascular surgery they underwent.

Among bypass patients, 69 percent were found to possess or use ACE inhibitors or ARBs compared to 78 percent of angioplasty patients. Bypass patients were found to take beta blockers 76 percent of the time and statins 83 percent of the time versus 78 percent and 84 percent, respectively, among angioplasty patients.

Researchers did not calculate aspirin use since it is available without prescription.

They did find that most, or 89 percent, of bypass patients did not fill a prescription for the common blood thinner clopidogrel (Plavix) while only 5 percent of angioplasty patients did not fill the same prescription. Among individuals who filled at least one prescription for clopidogrel, 40 percent of bypass patients were found to take the medication compared to 55 percent of angioplasty patients.

Researchers calculated that the difference in medication adherence shrank from 14 percent to a still-significant 9 percent after adjustments were made for age, gender, medical conditions and other influencing factors.

The study did not consider the reasons that bypass patients may be less likely to refill or take preventative medication, though researchers indicated that addressing these differences could be an opportunity to improve care following surgery to unclog arteries.

Sarah Samaan, MD, a cardiologist with Legacy Heart Center and co-director of the Women’s Cardiovascular Institute at the Baylor Heart Hospital, called the study "intriguing," and noted that it can be difficult for heart patients to stay motivated in taking cardiovascular medication because it doesn't necessarily make them feel better.

"My suspicion is that many people who undergo heart bypass operations believe that they are 'cured,'" said Dr. Samaan. "They may not understand that medication is just as critical for them as it is for those who have heart artery stenting procedures."

Dr. Samaan, also author of "Best Practices for a Healthy Heart: How to Stop Heart Disease Before or After It Starts," noted that while most heart surgeons are conscientious about prescribing medications in the hospital, it is not their role to manage blood pressure, cholesterol, and other nonsurgical heart issues for outpatients.

She said patients also may stop taking medications because of concerns over side effects or costs. At times other medications, such as those that are less expensive, may be a better fit, Dr. Samaan said.

Researchers suggested that future research should examine why bypass patients are less likely to take their medication, and how interventions may be able to aid patients in better medication adherence.

The study, funded by a grant from the American Heart Association, was recently published in the Journal of the American College of Cardiology.

Review Date: 
January 4, 2013