The importance of keeping patients with drug-eluting stents on dual antiplatelet therapy has been vastly underestimated, according to new warnings about the risk of late thrombosis issued by the Food and Drug Administration and several professional societies.
In January, the FDA announced on its Web site that it had “made detection of DES [drug-eluting stent] thrombosis signals a priority because of the potential for serious harm to patients [even though] stent thrombosis occurs at low rates.” The agency summarized recommendations issued in December by its Circulatory System Devices Advisory Panel, including that the off-label use of DESs—estimated to be about 60% of device placements—is associated with an increased risk of thrombosis, death, or myocardial infarction (www.fda.gov/cdrh//010407.html
Shortly thereafter, the Society for Cardiovascular Angiography and Interventions (SCAI) issued a clinical alert on DESs (Cathet. Cardiovasc. Interv. 2007 Jan. 11 [Epub DOI:10.1002/ccd.21093
The alert is “a wake-up call,” said Dr. Hodgson, SCAI past president and chief of academic cardiology at St. Joseph's Hospital and Medical Center, Phoenix. “We've gotten a little sloppy about putting stents in and not thinking through the entire process,” he said.
Physicians should first determine if any procedure—whether surgery or stenting—is required, Dr. Hodgson said. If a DES is chosen, then intravascular ultrasound should be used to “document appropriate longitudinal lesion coverage and adequate stent expansion,” according to the alert.
All risks and benefits—and the importance of maintaining dual antiplatelet therapy for at least 3-6 months, and for 12 months when bleeding risk is low—should be discussed with the patient. Using a DES “can't be the default strategy,” he said, noting that many patients are not appropriate candidates for the devices.
Lastly, the American Heart Association, the American College of Cardiology, SCAI, the American College of Surgeons, and the American Dental Association issued a joint science advisory on the dangers of premature discontinuation of dual antiplatelet therapy after DES placement. The advisory was published in Circulation, the Journal of the American College of Cardiology, and Catheterization and Cardiovascular Interventions.
The recommendation has been to give 75 mg daily of Plavix (clopidogrel) and 325 mg daily of aspirin for 1 month after bare-metal stent implantation, for 3 months after sirolimus-coated DES implantation, for 6 months after paclitaxel-coated DES, and up to 12 months if there is a low risk for bleeding. “That's gone out the door,” said lead advisory author Dr. Cindy Grines, a cardiologist at William Beaumont Hospital, Royal Oak, Mich., in an interview.
The new recommendation is dual therapy for 12 months whenever possible, according to Dr. Grines. It has become clear that many patients and physicians—primarily those who are not cardiologists—are stopping dual therapy early, and that they may not understand the consequences, she said. Reasons for halting therapy include its expense (about $120 per month) and the perceived risk of bleeding during a subsequent surgical or dental procedure, Dr. Grines said.
The AHA advisory urges physicians to discuss with patients the pros and cons of dual therapy and the need to continue it for at least 12 months. The advisory cited numerous studies showing that early stoppage led to vastly higher rates of stent thrombosis, MI, and death.
Patients at particular risk for DES-related thrombosis—those who are older or have acute coronary syndrome, diabetes, low ejection fraction, or renal failure—should consider taking dual therapy for as long as possible, according to the advisory.
If 1 year is not possible, or if patients are required to have invasive surgery within 12 months of the catheterization, alternatives to DES—including a bare-metal stent or balloon angioplasty—should be weighed.
And cardiologists need to be consulted before a patient stops antiplatelet therapy, even if they are asked to do so by another physician.
There may be benefits to dual therapy beyond 12 months, but with few solid studies, it was harder to get a consensus on extending the duration, Dr. Grines said.
Drug-eluting stents are not overused, she said, adding that this is especially true given that they've been shown to have an edge in restenosis.
“Personally, I still use drug-eluting stents in most of my patients,” said Dr. Grines, noting that she makes exceptions for those who have had a recent MI, who have surgery scheduled, or who can't or aren't willing to maintain dual antiplatelet therapy for a year.
The FDA lauded the AHA document, saying it will raise awareness of the importance of dual therapy among all providers.