Alert Urges Lengthier Antiplatelet Use for High-Risk Drug-Eluting Stent Patients

WASHINGTON, Jan. 11 -- Diabetic patients and others at high risk for late thrombosis after the use of drug-eluting stents should be considered for extended dual antiplatelet therapy -- longer than 12 months -- or dose escalation of Plavix (clopidogrel).

So said the Society for Cardiovascular Angiography and Interventions (SCAI) in a clinical alert issued today. The SCAI alert came a month after hearings into drug-eluting stent safety by the FDA's Circulatory Systems Device Advisory Panel.

The FDA advisers asked both the agency and professional societies to alert physicians to potential risks associated with drug-eluting stents, especially the risk of late thrombosis.

The FDA advisers agreed that the benefit of the drug-eluting stents -- a drastic reduction in restenosis and the need for revascularization -- outweighed the risk of late thrombosis when the devices are used according to label indications, meaning stable, single-vessel disease characterized by short lesions.

The SCAI estimated the excess risk of late thrombosis in this on-label population at about 0.2% per year, beginning at 12 months.

But when used drug-eluting stents are used off label -- in patients with diabetes, left-main disease, bifurcation lesions, or when multiple stents are needed -- the risk may be greater. The FDA estimated that 60% of drug eluting stents were implanted in patients who fall into off-label categories.

In addition to the recommendation about extended Plavix use and possible dose adjustment in high risk patients, the SCAI alert recommended that:

• Prior to any stent implantation, patients should meet accepted criteria for coronary intervention as described in guidelines jointly published by the American College of Cardiology/American Heart Association/SCAI.
• The decision to treat a patient with a drug-eluting stent-rather than a bare metal stent or bypass surgery-must be made on an individual patient basis, considering the relative risks and benefits of each therapy. This decision will vary according to each patient's medical history, coexisting illness, and lesion characteristics.
• Patients must be carefully evaluated for their ability to adhere to long-term therapy with dual anti-clotting medications.
• Careful attention must be paid to stent implantation technique, including the use of intravascular ultrasound, screening for arterial calcification, and pretreatment of complex lesions in some cases.
• Discontinuation of dual anti-clotting medication should follow careful consideration and must be individualized for each patient.

In addition, they pointed out that at the FDA advisory panel stent-safety meeting, questions were raised about the appropriateness of multivessel stenting, especially in comparison with coronary artery bypass surgery. They noted that this question is also under rigorous investigation.

The FREEDOM trial, they noted, is randomizing 2,400 patients with diabetes and multivessel disease to DES implantation versus bypass surgery.

Moreover, they pointed out, the SYNTAX trial is randomizing 1,700 patients with triple-vessel or unprotected left-main disease to DES implantation versus bypass surgery.

They concluded "until such time as these trials produce clear data for further recommendations we advise the practicing interventionalist to thoughtfully document the indications for intervention and the medical decision-making process by which the specific revascularization strategy was chosen."

John McB. Hodgson, M.D., chief of academic cardiology at St. Joseph's Hospital and Medical Center in Phoenix and lead author of the alert, also urged physicians to reassure patients that the implantation of a drug-eluting stent remained an extremely effective treatment for disabling symptoms of coronary artery disease.