In recent articles I have described the newly-recognized phenomenon of late restenosis in drug-coated stents. This form of restenosis is particularly dangerous. In drug-coated stents, restenosis is caused by the sudden formation of a blood clot within the stent, causing rapid occlusion of the coronary artery. Thus, it tends to manifest as a sudden, total blockage of the coronary artery, and therefore often presents as an acute myocardial infarction (heart attack) or even sudden death.
This is in stark contrast to the more typical, "classic" restenosis that occurs in non-drug-coated stents. Here, restenosis is caused by the growth of abnormal cells within the stent, and thus it most often occurs gradually, and usually leads to progressive (instead of sudden) symptoms. It was to prevent this kind of restenosis that drug-coated stents were developed in the first place. Indeed, the remarkable efficacy of drug-coated stents in preventing this "classic" restenosis has lead to their widespread adoption by cardiologists in the United States.
The use of clopidogrel (Plavix) appears to greatly reduce the risk of clot-induced late restenosis in drug-coated stents. Clopidogrel works by reducing the function of platelets, the tiny cells in the blood that help the blood to clot. But clopidogrel is very expensive, and it now begins to appear that very prolonged therapy with this drug (at least a year or two) ought to be used following the insertion of a drug-coated stent. Furthermore, taking clopidogrel greatly increases the risk of bleeding following most surgical procedures.
The emergence of late restenosis in drug-coated stents, and the subsequent requirement for long-term therapy with clopidogrel, has now created a dilemma for cardiologists. Drug-coated stents clearly reduce the risk of early restenosis that has plagued bare metal stents, and as long as the patient takes clopidogrel, the risk of late restenosis appears low. However, the need for clopidogrel creates fiscal problems for patients who need to buy their own drugs, and medical problems for patients who subsequently need surgery.
While this dilemma has not yet received much public airing, privately cardiologists are very concerned, and have initiated a vigorous internal debate regarding how to manage the use of clopidogrel after drug-coated stents are inserted.
Meanwhile, patients are getting mixed messages, and worse, are being placed in untenable positions. For example, here is a recent exchange on the Heart Disease Forum in which a patient is told by the surgeon that clopidogrel MUST be stopped before necessary surgery, and by the cardiologist that clopidogrel MUST NOT ever be stopped under any circumstances. Meanwhile, in an on-line forum for cardiologists (at TheHeart.org), doctors argue vociferously about when, or even whether, it is ever "safe" to stop clopidogrel after the use of a drug-coated stent - and some question whether these stents ought to be used at all in patients likely to need further medical procedures.
What this means for patients
Most cardiologists agree that drug-coated stents are still the right choice for patients who need coronary artery stenting. Still, there are several other options for treating coronary artery disease, and they all ought to be considered. Based on what we know today, cardiologists should feel obligated to tell their patients about this emerging downside to the use of drug-coated stents. The doctor should clearly describe the need for very prolonged, possibly permanent clopidogrel therapy, and the difficult issues that might arise if and when the patient should ever need future surgery. And before agreeing to receive a drug-coated stent, the patient should extract from the cardiologist a pledge that, should surgery become necessary in the future, the cardiologist will work in good faith with the surgeon to manage the use of clopidogrel in order to minimize both the risk of bleeding and the risk of restenosis.