Cardiologists warn of risks for patients with coronary stents who discontinue medications

In the September issue of the Journal of Invasive Cardiology, Jefferson cardiologists published a warning for physicians and patients alike about an alarming trend they are witnessing first hand – very, very late stent thrombosis.

By following a series of patients encountered in recent years, they have concluded that the risk of heart attack from stent thrombosis persists beyond five years after implantation of the drug-eluting stent (DES), particularly among patients who have stopped taking their medication.

''These sobering findings underscore the importance of long-term clinical vigilance in these patients and reinforce current guidelines which recommend continuing aspirin indefinitely after having a stent implanted,'' said  Michael Savage, MD., the Ralph J. Roberts Professor of Cardiology in the Sidney Kimmel Medical College at Thomas Jefferson University.

Drug-eluting stents have been an important advance in the treatment of heart disease and have helped many patients avoid coronary bypass surgery. However, to reduce potential serious complications, patients are prescribed anti-platelet medication (life-long aspirin and clopidogrel for at least one year).

Stent Thrombosis (ST), which occurs when a platelet-rich blood clot forms on the surface of the stent, usually results in a myocardial infarction (heart attack) and has a high mortality rate. ST more than one year after the implantation procedure is classified as very late ST. Until the current study, it was unknown whether the risk of ST eventually abates over time or persists indefinitely.

In the published paper, Jefferson cardiologists reported seven cases where patients experienced major heart attacks from ST more than five years post-stent implantation. The average interval between stent implantation and ST was six years, with the latest case being more than seven years.

None of the patients were taking clopidogrel and only two patients were taking aspirin. Therefore, five of the seven patients were on no anti-platelet therapy prior to ST. Importantly, six of the seven patients were active smokers at the time their heart attacks.

The published case series serves as a warning for patients and doctors that ongoing follow-up and adherence to recommendations can mean the difference between life and death. In addition, as the 10-year anniversary of the FDA approving DES has come and gone, additional long-term research is needed to guide medication recommendations.

Renu Virmani, MD., echoes the importance of future research to identify patients at risk for very, very late stent thrombosis in an accompanying, invited commentary entitled ''Insights into Very Late Stent Thrombosis from Wisdom of Pathology.'' Dr. Virmani is recognized as a leading researcher in the field of stent thrombosis.

''The essential point from a public health perspective is that these complications can be prevented by patients complying with their prescribed medication and practicing a heart healthy life-style long after their procedures. The silver lining of the study is that we did not observe a single case of very, very late stent thrombosis in patients who both took their aspirin and didn't smoke,'' concludes Dr. Savage.