Stent implantation is one of the most commonly performed cardiology procedures worldwide. Stents are used to open narrowed coronary arteries and reduce the risk of a repeat heart attack. While the long-term results after stent implantation are positive in most cases, late complications occur in about 1-2 percent of patients per year. A common cause of these complications is a phenomenon called neoatherosclerosis. Neoatherosclerosis occurs when new cholesterol deposits form in the lining of the stent, which can lead to blockage of the stent. Preventing such neoatherosclerosis reduces the risk of suffering stent complications years after the stent has been implanted.
Differences in stent coating
Today’s stents are often coated with a drug that prevents the lining of the vessel from growing too much and clogging the stent. These drug-eluting stents have a thin plastic layer (polymer) on the metal struts that releases the drug into the vessel wall. In some stents, this plastic layer remains permanently, while in other stents, the so-called “stents with biodegradable polymer”, it dissolves on its own after a few months. It was hoped that the dissolution of the plastic layer could reduce the inflammation in the vessel wall and thus reduce the risk of new deposits (neoatherosclerosis). However, it was unclear whether this was actually the case.
Comparison of stent types in heart attack patients
A comprehensive study led by Dr. med. Jonas Häner and Prof. Dr. med. Lorenz Räber from the University Clinic for Cardiology at the Inselspital Bern in collaboration with six Japanese hospitals has now investigated this question. For the study, 239 heart attack patients were randomly treated with either a stent with a degradable coating or a stent with a permanent plastic coating. Three years later, the inside of the stents was examined in the cardiac catheter laboratory using a high-resolution camera (optical coherence tomography) for signs of neoatherosclerosis. The results showed that neoatherosclerosis occurred at a similar rate in both groups (11.4 percent for stents with a degradable coating compared to 13.3 percent for conventional stents). Stents with a degradable coating therefore offer no advantage over stents with a permanent plastic layer.
Long-term protection through statins
According to Prof. Räber, head of the cardiac catheter laboratory, the study also revealed another interesting discovery: patients who took their cholesterol-lowering medication (statins) regularly over a three-year period had significantly fewer new cases of neoatherosclerosis in the stents than those who did not follow this therapy consistently (8.5 percent compared to 27.8 percent). These results are of great importance for the treatment of patients after a heart attack. While the choice of stent type may be less crucial, the study underscores the central role of consistently taking cholesterol-lowering medication for long-term health. A stent alone is not enough to be completely cured. “The results show how important it is for patients to keep an eye on their cholesterol levels after stent implantation,” emphasises Prof. Räber. “Consistently lowering cholesterol is crucial to avoiding later complications.” Dr. Häner, senior physician for interventional cardiology and co-author of the study, adds: “The right aftercare is just as important as the procedure itself.”
Source: Insel Gruppe
