By Tina Chang Albershardt
Coronary stenting is one of the several methods currently available to treat coronary diseases. To open up a blocked blood vessel, a stent (slotted tube) is placed inside the blocked vessel. A major problem associated with stenting is restenosis (the formation of another vessel blockage).
Restenosis develops because the body sees the stent as an intruding foreign object and thus initiates a healing response that results in the proliferation of smooth muscle cells (SMC) around the stent. This closes up the blood vessel again and requires another stenting procedure, aka subsequent revascularization.
In recent years, scientists have developed drugs that would prevent SMC proliferation. A drug-eluting stent (DES) is thus a bare-metal stent (BMS) with a coat of one of these drugs. By decreasing SMC proliferation, DES, compared to BMS, are able to decrease the rate of restenosis by 50%.
When DES became available in 2003, about 60% patients received them in a matter of months. “That’s revolutionary!” exclaimed Dr. David Malenka, a cardiologist at the DHMC. But soon after, reports flooded in noting that blood clots were found inside of the DES much later than expected, a phenomenon known as “late stent thrombosis.”
With access to Medicare claims of patients receiving coronary stenting, Malenka and colleagues thus asked, “What can we contribute to the understanding of this situation?” By looking at all Medicare-eligible patients aged 65 years or older who received a non-emergent coronary stent and by comparing their outcomes of stenting before and after the availability of DES,Malenka and colleagues were able to conclude in their recent publication in JAMA (vol. 299, p. 2868-2876) that “a decreased rate of restenosis and subsequent revascularization, with their attendant risks, could more than compensate for a small increased risk of stent thrombosis from drug-eluting stents… because people on average are actually doing better.”
Malenka’s study reassures both patients and physicians that there is a net benefit to the use of DES, although “we still need to learn more about how to minimize the risk of late stent thrombosis.” Patients currently have the option of staying on dual anti-platelet agents longer, or, depending on the characteristics of the blocked blood vessel and certain scenarios, patients may choose to use a BMS instead or alternative methods that are also available. Whichever is the case, patients and physicians should discuss patient-specific risk factors and benefits when deciding the optimal treatment, because, as Malenka points out, “People have options; people have choices. Nothing is risk-free.”
