The occurrence of stent thrombosis (ST) after a drug-eluting stent (DES) is implanted is not much higher than in bare-metal stents (BMS), but that does not mean every patient should receive a DES. Ron Waksman, MD, associate director, division of cardiology at the Washington Hospital Center in Washington, D.C., presented this lecture at the “Late Breaking Clinical Trials” presentation at the American Heart Association (AHA) conference held this week in Orlando, Fla.
Waksman and Washington Hospital Center colleagues investigated 8,402 patients with unrestricted percutaneous coronary intervention and at least one DES. Of those cases, 67 percent had Johnson & Johnson’s Cordis stent implanted; 28 percent had Boston Scientific’s Taxus stent implanted; and 5 percent had both types of stents. The majority of the patients, 8,192, did not suffer ST. In contrast, 127 patients endured definite probable ST (DPST) and 83 patients suffered definite ST (DST). Waksman clarified that, according to the Academic Research Consortium definition, DST means a clot needs to be present.
In the incidence slope, the DST slope rose 0.36 percent between 30 days and two years. Waksman commented that the DPST statistics slope was “slightly higher,” because it rose 0.84 percent between 30 days and two years.
Early ST, which occurs between zero and 30 days after implantation, was 0.8 percent for DST and 1.9 percent for DPST. Late ST, which occurs between 30 days and 360 days, was 0.4 percent for DST and 1.4 percent for DPST. Very late ST, which occurs beyond 360 days, was 0.4 percent for DST and 0.7 percent for DPST. At a two-year follow-up, there was “no plateau of DST but DPST is declining,” Waksman said.
Waksman reported that DST and DPST are associated with: history of diabetes mellitus; myocardial infarction during admission stent number; and DES placement in restonotic lesion.
Even though the DES statistics of this study are promising, Waksman said that he is “not mandating DES for everyone.” For instance, “DES should not be recommended for off-label use” and “no patients with acute MI should get DES,” he said. Waksman also cautioned his colleagues against multiple stenting, especially more than four to five stents.
Waksman stressed that the technical skill of the physician is also a risk factor for ST. He was encouraged that cardiologists have increased their reliance upon intravascular ultrasound. He said that usage is “up to 15 percent as opposed to 8 percent a few years ago.”
The presentation moderator, Raymond Gibbons, MD, the immediate past-president of the AHA and professor of medicine and co-director of the Nuclear Cardiology Lab at the Mayo Clinic in Rochester, Minn., concurred that technical skill affects the outcomes.
In regards to the effectiveness of dual anti-platelet therapy after stent implantation, “ST still seems to occur,” Waksman said. Gibbons added that “evidence for dual anti-platelet therapy is strong for the first few months,” but not after that. Waksman concluded that dual anti-platelet therapy is “not the magic bullet, but it is the best method we have today.”