Patients who had ischemic and bleeding events 12 to 33 months after undergoing coronary stenting had an increased mortality risk, according to a post hoc analysis of a randomized study.

The researchers examined patients who adhered to their dual antiplatelet therapy and were event-free for the first year following stenting.

Lead researcher Eric A. Secemsky, MD, MSC, of Massachusetts General Hospital and Harvard Medical School, and colleagues published their results online in JAMA Cardiology on March 15.

For this analysis, the researchers evaluated the Dual Antiplatelet Therapy (DAPT) study, which enrolled patients at 220 sites from 11 countries from August 2009 to May 2014. All of the patients were at least 18 years old and underwent PCI with a drug-eluting stent or a bare metal stent.

After stenting, the 25,682 patients were prescribed a dual antiplatelet regimen of thienopyridine plus aspirin for 12 months. The patients who did not have ischemic or bleeding events continued taking aspirin and were randomized to continue receiving thienopyridine or placebo for another 18 months. After the 30 months, the patients were followed for an additional three months while receiving just aspirin.

In all, 11,648 patients were randomized. Their mean age was 61.3 years old, and 25.1 percent were females. After 21 months, 4.1 percent of patients had a total of 502 ischemic events, including 306 with MI, 113 with stent thrombosis and 83 with ischemic stroke. There were also 235 bleeding events, including 155 moderate bleeding events and 80 severe bleeding events. In addition, 88 patients had cardiovascular deaths that were not due to MI, stent thrombosis or ischemic stroke.

Of the patients with ischemic events, 10.9 percent died, and 78.8 percent of the deaths were attributable to cardiovascular causes. The unadjusted annualized mortality rate after an ischemic event was 27.2 per 100 person-years. The cumulative incidence of death after an ischemic event among the total randomized study population was 0.5 percent.

In addition, 17.7 percent of patients with bleeding events died, while the annualized mortality rate after a bleeding event was 21.5 per 100 person-years. Further, 9.7 percent of patients died after a moderate bleeding event and 32.5 percent died after a severe bleeding event. The cumulative incidence of death after a bleeding event was 0.3 percent.

The researchers mentioned the study had a few limitations, including that they excluded patients with a history of significant bleeding and those treated with oral anticoagulants. They also noted that the incidences of ischemic and bleeding events depended on the definitions used. In addition, they excluded cardiovascular deaths that were not preceded by MI, stent thrombosis or ischemic stroke.

“Since our analysis found that the development of both ischemic and bleeding events portend a particularly poor overall prognosis, we conclude that we must be thoughtful when prescribing any treatment, such as dual antiplatelet therapy, that may include bleeding risk,” Secemsky said in a news release. “In order to understand the implications of therapies that have potentially conflicting effects—such as decreasing ischemic risk while increasing bleeding risk—we must understand the prognostic factors related to these events. Our efforts now need to be focused on individualizing treatment and identifying those who are at the greatest risk of developing recurrent ischemia and at the lowest risk of developing a bleed.”