There is an old belief and practice that  an aspirin a day truly keeps cardiovascular disease at bay in lower-risk individuals but now by a study, ARRIVE trial at the European Society of Cardiology (ESC) Congress 2018, published the Lancet,it remains unanswered, despite the efforts of a 12,000-patient randomized controlled trial that set out to settle the issue.“While no overall reduction was observed in the primary composite endpoint of CV events, results from ARRIVE are generally consistent with many other studies that tended to demonstrate aspirin’s ability to lower the risk of first nonfatal MI without affecting risk of total stroke,” said Gaziano.

                       The role of aspirin in the secondary prevention of coronary disease and stroke, as well as in the setting of acute MI and stroke, is well established. But as Gaziano reminded his audience, the use of aspirin for primary prevention has far fewer trials to support its use, with most being done among patients at low risk of CVD. A recent large meta-analysis of aspirin in primary prevention suggested that a high risk of bleeding may offset the cardiovascular benefits in lower-risk individuals, and prompted the US Preventive Services Task Force to tighten up its recommendations on aspirin, saying it should be restricted to people at high risk of events.

        ARRIVE therefore set out to establish the safety and efficacy of a daily dose of 100 mg, enteric-coated aspirin compared with placebo among 12,546 patients whose 10-year risk of a first acute cardiovascular event fell into the “moderate” range—between 10 to 20%. Patients at high risk for gastrointestinal bleeds or with diabetes were excluded from the trial.

           ARRIVE was conducted between July 2007 and November 2016 in seven countries and at more than 500 study sites, with follow-up conducted by primary care physicians during annual patient visits, and if those weren’t available then via phone calls and medical record checks.At a median of 60 months, the observed cardiovascular event rate was “considerably less than anticipated,” Gaziano said: 9% as opposed to the expected 17%. An event rate of less than 10% corresponds to a lower-risk group—one for whom the role of aspirin has been better studied, he noted.

                         For the primary endpoint—time to first occurrence of cardiovascular death, MI, unstable angina, stroke, and transient ischemic attack (TIA)—there were no significant differences between the groups assigned to aspirin versus placebo (4.29% vs 4.48%; HR 0.96; 95% CI 0.81-1.13). Likewise, there were no differences in the secondary endpoints, made up of the individual components of the primary endpoint alone or in different combinations.Overall rates of gastrointestinal bleeds were low, less than 1%, but twice as high in the aspirin group than in the placebo group, a statistically significant difference. Serious adverse events were relatively common (bleeding events as well as nonbleeding events such as osteoarthritis, cardiac events, and cancers), occurring in approximately one in five patients. Approximately 2.5% of patients in both groups died during the study. No significant effects were seen on short-term cancer, Graziano noted, adding that “the length of follow-up was insufficient to assess longer-term outcomes.”