Ischaemic Cardiac Outcomes in Patients With Atrial Fibrillation Treated With Vitamin K Antagonism or Factor Xa Inhibition: Results From the ROCKET AF Trial
What is the incidence of cardiovascular (CV) events in a large population of patients with atrial fibrillation (AF) receiving anticoagulant therapy, and the risk of CV events with rivaroxaban compared with warfarin?
In the ROCKET AF trial, 14,264 patients with nonvalvular AF were randomized to rivaroxaban or warfarin. The key efficacy outcome for these analyses was CV death, myocardial infarction (MI), and unstable angina (UA). This prespecified analysis was performed on patients while on treatment. Estimates and two-sided 95% confidence intervals (CIs) for the hazard ratio (HR) (rivaroxaban vs. warfarin) by prior MI were presented in the safety, on-treatment population for both the efficacy and safety endpoints.
Rates are per 100 patient-years. Overall, 2,468 (17%) patients had prior MI at enrollment. Compared with patients without prior MI, these patients were more likely to be male (75 vs. 57%), on aspirin at baseline (47 vs. 34%), have prior congestive heart failure (78 vs. 59%), diabetes (47 vs. 39%), hypertension (94 vs. 90%), higher mean CHADS2 score (3.64 vs. 3.43), and fewer prior strokes or transient ischemic attacks (46 vs. 54%). CV death, MI, or UA rates tended to be lower in patients assigned rivaroxaban compared with warfarin (2.70 vs. 3.15; hazard ratio [HR], 0.86; 95% confidence interval [CI], 0.73-1.00; p = 0.0509). CV death, MI, or UA rates were higher in those with prior MI compared with no prior MI (6.68 vs. 2.19; HR, 3.04; 95% CI, 2.59-3.56) with consistent results for CV death, MI, or UA for rivaroxaban compared with warfarin in prior MI compared with no prior MI (p interaction = 0.10).
The authors concluded that prior MI was common in patients with AF, and was associated with substantial risk for subsequent cardiac events.
In a trial population of patients with AF, prior MI was common, with ∼20% patients having a history of prior MI. There was some evidence that rivaroxaban was more beneficial in preventing CV events in those without prior MI than in those with prior MI, but the interaction analysis was nonsignificant. It should also be noted that patients with prior MI had worse major/NMCR bleeding outcomes with rivaroxaban compared with warfarin that likely were associated with higher use of concomitant aspirin, but consistent reductions in intracranial hemorrhage and fatal bleeding were observed with rivaroxaban compared with warfarin. Given subgroup nature of the analyses, small number of events, and use of multiple comparisons, prospective studies to assess the safety/efficacy of rivaroxaban in patients with prior MI are indicated.
Keywords: Vitamin K, Myocardial Infarction, Stroke, Ischemic Attack, Transient, Morpholines, Thiophenes, Warfarin, Risk Factors, Fibrinolytic Agents, Incidence, Blood Coagulation, Intracranial Hemorrhages, Heart Failure, Cardiovascular Diseases, Confidence Intervals, Embolism, Factor Xa, Hypertension, Diabetes Mellitus
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