The general assumption that β-blocker treatment may be beneficial in patients with cardiac atherothrombotic disease (ATD) has been challenged by recent reports in stable angina patients. Given the clinical implications of recent studies and the controversial reports regarding the usefulness of β-blockers for management of patients with and without prior MI or heart failure (HF), Bangalore et al (1) performed a post-hoc analysis from The Clopidogrel for High Atherothrombotic Risk and Ischemic Stabilization, Management, and Avoidance (CHARISMA) trial. The use of β-blockers was associated with a 31% lower risk of the primary outcome in patients with prior MI (HR 0.69; 95%CI 0.50-0.94), mainly due to a reduction in recurrent MI (HR 0.62; 95%CI 0.39-1.00, p=0.049), with no significant differences for the rest of outcomes. There was no risk reduction associated with β-blocker use in patients without prior MI, either with known ATD or with risk factors alone, for any of the outcomes. Importantly, a trend towards an increased risk of stroke (3.5% vs 1.5%, p=0.079) was found in patients treated with β-blockers compared with those not on β-blocker treatment. The implications of these findings and future needs in this area are discussed by Dr A. Vallejo-Vaz.
References
Bangalore S, Bhatt DL, Steg G, et al. β-Blockers and Cardiovascular Events in patients with and without Myocardial Infarction. Post hoc analysis from the CHARISMA trial. Circ Cardiovasc Qual Outcomes 2014;7 Sept, DOI: 10.1161/CIRCOUTCOMES.114.001073.
No risk reduction with beta blocker use in stable angina patients – Evidence for harm?
Bangalore et al. assessed the long-term efficacy of β-blockers depending on the presence of prior MI in subjects without heart failure (HF).  The patients were divided into 3 cohorts after excluding those with history of HF: patients with prior MI (n=4,772), patients without MI but with known athero-thrombotic disease (ATD) (cardiovascular, cerebrovascular or symptomatic peripheral vascular, n=7,804), and patients with risk factors alone without MI or known ATD (n=2,101). In each cohort, patients were grouped according to baseline β-blocker use and followed-up for 28 months. As mentioned in the ‘cardionote’, The use of β-blockers was associated with a 31% lower risk of the primary outcome in patients with prior MI (HR 0.69; 95%CI 0.50-0.94), mainly due to a reduction in recurrent MI (HR 0.62; 95%CI 0.39-1.00, p=0.049), with no significant differences for the rest of outcomes. There was no risk reduction associated with β-blocker use in patients without prior MI, either with known ATD or with risk factors alone, for any of the outcomes. Importantly, a trend towards an increased risk of stroke (3.5% vs 1.5%, p=0.079) was found in patients treated with β-blockers compared with those not on β-blocker treatment.
These results, though concordant with other previous reports, should be considered carefully, as some limitations must be acknowledged; for instance, the study is a non-prespecified post-hoc analysis, where β-blockers were not randomly assigned; data such as type of β-blocker, dosage, indication for therapy or patients’ compliance were not assessed; likewise, a β-blocker treatment could have been started, adjusted or removed during the follow-up. Additionally, while older β-blockers were used, the newer vasodilating β-blockers, with less metabolic effects, could influence the outcomes more favourably. Finally, the specific effect of β-blockers on ATD could differ on the cardiac, cerebral or peripheral beds.
This study adds to the last growing evidence suggesting a possible no benefit (or even a harmful effect in specific subsets) of β-blockers in the long-term in stable patients without MI or HF. Large randomized control trials specifically designed to assess this questions are needed to establish more definitive conclusions.
References
Bangalore S, Bhatt DL, Steg G, et al. β-Blockers and Cardiovascular Events in patients with and without Myocardial Infarction. Post hoc analysis from the CHARISMA trial. Circ Cardiovasc Qual Outcomes 2014;7 Sept, DOI: 10.1161/CIRCOUTCOMES.114.001073.
