Cardioprotective Effects and Duration of Beta Blocker Therapy in Anthracycline-Treated Patients: A Systematic Review and Meta-analysis.

Anthracycline-containing chemotherapy is commonly associated with irreversible cardiovascular toxicity. Beta blockers are currently recommended as first-line drugs for improving cardiac function. However, the effects of beta blocker on cardiac preservation and the duration of beta blocker intervention therapy in anthracycline-treated patients remain unclear. We systematically searched PubMed, Embase, and Cochrane for randomized controlled trials (published between January, 2000 and January, 2019) to determine the effectiveness of cardiac preservation of beta blocker in anthracycline-treated patients by accessing the change in left ventricular ejection fraction (LVEF) from pre- to post-chemotherapy. In addition, we conducted subgroup analysis based on the duration of beta blocker cardioprotective intervention and accumulative anthracycline dose. 11 RCTs were finally included. Beta blockers were associated with a significant smaller drop in the LVEF change (MD = 2.87, 95% CI 0.64 to 5.11, p = 0.01) compared to control groups. Besides, a subgroup analysis according to duration of beta blocker-based cardioprotective intervention (< 6 months vs = 6 months) showed significant subgroup difference in the LVEF change (MD = - 0.05, 95% CI - 0.91 to 0.81, p = 0.91; MD = 6.48, 95% CI 2.44 to 10.52, p = 0.002). An additional subgroup analysis according to accumulative anthracycline dose showed statistically significant difference in the LVEF change (MD = 4.61, 95% CI 0.78 to 8.45, p = 0.02) with moderate accumulative dose of anthracycline (doxorubicin between 250 and 400 mg/m). Prophylactic administration of beta blocker-based cardioprotective therapy may be beneficial to the myocardial preservation in anthracycline-treated patients. And long-term use of beta blocker appears to have a positive effect on ameliorating anthracycline-induced cardiomyopathy, especially in patients exposed to moderate accumulative doses of anthracycline.