Stroke Prevention Research Unit, Department of Clinical Neurology, University of Oxford, Oxford, UK.
Neurology. 2011 Aug 23;77(8):731-7. doi: 10.1212/WNL.0b013e31822b007a. Epub 2011 Jul 27.
β-Blockers increase variability in systolic blood pressure (SBP), which probably explains their lesser effectiveness in preventing stroke vs myocardial infarction compared with other agents. This increase in variability in blood pressure (BP) may be particularly marked on non-cardioselective agents, potentially calling into question the widespread first-line use of propranolol in migraine with aura, elderly patients with essential tremor or anxiety, and other groups at risk of stroke.
We determined β-blocker subclass effects on variability in BP and stroke risk in a systematic review of randomized controlled trials (RCTs) comparing different types of β-blocker with placebo or other agents. We determined pooled estimates of the effect of treatment on group variability in BP (ratio of the variances [VR]) and on the risk of stroke vs myocardial infarction during follow-up.
Compared with other antihypertensives, variability in SBP was increased more by nonselective β-blockers (VR=1.34, 1.13-1.59, p =0.002, 25 comparisons, 9,992 patients) than by β1-selective agents (VR=1.09, 95% confidence interval 1.00-1.19, p =0.053, 68 comparisons, 40,746 patients; difference-p =0.038). In direct comparisons, variability in SBP was also significantly lower with β1-selective vs nonselective β-blockers (VR=0.81, 0.68-0.97, p =0.03, 18 comparisons, 954 patients). In comparisons with other antihypertensives, the increase in stroke risk with nonselective β-blockers ([OR]=2.29, 1.32-3.96, p =0.002) was more marked than with β1-selective agents (OR=1.24, 1.08-1.42, p =0.003, difference-p =0.03), as was the risk of stroke relative to the risk of myocardial infarction: OR=1.50 (0.93-2.42) vs 0.99 (0.82-1.19).
Use of β1-selective rather than nonselective agents may be advisable when β-blockers are indicated for patients at risk of stroke.
β受体阻滞剂会增加收缩压（SBP）的变异性，这可能解释了与其他药物相比，β受体阻滞剂在预防中风方面的效果不如预防心肌梗死。这种血压（BP）变异性的增加在非心脏选择性药物中可能更为明显，这可能会让人质疑普萘洛尔在有先兆偏头痛、老年特发性震颤或焦虑症患者以及其他有中风风险的人群中作为一线药物的广泛使用。
我们通过对比较不同类型β受体阻滞剂与安慰剂或其他药物的随机对照试验（RCT）进行系统回顾，确定了β受体阻滞剂亚类对 BP 变异性和中风风险的影响。我们确定了治疗对 BP 组间变异性（方差比[VR]）和随访期间中风与心肌梗死风险的影响的汇总估计值。
与其他降压药相比，非选择性β受体阻滞剂（VR=1.34，1.13-1.59，p=0.002，25 项比较，9992 名患者）增加 SBP 变异性的程度大于β1 选择性药物（VR=1.09，95%置信区间 1.00-1.19，p=0.053，68 项比较，40746 名患者；差异 p=0.038）。直接比较时，β1 选择性与非选择性β受体阻滞剂相比，SBP 变异性也显著降低（VR=0.81，0.68-0.97，p=0.03，18 项比较，954 名患者）。与其他降压药相比，非选择性β受体阻滞剂增加中风风险的幅度（OR=2.29，1.32-3.96，p=0.002）大于β1 选择性药物（OR=1.24，1.08-1.42，p=0.003，差异 p=0.03），中风风险与心肌梗死风险的比值也是如此：OR=1.50（0.93-2.42）vs 0.99（0.82-1.19）。
当β受体阻滞剂对有中风风险的患者有指征时，使用β1 选择性药物而不是非选择性药物可能是明智的。
