Epstein Benjamin J, Anderson Shawn
Department of Pharmacy Practice, College of Pharmacy, University of Florida, Gainesville, Florida 32610, USA.
Pharmacotherapy. 2007 Sep;27(9):1322-33. doi: 10.1592/phco.27.9.1322.
The role of beta-blockers in uncomplicated hypertension has been challenged recently. Compared with other antihypertensives, beta-blockers are less effective for preventing cardiovascular events in patients with uncomplicated hypertension. Moreover, a recent meta-analysis of placebo-controlled clinical trials concluded that atenolol is not more efficacious than placebo for preventing cardiovascular events in patients with hypertension. Although these agents lower blood pressure measured conventionally over the brachial artery with a blood pressure cuff, they do not exert a commensurate effect on blood pressure in the central aorta. Central aortic blood pressure and aortic augmentation index are strong predictors of left ventricular hypertrophy, an independent risk factor for cardiovascular events. Emerging data are illuminating the antihypertensive paradox whereby antihypertensive agents may elicit discordant effects on central and peripheral blood pressure and hemodynamics. Vasodilatory antihypertensives, such as renin-angiotensin-aldosterone system inhibitors and calcium channel blockers, elicit reductions in central aortic blood pressure equal to or greater than that in the brachial artery. Conversely, beta-blockers lower central aortic blood pressure to a lesser degree even when blood pressure measured by sphygmomanometry is reduced substantially. Given the strong relationship between central aortic blood pressure and target organ damage, the effectiveness of beta-blockers may be overestimated in practice on the basis of conventional blood pressure measurements alone. Differences in central and peripheral blood pressure may account for the lack of cardiovascular protection afforded by beta-blockers in clinical trials and could account for a portion of the apparent "benefit beyond blood pressure" reduction with other classes of antihypertensive agents. Future studies should aim to better clarify the role of central aortic blood pressure in the treatment of hypertension. In the meantime, the effects of antihypertensive drugs on blood pressure "beyond the brachial blood pressure cuff" should be considered when prescribing antihypertensive agents for a patient.
β受体阻滞剂在单纯性高血压治疗中的作用最近受到了挑战。与其他抗高血压药物相比，β受体阻滞剂在预防单纯性高血压患者心血管事件方面效果较差。此外，最近一项对安慰剂对照临床试验的荟萃分析得出结论，阿替洛尔在预防高血压患者心血管事件方面并不比安慰剂更有效。尽管这些药物能降低使用血压袖带在肱动脉处常规测量的血压，但它们对主动脉中心血压并没有相应的影响。主动脉中心血压和主动脉增强指数是左心室肥厚的有力预测指标，而左心室肥厚是心血管事件的独立危险因素。新出现的数据揭示了抗高血压药物的矛盾现象，即抗高血压药物可能对中心血压和外周血压及血流动力学产生不一致的影响。血管舒张性抗高血压药物，如肾素-血管紧张素-醛固酮系统抑制剂和钙通道阻滞剂，能使主动脉中心血压降低程度等于或大于肱动脉血压降低程度。相反，即使通过血压计测量的血压大幅降低，β受体阻滞剂降低主动脉中心血压的程度也较小。鉴于主动脉中心血压与靶器官损害之间的密切关系，在实际应用中，仅根据传统血压测量可能会高估β受体阻滞剂的有效性。中心血压和外周血压的差异可能解释了β受体阻滞剂在临床试验中缺乏心血管保护作用的原因，也可能解释了其他类抗高血压药物明显的“血压降低之外的益处”的一部分原因。未来的研究应旨在更好地阐明主动脉中心血压在高血压治疗中的作用。与此同时，在为患者开抗高血压药物处方时，应考虑抗高血压药物对“血压计之外的血压”的影响。
