冠状动脉分支（图来源：康易健康）
英国一项新研究显示，当主动脉出现梗塞时，我们的心脏会启动一套后备血管系统来帮助应急，这套“后备系统”发育较好的人，在面临心血管疾病发病威胁时死亡率会更低。
伦敦大学学院等机构研究人员在新一期《欧洲心脏病学杂志》上报告说，他们研究了这套医学上称作“冠状动脉侧支循环”的“后备系统”的功效。据介绍，冠状动脉侧支循环由一些很小的血管组成，它们平时几乎不可见，但是如果主动脉出现梗塞，这些小血管的直径就会迅速扩大，允许较多血流通过，引导血流绕开阻塞部位。
研究人员调查了6000多名心血管疾病患者的资料，分析显示，那些冠状动脉侧支循环发育较好的人，在心肌梗死等发病时的死亡率要低36%。
领导这项研究的帕斯卡·迈耶说，这项研究首次显示冠状动脉侧支循环发育好坏与心血管疾病患者死亡率之间的关系。研究人员认为，经常进行体育锻炼有益于冠状动脉侧支循环。
相关英文论文摘要：
The impact of the coronary collateral circulation on mortality: a meta-analysis
Aims The coronary collateral circulation as an alternative source of blood supply has shown benefits regarding several clinical endpoints in patients with myocardial infarction (MI) such as infarct size and left ventricular remodelling. However, its impact on hard endpoints such as mortality and its impact in patients with stable coronary artery disease (CAD) is more controversial. The purpose of this systematic review and meta-analysis was to explore the impact of collateral circulation on all-cause mortality.
Methods and results We searched MEDLINE, EMBASE, ISI Web of Science (2001 to 25 April 2011), and conference proceedings for studies evaluating the effect of coronary collaterals on mortality. Random-effect models were used to calculate summary risk ratios (RR). A total of 12 studies enrolling 6529 participants were included in this analysis. Patients with high collateralization showed a reduced mortality compared with those with low collateralization [RR 0.64 (95% confidence interval 0.45–0.91); P= 0.012]. The RR for ‘high collateralization’ in patients with stable CAD was 0.59 [0.39–0.89], P= 0.012, in patients with subacute MI it was 0.53 [0.15–1.92]; P= 0.335, and for patients with acute MI it was 0.63 [0.29–1.39]; P= 0.257.
Conclusions In patients with CAD, the coronary collateralization has a relevant protective effect. Patients with a high collateralization have a 36% reduced mortality risk compared with patients with low collateralization.
