Cardiovascular Epidemiology Unit, Department of Public Health & Primary Care, University of Cambridge, UK (C.O.-W., M.S.).
Homerton College, University of Cambridge, UK (C.O.-W.).
Circulation. 2019 Mar 12;139(11):1371-1380. doi: 10.1161/CIRCULATIONAHA.118.036966.
Population screening for abdominal aortic aneurysm (AAA) has commenced in several countries, and has been shown to reduce AAA-related mortality by up to 50%. Most men who screen positive have an AAA <5.5 cm in diameter, the referral threshold for treatment, and are entered into an ultrasound surveillance program. This study aimed to determine the risk of ruptured AAA (rAAA) in men under surveillance.
Men in the National Health Service AAA Screening Programme who initially had a small (3-4.4 cm) or medium (4.5-5.4 cm) AAA were followed up. The screening program's database collected data on ultrasound AAA diameter measurements, dates of referral, and loss to follow-up. Local screening programs recorded adverse outcomes, including rAAA and death. Rupture and mortality rates were calculated by initial and final known AAA diameter.
A total of 18 652 men were included (50 103 person-years of surveillance). Thirty-one men had rAAA during surveillance, of whom 29 died. Some 952 men died of other causes during surveillance, mainly cardiovascular complications (26.3%) and cancer (31.2%). The overall mortality rate was 1.96% per annum, similar for men with small and medium AAAs. The rAAA risk was 0.03% per annum (95% CI, 0.02%-0.05%) for men with small AAAs and 0.28% (0.17%-0.44%) for medium AAAs. The rAAA risk for men with AAAs just below the referral threshold (5.0-5.4 cm) was 0.40% (0.22%-0.73%).
The risk of rAAA under surveillance is <0.5% per annum, even just below the present referral threshold of 5.5 cm, and only 0.4% of men under surveillance are estimated to rupture before referral. It can be concluded that men with small and medium screen-detected AAAs are safe provided they are enrolled in an intensive surveillance program, and that there is no evidence that the current referral threshold of 5.5 cm should be changed.
一些国家已经开始对腹主动脉瘤（AAA）进行人群筛查，结果表明，这种筛查可使 AAA 相关死亡率降低多达 50%。大多数经筛查呈阳性的男性的 AAA 直径都在 5.5 厘米以下，这是治疗的转诊阈值，然后他们会被纳入超声监测项目。本研究旨在确定接受监测的男性中 AAA 破裂（rAAA）的风险。
在国家卫生服务局 AAA 筛查项目中，最初 AAA 直径较小（3-4.4 厘米）或中等（4.5-5.4 厘米）的男性会接受随访。该筛查项目的数据库收集了关于超声 AAA 直径测量、转诊日期和失访的数据。当地筛查项目记录了不良结局，包括 rAAA 和死亡。根据初始和最终已知的 AAA 直径计算破裂率和死亡率。
共纳入 18652 名男性（50103 人年的监测）。31 名男性在监测期间发生 rAAA，其中 29 人死亡。在监测期间，还有 952 名男性死于其他原因，主要是心血管并发症（26.3%）和癌症（31.2%）。总死亡率为每年 1.96%，小型和中型 AAA 患者的死亡率相似。小型 AAA 患者的 rAAA 风险为每年 0.03%（95%CI，0.02%-0.05%），中型 AAA 患者的 rAAA 风险为每年 0.28%（0.17%-0.44%）。仅略低于转诊阈值（5.0-5.4 厘米）的 AAA 患者的 rAAA 风险为每年 0.40%（0.22%-0.73%）。
即使略低于目前 5.5 厘米的转诊阈值，监测下的 rAAA 风险也<0.5%/年，预计只有 0.4%的监测男性在转诊前会发生破裂。可以得出结论，只要小型和中型筛查发现的 AAA 患者纳入强化监测项目，他们就是安全的，而且没有证据表明目前的 5.5 厘米转诊阈值应该改变。
