Sim Ralene, Aris Izzuddin, Chong Yap-Seng, Wong Tien Yin, Li Ling-Jun
Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
Division of Chronic Disease Research Across the Lifecourse (CoRAL), Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, Boston, Massachusetts, USA.
BMJ Open Ophthalmol. 2019 Dec 11;4(1):e000355. doi: 10.1136/bmjophth-2019-000355. eCollection 2019.
Studies have shown that hypertensive disorders of pregnancy (HDP) are associated with both postpartum retinal microvascular changes and cardiovascular (CV) risks. However, the underlying mechanism of HDP transitioning to microvascular and macrovascular changes remains unknown, due to the interaction between microvasculature and CV risks. In this study, we examined whether associations between antenatal systolic blood pressure (SBP) and postpartum retinal arteriolar changes are independent of postpartum CV risks.
We included 276 Singaporean mothers attending both baseline index pregnancy (2009-2010) and 5-year postpartum follow-up visits (2014-2015). We measured SBP at baseline. At follow-up, we assessed retinal microvascular structure and function with retinal photography and dynamic vessel analyser, together with CV risks using a validated 2008 Framingham Risk Score (FRS). We performed a traditional four-step mediation analysis using linear regression by adjusting for a series of baseline characteristics: age, ethnicity, college degree, prepregnancy body mass index and gestational diabetes mellitus diagnosis at baseline.
We found that each 10 mm Hg increase in baseline SBP was associated with reduced arteriolar calibre (-1.3 µm; 95% CI -3.0 to 0.2) and fractal dimension (-0.4 degrees of freedom (df); -1.0 to 0.2), and significantly with increased arteriolar constriction (0.5%; 0.001 to 1.0) at 5-year postpartum. Even though baseline SBP was associated with postpartum FRS, the latter was not associated with any retinal arteriolar measures. Therefore, no further mediation analysis was required.
Our study suggested that elevated SBP during pregnancy was associated with suboptimal retinal arteriolar structure and function independent of postpartum CV risks.
研究表明，妊娠期高血压疾病（HDP）与产后视网膜微血管变化和心血管（CV）风险均相关。然而，由于微血管与CV风险之间的相互作用，HDP转变为微血管和大血管变化的潜在机制仍不清楚。在本研究中，我们检验了产前收缩压（SBP）与产后视网膜小动脉变化之间的关联是否独立于产后CV风险。
我们纳入了276名新加坡母亲，她们均参加了基线指数妊娠（2009 - 2010年）和产后5年随访（2014 - 2015年）。我们在基线时测量SBP。在随访时，我们使用视网膜摄影和动态血管分析仪评估视网膜微血管结构和功能，并使用经过验证的2008年弗雷明汉风险评分（FRS）评估CV风险。我们通过对一系列基线特征进行调整，即年龄、种族、大学学历、孕前体重指数和基线时的妊娠期糖尿病诊断，采用线性回归进行传统的四步中介分析。
我们发现，基线SBP每升高10 mmHg，与产后5年时小动脉管径减小（-1.3 µm；95%CI -3.0至0.2）、分形维数降低（-0.4自由度（df）；-1.0至0.2）以及小动脉收缩显著增加（0.5%；0.001至1.0）相关。尽管基线SBP与产后FRS相关，但后者与任何视网膜小动脉指标均无关。因此无需进一步进行中介分析。
我们的研究表明，孕期SBP升高与视网膜小动脉结构和功能欠佳相关，且独立于产后CV风险。
