RESUMEN
Background: Gestational diabetes, pregnancy-associated hypertension and small-for-gestational age babies are all associated with impaired placental vascularisation. This study compared the effects of these conditions the systemic small vessel calibre that was examined in the retina. Methods: This was a cross-sectional observational study of consecutive pregnant women recruited from an antenatal clinic. Participants underwent a Glucose Tolerance Test, BP measurements, and were examined for small-for-gestational age babies as per national guidelines. They also underwent retinal photography with a non-mydriatic camera, and vessel calibres were measured with a validated semi-quantitative system at a retinal grading centre. Some participants also underwent testing of retinal vascular responsiveness to a flickering light. Results: Women with gestational diabetes (n = 68) had a higher mean arterial pressure (85 ± 9 mm Hg) than normal pregnant women (n = 27, 80 ± 8 mmHg, p = 0.01). They also had smaller mean retinal arteriole (147.5 ± 13.6 µm and 159.7 ± 6.7 µm respectively, p < 0.01) and venular calibre (221.0 ± 13.4 µm and 232.8 ± 20.1 µm respectively, p < 0.01) than normal. However their babies' mean birth weights were not different from normal (3,311 ± 558 g and 3,401 ± 600 g respectively, p = 0.48). They also demonstrated a trend to reduced retinal arteriolar dilatation (3.5 ± 1.3%, n = 23) in response to vasodilatory stimuli (4.4 ± 1.8%) (n = 11) (p = 0.08) consistent with endothelial dysfunction. Women with pregnancy-associated hypertension (n = 35) had a higher mean arterial pressure (101 ± 12 mm Hg, p < 0.01), a smaller mean retinal arteriolar calibre (139.9 ± 10.6 µm, p < 0.0001), and a lower baby mean birth weight than for normal pregnancies (3,095 ± 443 g, p = 0.02). Likewise, women with small-for-gestational age babies (n = 31) had a higher mean arterial pressure (89 ± 19 mm Hg, p = 0.03), a smaller mean retinal arteriolar calibre (141.6 ± 12.8 µm, p < 0.01) and a lower baby mean birth weight than for normal pregnancies (2,468 ± 324 g, p < 0.0001). Conclusion: Mean retinal arterial calibre was reduced in women with gestational diabetes, pregnancy-associated hypertension or small-for-gestational age babies. The reduction in calibre was greatest in pregnancy-associated hypertension and small-for-gestational age babies. Systemic arteriole narrowing may contribute to the pathogenesis of placental vascular dysfunction in these conditions.
RESUMEN
Population-based studies have demonstrated that increased retinal venular calibre is a risk factor for cardiac disease, cardiac events and stroke. Venular dilatation also occurs with diabetes, obesity, dyslipidemia and autoimmune disease where it is attributed to inflammation. This study examined whether the inflammation associated with infections also affected microvascular calibre. Participants with infections and CRP levels > 100 mg/L were recruited from the medical wards of a teaching hospital and assisted to complete a demographic and vascular risk factor questionnaire, and to undergo non-mydriatic retinal photography (Canon CR5-45NM, Japan). They were then treated with appropriate antibiotics, and underwent repeat retinal imaging when their CRP levels had fallen to less than 100 mg/L. Retinal images were examined for arteriole and venular calibre using validated semi-automated software based on Knudtson's modification of the Parr-Hubbard formula (IVAN, U Wisconsin). Differences in inflammatory markers and calibre were examined using the paired t-test for continuous variables. Determinants of calibre were calculated from multiple linear regression analysis. Forty-one participants with respiratory (27, 66%), urinary (6, 15%), skin (5, 12%), or miscellaneous (3, 7%) infections were studied. After antibiotic treatment, participants' mean CRP levels fell from 172.9 ± 68.4 mg/L to 42.2 ± 28.2 mg/L (p < 0.0001) and mean neutrophil counts fell from 9 ± 4 × 109/L to 6 ± 3 × 109/L (p < 0.0001). The participants' mean venular calibre (CRVE) decreased from 240.9 ± 26.9 MU to 233.4 ± 23.5 MU (p = 0.0017) but arteriolar calibre (CRAE) was unchanged (156.9 ± 15.2 MU and 156.2 ± 16.0 MU, p = 0.84). Thirteen additional participants with infections had a CRP > 100 mg/L that persisted at review (199.2 ± 59.0 and 159.4 ± 40.7 mg/L, p = 0.055). Their CRAE and CRVE were not different before and after antibiotic treatment (p = 0.96, p = 0.78). Hospital inpatients with severe infections had retinal venular calibre that decreased as their infections resolved and CRP levels fell after antibiotic treatment. The changes in venular calibre with intercurrent infections may confound retinal vascular assessments of, for example, blood pressure control and cardiac risk.
