The Oxygen Saturation in the Retinal Vessels of Patients with Diabetes Mellitus – The Search for Determinants

Abstract

Introduction Oxygen saturation in retinal vessels can be non-invasively measured by a new method. It is known that oxygen extraction is lowered in diabetic retinopathy. In the cross-sectional study presented here, it has been investigated whether diabetes-specific changes and typical accompanying diseases could influence the measurements in oximetry.

Methods During a time span of seven months, 237 diabetics were included who came to our clinic for an intravitreal injection, who met the inclusion criteria, who showed no exclusion criteria and gave written consent. 203 eyes of 203 patients were evaluated. The oxygen saturation (SO₂) was measured in digitally stored fundus images taken with a fundus camera (Zeiss 450 FF). In its illumination beam, a filter was inserted with two transmission maxima at 584 nm and 610 nm (bandwidth 10 nm). With the program “Oximetry” (Imedos Systems, Jena, Germany), the venous and the arterial SO₂ were measured. The values were stored in a spreadsheet. Diabetes related data, clinical parameters and accompanying diseases were documented in the predefined scheme.

Results In the whole patient sample, the venous oxygen saturation (vSO₂) was 69 ± 12%, the arterial saturation (aSO₂) 99 ± 5% and the arteriovenous difference 31 ± 9%. A statistically significant association could not be found between the measurement values of oximetry and age, duration of diabetes and HbA_1c (Kruskal-Wallis ANOVA: p > 0.05). The differences in oximetry values between units of analysis (UOA) e.g. hypertension and non units of analysis (NOA) were analysed. Descriptive testing showed significant differences in vSO₂% in the following units of analysis: allergies n = 47: UOA vs. NUOA: 64 vs. 69 (t test: p < 0.02); sartan therapy n = 46: UOA vs. NUOA: 64 vs. 70 (p = 0.003); state after intravitreal injections n = 144: 68 vs. 71 (p = 0.02). Oxygen extraction from the retinal capillaries was improved in patients who had injections with VEGF inhibitors. An improvement in oxygen extraction is also seen in patients with allergies and hypertension in comparison to those without these units of analysis.

Conclusion The clinically observed improvement in the retinal state situation after intravitreal injections with VEGF inhibitors may be seen in association with the improved oxygen extraction. It seems reasonable to study whether a switch to sartans in the therapy of hypertension may improve retinal function.

Key words

retina - diabetes mellitus - oximetry - sartans - VEGF inhibitors - allergy

Publication History

Received: 12 August 2020

Accepted: 27 January 2021

Article published online:
17 May 2021

• References/Literatur

• 1 Hammer M, Vilser W, Riemer T. et al. Retinal vessel oximetry-calibration, compensation for vessel diameter and fundus pigmentation, and reproducibility. J Biomed Opt 2008; 13: 054015 DOI: 10.1117/1.2976032.
• 2 Palsson O, Geirsdottir A, Hardarson SH. et al. Retinal oximetry images must be standardized: a methodological analysis. Invest Ophthalmol Vis Sci 2012; 53: 1729-1733 DOI: 10.1167/iovs.11-8621.
• 3 Hardarson SH, Harris A, Karlsson RA. et al. Automatic retinal oximetry. Invest Ophthalmol Vis Sci 2006; 47: 5011-5016 DOI: 10.1167/iovs.06-0039.
• 4 Beach JM, Schwenzer KJ, Srinivas S. et al. Oximetry of retinal vessels by dual-wavelength imaging: calibration and influence of pigmentation. J Appl Physiol (1985) 1999; 86: 748-758
• 5 Jørgensen CM, Hardarson SH, Bek T. The oxygen saturation in retinal vessels from diabetic patients depends on the severity and type of vision-threatening retinopathy. Acta Ophthalmol 2014; 92: 34-39 DOI: 10.1111/aos.12283.
• 6 Stefánsson E, Olafsdottir OB, Einarsdottir AB. et al. Retinal Oximetry Discovers Novel Biomarkers in Retinal and Brain Diseases. Invest Ophthalmol Vis Sci 2017; 58: BIO227-BIO233 DOI: 10.1167/iovs.17-21776.
• 7 Wikipedia. Biomarker. Accessed May 30, 2020 at: https://de.wikipedia.org/wiki/Biomarker
• 8 Gaus W, Muche R. Medizinische Statistik. Stuttgart: Schattauer; 2014
• 9 Anschütz F. Indikation zum ärztlichen Handeln. Berlin: Springer; 1982
• 10 Bek T, Stefansson E, Hardarson SH. Retinal oxygen saturation is an independent risk factor for the severity of diabetic retinopathy. Br J Ophthalmol 2019; 103: 1167-1172 DOI: 10.1136/bjophthalmol-2018-312764.
• 11 Ramm L, Jentsch S, Peters S. et al. Investigation of blood flow regulation and oxygen saturation of the retinal vessels in primary open-angle glaucoma. Graefes Arch Clin Exp Ophthalmol 2014; 252: 1803-1810 DOI: 10.1007/s00417-014-2766-4.
• 12 Klemm PG. Keine Angst vor Biomathematik. Berlin: Ullstein Mosby; 1993
• 13 Hardarson SH, Stefansson E. Retinal oxygen saturation is altered in diabetic retinopathy. Br J Ophthalmol 2012; 96: 560-563 DOI: 10.1136/bjophthalmol-2011-300640.
• 14 Hammer M, Vilser W, Riemer T. et al. Diabetic patients with retinopathy show increased retinal venous oxygen saturation. Graefes Arch Clin Exp Ophthalmol 2009; 247: 1025-1030 DOI: 10.1007/s00417-009-1078-6.
• 15 Geirsdottir A, Palsson O, Hardarson SH. et al. Retinal vessel oxygen saturation in healthy individuals. Invest Ophthalmol Vis Sci 2012; 53: 5433-5442 DOI: 10.1167/iovs.12-9912.
• 16 Liu X, Jiang J, Liu X. et al. Gender-Specific Independent and Combined Effects of the Cortisol-to-Cortisone Ratio and 11-Deoxycortisol on Prediabetes and Type 2 Diabetes Mellitus: From the Henan Rural Cohort Study. J Diabetes Res 2019; 2019: 4693817 DOI: 10.1155/2019/4693817.
• 17 Shukla R, Basu AK, Mandal B. et al. 11β Hydroxysteroid dehydrogenase-1 activity in type 2 diabetes mellitus: a comparative study. BMC Endocr Disord 2019; 19: 15 DOI: 10.1186/s12902-019-0344-9.
• 18 Johar H, Emeny RT, Bidlingmaier M. et al. Sex-related differences in the association of salivary cortisol levels and type 2 diabetes. Findings from the cross-sectional population based KORA-age study. Psychoneuroendocrinology 2016; 69: 133-141 DOI: 10.1016/j.psyneuen.2016.04.004.
• 19 Lauerma AI, Reitamo S, Maibach HI. Systemic hydrocortisone/cortisol induces allergic skin reactions in presensitized subjects. J Am Acad Dermatol 1991; 24: 182-185 DOI: 10.1016/0190-9622(91)70024-v.
• 20 Solano MP, Kumar M, Fernandez B. et al. The pituitary response to ovine corticotropin-releasing hormone is enhanced in obese men and correlates with insulin resistance. Horm Metab Res 2001; 33: 39-43 DOI: 10.1055/s-2001-12625.
• 21 Patel V, Panja S, Venkataraman A. The HOPE Study and MICRO-HOPE Substudy: effects of ramipril on cardiovascular and microvascular outcomes in people with diabetes mellitus. Br J Diabetes Vasc Dis 2001; 1: 44-51 DOI: 10.1177/14746514010010010701.
• 22 Parving HH, Lehnert H, Brochner-Mortensen J. et al. The effect of irbesartan on the development of diabetic nephropathy in patients with type 2 diabetes. N Engl J Med 2001; 345: 870-878 DOI: 10.1056/NEJMoa011489.
• 23 Brenner BM, Cooper ME, de Zeeuw D. et al. Effects of losartan on renal and cardiovascular outcomes in patients with type 2 diabetes and nephropathy. N Engl J Med 2001; 345: 861-869 DOI: 10.1056/NEJMoa011161.
• 24 Swift PA, MacGregor GA. Renoprotection in Type 2 diabetes: blockade of the renin-angiotensin system with angiotensin II receptor blockers. J Renin Angiotensin Aldosterone Syst 2001; 2: 170-173 DOI: 10.3317/jraas.2001.023.