Abstract
Purpose :
To evaluate the impact of blood pressure and blood gas parameters on macular perfusion measured by OCTA.
Methods :
In total 107 eyes of 60 healthy volunteers were examined before and 2 minutes after dynamic exercise using Zeiss PLEX® Elite 9000 (ZEISS, Dublin, CA). The 6x6mm cube scans centered on the macula were used for quantitative analysis. The perfusion density (PD) as the total area of perfused vasculature in the superficial (SCP) and the deep capillary plexus (DCP). The result is a number ranging from 0 (no perfusion) to 1 (fully perfused). Blood pressure (systolic-SBP; diastolic DBP; mean arterial pressure-MAP); heart rate (HR) and in a subgroup of 23 eyes also blood gas test as oxygen (pO2) and carbon dioxide(pCO2) tension were measured from venous samples taken at the timepoint of OCTA measurements. The correlation among OCTA results and the BP and blood gas parameters were evaluated using univariable and multivariable analysis.
Results :
The mean age of healthy volunteers was 23.7 ± 2.6 years. The mean (±SD) HR; SBP and MAP increased significantly after exercise from 69.6±9.6 bpm; 115.7±10.5 and 86.6±7.2 mmHg to 93.9±15.4 bpm; 148± 17.1,93.7±7.9 mmHg respectively (P < 0.001). DBP significantly decreased from 72.0±7.2 to 66.5±8.6 mmHg (P < 0.001). The mean average PD decreased after exercise significantly in superficial capillary plexus (SCP) from 0.461±0.019 to 0.452±0.024 (P=0.02) and non-significantly in deep capillary plexus (DCP) from 0.261±0.069 to 0.229±0.056 (P=0.077). The mean pO2 and pCO2 changed significantly from 25.2±3.8 and 51.8±4.5 mmHg to 44.9±10.4 and 45.4±6.2 mmHg respectively (P < 0.001). In the multivariable analysis, only DBP at baseline [β=0.001; CI (0.001-0.002)]; DBP change [β=0.002; CI (0.001-0.002)] and the average PD at baseline [β=-0.710; CI (-1.068 - -0.351)] were significantly associated with the observed significant decrease of PD in SCP.
Conclusions :
The results of macular perfusion measured by OCTA significantly changed after physical activity. Our study showed that the changes of diastolic blood pressure and the baseline average perfusion density significantly influence the results of macular perfusion in healthy subjects. The changes of blood gas parameters did not significantly correlate with changes of PD. Further studies are needed to evaluate the impact of blood pressure changes on OCTA results in patients with retinal vascular diseases.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.