Dataset Information

Feasibility of optical coherence tomography angiography to assess changes in retinal microcirculation in ovine haemorrhagic shock.

ABSTRACT:

Background

This study aimed to investigate the feasibility of optical coherence tomography angiography (OCT-A) for quantitative analysis of flow density to assess changes in retinal perfusion in an experimental model of haemorrhagic shock.

Methods

Haemorrhagic shock was induced in five healthy, anaesthetized sheep by stepwise blood withdrawal of 3?×?10 ml?kg^-?1 body weight. OCT-A imaging of retinal perfusion was performed using an OCT device. Incident dark-field illumination microscopy videos were obtained for the evaluation of conjunctival microcirculation. Haemodynamic variables and flow density data in the OCT angiogram were analysed before and during progressive haemorrhage resulting in haemorrhagic shock as well as after fluid resuscitation with 10 ml?kg^-?1 body weight of balanced hydroxyethyl starch solution (6% HES 130/0.4). Videos of the conjunctival microcirculation were recorded at baseline, in haemorrhagic shock, and after resuscitation. Data are presented as median with interquartile range. Comparisons between time points were made using Friedman's test and the degree of correlation between two variables was expressed as Spearman's rank correlation coefficient.

Results

Mean arterial pressure and cardiac index (CI) decreased and lactate concentration increased after induction of shock, and haemodynamics recovered after resuscitation. The flow density in the superficial retinal OCT angiogram decreased significantly after shock induction (baseline 44.7% (40.3; 50.5) vs haemorrhagic shock 34.5% (32.8; 40.4); P?=?0.027) and recovered after fluid resuscitation (46.9% (41.7; 50.7) vs haemorrhagic shock; P?=?0.027). The proportion of perfused vessels of the conjunctival microcirculation showed similar changes. The flow density measured using OCT-A correlated with the conjunctival microcirculation (perfused vessel density: Spearman's rank correlation coefficient ??=?0.750, P?=?0.001) and haemodynamic parameters (CI: ??=?0.693, P?ConclusionsRetinal flow density, measured using OCT-A, significantly decreased in shock and recovered after fluid therapy in an experimental model of haemorrhagic shock. OCT-A is feasible to assess changes in retinal perfusion in haemorrhagic shock and fluid resuscitation.

SUBMITTER: Alnawaiseh M

PROVIDER: S-EPMC5975442 | biostudies-literature | 2018 May

REPOSITORIES: biostudies-literature

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Publications

Feasibility of optical coherence tomography angiography to assess changes in retinal microcirculation in ovine haemorrhagic shock.

Alnawaiseh Maged M Ertmer Christian C Seidel Laura L Arnemann Philip Helge PH Lahme Larissa L Kampmeier Tim-Gerald TG Rehberg Sebastian Willy SW Heiduschka Peter P Eter Nicole N Hessler Michael M

Critical care (London, England) 20180529 1

<h4>Background</h4>This study aimed to investigate the feasibility of optical coherence tomography angiography (OCT-A) for quantitative analysis of flow density to assess changes in retinal perfusion in an experimental model of haemorrhagic shock.<h4>Methods</h4>Haemorrhagic shock was induced in five healthy, anaesthetized sheep by stepwise blood withdrawal of 3 × 10 ml∙kg<sup>- 1</sup> body weight. OCT-A imaging of retinal perfusion was performed using an OCT device. Incident dark-field illumin ...[more]

PMID: 29843760

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Project description:PURPOSE:To detect macular perfusion defects in glaucoma using projection-resolved optical coherence tomography (OCT) angiography. DESIGN:Prospective observation study. PARTICIPANTS:A total of 30 perimetric glaucoma and 30 age-matched normal participants were included. METHODS:One eye of each participant was imaged using 6×6-mm macular OCT angiography (OCTA) scan pattern by 70-kHz 840-nm spectral-domain OCT. Flow signal was calculated by the split-spectrum amplitude-decorrelation angiography algorithm. A projection-resolved OCTA (PR-OCTA) algorithm was used to remove flow projection artifacts. Four en face OCTA slabs were analyzed: the superficial vascular complex (SVC), intermediate capillary plexus (ICP), deep capillary plexus (DCP), and all-plexus retina (SVC + ICP + DCP). The vessel density (VD), defined as the percentage area occupied by flow pixels, was calculated from en face OCTA. A novel algorithm was used to adjust the vessel density to compensate for local variations in OCT signal strength. MAIN OUTCOME MEASURES:Macular retinal VD, ganglion cell complex (GCC) thickness, and visual field (VF) sensitivity. RESULTS:Focal capillary dropout could be visualized in the SVC, but not the ICP and DVP, in glaucomatous eyes. In the glaucoma group, the SVC and all-plexus retinal VD (mean ± standard deviation: 47.2%±7.1% and 73.5%±6.6%) were lower than in the normal group (60.5%±4.0% and 83.2%±4.2%, both P < 0.001, t test). The ICP and DCP VD were not significantly lower in the glaucoma group. Among the overall macular VD parameters, the SVC VD had the best diagnostic accuracy as measured by the area under the receiver operating characteristic curve (AROC). The accuracy was even better when the worse hemisphere (inferior or superior) was used, achieving an AROC of 0.983 and a sensitivity of 96.7% at a specificity of 95%. Among the glaucoma participants, the hemispheric SVC VD values were highly correlated with the corresponding GCC thickness and VF sensitivity (P < 0.003). The reflectance compensation step in VD calculation significantly improved repeatability, normal population variation, and correlation with VF and GCC thickness. CONCLUSIONS:On the basis of PR-OCTA, glaucoma preferentially affects perfusion in the SVC in the macula more than the deeper plexuses. Reflectance-compensated SVC VD measurement by PR-OCTA detected glaucoma with high accuracy and could be useful in the clinical evaluation of glaucoma.

Dataset Information

Feasibility of optical coherence tomography angiography to assess changes in retinal microcirculation in ovine haemorrhagic shock.

Background

Methods

Results

Publications

Feasibility of optical coherence tomography angiography to assess changes in retinal microcirculation in ovine haemorrhagic shock.

Similar Datasets

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