Systolodiastolic variations of blood flow during central retinal vein occlusion: exploration by dynamic angiography

Abstract

Background/aim: In patients with acute central retinal vein occlusion (CRVO), dynamic angiography may reveal the presence of pulsatile flow (termed here pulsatile venular outflow, PVO) within first order veins (that is, the large veins). The main goal of this study was to investigate the mechanism underlying PVO. Methods: 10 patients with CRVO and PVO were included. Quantitative and qualitative analysis of venous flow on dynamic angiograms allowed the correlation, temporally, of second and first order vein flow on the one hand, and venous flow and systolic cycle on the other. Results: Analysis of the time-velocity curve showed that (1) the onset of arterial systole preceded the onset of PVO by less than 0.08 seconds (n = 5); (2) PVO onset was simultaneous to the time of onset of minimal flow (V min ) in first order veins (n = 10); (3) the time of onset of maximal flow (V max ) in first order veins occurred 0.20-0.44 seconds after the onset of PVO (n = 6). Conclusions: During CRVO with severe reduction in blood flow, the presence of PVO is the result of the existence of a distinct haemodynamic regimen in first and second order veins. These data support the hypothesis that second order veins flow is synchronous with the arterial flow, while the delayed peak flow in first order veins may reflect the consequences of the delayed IOP curve and/or of intermittent venous compression.

Quantitative Analysis of Fundus-Image Sequences Reveals Phase of Spontaneous Venous Pulsations

“…60,61 Interestingly, arteriovenous waveforms presented recently by Morgan et al 62 and measured in glaucomatous patients show a similar matching (data of Figure 3d after additional peak-to-peak normalization).…”

Evidence for an enduring ischaemic penumbra following central retinal artery occlusion, with implications for fibrinolytic therapy

“…In future, however, new OCT modalities such as en face OCT angiography (OCT-A) may help to determine whether the middle retinal amplification of the ischaemic pathology is primarily a consequence of its exaggerated energy requirements or if it reflects preferential perfusion of the SCP (Tokayer et al, 2013). Of note, in eyes with CRVO, the superficial inner retina may be in receipt of additional oxygenation by convective (or "flow-assisted") diffusion related to the vigorous pulsation of the distended retinal vessels (Paques et al, 2005;Bertuglia et al, 2005). In this regard, the IPL may also have a role in restricting the movement of (oxygen-carrying) extracellular fluid into the middle retina (Antcliff et al, 2001), thus magnifying the differential susceptibility to hypoperfusion-induced damage.…”

The 3D Retinal Capillary Circulation in Pigs Reveals a Predominant Serial Organization

“…The serial organization of retinal layers provides a straightforward explanation for the localization of perivenular whitening in the DVP. [29][30][31] Indeed, there is angiographic evidence that the latter presentation is linked to panretinal hypoperfusion, 32 that is, severely impaired arterial inflow leading to a premature oxygen desaturation in precapillary arterioles. Our model suggested that perivenular whitening is initiated and/or more severe at the origin of draining venules (i.e., in the center of watersheds).…”