Systolodiastolic variations of blood flow during central retinal vein occlusion: exploration by dynamic angiography.
OBJECTIVE
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 (Vmin) in first order veins (n = 10); (3) the time of onset of maximal flow (Vmax) 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.
Paques
M
M
Department of Ophthalmology, Fondation Ophtalmologique Rothschild, 25 rue Manin, 75019 Paris, France. michel.paques@laposte.net
Baillart
O
O
Genevois
O
O
Gaudric
A
A
Lévy
B I
BI
Sahel
J
J
D000208:Acute Disease; D000328:Adult; D000368:Aged; D000792:Angiography / Q000379:methods; D001783:Blood Flow Velocity; D004396:Coloring Agents; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007208:Indocyanine Green; D008297:Male; D008875:Middle Aged; D009887:Ophthalmoscopy; D011379:Prognosis; D011446:Prospective Studies; D011673:Pulsatile Flow; D012039:Regional Blood Flow; D012170:Retinal Vein Occlusion / Q000175:diagnosis* / Q000503:physiopathology; D013699:Temporal Arteries / Q000000981:diagnostic imaging; D018608:Ultrasonography, Doppler
D004396:Coloring Agents; D007208:Indocyanine Green