Impact of collateral flow on tissue fate in acute ischaemic stroke.
BACKGROUND
Collaterals may sustain penumbra prior to recanalisation yet the influence of baseline collateral flow on infarct growth following endovascular therapy remains unknown.


METHODS
Consecutive patients underwent serial diffusion and perfusion MRI before and after endovascular therapy for acute cerebral ischaemia. We assessed the relationship between MRI diffusion and perfusion lesion indices, angiographic collateral grade and infarct growth. Tmax perfusion lesion maps were generated and diffusion-perfusion mismatch regions were divided into Tmax >or=4 s (severe delay) and Tmax >or=2 but <4 s (mild delay).


RESULTS
Among 44 patients, collateral grade was poor in 7 (15.9%), intermediate in 20 (45.5%) and good in 17 (38.6%) patients. Although diffusion-perfusion mismatch volume was not different depending on the collateral grade, patients with good collaterals had larger areas of milder perfusion delay than those with poor collaterals (p = 0.005). Among 32 patients who underwent day 3-5 post-treatment MRIs, the degree of pretreatment collateral circulation (r = -0.476, p = 0.006) and volume of diffusion-perfusion mismatch (r = 0.371, p = 0.037) were correlated with infarct growth. Greatest infarct growth occurred in patients with both non-recanalisation and poor collaterals. Multiple regression analysis revealed that pretreatment collateral grade was independently associated with infarct growth.


CONCLUSIONS
Our data suggest that angiographic collateral grade and penumbral volume interactively shape tissue fate in patients undergoing endovascular recanalisation therapy. These angiographic and MRI parameters provide complementary information about residual blood flow that may help guide treatment decision making in acute cerebral ischaemia.
Bang
O Y
OY
Department of Neurology, Samsung Medical Centre, Sungkyunkwan University, Seoul, South Korea.
Saver
J L
JL
Buck
B H
BH
Alger
J R
JR
Starkman
S
S
Ovbiagele
B
B
Kim
D
D
Jahan
R
R
Duckwiler
G R
GR
Yoon
S R
SR
Viñuela
F
F
Liebeskind
D S
DS
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001783:Blood Flow Velocity / Q000187:drug effects; D002533:Cerebral Angiography; D002540:Cerebral Cortex / Q000098:blood supply*; D003097:Collateral Circulation / Q000187:drug effects* / Q000502:physiology; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D020244:Infarction, Middle Cerebral Artery / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D015427:Reperfusion Injury / Q000175:diagnosis / Q000503:physiopathology; D017131:Thrombectomy; D016896:Treatment Outcome