The collateral circulation determines cortical infarct volume in anterior circulation ischemic stroke

Abstract

BackgroundAcute ischemic stroke (AIS) is a common neurological event that causes varying degrees of disability. AIS outcome varies considerably, from complete recovery to complete loss of tissue and function. This diversity is partly explained by the compensatory ability of the collateral circulation and the ensuing cerebral flow grade.The collateral flow to the anterior circulation largely supplies the cortical areas. The deep brain tissue is supplied by penetrating arteries and has little or no collateral supply. Although these brain compartments differ substantially in their collateral supply, there are no published data on the different effects the collateral circulation has on them. In addition, the influence of baseline collateral flow on the final infarct size following endovascular or reperfusion therapies remains unknown. This study was designed to determine the effect of the collateral circulation on cortical infarct volume and deep infarct volume, and to investigate the relation between the collateral grade, response to reperfusion therapy and clinical outcome.MethodsWe studied consecutive patients presenting to our medical center between April 2008 and April 2012 with AIS and anterior proximal artery occlusion. To be included patients had to undergo a computerized tomographic angiographic study within 12 h of symptom onset demonstrating the occlusion. Imaging data and clinical and laboratory values were extracted retrospectively from the original scans and medical records. Cortical infarct volume (CIV) and deep infarct volume (DIV) were calculated as well as collateral grade. Clinical outcome was assessed at discharge using the modified Rankin Scale (mRS).ResultsOf the 51 study patients, 13 were treated conservatively, 22 received intravenous recombinant tissue plasminogen activator, and 16 received intra-arterial thrombolysis. The collateral grading was similar for all three treatment groups. While there was a moderate inverse correlation between the collateral grade and CIV (Spearman’s rho = −0.49, P < 0.001), no comparable correlation was observed between the collateral grade and DIV (Spearman’s rho =0.03, P = 0.85). Clinical outcome was significantly related to CIV but not to DIV (Spearman’s rho =0.6 P < 0.001 versus Spearman’s rho =0.09 P = 0.54, respectively). The correlation between the collateral grade and CIV was greatly diminished and lost its statistical significance in patients with successful recanalization (Spearman’s rho = 0.2, p = 0.3).ConclusionsOur data shows that the collateral circulation is an important determinant of cortical infarct volume and, in turn, of clinical outcome in the setting of anterior circulation major artery occlusion. Our findings further demonstrate the benefit of recanalization in sparing cortical tissue from injury. Additional studies are needed to determine the impact of stroke therapy on the final infarct volume in relation to the collateral grade.

What influenced the lesion patterns and hemodynamic characteristics in patients with internal carotid artery stenosis? A retrospective study

“…This distribution may be because the perforating artery was more easily involved in atherosclerosis and was more easily influenced by hypoperfusion compared to the cortical arteries. This possibility is consistent with the result of several recent studies that show that cortical arteries possess higher flow velocity and collateral circulation than perforating arteries, especially in the periventricular region [17,18]. In this study, the average number of small lesions did not increase with aggravation of ICAS but increased in patients without largearea infarcts, indicating that aggravation of ICAS contributed to the occurrence and development of small lesions, and these small lesions were probably covered by large-area infarcts in patients with large-area lesions.…”

Signal variance-based collateral index in DSC perfusion: A novel method to assess leptomeningeal collateralization in acute ischaemic stroke

“…42 The degree of collateralization has an impact on both the ischaemic core volume 43 and pattern at the time of admission and patients with poor collaterals have larger cortical ischaemic lesions. 41 Additionally, patients with a good collateral supply display a larger amount of salvageable tissue and less severe hypoperfusion 21,44 and thus are more likely to be promising candidates for endovascular reperfusion. Note: The score for collateral assessment with CTA ranges from 0 (poor collaterals) to 20 (good collaterals), the score used for DSA from 1 (good collaterals) to 5 (poor collaterals).…”

Reperfusion therapy in acute ischemic stroke: dawn of a new era?

“…According to a meta-analysis, good baseline collaterals were associated with favourable outcome at 90 days, decrease in the risk of symptomatic ICH, and decrease in risk of death at 90 days in patients with AIS receiving endovascular treatment [ 176 ]. Good baseline collaterals have been found to be associated with 24 h perilesional hyperperfusion [ 185 ], good clinical outcome [ 176 , 186 – 189 ], lower rates of symptomatic ICH and mortality [ 176 ], improved radiologic outcome [ 188 ], cortical infarct volume [ 190 ], good reperfusion [ 191 ], and stroke severity [ 191 ]. On the other hand, delayed-cortical vein filling was independently associated with reduced baseline collateral status in AIS [ 185 ].…”