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21-07-2011 | Article

Endovascular therapy may do harm in stroke patients with poor collaterals


Free abstract

MedWire News: Stroke patients with poor collateral blood flow have worse outcomes if they achieve recanalization with endovascular therapy than if they do not, report researchers.

"Our data raise the possibility that although patients who showed baseline poor collateral status are expected to have an unfavorable outcome, the efforts to achieve revascularization may not be beneficial and may possibly even be harmful," say David Liebeskind (University of California, Los Angeles, USA) and colleagues.

The findings emerge from an analysis of 222 stroke patients who underwent endovascular therapy in two stroke centers - one in South Korea and one in the USA. Hemorrhagic transformation occurred in 46.4% of these patients, and symptomatic hemorrhagic transformation occurred in 18.9%.

The researchers grouped the patients according to their pretreatment collateral blood flow grade and whether or not they achieved recanalization.

The lowest rate of symptomatic hemorrhagic transformation occurred in patients who had good collateral flow and achieved recanalization, at 14.3%.

But the rate was significantly higher among those who had poor collateral flow but achieved recanalization, at 30.2%.

The other two groups, of patients who did not achieve recanalization and had either good or poor collateral flow had intermediate rates of symptomatic hemorrhagic transformation, of 17.4% and 20.0%, respectively.

The results were similar for hemorrhagic transformation on brain imaging, with rates of 42.9% versus 65.1% among patients with recanalization and good or poor collateral flow, respectively. Again, the other two groups had intermediate rates.

The combination of poor collaterals and recanalization remained associated with hemorrhagic transformation after adjusting for factors including stroke severity, occlusion site, mode of treatment, and time from onset to treatment. It conferred a 2.7-fold risk increase relative to no recanalization.

Also, an aggressive treatment strategy, such as mechanical clot disruption or retrieval, especially when combined with intra-arterial fibinolytics, raised patients' risk for hemorrhagic transformation relative to treatment with intra-arterial fibinolytics alone.

"Our data indicate that a tailored approach is needed to maximize the beneficial effects of endovascular therapy," the researchers write in the journal Stroke.

"Angiographic collaterals should be considered individually in these patients, and the decision for more aggressive endovascular treatment should be refined with the information on collaterals readily available from baseline angiography."

They note that their study provides no insight into how to manage patients with poor collaterals. "In cases in which collateral flow is marginal, evolving hemodynamic strategies to improve ischemia through augmentation of collateral perfusion may be warranted," they suggest.

MedWire ( is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2011

By Eleanor McDermid