MedWire News: Stroke patients undergoing thrombolysis have a higher rate of parenchymal hemorrhage and worse outcomes if they have elevated levels of vascular adhesion molecule-1 semicarbazide-sensitive amine oxidase (VAP-1/SSAO) activity, research shows.
“Thus, we suggest that [VAP-1/SSAO] quantification may help physicians to estimate the risks of thrombolysis on a patient and consequently improve the safety profile of this treatment,” say Joan Montaner (Hospital Vall d’Hebron, Barcelona, Spain) and colleagues.
The researchers chose to study VAP-1 because it helps to stimulate leukocyte migration. Accumulation of leukocytes at the infarct site of stroke patients has been shown to lead to basal lamina degradation, which compromises the blood–brain barrier, thus promoting hemorrhage. The team measured VAP1/SSAO activity in blood samples taken from 141 stroke patients, before they underwent thrombolysis. Subsequently, 48 patients suffered hemorrhagic transformation, with 13 suffering parenchymal hemorrhage.
Average VAP-1/SSAO activity was 2.48 pmol/min/mg in patients with no hemorrhage, 2.79 pmol/min/mg in those with hemorrhagic infarction, and 3.41 pmol/min/mg in those with parenchymal hemorrhage.
Baseline VAP-1/SSAO activity was the only independent predictor of parenchymal hemorrhage, raising the risk 11.2- and 8.9-fold at cutoffs of 2.70 and 3.07 pmol/min/mg, respectively.
VAP-1/SSAO activity also correlated with the extent of bleeding on computed tomography, the team notes in the journal Stroke.
In addition, the 10.8% of patients whose condition worsened between admittance and 48 hours had significantly higher VAP-1/SSAO activity than the 61.9% who improved, at 3.12 versus 2.48 pmol/min/mg.
Montaner et al investigated the effect of VAP-1/SSAO further in a rat model of stroke. Animals treated with delayed thrombolysis had larger infarcts than untreated rats, but those cotreated with the SSAO inhibitor semicarbazide had significantly smaller infarcts than rats given delayed thrombolysis, at 8.73% versus 35.46%. Mortality was also reduced, at corresponding rates of 18% versus 38%.
The team therefore suggests that administering a SSAO inhibitor to patients undergoing thrombolysis has the potential to reduce the hemorrhagic transformation rate associated with this procedure.
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