Effects of iodinated contrast media in a novel model for cerebral vasospasm

Abstract

Objective: We developed an in vitro model for vasospasm post subarachnoid hemorrhage that was suitable for investigating brain vessel autoregulation. We further investigated the effects of iodinated contrast medium on the vascular tone and the myogenic response of spastic cerebral vessels. Method: We isolated and perfused the superior cerebellar arteries of rats. The vessels were pressurized and studied under isobaric conditions. Coagulated blood was used to simulate subarachnoid hemorrhage. The contrast medium iodixanol was applied intraluminally. Results: Vessels exposed to blood developed significantly stronger myogenic tone (65.7 ± 2.0% vs 77.1 ± 1.2% of the maximum diameter, for the blood and the control group, respectively) and significantly decreased myogenic response, compared with the control groups. The contrast medium did not worsen the myogenic tone or the myogenic response in any group. Conclusion: Our results show that deranged myogenic response may contribute to cerebral blood flow disturbances subsequent to subarachnoid hemorrhage. The contrast medium did not have any negative influence on vessel tone or myogenic response in this experimental setting.Keywords: brain ischemia, cerebral angiography, contrast media, hemodynamics, intracranial aneurysm, intracranial vasospasm, subarachnoid hemorrhage. RESUMOObjetivo: Desenvolvemos um modelo in vitro para vasoespasmo subsequente à hemorragia subaracnóide que foi adequado para investigar a autorregularão dos vasos cerebrais. Em seguida investigamos os efeitos o meio de contraste iodado no tônus vascular e na resposta miogênica dos vasos cerebrais espásticos. Método: Isolamos e perfundimos as artérias cerebelares superiores de ratos. Os vasos foram pressurizados e estudados em condições isobáricas. Sangue coagulado foi utilizado para simular hemorragia subaracnóide. O meio de contraste iodixanol foi aplicado intraluminarmente. Resultados: Os vasos expostos ao sangue desenvolveram aumento significativo do tônus miogênico (65.7 ± 2.0% vs 77.1 ± 1.2% do maior diâmetro, para o grupo de sangue e o grupo controle, respectivamente) com resposta miogênica significativamente menor do que aquela dos controles. O meio de contraste iodado não piorou o tônus miogênico ou a resposta miogênica em nenhum dos grupos. Conclusão: Nossos resultados mostram que uma resposta miogênica pode contribuir para as alterações de fluxo sanguíneo cerebral subsequentes à hemorragia subaracnóide. O meio de contraste iodado não teve nenhuma influência negativa no tônus vascular ou na resposta miogênica neste modelo experimental.Palavras-chave: isquemia cerebral, angiografia cerebral, meio de contraste, hemodinâmica, aneurisma intracraniano, vasoespasmo intracraniano, hemorragia subaracnóide.Cerebral delayed vasospasm is a severe complication following spontaneous subarachnoid hemorrhage (SAH). Vasospasm is an important cause of death and contributes 10-12% to the overall mortality after SAH, which reaches approximately 50% within the first month 1,2,3 .There is nowadays no speci...

Contrast-induced encephalopathy

“…Non-ionic contrast agents (including iodixanol) are also able to damage BBB, despite their low osmolality. Nikita et al (28) studied the effect of iodixanol by using an in vitro model for investigating brain vessel autoregulation. The hypothesis that contrast agents affect vessel tone has not been confi rmed.…”