Effects Of Iodinated Contrast Media On A Novel Model Of Vasospasm Due To Subarachnoid Hemorrhage

Objective: Application of iodinated contrast media (CM) in patients with vasospasm after subarachnoid haemorrhage (SAH) may influence the vascular function of spastic brain vessels, with possible consequences for SAH morbidity and mortality. We developed an in vitro model of vasospasm post SAH to investigate the effects of CM on spontaneous myogenic tone and myogenic response of brain vessels. Methods: We used a model of isolated, pressurized rat superior cerebellar arteries. Coagulated blood was deployed in the chamber of a perfusion myograph to simulate SAH. Either vehicle or iodixanol was applied intraluminally. Vessel diameter was monitored in stable conditions and during controlled changes of intraluminal pressure. The myogenic response was quantified as the change in the diameter after each change in intraluminal pressure. Results: Vessels treated with coagulated blood developed a stronger spontaneous myogenic tone compared to the control groups (65.7% and 62.1% in comparison to 77.8% and 78.6% of initial diameter), as well as a significant decrease of the myogenic response. CM did not worsen the myogenic tone and the myogenic response. However, the myogenic response was significantly less impaired for higher pressure changes in vessels exposed to coagulated blood and CM in comparison to coagulated blood alone. The variability of the myogenic response was decreased in the groups receiving CM. Conclusion: Our in vitro model of cerebral vasospasm reflects the clinical evidence that the autoregulation of cerebral blood flow may be impaired after SAH. CM had no negative influence on vessel spontaneous myogenic tone and myogenic response in this model.