Dr Georgios Varsos University positionPhD student DepartmentsDepartment of Clinical Neurosciences InstitutesHome pagehttp://www.georgios-varsos.com (personal home page) Research ThemeInterestsMy focus has been on modelling of brain haemodynamics, particularly describing a terminal situation of cerebral circulation, associated with ischemic strokes. A new methodology was created which can be used for estimating brain’s zero-flow pressure or critical closing pressure (CrCP): a critical threshold for arterial blood pressure (ABP). If ABP falls below CrCP, the local blood pressure inside small vessels of microcirculation is no longer adequate to keep them open, leading them to a collapse, ceasing blood flow. The new method eliminated the main drawback of previous methods, which were presenting non-physiological negative values; CrCP can now instead be considered as a reliable tool for physicians. A new mechanism was further introduced, which can quantify a patient’s ischemic risk during haemodynamic changes. In neurointensive care, this mechanism might provide a reference point to guidance of treatment in terms of terminal ischemia associated with collapsing vessels.  A new mechanism for assesing brain ischemia during intracranial hypertension Click image to view full-size Research Focus
EquipmentComputational modelling Haemodynamic monitoring Collaborators
Associated News ItemsKey publicationsVarsos GV, de Riva N, Smielewski P, Pickard JD, Brady KM, Reinhard M, Avolio A, Czosnyka M (2013), “Critical Closing Pressure During Intracranial Pressure Plateau Waves.” Neurocrit Care Details Varsos GV, Richards HK, Kasprowicz M, Reinhard M, Smielewski P, Brady KM, Pickard JD, Czosnyka M (2013), “Cessation of Diastolic Cerebral Blood Flow Velocity: The Role of Critical Closing Pressure.” Neurocrit Care Details Varsos GV, Richards H, Kasprowicz M, Budohoski KP, Brady KM, Reinhard M, Avolio A, Smielewski P, Pickard JD, Czosnyka M (2012), “Critical closing pressure determined with a model of cerebrovascular impedance.” J Cereb Blood Flow Metab Details Publications2015Phang I, Werndle MC, Saadoun S, Varsos GV, Czosnyka M, Zoumprouli A, Papadopoulos MC (2015), “Expansion Duroplasty Improves Intraspinal Pressure, Spinal Cord Perfusion Pressure and Vascular Pressure Reactivity Index in Patients with Traumatic Spinal Cord Injury.” J Neurotrauma Details Varsos GV, Kolias AG, Smielewski P, Brady KM, Varsos VG, Hutchinson PJ, Pickard JD, Czosnyka M (2015), “A noninvasive estimation of cerebral perfusion pressure using critical closing pressure.” J Neurosurg :1-11 Details 2014Budohoski KP, Czosnyka M, Kirkpatrick PJ, Reinhard M, Varsos GV, Kasprowicz M, Ząbek M, Pickard JD, Smielewski P (2014), “Bilateral Failure of Cerebral Autoregulation is Related to Unfavorable Outcome After Subarachnoid Hemorrhage.” Neurocrit Care Details Budohoski KP, Kirkpatrick PJ, Smielewski P, Reinhard M, Varsos GV, Kasprowicz M, Zabek M, Pickard JD, Czosnyka M (2014), “Galbraith Award 133 Bilateral Failure of Cerebral Autoregulation is Related to Unfavorable Outcome After Subarachnoid Hemorrhage.” Neurosurgery 61 Suppl 1:203 Details Donnelly J, Czosnyka M, Sudhan N, Varsos GV, Nasr N, Jalloh I, Liu X, Dias C, Sekhon MS, Carpenter KL, Menon DK, Hutchinson PJ, Smielewski P (2014), “Increased Blood Glucose is Related to Disturbed Cerebrovascular Pressure Reactivity After Traumatic Brain Injury.” Neurocrit Care Details Liu X, Czosnyka M, Donnelly J, Budohoski KP, Varsos GV, Nasr N, Brady KM, Reinhard M, Hutchinson PJ, Smielewski P (2014), “Comparison of frequency and time domain methods of assessment of cerebral autoregulation in traumatic brain injury.” J Cereb Blood Flow Metab Details Nasr N, Czosnyka M, Pavy-Le Traon A, Custaud MA, Liu X, Varsos GV, Larrue V (2014), “Baroreflex and Cerebral Autoregulation Are Inversely Correlated.” Circ J Details Rhee CJ, Fraser Iii CD, Kibler K, Easley RB, Andropoulos DB, Czosnyka M, Varsos GV, Smielewski P, Rusin CG, Brady KM, Kaiser JR (2014), “The ontogeny of cerebrovascular pressure autoregulation in premature infants.” J Perinatol Details Swallow DM, Fellner N, Varsos GV, Czosnyka M, Smielewski P, Pickard JD, Czosnyka Z (2014), “Repeatability of cerebrospinal fluid constant rate infusion study.” Acta Neurol Scand Details Varsos GV, Budohoski KP, Czosnyka M, Kolias AG, Nasr N, Donnelly J, Liu X, Kim DJ, Hutchinson PJ, Kirkpatrick PJ, Varsos VG, Smielewski P (2014), “Cerebral vasospasm affects arterial critical closing pressure.” J Cereb Blood Flow Metab Details Varsos GV, Budohoski KP, Kolias AG, Liu X, Smielewski P, Varsos VG, Hutchinson PJ, Pickard JD, Czosnyka M (2014), “Relationship of Vascular Wall Tension and Autoregulation Following Traumatic Brain Injury.” Neurocrit Care Details 2013Dias C, Maia I, Cerejo A, Varsos G, Smielewski P, Paiva JA, Czosnyka M (2013), “Pressures, Flow, and Brain Oxygenation During Plateau Waves of Intracranial Pressure.” Neurocrit Care Details Varsos GV, Kasprowicz M, Smielewski P, Czosnyka M (2013), “Model-based Indices Describing Cerebrovascular Dynamics.” Neurocrit Care Details Werndle MC, Saadoun S, Phang I, Czosnyka M, Varsos GV, Czosnyka ZH, Smielewski P, Jamous A, Bell BA, Zoumprouli A, Papadopoulos MC (2013), “Monitoring of Spinal Cord Perfusion Pressure in Acute Spinal Cord Injury: Initial Findings of the Injured Spinal Cord Pressure Evaluation Study.” Crit Care Med Details 2012Budohoski KP, Czosnyka M, Smielewski P, Varsos GV, Kasprowicz M, Brady KM, Pickard JD, Kirkpatrick PJ (2012), “Cerebral autoregulation after subarachnoid hemorrhage: comparison of three methods.” J Cereb Blood Flow Metab Details |