Vivek Rai, MD
Hou Q, Zuo Z, Michel P, Zhang Y, Eskandari A, Man F, et al. Influence of Chronic Hyperglycemia on Cerebral MicrovascularRemodeling: An In Vivo Study Using Perfusion Computed Tomography inAcute Ischemic Stroke Patients. Stroke. 2013.
Wintermark and colleagues investigated the use of CT Perfusion (CTP) for assessment of cerebral microvascular remodeling in chronic hyperglycemic patients who presented with acute stroke. In this small retrospective analysis of 26 patients, authors suggest that Mean Transit Time (MTT) may be used as a marker for exposure to long-term hyperglycemia and subsequent cerebral microvascular remodeling based on the finding of prolonged MTT in non-ischemic cerebral hemisphere of patients with glycated hemoglobin (HbA1c) >6.5.
While this is an interesting finding, I would approach the results with caution. The analysis included very small number of patients and patients in hyperglycemic group had more severe elevation of blood pressure (this almost reached statistical significance, p=0.06). Acute phase of stroke is a very dynamic process and any change in hemodynamic state, which may be quite short lasting, may alter the results of CTP. For this reason, although it is likely that microvascular remodeling does occur as a consequence of chronic hyperglycemia, I think that any marker studying this effect (including CTP) should be studied in a more stable, chronic clinical setting rather than during acute phase of stroke. As the authors suggested, a larger trial is necessary to answer this question and I will be looking forward to such a trial.