Importance of erythropoietin in brain protection after cardiac surgery: a pilot study.

BACKGROUND: Neurologic complications after cardiac operations present an important medical problem, as well as a financial burden. They increase the morbidity and hospital stays of patients who have otherwise undergone successful heart operations. The current protocols for perioperative brain protection against ischemic events are not optimal. Because of its different pleiotropic mechanisms of action, recombinant human erythropoietin might provide neuroprotection. METHODS: In this study, we included 20 patients who were older than 18 years and required surgical revascularization of the heart with the use of the heart-lung machine. Ten patients received 3 consecutive intravenous doses (24,000 IU) of recombinant human erythropoietin (rHuEpo). Neurologic and magnetic resonance imaging (MRI) examinations were done before and in the first 5 days after surgery. RESULTS: The erythropoietin-treated and control groups were comparable with respect to study protocol outcomes: number of coronary artery bypass grafts (3.3 and 3.2 grafts/patient, respectively), operative time (4.12 and 4.6 hours), and transfusion volume per patient (708 and 674 mL). The groups were also comparable with respect to blood pressure values at all stages of the operation. MRI scans revealed that 4 of 10 patients from the control group had fresh ischemic brain lesions after open heart surgery. None of the patients in the erythropoietin-treated group had fresh ischemic brain lesions. CONCLUSION: Although the number of patients was small, the results regarding brain protection with rHuEpo are encouraging. rHuEpo is a promising neuroprotective agent.

Perfusion CT measurements in healthy cervical spinal cord: feasibility and repeatability of the study as well as interchangeability of the perfusion estimates using two commercially available software packages.

Our purpose was to examine the feasibility and reproducibility of perfusion CT studies in the cervical spinal cord and the interchangeability of the values obtained by two post-processing methods. The perfusion CT studies of 40 patients with neck tumours were post-processed using two software packages (Software-1: deconvolution-based analysis with adiabatic tissue homogeneity approach and Software-2: maximum-slope-model with Patlak analysis). Eight patients were examined twice for assessing the reproducibility of the technique. Two neuroradiologists separately post-processed the images with two arterial input functions (AIFs): (1) the internal carotid artery (ICA) and (2) the vertebral artery (VA). Maps of blood flow (F) in ml/min/100 g, blood volume (V) in ml/100 g, mean transit time (MTT) in seconds (s) and permeability (PS) in ml/min/100 g were generated. The mean F, V, MTT and PS (Software-1) with VA-AIF and ICA-AIF were 8.93, 1.12, 16.3, 1.88 and 8.57, 1.19, 16.85 and 1.94, respectively. The reproducibility of the techniques was satisfactory, while the V and MTT values (in Software-1) and the F and V values (in Software-2) were dependent on the site of the AIF (p >or= 0.03 and p=0.02, respectively). The interobserver agreement was very good. The significant differences in measurements for a single patient (%) using Software-1/Software-2 were +/-120%/110%, 90%/80%, 180% and 250%/130% for F, V, MTT and PS, respectively. Only F and PS values in the healthy tissue seemed to be interchangeable. Our results were in essential agreement with those derived by invasive measurements in animals. The cervical spine perfusion CT studies are feasible and reproducible. The present knowledge has to be validated with studies in spinal cord tumours in order to decide the usefulness of the perfusion CT in this field.