Endovascular treatment of complex cerebral aneurysms with onyx hd-500® in 38 patients.

OBJECTIVE: To report our experience with Onyx HD-500(®) (Micro Therapeutics, Inc., Irvine, CA, USA) in the endovascular treatment of complex intracranial aneurysms as an alternative to treatment with platinum coils. PATIENTS AND METHODS: Between October 2003 and December 2007, 38 patients (20 female and 18 male) were selected for inclusion in the study based on aneurysm size and dome-to-neck ratio. Altogether, 37 (97.3%) aneurysms were located in the anterior circulation, and one (2.7%) was in the posterior circulation. Of these, 35 (92.1%) had wide necks (>4mm and/or a dome-to-neck ratio<2). Clinical and angiographic follow-ups were performed at six and 12 months. RESULTS: Successful embolization was achieved in 36 of the 38 patients. Complete occlusion was seen in 29 patients (80.5%), and seven (19.4%) had subtotal occlusion on the immediate angiographic control. After six months, 29 patients (80.5%) initially with total occlusion were stable, while four with subtotal occlusion had progressed to total occlusion and three showed recanalization. Of the latter, two were reembolized and the third patient did not return for retreatment. The one-year angiographic follow-up showed no changes. The morbidity rate was 8.3% (3/36) and procedural mortality was 0%. CONCLUSION: The Onyx HD-500 liquid embolic system is a feasible and safe therapeutic option for patients presenting with complex aneurysms, but who are not candidates for other techniques or in whom previous treatment has failed.

Role of endogenous opioids in the cardiovascular responses to asphyxia in fetal sheep.

Intravenous administration of the opioid receptor antagonist naloxone to asphyxiated fetal sheep increases the arterial blood pressure. We examined the hypothesis that endogenous opioids modify the cardiac output distribution during asphyxia due to changes in the vascular resistance of some fetal organs. Thirteen fetal sheep (0.8-0.9 of gestation) were chronically catheterized. Fetal asphyxia was induced by reducing the uterine blood flow with an inflatable occluder around the common internal iliac artery to approximately 50% of control for 40 min. Naloxone solution or the solvent alone was added for the last 20 min. Asphyxia caused hypertension, and the fetal arterial blood pressure further increased when asphyxiated fetuses received naloxone. Heart, brain, and adrenal blood flows increased due to the increase in blood pressure, with no changes in their vascular resistances. In contrast, kidney and carcass blood flows decreased, and their vascular resistances increased. We conclude that endogenous opioids inhibit the vasoconstriction of these vascular beds during fetal asphyxia.