Vortex formation and recirculation zones in left anterior descending artery stenoses: computational fluid dynamics analysis.

Flow patterns may affect the potential of thrombus formation following plaque rupture. Computational fluid dynamics (CFD) were employed to assess hemodynamic conditions, and particularly flow recirculation and vortex formation in reconstructed arterial models associated with ST-elevation myocardial infraction (STEMI) or stable coronary stenosis (SCS) in the left anterior descending coronary artery (LAD). Results indicate that in the arterial models associated with STEMI, a 50% diameter stenosis immediately before or after a bifurcation creates a recirculation zone and vortex formation at the orifice of the bifurcation branch, for most of the cardiac cycle, thus allowing the creation of stagnating flow. These flow patterns are not seen in the SCS model with an identical stenosis. Post-stenotic recirculation in the presence of a 90% stenosis was evident at both the STEMI and SCS models. The presence of 90% diameter stenosis resulted in flow reduction in the LAD of 51.5% and 35.9% in the STEMI models and 37.6% in the SCS model, for a 10 mmHg pressure drop. CFD simulations in a reconstructed model of stenotic LAD segments indicate that specific anatomic characteristics create zones of vortices and flow recirculation that promote thrombus formation and potentially myocardial infarction.

Acute lung injury probably associated with infusion of propofol emulsion.

We present a case of acute lung injury associated with propofol infusion in a mechanically ventilated patient with intracerebral haemorrhage. Diagnosis was based on the exclusion of other risk factors inducing acute lung injury and on the clinical improvement after discontinuation of the propofol emulsion. Laboratory data such as the increase in total phospholipids, neutral lipids and free fatty acids in the broncho-alveolar lavage fluid, the remarkably high percentage of alveolar macrophages including fat droplets and the similar lipid composition of propofol and broncho-alveolar lavage fluid support the relationship between propofol and acute lung injury.