John Doe, an 81-year-old patient with a significant distal left main (LM) stenosis, was treated using a provisional stenting approach. As part of an European Bifurcation Club (EBC) project, the ...complete stenting procedure was repeated using computational modelling. First, a tailored three-dimensional (3D) reconstruction of the bifurcation anatomy was created by fusion of multislice computed tomography (CT) imaging and intravascular ultrasound. Second, finite element analysis was employed to deploy and post-dilate the stent virtually within the generated patient-specific anatomical bifurcation model. Finally, blood flow was modelled using computational fluid dynamics. This proof-of-concept study demonstrated the feasibility of such patient-specific simulations for bifurcation stenting and has provided unique insights into the bifurcation anatomy, the technical aspects of LM bifurcation stenting, and the positive impact of adequate post-dilatation on blood flow patterns. Potential clinical applications such as virtual trials and preoperative planning seem feasible but require a thorough clinical validation of the predictive power of these computer simulations.
Statins are widely used to treat hypercholesterolemia and atherosclerotic disease. Noninvasive MRI allows serial monitoring of atherosclerotic plaque size changes. Our aim was to investigate the ...effects of lipid lowering with simvastatin on atherosclerotic lesions.
A total of 44 aortic and 32 carotid artery plaques were detected in 21 asymptomatic hypercholesterolemic patients at baseline. The effects of statin on these atherosclerotic lesions were evaluated as changes versus baseline in lumen area (LA), vessel wall thickness (VWT), and vessel wall area (VWA) by MRI. Maximal reduction of plasma total and LDL cholesterol by simvastatin (23% and 38% respectively; P<0.01 versus baseline) was achieved after approximately 6 weeks of therapy and maintained thereafter throughout the study. Significant (P<0.01) reductions in maximal VWT and VWA at 12 months (10% and 11% for aortic and 8% and 11% for carotid plaques, respectively), without changes in LA, have been reported. Further decreases in VWT and VWA ranging from 12% to 20% were observed at 18 and 24 months. A slight but significant increase (ranging from 4% to 6%) in LA was seen in both carotid and aortic lesions at these later time points.
The present study demonstrates that maintained lipid-lowering therapy with simvastatin is associated with significant regression of established atherosclerotic lesions in humans. Our observations indicate that lipid-lowering therapy is associated with sustained vascular remodeling and emphasize the need for longer-term treatment.
Recent evidence suggests that conduits implanted in Fontan patients at the age of 2-4 years become undersized for adulthood. The objective of this study is to use computational fluid dynamic models ...to evaluate the effect of virtual expansion of the Fontan conduit on haemodynamics and energetics of the total cavopulmonary connection under resting conditions and increased flow conditions.
Patient-specific, magnetic resonance imaging-based simulation models of the total cavopulmonary connection were performed during resting and increased flow conditions. The original 16 mm conduits were virtually enlarged to three new sizes. The proposed conduit sizes were defined based on MRI-derived conduit flow in each patient. Flow efficiency was evaluated based on power loss, pressure drop and resistance and thrombosis risk was based on flow stagnation volume and relative residence time.
Models of five adult patients with a 16 mm extracardiac Fontan connection were simulated and subsequently virtually expanded to 24-32mm depending on patient-specific conduit flow. Virtual expansion led to a 40-65% decrease in pressure gradient across the total cavopulmonary connection depending on virtual conduit size. Despite improved energetics of the entire total cavopulmonary connection, the pulmonary arteries remained a significant contributor to energy loss (60-73% of total loss) even after virtual surgery. Flow stagnation volume inside the virtual conduit and surface area in case of elevated relative residence time (> 20 Pa-1) increased after conduit enlargement but remained negligible (flow stagnation <2% of conduit volume in rest, <0.5% with exercise and elevated relative residence time <3% in rest, <1% with exercise).
Virtual expansion of 16 mm conduits to 24-32mm, depending on patient-specific conduit flow, in Fontan patients significantly improves total cavopulmonary connection efficiency while thrombosis risk presumably remains low.
The clinical presentation was stable angina in 23 patients (52.3%), unstable angina in 10 patients (22.7%) and acute myocardial infarction in 11 patients (5%); the mean age of the patients was 58.8 ± ...11.5 years, and 33 patients (75%) were male. ...these results may provide another potential explanation for the higher risk of restenosis after percutaneous coronary intervention of bifurcation lesions.
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