Patient-specific pulmonary venous flow characterization and its impact on left atrial appendage thrombosis in atrial fibrillation patients.

BACKGROUND: Cardioembolic strokes are commonly occurred in non-valvular atrial fibrillation (AF) patients, with over 90% of cases originating from clot in left atrial appendage (LAA), which is believed to be greatly related with hemodynamic characters. Numerical simulation is widely accepted in the hemodynamic analysis, and patient-specific boundaries are required for realistic numerical simulations. METHOD: This paper firstly proposed a method that maps personalized pulmonary venous flow (PVF) by utilizing the volume changes of the left atrium (LA) over the cardiac cycle. Then we used data from patients with AF to investigate the correlation between PVF patterns and hemodynamics within the LAA. Meanwhile, we conducted a fluid-structure interaction analysis to assess the impact of velocity- and time-related PVF parameters on LAA hemodynamic characters. RESULTS: The analysis reveal that the ratio of systolic to diastolic peak velocity (VS/VD), and systolic velocity-time integral (VTI) showed a significant influence on LAA velocity in patients with atrial fibrillation, and the increases of velocity- and time-related parameters were found to be positively correlated with the blood update in the LAA. CONCLUSIONS: This study established a method for mapping patient-specific PVF based on LA volume change, and evaluated the relationship between PVF parameters and thrombosis risk. The present work provides an insight from PVF characters to evaluate the risk of thrombus formation within LAA in patients with AF.

Non-targeted metabolomic analysis on multidrug resistance hepatocellular carcinoma cell and reversal effect of annonaceous acetogenins.

Multidrug-resistance (MDR) has been shown to play a critical role in the development of many diseases. In this study, we used metabolomic method to evaluate the MDR in hepatocellular carcinoma, and investigate regulatory of annonaceous acetogenins on MDR of hepatocellular carcinoma. Multivariate statistical analysis revealed that the MDR of SMMC 7721 together with changes in glutathione metabolism, arginine and proline metabolism, sphingolipid metabolism. Annonaceous acetogenins impact these metabolism pathways. Metabolic pathway analysis coupled with stoichiometry analysis can be an effective tool to understand MDR mechanism and to potentially find new MDR reversal agents.