Pump thrombosis and stroke are serious complications of left ventricular assist device (LVAD) support. The aim of this study was to test the ability of an accelerometer to detect pump thrombosis and thromboembolic events (TEs) using real-time analysis of pump vibrations. An accelerometer sensor was attached to a HeartWare HVAD and tested in three in vitro experiments using different pumps for each experiment. Each experiment included thrombi injections sized 0.2-1.0 mL and control interventions: pump speed change, afterload increase, preload decrease, and saline bolus injections. A spectrogram was calculated from the accelerometer signal, and the third harmonic amplitude was used to test the sensitivity and specificity of the method. The third harmonic amplitude was compared with the pump energy consumption. The acceleration signals were of high quality. A significant change was identified in the accelerometer third harmonic during the thromboembolic interventions. The third harmonic detected thromboembolic events with higher sensitivity/specificity than LVAD energy consumption: 92%/94% vs. 72%/58%, respectively. A total of 60% of thromboembolic events led to a prolonged third harmonic amplitude change, which is indicative of thrombus mass residue on the impeller. We concluded that there is strong evidence to support the feasibility of real-time continuous LVAD monitoring for thromboembolic events and pump thrombosis using an accelerometer. Further in vivo studies are needed to confirm these promising findings.
The LVADHTx and HTx groups showed excellent one- and five-year survival. The combined group of DWL and HTx patients had similar survival to the combined groups of MCS, but use of LVAD pre-transplant quadrupled the cost.
This survey showed specific differences in outpatient management strategies that were previously unreported. However, further studies with correlations to patient outcomes are necessary to determine optimal patient management recommendations.
Circulating compounds such as drugs and nutritional components might adhere to the oxygenator fibers and tubing during ECMO support. This study evaluated the amount of nutritional supplements adsorbed to the ECMO circuit under controlled ex vivo conditions. Six identical ECMO circuits were primed with fresh human whole blood and maintained under physiological conditions at 36 °C for 24 h. A dose of nutritional supplement calculated for a 70 kg patient was added. 150 mL volume was drawn from the priming bag for control samples and kept under similar conditions. Blood samples were obtained at predetermined time points and analyzed for concentrations of vitamins, minerals, lipids, and proteins. Data were analyzed using mixed models with robust standard errors. No significant differences were found between the ECMO circuits and the controls for any of the measured variables: cobalamin, folate, vitamin A, glucose, minerals, HDL cholesterol, LDL cholesterol, total cholesterol, triglycerides or total proteins. There was an initial decrease and then an increase in the concentration of cobalamin and folate. Vitamin A concentrations decreased in both groups over time. There was a decrease in concentration of glucose and an increased concentration of lactate dehydrogenase over time in both groups. There were no significant alterations in the concentrations of nutritional supplements in an ex vivo ECMO circuit compared to control samples. The time span of this study was limited, thus, clinical studies over a longer period of time are needed.
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