Impact of Preoperative Lymphopenia on Survival Following Left Ventricular Assist Device Placement

Nutritional Risk Assessment and Adverse Events in Patients Undergoing Left Ventricular Assist Device Implantation-A Retrospective Cohort Study Using Hospital Information System

Clinical or subclinical malnutrition occurs in 30% to 70% of patients with advanced heart failure and increases the risk of postoperative adverse events. The main objective of this study was to assess the nutritional status of patients prior to left ventricular assist device (LVAD) implantation using different methods of malnutrition assessment and to evaluate the relationship between nutritional status and postoperative adverse events. A retrospective cohort study included 120 patients aged 26-74 years referred for LVAD surgery. Preoperative nutritional status (NRS-2002-Nutritional Risk Score 2002, NRI-Nutritional Risk Index, PNI-Prognostic Nutritional Index; TLC-total lymphocyte count) and postoperative adverse events were assessed. Moderate to severe malnutrition was found in 55.8%, 43.3%, 40.0%, and 20% of all patients, respectively, according to the PNI, NRI, TLC, and NRS-2002 scores. Patients with a TLC < 1200 cells/m3 had a higher risk of postoperative acute renal failure [hazard ratio (HR): 2.5; 95% confidence interval (95% CI): 1.01-6.3] and death during the observation period [HR = 2.1; 95% CI: 1.2-3.5]. Moderate to severe malnutrition was also associated with a significantly increased risk of in-hospital death [for the NRI score, HR = 4.9 (95% CI: 1.1-22.0); for the PNI score, HR = 5.0 (95% CI: 1.1-22.3)]. In conclusion, moderate to severe malnutrition prior to LVAD implantation has been identified as a risk factor for postoperative acute renal failure and mortality. Assessment of nutritional risk may improve patient selection and early initiation of nutritional support.

Resonantly Coupled High-Efficiency Sensors for Assessment of Ventricular Chamber Size for Autonomous Control of Left Ventricular Assist Device

Current left ventricular assist devices (LVADs) are set to a fixed rpm and are unable to adjust to physiological demands irrespective of preload or afterload. Autonomous control of LVADs has the potential to reduce septal shift, preserve right ventricle function, and meet physiological demands. A highly innovative resonantly coupled regimen is presented which can achieve this goal. We introduce sensors based on a highly sensitive relationship between transmission coefficient and spatial separation in a resonantly coupled regimen. This relationship represents a polynomial regression. A regimen of an apical sensor and multiple outflow sensors is investigated. A range of separations varying from 50-200 mm was systematically investigated. These ranges consider anatomical & physiological variation(s) in cardiac chamber size. Validation was obtained in porcine heart preparation. The polynomial regression model predicted distance between the sensors with a mean absolute percentage error of 0.77%, 1.07%, and 5.75% for the three putative positions of the outflow sensors and apical sensor when compared with experimental results. A high degree of accuracy (95%) between the predicted and observed distance was obtained. Continuous measurements were done over 90 days to examine drift, with no statistically detectable change in measurements over million sampling cycles. We have demonstrated a reliable sensor methodology without drift for assessing ventricular chamber size in an LVAD setup. This has the potential to allow autonomous control of LVAD based on ventricular chamber size to address some of the adverse events.