Impact of digoxin utilization on clinical outcomes following left ventricular assist device implantation.

INTRODUCTION: We aimed to assess the impact of digoxin use following left ventricular assist device (LVAD) implantation on clinical outcomes. METHODS: Patients implanted with continuous flow LVADs at a single academic medical center and survived to initial hospital discharge were included in the analysis (n = 346). Clinical events were captured at a maximum of 2 years of follow up. Digoxin use was defined as 30-day continuous use post-LVAD. Negative binomial regression and Kaplan-Meier method were used to assess the association between digoxin use and clinical outcomes. RESULTS: Mean age of the cohort was 56 years (±13) and 23% (79/346) were female sex. Digoxin was used in 144 patients (41.6%) for a median of 268 days (IQR 154, 616). Digoxin use was associated with a significant reduction in cumulative incidence of gastrointestinal bleeding (GIB) (15% vs 26%, p = 0.004). After adjusting for age, hypertension, post-operative hemoglobin, RDW, potassium, and GFR, and use of angiotensin receptor/neprilysin inhibitor, there remained a significant 47% reduction in GIB incidence in patients treated with digoxin. There was no significant difference in cumulative incidence in right ventricular failure (RVF) between the two groups. There was no difference in overall 2-year survival between groups. CONCLUSIONS: Digoxin use was associated with reduction in GIB events, but not in RVF or mortality. Further studies are needed to confirm these findings and to investigate optimal timing and patient population.

Pulmonary Function Testing Pre-heart Transplant Predicts Posttransplant Survival.

Although pulmonary function testing (PFT) is typically performed for heart transplant evaluation, the prognostic utility of PFTs after transplantation is unknown. We evaluated whether PFT parameters were correlated with outcomes following heart transplantation. METHODS: International Society for Heart and Lung Transplantation Thoracic Organ Transplant Registry data were utilized. Survival was assessed using Kaplan-Meier method and compared via log-rank test. Cox proportional hazard modeling was used to evaluate univariate and multivariate predictors of survival. RESULTS: Eight hundred two patients pretransplant PFT data were available for evaluation. Forced expiratory volume in 1 s (FEV1) < 50% predicted (P < 0.0001), and forced vital capacity (FVC) < 50% predicted each had significantly higher mortality (P = 0.001) compared with patients with FEV1 or FVC 50%-80% or >80%. FEV1/FVC < 0.7 was not associated with increased mortality. FEV1 and FVC below 50% both predicted longer lengths of stay (P = 0.028 for FEV1 and P = 0.0075 for FVC). After adjusting for male gender, age, body mass index, smoking history, chronic obstructive pulmonary disease, creatinine, albumin, and total bilirubin, FEV1 < 50% (hazard ratio, 4.91; P < 0.0001; 95% confidence interval, 2.69-8.94) and FVC < 50% (hazard ratio, 2.75; P = 0.003; 95% confidence interval, 1.4-5.4) both remained independent predictors of mortality. CONCLUSIONS: Abnormal pulmonary function (FEV1 or FVC below 50% of predicted) pre-heart transplantation is associated with increased mortality and longer lengths of stay posttransplant.

Glycogen storage and degradation during in vitro growth and differentiation of Giardia intestinalis.

Giardia intestinalis is the causative agent of human giardiasis, a common diarrheal illness worldwide. Despite its global distribution and prevalence, many questions regarding its basic biology and metabolism remain unanswered. In this study, we examine the accumulation and degradation of glycogen, an important source of stored carbon and energy, during the in vitro growth and differentiation of G. intestinalis . We report that, as G. intestinalis progresses through its growth cycle, cultures of trophozoites accumulate glycogen during the lag and early logarithmic phases of growth and then utilize this compound during their remaining logarithmic growth. As cultures enter the stationary phase of growth, they re-accumulate glycogen stores. The activity of glycogen phosphorylase, an enzyme involved in glycogen metabolism, also varied throughout in vitro trophozoite growth. During the in vitro induction of trophozoite differentiation into water-resistant cyst forms, the cultures initially accumulated stores of glycogen which diminished throughout transition to the cyst form. This observation is suggestive of a role for glycogen in the differentiation process. These studies represent the first thorough analysis of changes in glycogen content and glycogen phosphorylase activity during G. intestinalis growth and differentiation.