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Sepsis costs the healthcare system $23 billion annually and has a mortality rate between 10 and 40%. An early indication of sepsis is the onset of hyperglycemia, which is the result of sepsis-induced insulin resistance in skeletal muscle. Previous investigations have focused on events in the myocyte (e.g., insulin signaling and glucose transport and subsequent metabolism) as the causes for this insulin-resistant state. However, the delivery of insulin to the skeletal muscle is also an important determinant of insulin action. Skeletal muscle microvascular blood flow, which delivers the insulin to the muscle, is known to be decreased during sepsis. Here we test whether the reduced capillary blood flow to skeletal muscle belies the sepsis-induced insulin resistance by reducing insulin delivery to the myocyte. We hypothesize that decreased capillary flow and consequent decrease in insulin delivery is an early event that precedes gross cardiovascular alterations seen with sepsis. This hypothesis was examined in mice treated with either lipopolysaccharide (LPS) or polymicrobial sepsis followed by intravital microscopy of the skeletal muscle microcirculation. We calculated insulin delivery to the myocyte using two independent methods and found that LPS and sepsis rapidly reduce insulin delivery to the skeletal muscle by ~50%; this was driven by decreases in capillary flow velocity and the number of perfused capillaries. Furthermore, the changes in skeletal muscle microcirculation occur before changes in both cardiac output and arterial blood pressure. These data suggest that a rapid reduction in skeletal muscle insulin delivery contributes to the induction of insulin resistance during sepsis.
BACKGROUND - Although studies involving preterm infants ≤34 weeks gestation report a decreased incidence of patent ductus arteriosus after antenatal betamethasone, studies involving younger gestation infants report conflicting results.
METHODS - We used preterm baboons, mice, and humans (≤27 weeks gestation) to examine betamethasone's effects on ductus gene expression and constriction both in vitro and in vivo.
RESULTS - In mice, betamethasone increased the sensitivity of the premature ductus to the contractile effects of oxygen without altering the effects of other contractile or vasodilatory stimuli. Betamethasone's effects on oxygen sensitivity could be eliminated by inhibiting endogenous prostaglandin/nitric oxide signaling. In mice and baboons, betamethasone increased the expression of several developmentally regulated genes that mediate oxygen-induced constriction (K channels) and inhibit vasodilator signaling (phosphodiesterases). In human infants, betamethasone increased the rate of ductus constriction at all gestational ages. However, in infants born ≤25 weeks gestation, betamethasone's contractile effects were only apparent when prostaglandin signaling was inhibited, whereas at 26-27 weeks gestation, betamethasone's contractile effects were apparent even in the absence of prostaglandin inhibitors.
CONCLUSIONS - We speculate that betamethasone's contractile effects may be mediated through genes that are developmentally regulated. This could explain why betamethasone's effects vary according to the infant's developmental age at birth.
OBJECTIVES - This study sought to assess long-term left atrial appendage (LAA) closure efficacy of the Atriclip applied via totally thoracoscopic (TT) approach with computed tomographic angiography.
BACKGROUND - LAA closure is associated with a low risk for atrial fibrillation-related embolic stroke. The Atriclip exclusion device allows epicardial LAA closure, avoiding the need for post-operative oral anticoagulation. Previous data with Atriclip during open chest procedures show a high efficacy rate of closure >95%.
METHODS - Three-dimensional volumetric 2-phase computed tomographic angiography ≥90 days post-implantation was independently assessed by chest radiology for complete LAA closure on all consented subjects identified retrospectively as having had a TT-placed Atriclip at Vanderbilt University Medical Center from June 13, 2011, to October 6, 2015.
RESULTS - Complete LAA closure (defined by complete exclusion of the LAA with no exposed trabeculations, and clip within 1 cm from the left circumflex artery) was found in 61 of 65 subjects (93.9%). Four cases had incomplete closure (6.2%). Two clips were placed too distally, leaving a large stump with exposed trabeculae. Two clips failed to address a secondary LAA lobe. No major complications were associated with TT placement of the Atriclip. Follow-up over 183 patient-years revealed 1 stroke in a patient with complete LAA closure and no thrombus (hypertensive cerebrovascular accident).
CONCLUSIONS - Angiographic LAA closure efficacy with a TT-placed Atriclip is high (93.9%). The clinical significance of a remnant stump is unknown. Confirmation of complete LAA occlusion should be made before cessation of systemic anticoagulation.
Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.
BACKGROUND - Pulmonary transit time (PTT) obtained from contrast echocardiography is a marker of global cardiopulmonary function. Pulmonary blood volume (PBV), derived from PTT, may be a noninvasive surrogate for left-sided filling pressures, such as pulmonary artery wedge pressure (PAWP). We sought to assess the relationship between PBV obtained from contrast echocardiography and PAWP.
METHODS - Participants were adult survivors of childhood cancer that had contrast echocardiography performed nearly simultaneously with right-heart catheterization. PTT was derived from time-intensity curves of contrast passage through the right ventricle (RV) and left atrium (LA). PBV relative to overall stroke volume (rPBV) was estimated from the product of PTT and heart rate during RV-LA transit. PAWP was obtained during standard right-heart catheterization. The Spearman correlation coefficient was used to assess the relationship between rPBV and PAWP.
RESULTS - The study population consisted of 7 individuals who had contrast echocardiography and right-heart catheterization within 3 hours of each other. There was a wide range of right atrial (1-17 mm Hg), mean pulmonary artery (18-42 mm Hg), and PAW pressures (4-26 mm Hg) as well as pulmonary vascular resistance (<1-6 Wood Units). We observed a statistically significant correlation between rPBV and PAWP (r = .85; P = .02).
CONCLUSION - Relative PBV derived from contrast echocardiography correlates with PAWP. If validated in larger studies, rPBV could potentially be used as an alternative to invasively determine left-sided filling pressure.
© 2018 Wiley Periodicals, Inc.
Diastolic dysfunction (DD), an abnormality in cardiac left ventricular (LV) chamber compliance, is associated with increased morbidity and mortality. Although DD has been extensively studied in older populations, co-morbidity patterns are less well characterized in middle-aged subjects. We screened 156,434 subjects with transthoracic echocardiogram reports available through Vanderbilt's electronic heath record and identified 6,612 subjects 40 to 55 years old with an LV ejection fraction ≥50% and diastolic function staging. We tested 452 incident and prevalent clinical diagnoses for associations with early-stage DD (n = 1,676) versus normal function. There were 44 co-morbid diagnoses associated with grade 1 DD including hypertension (odds ratio [OR] = 2.02, 95% confidence interval [CI] 1.78 to 2.28, p <5.3 × 10-29), type 2 diabetes (OR 1.96, 95% CI 1.68 to 2.29, p = 2.1 × 10-17), tachycardia (OR 1.38, 95% CI 0.53 to 2.19, p = 2.9 × 10-6), obesity (OR 1.76, 95% CI 1.51 to 2.06, p = 1.7 × 10-12), and clinical end points, including end-stage renal disease (OR 3.29, 95% CI 2.19 to 4.96, p = 1.2 × 10-8) and stroke (OR 1.5, 95% CI 1.12 to 2.02, p = 6.9 × 10-3). Among the 60 incident diagnoses associated with DD, heart failure with preserved ejection fraction (OR 4.63, 95% CI 3.39 to 6.32, p = 6.3 × 10-22) had the most significant association. Among subjects with normal diastolic function and blood pressure at baseline, a blood pressure measurement in the hypertensive range at the time of the second echocardiogram was associated with progression to stage 1 DD (p = 0.04). In conclusion, DD was common among subjects 40 to 55 years old and was associated with a heavy burden of co-morbid disease.
Copyright © 2018 Elsevier Inc. All rights reserved.
Inactivation of the retinoblastoma gene () product, pRB, is common in many human cancers. Targeting downstream effectors of pRB that are central to tumorigenesis is a promising strategy to block the growth of tumors harboring loss-of-function mutations. One such effector is retinoblastoma-binding protein 2 (RBP2, also called JARID1A or KDM5A), which encodes an H3K4 demethylase. Binding of pRB to RBP2 has been linked to the ability of pRB to promote senescence and differentiation. Importantly, genetic ablation of RBP2 is sufficient to phenocopy pRB's ability to induce these cellular changes in cell culture experiments. Moreover, germline deletion significantly impedes tumorigenesis in mice. The value of RBP2 as a therapeutic target in cancer, however, hinges on whether loss of RBP2 could block the growth of established tumors as opposed to simply delaying their onset. Here we show that conditional, systemic ablation of RBP2 in tumor-bearing mice is sufficient to slow tumor growth and significantly extend survival without causing obvious toxicity to the host. These findings show that established -null tumors require RBP2 for growth and further credential RBP2 as a therapeutic target in human cancers driven by inactivation.
OBJECTIVE - To determine whether the duration of diabetes and duration of prediabetes estimated during a 25-year period in early adulthood are each independently associated with coronary artery calcified plaque (CAC) and abnormalities in left ventricular structure and function later in life.
RESEARCH DESIGN AND METHODS - Participants were 3,628 white and black adults aged 18-30 years without diabetes or prediabetes at baseline (1985-1986) in the Coronary Artery Risk Development in Young Adults (CARDIA) Study. Durations of diabetes and prediabetes were estimated based on their identification at examinations 7, 10, 15, 20, and 25 years later. CAC was identified by computed tomography at years 15, 20, and 25. Left ventricular structure and function were measured via echocardiogram at year 25.
RESULTS - Of the 3,628 individuals, 12.7% and 53.8% developed diabetes and prediabetes, respectively; average (SD) duration was 10.7 (10.7) years and 9.5 (5.4) years. After adjustment for sociodemographic characteristics and other cardiovascular risk factors, and mutual adjustment for each other, the hazard ratio for the presence of CAC was 1.15 (95% CI 1.06, 1.25) and 1.07 (1.01, 1.13) times higher for each 5-year-longer duration of diabetes and prediabetes, respectively. Diabetes and prediabetes duration were associated with worse subclinical systolic function (longitudinal strain [ < 0.001 for both]) and early diastolic relaxation (e' [ 0.004 and 0.002, respectively]). Duration of diabetes was also associated with a higher diastolic filling pressure (E-to-e' ratio [ 0.001]).
CONCLUSIONS - Durations of diabetes and prediabetes during adulthood are both independently associated with subclinical atherosclerosis and left ventricular systolic and diastolic dysfunction in middle age.
© 2018 by the American Diabetes Association.
RATIONALE - The epidemiology and prognostic impact of increased pulmonary pressure among HIV-infected individuals in the antiretroviral therapy era is not well described.
OBJECTIVES - To examine the prevalence, clinical features, and outcomes of increased echocardiographic pulmonary pressure in HIV-infected and -uninfected individuals.
METHODS - This study evaluated 8,296 veterans referred for echocardiography with reported pulmonary artery systolic pressure (PASP) estimates from the Veterans Aging Cohort study, an observational cohort of HIV-infected and -uninfected veterans matched by age, sex, race/ethnicity, and clinical site. The primary outcome was adjusted mortality by HIV status.
MEASUREMENTS AND MAIN RESULTS - PASP was reported in 2,831 HIV-infected and 5,465 HIV-uninfected veterans (follow-up [mean ± SD], 3.8 ± 2.6 yr). As compared with uninfected veterans, HIV-infected veterans with HIV viral load greater than 500 copies/ml (odds ratio, 1.27; 95% confidence interval [CI], 1.05-1.54) and those with CD4 cell count less than 200 cells/μl (odds ratio, 1.28; 95% CI, 1.02-1.60) had a higher prevalence of PASP greater than or equal to 40 mm Hg. As compared with uninfected veterans with a PASP less than 40 mm Hg, HIV-infected veterans with a PASP greater than or equal to 40 mm Hg had an increased risk of death (adjusted hazard ratio, 1.78; 95% CI, 1.57-2.01). This risk persisted even among participants without prevalent comorbidities (adjusted hazard ratio, 3.61; 95% CI, 2.17-6.01). The adjusted risk of mortality in HIV-infected veterans was higher at all PASP values than in uninfected veterans, including at values currently considered to be normal.
CONCLUSIONS - HIV-infected people with high HIV viral loads or low CD4 cell counts have a higher prevalence of increased PASP than uninfected people. Mortality risk in HIV-infected veterans increases at lower values of PASP than previously recognized and is present even among those without prevalent comorbidities. These findings may inform clinical decision-making regarding screening and surveillance of pulmonary hypertension in HIV-infected individuals.
Importance - Pulmonary hypertension (PH) is diagnosed by a mean pulmonary arterial pressure (mPAP) value of at least 25 mm Hg during right heart catheterization (RHC). While several studies have demonstrated increased mortality in patients with mPAP less than that threshold, little is known about the natural history of borderline PH.
Objective - To test the hypothesis that patients with borderline PH have decreased survival compared with patients with lower mPAP and frequently develop overt PH and to identify clinical correlates of borderline PH.
Design, Setting, and Participants - Retrospective cohort study from 1998 to 2014 at Vanderbilt University Medical Center, comprising all patients undergoing routine RHC for clinical indication. We extracted demographics, clinical data, invasive hemodynamics, echocardiography, and vital status for all patients. Patients with mPAP values of 18 mm Hg or less, 19 to 24 mm Hg, and at least 25 mm Hg were classified as reference, borderline PH, and PH, respectively.
Exposures - Mean pulmonary arterial pressure.
Main Outcome and Measures - Our primary outcome was all-cause mortality after adjusting for clinically relevant covariates in a Cox proportional hazards model. Our secondary outcome was the diagnosis of overt PH in patients initially diagnosed with borderline PH. Both outcomes were determined prior to data analysis.
Results - We identified 4343 patients (mean [SD] age, 59  years, 51% women, and 86% white) among whom the prevalence of PH and borderline PH was 62% and 18%, respectively. Advanced age, features of the metabolic syndrome, and chronic heart and lung disease were independently associated with a higher likelihood of borderline PH compared with reference patients in a logistic regression model. After adjusting for 34 covariates in a Cox proportional hazards model, borderline PH was associated with increased mortality compared with reference patients (hazard ratio, 1.31; 95% CI, 1.04-1.65; P = .001). The hazard of death increased incrementally with higher mPAP, without an observed threshold. In the 70 patients with borderline PH who underwent a repeated RHC, 43 (61%) had developed overt PH, with a median increase in mPAP of 5 mm Hg (interquartile range, -1 to 11 mm Hg; P < .001).
Conclusions and Relevance - Borderline PH is common in patients undergoing RHC and is associated with significant comorbidities, progression to overt PH, and decreased survival. Small increases in mPAP, even at values currently considered normal, are independently associated with increased mortality. Prospective studies are warranted to determine whether early intervention or closer monitoring improves clinical outcomes in these patients.
BACKGROUND & AIMS - Cardiovascular disease (CVD) is the leading cause of death among patients with nonalcoholic fatty liver disease (NAFLD). Moderate drinking (vs abstinence) is associated with lower risk of CVD in the general population. We assessed whether alcohol use is associated with CVD risk in patients with NAFLD.
METHODS - We analyzed data from participants in the Coronary Artery Risk Development in Young Adults longitudinal cohort study of 5115 black and white young adults, 18-30 years old, recruited from 4 cities in the United States from 1985 through 1986. Participants self-reported alcohol use at study entry and then again after 15, 20, and 25 years. At year 25 (2010-2011), participants underwent computed tomography examination of the thorax and abdomen and tissue Doppler echocardiography with myocardial strain measured by speckle tracking. Coronary artery calcification was defined as an Agatston score above 0. NAFLD was defined as liver attenuation <51 Hounsfield Units after exclusions. Drinkers reported 1-21 (men) or 1-14 (women) standard drinks/week at years 15, 20, or 25. Nondrinkers reported no alcohol use at years 15, 20, and 25.
RESULTS - Of the 570 participants with NAFLD (mean age, 50 years; 54% black; 46% female), 332 (58%) were drinkers; significantly higher proportions of drinkers were white, male, and with higher levels of education compared with nondrinkers (P < .05 for all). Higher proportions of drinkers had obesity, diabetes, and metabolic syndrome compared with nondrinkers (P < .01). There was no difference in liver attenuation between groups (P = .12). After multivariable adjustment, there was no association between alcohol use and CVD risk factors (diabetes, hypertension, hyperlipidemia) or subclinical CVD measures (coronary artery calcification, early transmitral velocity/late (atrial) transmitral velocity (E/A) ratio, global longitudinal strain).
CONCLUSIONS - In a population-based sample of individuals with NAFLD in midlife, prospectively assessed alcohol use is not associated with significant differences in risk factors for CVD or markers of subclinical CVD. In contrast to general population findings, alcohol use may not reduce the risk of CVD in patients with NAFLD.
Copyright © 2017 AGA Institute. Published by Elsevier Inc. All rights reserved.