Atrial fibrillation in patients with high-risk acute myocardial infarction – the PARADISE-MI trial

Background

Atrial fibrillation or flutter (AFF) is common in both patients with myocardial infarction (MI) and those with heart failure (HF). However, its impact on the risk of adverse outcomes in MI complicated by either reduced LVEF and/or transient pulmonary congestion is less known.

Purpose

To assess the relationship between AFF and outcomes and whether AFF modified the treatment response to sacubitril/valsartan in the PARADISE-MI (Prospective ARNI versus ACEi trial to determine superiority in reducing HF events after MI) trial.

Methods

5656 patients enrolled in the PARADISE-MI trial were divided into 3 groups: no known AFF, history of AFF without AFF at enrolment, and AFF occurring with the index MI event. We assessed outcomes and the treatment response to sacubitril/valsartan in all groups. The primary outcome of the PARADISE-MI trial was death from cardiovascular (CV) causes or incident HF. The outcome analyses were adjusted for the number of risk augmenting factors, age, pulmonary congestion, percutaneous coronary intervention, LVEF and hypertension.

Results

259 patients (4.6%) had only a history of AFF, 525 patients (9.3%) had AFF associated with index MI. Patients with a history of AFF and AFF with index MI were older, with a higher rate of pulmonary congestion and hypertension, lower eGFR values but lower rates of diabetes, compared with those without AFF (Table 1). In unadjusted analyses, history of AFF and AFF with index MI were associated with a significant increase in the risk of the primary outcome (hazard ratio (HR): 1.76; 95% confidence interval (CI): 1.32–2.35 and HR 1.69, 95% CI 1.37–2.10, respectively), remaining significant after adjustment only in those with AFF with index MI (HR=1.40, 95% CI 1.12–1.74) (Fig. 1). This was primarily driven by an increase in the crude and adjusted risk of incident HF, both in those with a history of AFF and AFF with index MI (adjusted HR=1.56, 95% CI 1.10–2.22 and HR=1.55, 95% CI 1.18–2.03, respectively). An increase in the crude risk of CV death was present in patients with a history of AFF and AFF with index MI (HR=1.57, 95% CI 1.04–2.39 and HR=1.66, 95% CI 1.23–2.24, respectively), yet did not remain significant after adjustment. The risk of the composite outcome of death from coronary heart disease, non-fatal MI, hospitalisation for angina or coronary was not associated with either a history of AFF or AFF with index MI, in unadjusted or adjusted analyses (adjusted HR=0.83, 95% CI 0.57–1.19 and HR=1.00, 95% CI 0.78–1.29, respectively) (Fig. 1). Neither history of AFF nor AFF with index MI modified the treatment effect of sacubitril/valsartan (p>0.05).

Conclusions

In this post-MI cohort, history of AFF and AFF occurring with the index MI event were associated with an increased risk of CV death or incident heart failure, primarily driven by an increased risk of incident HF. However, the risk of the composite coronary outcome was not associated with AFF status, compared to other studied outcomes.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): The PARADISE-MI trial was funded by Novartis

P3520Admission hyperglycemia is a predictor of mortality of acute heart failure: comparison between patients with and without diabetes mellitus

Background

Regardless of diabetes mellitus (DM), admission hyperglycemia is not uncommon in patients with acute heart failure (AHF). Although DM is a well-known predictor of mortality in AHF, the impacts of admission hyperglycemia on clinical outcomes in non-DM patients with AHF have been poorly studied. The aim of this study, therefore, was to compare the impact of admission hyperglycemia on long-term clinical outcomes in AHF patients with or without DM.

Methods

Among 5,625 AHF patients enrolled in a nationwide registry, a total of 5,541 patients were enrolled and divided into 2 groups; DM group (n=2,125, 70.4±11.4 years) vs. non-DM group (n=3,416, 67.3±16.0 years). Each group were further divided into 2 groups according to the presence of admission hyperglycemia (admission serum glucose level >200mg/dl); admission hyperglycemia (n=248) and no hyperglycemia (n=3,168) in non-DM; admission hyperglycemia (n=799) and no hyperglycemia (n=1,326) in DM. All-cause death and hospitalization due to HF (HHF) during 1-year follow-up were compared.

Results

Death was developed in 1,220 patients (22.2%) including 269 inhospital deaths (4.9%) during 1-year of follow-up. Death rate were significantly higher in DM than in non-DM group (24.8% vs 20.5%, p<0.001), however there was no difference in inhospital death (5.1% vs 4.7%, p=0.534). Both inhospital death (7.6% vs. 4.2%, p<0.001) and 1-year death (26.2% vs. 21.3%, p=0.001) were more frequent in AHF patients with hyperglycemia. On Kaplan-Meier survival curve analysis, however, admission hyperglycemia was associated with significantly higher death (p<0.001 by log-rank test) and rehospitalization (p=0.006 by log-rank test) in non-DM group, but not in DM group. In non-DM group, admission hyperglycemia was an independent predictor of 1-year mortality (HR 1.46, 95% CI 1.10–1.93, p=0.009).

Conclusion

DM was a significant predictor of long-term mortality in patients with AHF. Admission hyperglycemia was associated with both higher inhospital and 1-year mortality. The present study also demonstrated that admission hyperglycemia is an independent predictor of mortality in non-DM patients with AHF, but not in DM patients. In addition to the presence of DM, admission hyperglycemia would be a useful marker in the risk stratification of AHF, especially in non-DM patients.

P3453Gender difference in impact of ischemic heart disease on long-term outcome in patients with heart failure reduced ejection fraction

Background

Ischemic heart disease (IHD) is a major underlying etiology in patients with heart failure (HF). Although the impact of IHD on HF is evolving, there is a lack of understanding of how IHD affects long-term clinical outcomes and uncertainty about the role of IHD in determining the risk of clinical outcomes by gender.

Purpose

This study aims to evaluate the gender difference in impact of IHD on long-term clinical outcomes in patients with heart failure reduced ejection fraction (HFrEF).

Methods

Study data were obtained from the nationwide registry which is a prospective multicenter cohort and included patients who were hospitalized for HF composed of 3,200 patients. A total of 1,638 patients with HFrEF were classified into gender (women 704 and men 934). The primary outcome was all-cause death during follow-up and the composite clinical events of all-cause death and HF readmission during follow-up were also obtained. HF readmission was defined as re-hospitalization because of HF exacerbation.

Results

133 women (18.9%) were died and 168 men (18.0%) were died during follow-up (median 489 days; inter-quartile range, 162–947 days). As underlying cause of HF, IHD did not show significant difference between genders. Women with HFrEF combined with IHD had significantly lower cumulative survival rate than women without IHD at long-term follow-up (74.8% vs. 84.9%, Log Rank p=0.001, Figure 1). However, men with HFrEF combined with IHD had no significant difference in survival rate compared with men without IHD (79.3% vs. 83.8%, Log Rank p=0.067). After adjustment for confounding factors, Cox regression analysis showed that IHD had a 1.43-fold increased risk for all-cause mortality independently only in women. (odds ratio 1.43, 95% confidence interval 1.058–1.929, p=0.020). On the contrary to the death-free survival rates, there were significant differences in composite clinical events-free survival rates between patients with HFrEF combined with IHD and HFrEF without IHD in both genders.

Figure 1

Conclusions

IHD as predisposing cause of HF was an important risk factor for long-term mortality in women with HFrEF. Clinician need to aware of gender-based characteristics in patients with HF and should manage and monitor them appropriately and gender-specifically. Women with HF caused by IHD also should be treated more meticulously to avoid a poor prognosis.

Acknowledgement/Funding

None

Inhibition of nitric oxide synthesis increases apoptotic cardiomyocyte death and myocardial angiotensin-converting enzyme gene expression in ischemia/reperfusion-injured myocardium of rats

Cardiomyocyte apoptosis is an important pathogenic mechanism in myocardial ischemia/reperfusion (I/R) injury. It has been shown that nitric oxide (NO) and the renin-angiotensin system (RAS) are closely related, and both systems regulate apoptotic cell death. However, the effects of NO modulation on myocardial apoptotic cell death and changes in the RAS in the I/R-injured myocardium have not been studied. Female Sprague-Dawley rats were randomized into three groups: NO synthesis inhibitor, N(G)-nitro-L-arginine-methyl ester (L-NAME, 10mg/kg); NO precursor, L-arginine (540mg/kg); and vehicle. The rats were then subjected to 45 min coronary occlusion followed by 4 h reperfusion. The TdT-mediated in situ nick and labeling (TUNEL) indices were 39.9%+/-0.8% at the border and 30.9%+/-1.2% at the center of the I/R area in the vehicle group. L-NAME administration significantly increased these TUNEL-positive cells to 45.3%+/-1.9% and 37.9%+/-1.3%, respectively (P < 0.05 each). L-arginine administration reduced the TUNEL index at the border zone with marginal significance (P = 0.08 vs vehicle group). I/R injury significantly reduced the angiotensin-converting enzyme (ACE) mRNA expression in the left (ventricular) free wall of vehicle group rats. However, ACE mRNA expression was 1.9 times greater in the L-NAME group than that in the vehicle group (P < 0.05). This study showed that the inhibition of NO synthesis increased apoptotic cardiomyocyte death and local ACE mRNA expression in the I/R-injured myocardium. Our observations indicate that NO, ACE, and apoptotic cardiomyocyte death are related to each other during I/R injury.

Both E6 and E7 oncoproteins of human papillomavirus 16 inhibit IL-18-induced IFN-gamma production in human peripheral blood mononuclear and NK cells

Cervical carcinoma is the predominant cancer among malignancies in women throughout the world, and human papillomavirus (HPV) 16 is the most common agent linked to human cervical carcinoma. The present study was performed to investigate the mechanisms of immune escape in HPV-induced cervical cancer cells. The presence of HPV oncoproteins E6 and E7 in the extracellular fluids of HPV-containing cervical cancer cell lines SiHa and CaSki was demonstrated by ELISA. The effect of HPV 16 oncoproteins E6 and E7 on the production of IFN-gamma by IL-18 was assessed. E6 and E7 proteins reduced IL-18-induced IFN-gamma production in both primary PBMCs and the NK0 cell line. FACS analysis revealed that the viral oncoproteins reduced the binding of IL-18 to its cellular surface receptors on NK0 cells, whereas there was no effect of oncoproteins on IL-1 binding to its surface IL-1 receptors on D10S, a subclone of the murine Th cell D10.G4.1. In vitro pull-down assays also revealed that the viral oncoproteins and IL-18 bound to IL-18R alpha-chain competitively. These results suggest that the extracellular HPV 16 E6 and E7 proteins may inhibit IL-18-induced IFN-gamma production locally in HPV lesions through inhibition of IL-18 binding to its alpha-chain receptor. Down-modulation of IL-18-induced immune responses by HPV oncoproteins may contribute to viral pathogenesis or carcinogenesis.

Dendritic cell-specific MHC class II transactivator contains a caspase recruitment domain that confers potent transactivation activity

The MHC class II transactivator (CIITA) is a critical transcription factor that regulates genes involved in antigen presentation function. At least three functional forms of CIITA gene products are transcribed from three different promoters. The CIITA gene expressed in dendritic cells (DC-CIITA) has a unique first exon encoding an extended N-terminal region of CIITA. Here, we show that the N terminus of DC-CIITA has high homology to a caspase recruitment domain (CARD) found in components of apoptosis and nuclear factor-kappaB signaling pathways. However, DC-CIITA does not regulate cell death, nor does it induce nuclear factor-kappaB activity. Instead, DC-CIITA is transcriptionally a more potent activator of the MHC class II gene than the form expressed in B cells. A single amino acid substitution in the CARD of DC-CIITA, predicted to disrupt CARD-CARD interactions, diminished the transactivation potential of DC-CIITA. These results indicate that the CARD in the context of CIITA serves as a regulatory domain for transcriptional activity and may function to selectively enhance MHC class II gene expression in dendritic cells.

Defective beta-adrenergic receptor signaling precedes the development of dilated cardiomyopathy in transgenic mice with calsequestrin overexpression

Calsequestrin is a high capacity Ca(2+)-binding protein in the junctional sarcoplasmic reticulum that forms a quaternary complex with junctin, triadin, and the ryanodine receptor. Transgenic mice with cardiac-targeted calsequestrin overexpression show marked suppression of Ca(2+)-induced Ca(2+) release, myocyte hypertrophy, and premature death by 16 weeks of age (Jones, L. R., Suzuki, Y. J., Wang, W., Kobayashi, Y. M., Ramesh, V., Franzini-Armstrong, C., Cleemann, L., and Morad, M. (1998) J. Clin. Invest. 101, 1385-1393). To investigate whether alterations in intracellular Ca(2+) trigger changes in the beta-adrenergic receptor pathway, we studied calsequestrin overexpressing transgenic mice at 7 and 14 weeks of age. As assessed by echocardiography, calsequestrin mice at 7 weeks showed mild left ventricular enlargement, mild decreased fractional shortening with increased wall thickness. By 14 weeks, the phenotype progressed to marked left ventricular enlargement and severely depressed systolic function. Cardiac catheterization in calsequestrin mice revealed markedly impaired beta-adrenergic receptor responsiveness in both 7- and 14- week mice. Biochemical analysis in 7- and 14-week mice showed a significant decrease in total beta-adrenergic receptor density, adenylyl cyclase activity, and the percent high affinity agonist binding, which was associated with increased beta-adrenergic receptor kinase 1 levels. Taken together, these data indicate that alterations in beta-adrenergic receptor signaling precede the development of overt heart failure in this mouse model of progressive cardiomyopathy.

Enhanced contractility and decreased beta-adrenergic receptor kinase-1 in mice lacking endogenous norepinephrine and epinephrine

BACKGROUND

Elevated circulating norepinephrine (NE) has been implicated in causing the profound beta-adrenergic receptor (betaAR) downregulation and receptor uncoupling that are characteristic of end-stage human dilated cardiomyopathy, a process mediated in part by increased levels of beta-adrenergic receptor kinase (betaARK1). To explore whether chronic sustained NE stimulation is a primary stimulus that promotes deterioration in cardiac signaling, we characterized a gene-targeted mouse in which activation of the sympathetic nervous system cannot lead to an elevation in plasma NE and epinephrine.

METHODS AND RESULTS

Gene-targeted mice that lack dopamine beta-hydroxylase (dbh-/-), the enzyme needed to convert dopamine to NE, were created by homologous recombination. In vivo contractile response to the beta1AR agonist dobutamine, measured by a high-fidelity left ventricular micromanometer, was enhanced in mice lacking the dbh gene. In unloaded adult myocytes isolated from dbh-/- mice, basal contractility was significantly increased compared with control cells. Furthermore, the increase in betaAR responsiveness and enhanced cellular contractility were associated with a significant reduction in activity and protein level of betaARK1 and increased high-affinity agonist binding without changes in betaAR density or G-protein levels.

CONCLUSIONS

Mice that lack the ability to generate NE or epinephrine show increased contractility associated primarily with a decrease in the level of betaARK1 protein and kinase activity. This animal model will be valuable in testing whether NE is required for the pathogenesis of heart failure through mating strategies that cross the dbh-/- mouse into genetically engineered models of heart failure.

Transgenic mice with cardiac overexpression of alpha1B-adrenergic receptors. In vivo alpha1-adrenergic receptor-mediated regulation of beta-adrenergic signaling

Transgenic mice were generated with cardiac-specific overexpression of the wild-type (WT) alpha1B-adrenergic receptor (AR) using the murine alpha-myosin heavy chain gene promoter. Previously, we described transgenic mice with alpha-myosin heavy chain-directed expression of a constitutively active mutant alpha1B-AR that had a phenotype of myocardial hypertrophy (Milano, C. A., Dolber, P. C., Rockman, H. A., Bond, R. A., Venable M. E., Allen, L. F., and Lefkowitz, R. J. (1994) Proc. Natl. Acad. Sci. U. S. A. 91, 10109-10113). In animals with >40-fold WT alpha1-AR overexpression, basal myocardial diacylglycerol content was significantly increased, indicating enhanced alpha1-adrenergic signaling and phospholipase C activity. In contrast to the mice overexpressing constitutively active mutant alpha1B-ARs, the hearts of these mice did not develop cardiac hypertrophy despite an 8-fold increase in ventricular mRNA for atrial natriuretic factor. In vivo physiology was studied in anesthetized intact animals and showed left ventricular contractility in response to the beta-agonist isoproterenol to be significantly depressed in animals overexpressing WT alpha1B-ARs. Membranes purified from the hearts of WT alpha1BAR-overexpressing mice demonstrated significantly attenuated adenylyl cyclase activity basally and after stimulation with isoproterenol, norepinephrine, or phenylephrine. Interestingly, these in vitro changes in signaling were reversed after treating the mice with pertussis toxin, suggesting that the extraordinarily high levels of WT alpha1B-ARs can lead to coupling to pertussis toxin-sensitive G proteins. Another potential contributor to the observed decreased myocardial signaling and function could be enhanced beta-AR desensitization as beta-adrenergic receptor kinase (betaARK1) activity was found to be significantly elevated (>3-fold) in myocardial extracts isolated from WT alpha1B-AR-overexpressing mice. This type of altered signal transduction may become critical in disease conditions such as heart failure where betaARK1 levels are elevated and beta-ARs are down-regulated, leading to a higher percentage of cardiac alpha1-ARs. Thus, these mice serve as a unique experimental model to study the in vivo interactions between alpha- and beta-ARs in the heart.