Troponin elevation in patients with heart failure: on behalf of the third Universal Definition of Myocardial Infarction Global Task Force: Heart Failure Section

Cardiac troponin testing is commonly performed in patients with heart failure (HF). Despite being strongly linked to spontaneous (Type I) acute myocardial infarction (MI)-a common cause of acute HF syndromes-it is well recognized that concentrations of circulating troponins above the 99th percentile of a normal population in the context of both acute and chronic HF are highly prevalent, and frequently unrelated to Type I MI. Other mechanism(s) leading to troponin elevation in HF syndromes remain elusive in many cases but prominently includes supply-demand inequity (Type II MI), which may be associated with coronary artery obstruction and endothelial dysfunction, or may occur in the absence of coronary obstruction due to increased oxygen demand related to increased wall tension, anaemia, or other factors provoking subendocardial injury. Non-coronary triggers, such as cellular necrosis, apoptosis, or autophagy in the context of wall stress may explain the troponin release in HF, as can toxic effects of circulating neurohormones, toxins, inflammation, and infiltrative processes, among others. Nonetheless, across a wide spectrum of HF syndromes, when troponin elevation occurs, independent of mechanism, it is strongly predictive of an adverse outcome. Clinicians should be aware of the high frequency of troponin elevation when measuring the marker in patients with HF, should keep in mind the possible causes of this phenomenon, and, independent of a diagnosis of 'acute MI', should recognize the considerable ramifications of troponin elevation in this setting.     

Levosimendan: Molecular mechanisms and clinical implications: consensus of experts on the mechanisms of action of levosimendan

The molecular background of the Ca(2+)-sensitizing effect of levosimendan relates to its specific interaction with the Ca(2+)-sensor troponin C molecule in the cardiac myofilaments. Over the years, significant preclinical and clinical evidence has accumulated and revealed a variety of beneficial pleiotropic effects of levosimendan and of its long-lived metabolite, OR-1896. First of all, activation of ATP-sensitive sarcolemmal K(+) channels of smooth muscle cells appears as a powerful vasodilator mechanism. Additionally, activation of ATP-sensitive K(+) channels in the mitochondria potentially extends the range of cellular actions towards the modulation of mitochondrial ATP production and implicates a pharmacological mechanism for cardioprotection. Finally, it has become evident, that levosimendan possesses an isoform-selective phosphodiesterase-inhibitory effect. Interpretation of the complex mechanism of levosimendan action requires that all potential pharmacological interactions are analyzed carefully in the framework of the currently available evidence. These data indicate that the cardiovascular effects of levosimendan are exerted via more than an isolated drug-receptor interaction, and involve favorable energetic and neurohormonal changes that are unique in comparison to other types of inodilators.     

Expanded, but not regulated: ambiguity in home-care policy in Ireland

This article argues that home-care policy in Ireland was ambiguous throughout the first decade of the 21st century: policy-makers expanded home care, but failed to develop policies to govern this expanded provision. As a result, home care became more widely available in the absence of a framework to govern access to services and to regulate care providers. We analysed official policy documents, statistics and policy critiques published between 2000 and 2010 in order to understand this incongruity between the expansion of home-care services and the failure to develop policies to govern access to and quality of services. The key factors that motivated home-care expansion in the Irish case were: (1) problems in the acute hospital sector and the perception of home care as a partial solution to these (political blame avoidance) and (2) significant GDP growth (until 2007) that provided politicians with the means to fund expansion in home-care services (political credit claiming). The key factors that inhibited the development of a policy framework to govern home-care services were: (1) weak governance structures in health services and decision-making at national level based on short-term political gain; (2) Ireland's adherence to the liberal welfare state model and concern about uncontrollable care costs in the face of population ageing; (3) until 2010, paucity of attention to home-care issues in the Irish media and (4) weak provider interest representation. The recent budgetary cutbacks in Ireland bring into sharp relief the political expediency of an unregulated domiciliary care sector and absence of entitlements to home care. We conclude that the forces that drive expanded provision are different from drivers of policy to govern home care and that weakness of governance structures and political advantages of the absence of regulation are the main reasons for the lack of standards and entitlement rules.     

Laparoscopic Roux‐en‐Y gastric bypass surgery influenced pharmacokinetics of several drugs given as a cocktail with the highest impact observed for CYP1A2, CYP2C8 and CYP2E1 substrates

There is a lack of information about the changes in drug pharmacokinetics and cytochrome P450 (CYP) metabolism after bariatric surgery. Here, we investigated the effects of laparoscopic Roux‐en‐Y gastric bypass (LRYGB) surgery on pharmacokinetics of nine drugs given simultaneously which may reveal changes in the activities of the main CYPs. Eight obese subjects undergoing LRYGB received an oral cocktail containing nine drugs, substrates of various CYPs: melatonin (CYP1A2), nicotine (CYP2A6), bupropion (CYP2B6), repaglinide (CYP2C8), losartan (CYP2C9), omeprazole (CYP2C19/CYP3A4), dextromethorphan (CYP2D6), chlorzoxazone (CYP2E1) and midazolam (CYP3A). The 6‐hours pharmacokinetic profiles in serum and urine of each drug or corresponding metabolite as well as their metabolic ratios were compared before surgery with those at a median 1 year later. LRYGB exerted variable effects on the pharmacokinetics of these drugs. The geometric mean AUC_0‐6 (90% confidence interval) of melatonin, bupropion, repaglinide, chlorzoxazone and midazolam after LRYGB was 27 (19%‐41%), 54 (43%‐67%), 44 (29%‐66%), 160 (129%‐197%) and 74 (62%‐90%) of the pre‐surgery values, respectively. The pharmacokinetics of losartan, omeprazole and dextromethorphan did not change in response to surgery. Nicotine was not detected in serum, while geometric mean of AUC_0‐6 of its metabolite, cotinine, increased by 1.7 times after surgery. There were 3.6‐ and 1.3‐fold increases in the AUC ratios of 6‐hydroxymelatonin/melatonin and hydroxybupropion/bupropion, respectively. The cocktail revealed multiple pharmacokinetic changes occurring after LRYGB with the greatest effects observed for CYP1A2, CYP2C8 and CYP2E1 substrates. Future studies should be focused on CYP1A2, CYP2A6, CYP2C8 and CYP2B6 to clarify the changes in activities of these enzymes after LRYGB.