Different outcomes of a cardiac rehabilitation programme in functional parameters among myocardial infarction survivors according to ejection fraction.

INTRODUCTION: Exercise-based cardiac rehabilitation (EBCR) is part of the management of patients who have suffered an acute myocardial infarction (AMI). Patients with a reduced ejection fraction (EF) comprise a higher-risk subgroup and are referred less often for these programmes. This study aimed at assessing the impact of the baseline EF on the functional benefits, as assessed by peak oxygen uptake (pVO2) and exercise duration, of an EBCR programme in AMI survivors. METHODS: Observational, retrospective cohort study including all patients admitted to a tertiary centre due to an AMI who completed a phase II EBCR programme after discharge, between November 2012 and April 2017. Functional parameters were assessed by a symptom-limited cardiopulmonary exercise test. RESULTS: A total of 379 patients were included [40.9% with reduced EF (<50%) at discharge]. After the programme, pVO2 and exercise duration increased significantly (p < 0.001). Patients with a reduced EF had a lower pVO2 and completed a shorter duration of exercise at the beginning and end of the programme. This group presented a higher increase in pVO2 (p = 0.001) and exercise duration (p = 0.007). This was maintained after adjusting for age, gender, history of coronary artery disease, number of sessions, Killip classification, arterial hypertension, dyslipidaemia, diabetes mellitus, smoking status and baseline pVO2. CONCLUSION: A phase II EBCR programme was associated with significant improvements in pVO2 and exercise duration among AMI survivors, irrespective of baseline EF classification. Those with a reduced baseline EF derived an even greater improvement, highlighting the importance of EBCR in this subgroup of patients.

Effects of lipopolysaccharide on vascular reactivity and mortality in rats.

1 The effects of intraperitoneal (i.p.) lipopolysaccharide on vascular reactivity to noradrenaline in rat aorta under different conditions of passive tension, as well as on mortality in normotensive and hypertensive rats, were studied. 2 Concentration-response curves to noradrenaline were obtained in aorta rings, at two levels of passive tension: 3 and 0.5 g, from control and lipopolysaccharide-treated Wistar rats. Contractile responses were expressed as percentage of the maximal response to noradrenaline obtained in the beginning of the experiment at a resting tension of 2 g. The maxima were significantly larger (P<0.05) at 3 g than at 0.5 g in both groups of rats: 117.8 vs. 62.3%, respectively, for control animals; 85.8 vs. 32.5%, respectively, for lipopolysaccharide-treated rats. 3 The 24-h mortality after the i.p. administration of lipopolysaccharide was lower in spontaneously hypertensive rats (1/12; 8%), when compared with control Wistar-Kyoto rats (5/11; 45%). However, mortality was higher in Wistar-Kyoto made hypertensive by 8-day administration of corticosterone (6/6; 100%). 4 We conclude that a differential sensitivity to noradrenaline of aortic smooth muscle at two different levels of passive tension is still present in lipopolysaccharide-treated animals. Chronic hypertension in SHR rats is associated with resistance to the lethal effects of lipopolysaccharide, whereas abrupt-onset hypertension induced by corticosterone leads to an increased mortality. 5 These results are compatible with the myofibrillary hypothesis, which explains vascular hyper-reactivity in chronic arterial hypertension, by postulating that a more favourable relative position (and/or proportion) for actin and myosin occurs, whereas in states of vascular hyporeactivity, such as vasodilatory shock, the opposite phenomenon may exist.

Functional importance of the actin cytoskeleton in contraction of bovine iris sphincter muscle.

1. The contractile capacity of smooth muscle cells depends on the cytoskeletal framework of the cell. The aim of this study was to determine the functional importance of both the actin and the tubulin components of the cytoskeleton in contractile responses of the bovine isolated iris sphincter muscle. 2. In each preparation, two contractions to the muscarinic agonist carbachol were obtained. The maximum responses of the first contractions were taken as 100%. The second contractions to carbachol were elicited in the presence of either cytochalasin B (50 and 5 microm), an inhibitor of the actin cytoskeleton, or colchicine (100 microm), an inhibitor of the tubulin cytoskeleton (30 min incubation). 3. Cytochalasin B, at a concentration of 50 microm, significantly decreased the contractions induced by carbachol, with the maximum response reduced to 21.8 +/- 6.6% (n = 12) of the initial maximum. The maximal contractions to carbachol in the presence of colchicine reached 96.2 +/- 7.9% (n = 9) of the initial contraction, which was not significantly different from control second responses to carbachol with neither drug present, which reached 113.3 +/- 7.6% (n = 7). 4. The effect of cytochalasin B was dose-dependent, since at a lower concentration of 5 microm, the drug decreased the maximum contraction to carbachol to 60.3 +/- 8.8% (n = 6). The effect of cytochalasin B was at least partially reversible, since after the use of the higher concentration of 50 microm, contractions to carbachol increased to 62.3 +/- 15.5% (n = 4) of the maximal response, after 1 h repeated washing of the preparations. 5. Cytochalasin D, at a concentration of 50 microm, completely abolished the contractions induced by carbachol (n = 4). 6. These findings suggest that in bovine iris sphincter muscle, contractions to carbachol are highly dependent, from a functional point of view, on actin polymerization, and not, to any important degree, on the polymerization of tubulin.

Acute myocardial infarction associated to DPP-4 inhibitors.

INTRODUCTION: Diabetes mellitus is associated with cardiovascular disease. Anti-diabetic therapy has a limited capability (if any) of changing the incidence of either death or major cardiovascular disease, and cardiovascular safety concerns have been raised. We aimed at identifying episodes of acute myocardial infarction associated to a relatively new class of drugs, dipeptidyl peptidase-4 inhibitors. METHODS: Retrospective study: from 954 admissions (15 month period) in the coronary care unit, we selected 200 admissions corresponding to 196 patients with myocardial infarction and diabetes. 35 of these patients were receiving therapy with dipeptidyl peptidase-4 inhibitors (the vast majority, in association to metformin). We evaluated the peak plasma cardiac troponin I as the main study parameter. RESULTS: Patients on dipeptidyl peptidase-4 inhibitors therapy had a mean peak cardiac troponin plasma level of 50.2±121.3 ng/ml (n=35), the corresponding value for insulin being 39.2±108.4 ng/ml (n=56), for metformin the value was 45.8±97.3 ng/ml (n=93) and for sulfonylureas, 42.4±77.7 ng/ml (n=52). None of these values differed significantly from the corresponding control group of patients not taking each class of drug. The linear regression study also yielded a negative result relating therapy with dipeptidyl peptidase-4 inhibitors and peak troponin values. Acute myocardial infarctions associated to dipeptidyl peptidase-4 inhibitors varied widely in the clinical characteristics of the patients. CONCLUSIONS: We found no evidence that peak plasma troponin I was different between patient with acute myocardial infarction and use of dipeptidyl peptidase-4 inhibitors when compared to cases not under such therapy.

High-sensitivity troponin after running--a systematic review.

A systematic review was carried out to study the pattern of high-sensitivity cardiac troponin release after running (search performed on PubMed, ISI Web of Knowledge and Scopus databases). A total of ten reports were identified as meeting the pre-specified criteria (eight using high-sensitivity troponin T and two using high-sensitivity troponin I). The papers were published between 2009 and 2013, amounting to a total of 479 participants under study. Eight reports provided data comparing post-running troponin levels with the 99th percentile reference value. A total number of 296 participants, out of 424, showed post-running high-sensitivity troponin values higher than the 99th percentile reference value (69.8%). In conclusion, using high-sensitivity cardiac troponin assays, studies have shown that elevated post-running values are seen in more than two-thirds of runners. Whether troponin release in this setting represents a fully reversible phenomenon is currently unknown; the effects of strenuous running on long-term health are also uncertain.

Systematic review and meta-analysis of clinical trials of the effects of low carbohydrate diets on cardiovascular risk factors.

A systematic review and meta-analysis were carried out to study the effects of low-carbohydrate diet (LCD) on weight loss and cardiovascular risk factors (search performed on PubMed, Cochrane Central Register of Controlled Trials and Scopus databases). A total of 23 reports, corresponding to 17 clinical investigations, were identified as meeting the pre-specified criteria. Meta-analysis carried out on data obtained in 1,141 obese patients, showed the LCD to be associated with significant decreases in body weight (-7.04 kg [95% CI -7.20/-6.88]), body mass index (-2.09 kg m(-2) [95% CI -2.15/-2.04]), abdominal circumference (-5.74 cm [95% CI -6.07/-5.41]), systolic blood pressure (-4.81 mm Hg [95% CI -5.33/-4.29]), diastolic blood pressure (-3.10 mm Hg [95% CI -3.45/-2.74]), plasma triglycerides (-29.71 mg dL(-1) [95% CI -31.99/-27.44]), fasting plasma glucose (-1.05 mg dL(-1) [95% CI -1.67/-0.44]), glycated haemoglobin (-0.21% [95% CI -0.24/-0.18]), plasma insulin (-2.24 micro IU mL(-1) [95% CI -2.65/-1.82]) and plasma C-reactive protein, as well as an increase in high-density lipoprotein cholesterol (1.73 mg dL(-1) [95%CI 1.44/2.01]). Low-density lipoprotein cholesterol and creatinine did not change significantly, whereas limited data exist concerning plasma uric acid. LCD was shown to have favourable effects on body weight and major cardiovascular risk factors; however the effects on long-term health are unknown.

Prognostic value of cardiac troponin I in patients with COPD acute exacerbation.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is frequently associated with right ventricular loading and pulmonary hypertension. We aimed to evaluate a possible association between cardiac troponin I (cTnI) levels and adverse events in hospitalised patients with acute exacerbation of COPD . METHODS: Retrospective cohort study, with analysis of admissions for acute exacerbation of COPD , with cTnI obtained in the first 48 hours of admission. A positive cTnI test was defined as 0.012 ng/ml or higher (99th percentile). Baseline and peak troponin I levels were taken as independent variables, and outcome variables included length of hospital stay, complications during hospitalisation, and in-hospital and extra-hospital mortality (evaluated 18 months post-discharge). RESULTS: Data concerned 173 patients (105 male, 68 female), with a median age of 77 years (interquartile range of 11 years). The median baseline cTnI was 0.030 ng/ml (n=173), and the median peak cTnI was 0.040 ng/ml (n=173; absolute peak value of 1.260 ng/ml). Nearly 70% of cases had a positive cTnI at admission. Both baseline and peak cTnI correlated significantly with the need for noninvasive ventilatory support. We were not able to find significant differences in in-hospital survival associated with the two troponin groups, but overall 18-month survival was significantly higher among patients with lower values of baseline and peak cTnI. CONCLUSIONS: In patients hospitalised for acute COPD exacerbations, elevated baseline and peak cTnI were associated with a greater need for noninvasive ventilatory support and were significant predictors of 18-month overall survival.