3 SAFETY OF NOVEL ORAL ANTICOAGULANTS COMPARED TO VITAMIN K ANTAGONISTS IN THE TREATMENT OF VENOUS THROMBOEMBOLISM: A SYSTEMATIC REVIEW AND META-ANALYSIS

Background

Individual randomized controlled trials (RCTs) enrolling patients with venous thromboembolism (VTE) have demonstrated that novel oral anticoagulants (NOACs) are comparable to vitamin K antagonists (VKAs) in reducing the risk of recurrent VTE but hold a safer bleeding profile. Nonetheless, pooled data from RCTs on the safety of NOACs versus VKAs in patients with VTE are still scarce.

Purpose

We aimed to compare the effect of NOACs versus VKA on the risk of fatal bleeding, major bleeding, clinically relevant non-major bleeding (CRNMB) and any bleeding in patients with VTE through a meta-analysis of RCTs.

Methods

We performed a systematic review of the literature, from January 1970 to December 2021, using PubMed database with four independent reviewers (L.R.; G.M.; V.C.; F.G.). Discrepancies were solved by consensus with a senior researcher (D.M.). Phase 3 randomized controlled trials comparing NOACs versus VKAs, either as an acute treatment or as an extended therapy, in patients with pulmonary embolism or deep vein thrombosis were selected. We performed a meta-analysis using a random-effects model with the Mantel–Haenszel method for each safety endpoint. Study outcomes were expressed as odd ratios (OR) with 95% confidence interval (CI) and illustrated in a Forest plot diagram. A two-sided p-value <0.05 was considered statistically significant. Heterogeneity was tested using the I2-statistic.

Results

Seven trials were included (n=29,879 patients), either investigating the direct thrombin inhibitor dabigatran (RE-COVER, RE-COVER II and RESONATE trials) or the factor Xa inhibitors rivaroxaban (EINSTEIN-DVT and EINSTEIN-PE studies), apixaban (AMPLIFY study) and edoxaban (Hokusai-VTE study). Compared to VKAs, treatment with NOACs was associated with lower risk of fatal bleeding (OR 0.35; 95% CI 0.16-0.81), major bleeding (OR 0.60; 95% CI 0.45-0.80), and any bleeding (OR 0.62; 95% CI 0.54-0.72) - fig. 1. There was no significant difference between the two groups concerning the risk of CRNMB.

Conclusions

In patients with VTE, treatment with NOACs was associated with fewer bleeding complications compared with VKAs.

Comparison of the efficacy and safety between different oral P2Y12 receptor inhibitors in patients with acute coronary syndrome: a systematic review and meta-analysis

Introduction

Dual antiplatelet therapy (DAPT) with aspirin and a P2Y12 receptor inhibitor for at least 1 month is the mainstay of therapy after an acute coronary syndrome (ACS). Despite several randomized controlled trials (RCTs) having compared different DAPT regimens after an ACS, the choice of the optimal P2Y12 receptor inhibitor is still debated.

Purpose

We aimed to compare the efficacy and safety profiles of the new P2Y12 receptor inhibitors (prasugrel and ticagrelor) versus clopidogrel in patients with ACS through a meta-analysis of RCTs.

Methods

We performed an extensive literature search, from January 1970 to December 2021 using PubMed database. Studies were eligible if they were RCTs directly comparing different oral P2Y12 receptor inhibitors in patients with ACS. Data on study methods, patient characteristics, and outcomes of interest (all-cause and cardiovascular death, recurrent myocardial infarction, stroke, major and non-major bleeding) were extracted from the original publications. We performed a meta-analysis using a random-effects model with the Mantel–Haenszel method. The effect measures of each study included were calculated and reported as odds ratio (OR) with 95% confidence interval (CI), visually presented in forest plots. A two-sided p-value <0.05 was considered statistically significant. Heterogeneity was tested using the I2-statistic.

Results

A total of 117 studies were available for the analysis; after full reading 11 studies were eligible to be analyzed. The 11 studies reported data on 50,722 patients: 25,424 [50.1%] taking a new oral P2Y12 receptor inhibitor and 25,298 [49.9%] taking clopidogrel. Patients receiving ticagrelor or prasugrel showed a lower risk of all-cause mortality (OR 0.88, 95% confidence interval [CI] 0.80–0.97, I2=8%), cardiovascular mortality (OR 0.88, 95% CI 0.81–0.95, I2=0%), and recurrent myocardial infarction (OR 0.86, 95% CI 0.76–0.97, I2=43%) compared to those receiving clopidogrel. The two groups did not differ significantly concerning the risk of stroke (OR 0.98, 95% CI 0.82–1.17, I2=0%), major bleeding (OR 1.05, 95% CI 0.97–1.15, I2=0%), or non-major bleeding (OR 1.36, 95% CI 0.85–2.20, I2=67%). By restricting the analysis to the studies comparing ticagrelor versus clopidogrel, the ticagrelor group showed a lower risk of all-cause mortality (OR 0.79, 95% CI 0.70–0.90, I2=0%), but a higher risk of non-major bleeding (OR 1.67, 95% CI 1.05–2.66, I2=30%). There was no significant difference between ticagrelor and clopidogrel in terms of cardiovascular death (OR 0.87, 95% CI 0.73–1.05, I2=0%), stroke (OR 1.06, 95% CI 0.85–1.13, I2=0%), or major bleeding (OR 1.02, 95% CI 0.93–1.12, I2=0%).

Conclusions

In patients with an ACS, a DAPT strategy with aspirin plus either prasugrel or ticagrelor is associated with a reduced risk of all-cause and cardiovascular mortality as well as of recurrent myocardial infarction compared to aspirin plus clopidogrel, without an increased risk of bleeding.

Funding Acknowledgement

Type of funding sources: None.

Mitochondrial DNA integrity and function are critical for endothelium-dependent vasodilation in rats with metabolic syndrome

Endothelial dysfunction in diabetes is generally attributed to oxidative stress, but this view is challenged by observations showing antioxidants do not eliminate diabetic vasculopathy. As an alternative to oxidative stress-induced dysfunction, we interrogated if impaired mitochondrial function in endothelial cells is central to endothelial dysfunction in the metabolic syndrome. We observed reduced coronary arteriolar vasodilation to the endothelium-dependent dilator, acetylcholine (Ach), in Zucker Obese Fatty rats (ZOF, 34 ± 15% [mean ± standard deviation] 10^-3 M) compared to Zucker Lean rats (ZLN, 98 ± 11%). This reduction in dilation occurred concomitantly with mitochondrial DNA (mtDNA) strand lesions and reduced mitochondrial complex activities in the endothelium of ZOF versus ZLN. To demonstrate endothelial dysfunction is linked to impaired mitochondrial function, administration of a cell-permeable, mitochondria-directed endonuclease (mt-tat-EndoIII), to repair oxidatively modified DNA in ZOF, restored mitochondrial function and vasodilation to Ach (94 ± 13%). Conversely, administration of a cell-permeable, mitochondria-directed exonuclease (mt-tat-ExoIII) produced mtDNA strand breaks in ZLN, reduced mitochondrial complex activities and vasodilation to Ach in ZLN (42 ± 16%). To demonstrate that mitochondrial function is central to endothelium-dependent vasodilation, we introduced (via electroporation) liver mitochondria (from ZLN) into the endothelium of a mesenteric vessel from ZOF and restored endothelium-dependent dilation to vasoactive intestinal peptide (VIP at 10^-5 M, 4 ± 3% vasodilation before mitochondrial transfer and 48 ± 36% after transfer). Finally, to demonstrate mitochondrial function is key to endothelium-dependent dilation, we administered oligomycin (mitochondrial ATP synthase inhibitor) and observed a reduction in endothelium-dependent dilation. We conclude that mitochondrial function is critical for endothelium-dependent vasodilation.

160 The obesity paradox in atrial fibrillation

Aims

The World Health Organization (WHO) defines obesity as a body mass index (BMI) of ≥ 30 kg/m2. Obesity has been established as an independent risk factor for new-onset atrial fibrillation (AF). Despite the association between obesity and major cardiovascular risk factors and outcomes, some studies showed that obesity may have a protective effect on AF-related outcomes, leading to the controversial concept of the ‘obesity paradox’. We carried out a systematic review to explore the ‘obesity paradox’, providing an overview of the randomized controlled trials (RCTs) and the impact of BMI on AF-related outcomes.

Methods and results

We performed an extensive literature search, from 2000 up to 2021, using the PubMed database, with two independent reviewers (M. F. and F.G.). Discrepancies were resolved by consensus with a senior researcher (D.M.). Studies were eligible if they were RCTs and included outcome comparisons (cardiovascular death, all death, stroke, and major bleeding) with allocation to BMI. We excluded from the analysis trials in which the number of events was not reported. The effect measures of each included study were calculated and reported as hazard ratio (HR) with 95% confidence interval (CI), visually presented in forest plots. A total of 683 studies were available for the analysis; 74 records were included after reading the title; after full reading 8 studies were eligible to be analysed. The meta-analysis of the eight selected randomized controlled clinical trials demonstrated a significantly lower risk of stroke or systemic embolism and all causes of death in obese patient (Figures 1 and 2). A meta-analysis on cardiovascular mortality was not conducted because this was reported only for three trials.

Conclusions

This meta-analysis demonstrated lower stroke and death risk with increasing BMI. Our meta-analysis included only data from RCTs. Observational studies rendered more conflicting results. Because of the few studies included, these apparently protective effects of obesity on the risk of stroke in patients with atrial fibrillation should still be interpreted with caution.

76 Pre-treatment high-sensitivity troponin T for the short-term prediction of cardiac outcomes in patients on immune checkpoint inhibitors

Aims

Immune checkpoint inhibitors (ICIs) are an emerging option for several advanced metastatic cancers, but have been associated with cardiotoxicity. The prognostic value of high-sensitivity troponin T (hs-TnT) measured before treatment start has never been investigated.

Methods and results

Thirty consecutive patients underwent measurement of hs-TnT before starting ICI therapy (pembrolizumab, 23%; nivolumab, 12%; atezolizumab, 6%; durvalumab, 5%). The primary endpoint was a composite of cardiovascular death, stroke or transient ischaemic attack, pulmonary embolism and new-onset heart failure. The secondary endpoint was progression of cardiac involvement according to the CARDIOTOX staging system. Patients (median age 68 years, 77% men, 13% with coronary artery disease, 90% current or former smokers, 67% overweight or obese, and 43% hypertensive) had a median hs-TnT of 12 ng/L (interquartile interval 8-23). At the 3-month timepoint, 7 patients (23%) had experienced the primary endpoint, and 13 (43%) the secondary endpoint. Area under the curve values were 0.909 for the primary, and 0.757 for the secondary endpoint. The best troponin-T cut-off was 14 ng/L for both the primary (100% sensitivity, 73% specificity) and secondary endpoint (sensitivity 75%, specificity 77%). Over a median follow-up duration of 2.6 months (2.0-3.6), survival free from the primary endpoint was shorter in patients with hs-TnT ≥14 ng/L (Log-rank: 10.3, p = 0.001), and all patients developing the primary endpoint had hs-TnT ≥14 ng/L at baseline.

Conclusion

In patients on ICIs, baseline hs-TnT predicts a composite cardiovascular endpoint and the progression of cardiac involvement at 3 months, with 14 ng/L as the best cut-off.

Echo-derived peak cardiac power output-to-left ventricular mass with cardiopulmonary exercise testing predicts outcome in patients with heart failure and depressed systolic function

AIMS

Peak cardiac power output-to-mass (CPOM) represents a measure of the rate at which cardiac work is delivered respect to the potential energy stored in left ventricular (LV) mass. We studied the value of CPOM and cardiopulmonary exercise test (CPET) in risk stratification of patients with heart failure (HF).

MATERIALS AND RESULTS

We studied 159 patients with chronic HF (mean rest LV ejection fraction 30%) undergoing CPET and exercise stress echocardiography. CPOM was calculated as the product of a constant (K = 2.22 × 10-1) with cardiac output (CO) and the mean blood pressure (MBP), divided by LV mass (M), and expressed in the unit of W/100 g: CPOM = [K × CO (L/min) × MBP (mmHg)]/LVM(g). Patients were followed-up for the primary endpoint, including all-cause death, ventricular assist device implantation, and heart transplantation, and the secondary endpoint that comprised hospitalization for HF. In multivariate Cox regression analyses, peak CPOM was selected as the most powerful independent predictor of both primary and secondary endpoint [hazard ratio (HR) 0.004, 95% confidence interval (CI) 0.004-0.3; P = 0.002 and HR 0.09, 95% CI 0.02-0.55; P = 0.009]. Sixty-month survival free from the combined endpoint was 85% in those exhibiting oxygen consumption (VO2) > 14 mL/min/kg and peak CPOM > 0.6 W/100 g. Peak VO2 ≤ 14 mL/min/kg provided incremental prognostic value over demographic and clinical variables, brain natriuretic peptide, and resting echocardiographic parameters (χ2 from 58 to 64; P = 0.04), that was further increased by peak CPOM ≤ 0.6 W/100 g (χ2 77; P < 0.001).

CONCLUSION

Peak CPOM and peak VO2 showed independent and incremental prognostic values in patients with chronic HF.

Myocardial ischemia: From disease to syndrome

Although current guidelines on the management of stable coronary artery disease acknowledge that multiple mechanisms may precipitate myocardial ischemia, recommended diagnostic, prognostic and therapeutic algorithms are still focused on obstructive epicardial atherosclerotic lesions, and little progress has been made in identifying management strategies for non-atherosclerotic causes of myocardial ischemia. The purpose of this consensus paper is three-fold: 1) to marshal scientific evidence that obstructive atherosclerosis can co-exist with other mechanisms of ischemic heart disease (IHD); 2) to explore how the awareness of multiple precipitating mechanisms could impact on pre-test probability, provocative test results and treatment strategies; and 3) to stimulate a more comprehensive approach to chronic myocardial ischemic syndromes, consistent with the new understanding of this condition.

Trimetazidine and Other Metabolic Modifiers

Treatment goals for people with chronic angina should focus on the relief of symptoms and improving mortality rates so the patient can feel better and live longer. The traditional haemodynamic approach to ischaemic heart disease was based on the assumption that increasing oxygen supply and decreasing oxygen demand would improve symptoms. However, data from clinical trials, show that about one third of people continue to have angina despite a successful percutaneous coronary intervention and medical therapy. Moreover, several trials on chronic stable angina therapy and revascularisation have failed to show benefits in terms of primary outcome (survival, cardiovascular death, all-cause mortality), symptom relief or echocardiographic parameters. Failure to significantly improve quality of life and prognosis may be attributed in part to a limited understanding of ischaemic heart disease, by neglecting the fact that ischaemia is a metabolic disorder. Shifting cardiac metabolism from free fatty acids towards glucose is a promising approach for the treatment of patients with stable angina, independent of the underlying disease (macrovascular and/or microvascular disease). Cardiac metabolic modulators open the way to a greater understanding of ischaemic heart disease and its common clinical manifestations as an energetic disorder rather than an imbalance between the demand and supply of oxygen and metabolites.

Impaired coronary metabolic dilation in the metabolic syndrome is linked to mitochondrial dysfunction and mitochondrial DNA damage

Mitochondrial dysfunction in obesity and diabetes can be caused by excessive production of free radicals, which can damage mitochondrial DNA. Because mitochondrial DNA plays a key role in the production of ATP necessary for cardiac work, we hypothesized that mitochondrial dysfunction, induced by mitochondrial DNA damage, uncouples coronary blood flow from cardiac work. Myocardial blood flow (contrast echocardiography) was measured in Zucker lean (ZLN) and obese fatty (ZOF) rats during increased cardiac metabolism (product of heart rate and arterial pressure, i.v. norepinephrine). In ZLN increased metabolism augmented coronary blood flow, but in ZOF metabolic hyperemia was attenuated. Mitochondrial respiration was impaired and ROS production was greater in ZOF than ZLN. These were associated with mitochondrial DNA (mtDNA) damage in ZOF. To determine if coronary metabolic dilation, the hyperemic response induced by heightened cardiac metabolism, is linked to mitochondrial function we introduced recombinant proteins (intravenously or intraperitoneally) in ZLN and ZOF to fragment or repair mtDNA, respectively. Repair of mtDNA damage restored mitochondrial function and metabolic dilation, and reduced ROS production in ZOF; whereas induction of mtDNA damage in ZLN reduced mitochondrial function, increased ROS production, and attenuated metabolic dilation. Adequate metabolic dilation was also associated with the extracellular release of ADP, ATP, and H2O2 by cardiac myocytes; whereas myocytes from rats with impaired dilation released only H2O2. In conclusion, our results suggest that mitochondrial function plays a seminal role in connecting myocardial blood flow to metabolism, and integrity of mtDNA is central to this process.

Prediction of Post Percutaneous Coronary Intervention Myocardial Ischaemia

Following revascularisation the majority of patients obtain symptom relief and improved quality of life. However, myocardial ischaemia may recur or persist in a significant patient subset. Symptom recurrence is usually attributed to inaccurate evaluation of epicardial stenosis, incomplete revascularisation or stent failure and disease progression. However, technological advances with modern imaging and/or physiological evaluation of epicardial plaques have not solved this issue. Conversely, recent clinical studies have shown that abnormal coronary vasomotion and increased myocardial resistance are frequent determinants of post-percutaneous coronary intervention (PCI) myocardial ischaemia. Strategies to enhance prediction of post-PCI angina include proper selection of patients undergoing revascularisation, construction of clinical prediction models, and further invasive evaluation at the time of coronary angiography in those with high likelihood.

Stress Testing After Complete and Successful Coronary Revascularization

BACKGROUND

Noninvasive stress tests play a determinant role in the initial management of patients with chronic angina. Nonetheless, their use in the same patient population is considered inappropriate within 2 years after percutaneous coronary intervention (PCI). Indeed, early abnormal results correlate less well with angiographic control and are attributed to a number of confounding factors. We prospectively assessed prevalence and impact on the quality of life of abnormal stress test results in a highly selected patient population.

METHODS

Patients with no cardiac comorbidities who underwent successful and complete PCI with stenting for typical angina and had an abnormal exercise stress test (EST) under guideline-directed medical treatment were administered the Seattle Angina Questionnaire (SAQ). Clinical evaluation, EST, and the SAQ were repeated at 1, 6, and 12 months after the index PCI.

RESULTS

One hundred ninety-eight patients qualified and were included in the study (mean age, 64 years; 79% men). Although the majority had normal EST results or an increased threshold to angina, at 1 month after the index PCI, 29% of patients still had an abnormal result. At 6 and 12 months, 31% and 29% of patients had abnormal results, respectively. Quality-of-life assessment by the SAQ showed consistent results, with persistent angina in one third of patients. Control angiography documented a critical lesion, attributable to in-stent coronary restenosis, in only 8% of patients.

CONCLUSIONS

When stress testing is systematically performed after PCI, the prevalence of abnormal results is high and is associated with impaired quality of life. Prognostic significance along with the underlying pathophysiological mechanisms of such findings should be investigated.

BCNU-induced gR2 defect mediates S-glutathionylation of Complex I and respiratory uncoupling in myocardium

A deficiency of mitochondrial glutathione reductase (or GR2) is capable of adversely affecting the reduction of GSSG and increasing mitochondrial oxidative stress. BCNU [1,3-bis (2-chloroethyl)-1-nitrosourea] is an anticancer agent and known inhibitor of cytosolic GR ex vivo and in vivo. Here we tested the hypothesis that a BCNU-induced GR2 defect contributes to mitochondrial dysfunction and subsequent impairment of heart function. Intraperitoneal administration of BCNU (40 mg/kg) specifically inhibited GR2 activity by 79.8 ± 2.7% in the mitochondria of rat heart. However, BCNU treatment modestly enhanced the activities of mitochondrial Complex I and other ETC components. The cardiac function of BCNU-treated rats was analyzed by echocardiography, revealing a systolic dysfunction associated with decreased ejection fraction, decreased cardiac output, and an increase in left ventricular internal dimension and left ventricular volume in systole. The respiratory control index of isolated mitochondria from the myocardium was moderately decreased after BCNU treatment, whereas NADH-linked uncoupling of oxygen consumption was significantly enhanced. Extracellular flux analysis to measure the fatty acid oxidation of myocytes indicated a 20% enhancement after BCNU treatment. When the mitochondria were immunoblotted with antibodies against GSH and UCP3, both protein S-glutathionylation of Complex I and expression of UCP3 were significantly up-regulated. Overexpression of SOD2 in the myocardium significantly reversed BCNU-induced GR2 inhibition and mitochondrial impairment. In conclusion, BCNU-mediated cardiotoxicity is characterized by the GR2 deficiency that negatively regulates heart function by impairing mitochondrial integrity, increasing oxidative stress with Complex I S-glutathionylation, and enhancing uncoupling of mitochondrial respiration.

Microvascular function/dysfunction downstream a coronary stenosis

For decades coronary macrovascular atherosclerosis has been considered the principal manifestation of coronary heart disease, with most of our effort dedicated to identifying and removal of coronary stenosis. However, growing body of literature indicates that coronary microcirculation also contributes substantially to the pathophysiology of cardiovascular disease. An understanding of mechanisms regulating microvascular function is of critical importance in understanding its role in disease, especially because these regulatory mechanisms vary substantially across species, vascular bed and due to comorbidities. Indeed, the most obvious consequence of coronary stenosis is that it may limit blood supply to the dependent myocardium to the point of causing ischaemia during exercise or even at rest. However, this flow limiting effect is not only due to the passive hydraulic effect of a narrowed conduit, but also to active responses in the coronary microcirculation triggered by the presence of an epicardial stenosis. To understand this problem it is important to review the inter-related mechanisms that regulate flow to the left ventricular wall and modulate transmural distribution of flow. These regulatory mechanisms operate hierarchically and are heterogeneously distributed along the coronary vascular tree. It is also important to discuss the effect of myocardial performance in modulating both blood flow demands and coronary resistance. Some of the interactions between coronary stenosis and microcirculation are transient, like those documented in acute coronary syndromes or during percutaneous interventions. However, microcirculatory remodeling may be triggered by a chronic coronary stenosis, leading to a sustained impairment of blood supply even after successful removal of the epicardial stenosis. A deeper understanding of these phenomena may explain paradoxical findings in patients undergoing coronary revascularization, particularly when functional tests are used in their assessment. These aspects are discussed in detail in this review.

Defining the role of high-dose statins in PCI

Several studies have reported a significant reduction in morbidity and mortality in patients with acute coronary syndrome (ACS) or in patients with stable ischemic heart disease with the use of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins). Based on these findings, current guidelines recommend the use of statin therapy before hospital discharge for all patients with ACS regardless of the baseline low-density lipoprotein level. Statins are also recommended to patients at high risk for cardiovascular disease. Statins have been introduced in the clinical arena to reduce the low-density lipoprotein (LDL) cholesterol level that is associated with coronary atherosclerosis; however, a growing body of evidence suggests that other mechanisms of action beyond the modification of the lipid profile may come into action. In particular, statins exert antiinflammatory effects, modulate endothelial function, and inhibit the thrombotic signaling cascade. All together the non-LDL cholesterol-lowering effects of statins are called pleiotropic effects. In this article we will review the evidence supporting the use of high-dose statins in patients undergoing percutaneous coronary intervention, and we will also attempt to highlight the possible mechanisms of action.

Ultrasound assessment of the force-frequency relationship from the law of conservation of momentum in patients with left ventricular dysfunction

Measurement of force-frequency relationship (FFR) is useful in the evaluation of heart rate-dependent contractile dysfunction. The purpose of this study was to evaluate a new Doppler-derived method for assessing FFR. Doppler velocity spectra at the left ventricular (LV) outflow tract was used to estimate mean blood flow velocity (mBFV), ejection time (ET) and velocity-time integral. LV ejection force (LVF) was then calculated according to the law of conservation of momentum: 1060 kg/m³ × (mBFV[m/sec]/ET [s]) × Stroke volume (mL). A symptom-limited, graded, bicycle semi-supine exercise test was performed in 56 patients with LV dysfunction (LV ejection fraction = 27 ± 6%). Measurements were obtained at baseline and serially during the test. The change in FFR was defined as up-sloping when the peak LVF was higher than the baseline value. The change was biphasic when the trend was initially up-sloping, then down-sloping; it was flat or negative when peak LVF was less than the baseline value. LVF was 30 ± 12 mN in patients with up-sloping FFR (n = 39) and 15 ± 6 mN in those with biphasic or flat FFR (n = 17; p < 0.0001). The ultrasound assessment of the FFR was highly concordant with a previously validated method based on pressure-end-systolic volume index ratio (κ = 0.75; 95% confidence interval, 0.55-94.0). The evaluation of the LVF using Doppler is an alternative method for the assessment of FFR during stress echocardiography in patients with LV dysfunction.

The second law of thermodynamics and the heart

The second law of thermodynamics explains the phenomenon of irreversibility and the increasing entropic trend of nature. Similar to human-made machines, living structures are subjected to entropy generation, becoming ‘worn’ and ‘damaged’ from use. However, they have the possibility of eluding or deferring these processes. According to nonequilibrium thermodynamics, the heart could be considered as an open dissipative system, since it has the potential to offset the body’s increasing entropic burden by using energy to export entropy to the surroundings. By organizing the tissues’ molecules in order to perform external work as a result of its ability to provide oxygen and nutrients and remove waste products, the heart maintains the organization of the living structure and acts as an open dissipative system. However, the increase in tissues’ randomness and disorder as a result of a number of disease states may be responsible for the intervening cardiac damage and entropy generation. This effect is known as the ‘Dorian Gray effect’ of the heart. Technical advances, including MRI and 3D echocardiography, may provide a means to improve the understanding of thermodynamic aspects of cardiovascular physiology and heart disease.

Right ventricular dysfunction is associated with chronic kidney disease and predicts survival in patients with chronic systolic heart failure

AIMS

Chronic kidney disease (CKD) and right ventricular (RV) dysfunction are important predictors of prognosis in heart failure (HF). We investigated the relationship between RV dysfunction and CKD in outpatients with chronic systolic HF, an association which remains poorly defined.

METHODS AND RESULTS

Outpatients (n = 373) with chronic HF and left ventricular ejection fraction (LVEF) ≤45% underwent clinical and echo-Doppler evaluations and were followed up for 31 ± 24 months. Tricuspid annular plane systolic excursion (TAPSE) assessed RV dysfunction. The estimated glomerular filtration rate (GFR) was measured by the simplified Modification of Diet in Renal Disease (MDRD) formula. Correlation analysis was used to characterize the association between TAPSE and estimated GFR. Odds ratios (ORs) for CKD and hazard ratios (HRs) for all-cause mortality were assessed using multivariable logistic or proportional hazards regression models. TAPSE and estimated GFR were significantly correlated (r = 0.38, P < 0.0001). TAPSE ≤14 mm was associated with elevated estimated right atrial pressure and N-terminal pro brain natriuretic peptide levels. TAPSE ≤14 mm increased the odds of estimated GFR <60 mL/min/1.73 m(2), OR [95% confidence interval (CI)] = 2.51(1.44-4.39), P < 0.0001 and predicted all-cause mortality, HR (95% CI) = 1.80 (1.20-2.71) after multivariable adjustment.

CONCLUSIONS

Right ventricular dysfunction is cross-sectionally associated with CKD and prospectively predicts survival in outpatients with chronic systolic HF. These data suggest RV dysfunction to be one of the possible mechanistic links between HF and CKD.

Disruption of TRPV1-mediated coupling of coronary blood flow to cardiac metabolism in diabetic mice: role of nitric oxide and BK channels

We have previously shown transient receptor potential vanilloid subtype 1 (TRPV1) channel-dependent coronary function is compromised in pigs with metabolic syndrome (MetS). However, the mechanisms through which TRPV1 channels couple coronary blood flow to metabolism are not fully understood. We employed mice lacking TRPV1 [TRPV1((-/-))], db/db diabetic, and control C57BKS/J mice to determine the extent to which TRPV1 channels modulate coronary function and contribute to vascular dysfunction in diabetic cardiomyopathy. Animals were subjected to in vivo infusion of the TRPV1 agonist capsaicin to examine the hemodynamic actions of TRPV1 activation. Capsaicin (1-100 μg·kg(-1)·min(-1)) dose dependently increased coronary blood flow in control mice, which was inhibited by the TRPV1 antagonist capsazepine or the nitric oxide synthase (NOS) inhibitor N-nitro-l-arginine methyl ester (L-NAME). In addition, the capsaicin-mediated increase in blood flow was attenuated in db/db mice. TRPV1((-/-)) mice exhibited no changes in coronary blood flow in response to capsaicin. Vasoreactivity studies in isolated pressurized mouse coronary microvessels revealed a capsaicin-dependent relaxation that was inhibited by the TRPV1 inhibitor SB366791 l-NAME and to the large conductance calcium-sensitive potassium channel (BK) inhibitors iberiotoxin and Penetrim A. Similar to in vivo responses, capsaicin-mediated relaxation was impaired in db/db mice compared with controls. Changes in pH (pH 7.4-6.0) relaxed coronary vessels contracted to the thromboxane mimetic U46619 in all three groups of mice; however, pH-mediated relaxation was blunted in vessels obtained from TRPV1((-/-)) and db/db mice compared with controls. Western blot analysis revealed decreased myocardial TRPV1 protein expression in db/db mice compared with controls. Our data reveal TRPV1 channels mediate coupling of myocardial blood flow to cardiac metabolism via a nitric oxide-dependent, BK channel-dependent pathway that is corrupted in diabetes.

Resolution of mitochondrial oxidative stress rescues coronary collateral growth in Zucker obese fatty rats

OBJECTIVE

We have previously found abrogated ischemia-induced coronary collateral growth in Zucker obese fatty (ZOF) rats compared with Zucker lean (ZLN) rats. Because ZOF rats have structural abnormalities in their mitochondria suggesting dysfunction and also show increased production of O(2), we hypothesized that mitochondrial dysfunction caused by oxidative stress impairs coronary collateral growth in ZOF.

METHODS AND RESULTS

Increased levels of reactive oxygen species were observed in aortic endothelium and smooth muscle cells in ZOF rats compared with ZLN rats. Reactive oxygen species levels were decreased by the mitochondria-targeted antioxidants MitoQuinone (MQ) and MitoTempol (MT) as assessed by MitoSox Red and dihydroethidine staining. Lipid peroxides (a marker of oxidized lipids) were increased in ZOF by ≈47% compared with ZLN rats. The elevation in oxidative stress was accompanied by increased antioxidant enzymes, except glutathione peroxidase-1, and by increased uncoupling protein-2 in ZOF versus ZLN rats. In addition, elevated respiration rates were also observed in the obese compared with lean rats. Administration of MQ significantly normalized the metabolic profiles and reduced lipid peroxides in ZOF rats to the same level observed in lean rats. The protective effect of MQ also suppressed the induction of uncoupling protein-2 in the obese rats. Resolution of mitochondrial oxidative stress by MQ or MT restored coronary collateral growth to the same magnitude observed in ZLN rats in response to repetitive ischemia.

CONCLUSIONS

We conclude that mitochondrial oxidative stress and dysfunction play a key role in disrupting coronary collateral growth in obesity and the metabolic syndrome, and elimination of the mitochondrial oxidative stress with MQ or MT rescues collateral growth.

Induction of vascular progenitor cells from endothelial cells stimulates coronary collateral growth

RATIONALE

A well-developed coronary collateral circulation improves the morbidity and mortality of patients following an acute coronary occlusion. Although regenerative medicine has great potential in stimulating vascular growth in the heart, to date there have been mixed results, and the ideal cell type for this therapy has not been resolved.

OBJECTIVE

To generate induced vascular progenitor cells (iVPCs) from endothelial cells, which can differentiate into vascular smooth muscle cells (VSMCs) or endothelial cells (ECs), and test their capability to stimulate coronary collateral growth.

METHODS AND RESULTS

We reprogrammed rat ECs with the transcription factors Oct4, Klf4, Sox2, and c-Myc. A population of reprogrammed cells was derived that expressed pluripotent markers Oct4, SSEA-1, Rex1, and AP and hemangioblast markers CD133, Flk1, and c-kit. These cells were designated iVPCs because they remained committed to vascular lineage and could differentiate into vascular ECs and VSMCs in vitro. The iVPCs demonstrated better in vitro angiogenic potential (tube network on 2-dimensional culture, tube formation in growth factor reduced Matrigel) than native ECs. The risk of teratoma formation in iVPCs is also reduced in comparison with fully reprogrammed induced pluripotent stem cells (iPSCs). When iVPCs were implanted into myocardium, they engrafted into blood vessels and increased coronary collateral flow (microspheres) and improved cardiac function (echocardiography) better than iPSCs, mesenchymal stem cells, native ECs, and sham treatments.

CONCLUSIONS

We conclude that iVPCs, generated by partially reprogramming ECs, are an ideal cell type for cell-based therapy designed to stimulate coronary collateral growth.

Endothelin-mediated in vivo pressor responses following TRPV1 activation

Transient receptor potential vanilliod 1 (TRPV1) channels have recently been postulated to play a role in the vascular complications/consequences associated with diabetes despite the fact that the mechanisms through which TRPV1 regulates vascular function are not fully known. Accordingly, our goal was to define the mechanisms by which TRPV1 channels modulate vascular function and contribute to vascular dysfunction in diabetes. We subjected mice lacking TRPV1 [TRPV1(−/−)], db/ db, and control C57BLKS/J mice to in vivo infusion of the TRPV1 agonist capsaicin or the α-adrenergic agonist phenylephrine (PE) to examine the integrated circulatory actions of TRPV1. Capsaicin (1, 10, 20, and 100 μg/kg) dose dependently increased MAP in control mice (5.7 ± 1.6, 11.7 ± 2.1, 25.4 ± 3.4, and 51.6 ± 3.9%), which was attenuated in db/db mice (3.4 ± 2.1, 3.9 ± 2.1, 7.0 ± 3.3, and 17.9 ± 6.2%). TRPV1(−/−) mice exhibited no changes in MAP in response to capsaicin, suggesting the actions of this agonist are specific to TRPV1 activation. Immunoblot analysis revealed decreased aortic TRPV1 protein expression in db/db compared with control mice. Capsaicin-induced responses were recorded following inhibition of endothelin A and B receptors (ETA /ETB). Inhibition of ETA receptors abolished the capsaicin-mediated increases in MAP. Combined antagonism of ETA and ETB receptors did not further inhibit the capsaicin response. Cultured endothelial cell exposure to capsaicin increased endothelin production as shown by an endothelin ELISA assay, which was attenuated by inhibition of TRPV1 or endothelin-converting enzyme. TRPV1 channels contribute to the regulation of vascular reactivity and MAP via production of endothelin and subsequent activation of vascular ETA receptors. Impairment of TRPV1 channel function may contribute to vascular dysfunction in diabetes.

Technological behaviour and recycling potential of spent foundry sands in clay bricks

The feasibility of recycling spent foundry sand in clay bricks was assessed in laboratory, pilot line and industrial trials, using naturally occurring sand as a reference. Raw materials were analyzed by X-ray fluorescence, X-ray diffraction, particle size distribution, and leaching and combined to produce bodies containing up to 35% wt. sand. The extrusion, drying and firing behaviour (plasticity, drying sensitivity, mechanical strength, bulk density, water absorption, and shrinkage) were determined. The microstructure, phase composition, durability and leaching (EN 12457, granular materials, end-life step, European Waste Landfill Directive; NEN 7345, monolithic materials, use-life step, Dutch Building Material Decree) were evaluated for bricks manufactured at optimal firing temperature. These results demonstrate that spent foundry sand can be recycled in clay bricks. There are no relevant technological drawbacks, but the feasibility strongly depends on the properties of the raw materials. Spent foundry sand may be introduced into bricks up to 30% wt. Most of the hazardous elements from the spent foundry sand are inertized during firing and the concentrations of hazardous components in the leachates are below the standard threshold for inert waste category landfill excepting for chromium and lead; however, their environmental risk during their use-life step can be considered negligible.

Recycling PC and TV waste glass in clay bricks and roof tiles

Disposal of PC monitors and TV sets is a growing problem, with over 40% of the weight of these systems comprised of waste glasses with high Pb (funnel) or Ba-Sr concentrations (panel), making them unsuitable for recycling and manufacturing new glass. A possible way to re-use these glasses is in the manufacturing of clay bricks and roof tiles. This possibility was appraised by laboratory simulation of the brickmaking process and technological characterization of unfired and fired products. The recycling of both funnel and panel glasses into clay bodies is technologically feasible, resulting in a substantially reduced plasticity behaviour during shaping-drying (implying a reduction of mechanical strength), and a promotion of sintering during firing. No significant release of Pb, Ba, and Sr was observed during the firing and leaching test for the carbonate-poor body; in contrast, some Pb volatilization during firing and Sr leaching were observed for the carbonate-rich body. Additions of 2 wt.% appear to be practicable, while 5 wt.% glass induces unacceptable modifications of technological properties. The recommended amount is within 2 and 4 wt.%, depending on the characteristics of the clay bodies. The main constraint is that the glass must have a particle size below the limit of the pan mills used in brickmaking (<1mm).

Heart rate stationarity in heart transplanted patients

The heart rate stationary was studied by tachographic of 24 Holter analysis in 15 normal subjects and in 13 recipient subjects that were heart transplanted at least 5 years and that, at the time of our research, presented a very good post-operative course. To test the stationary heart rate we performed a scanning of Holter in qualified strips of four beats in which the three consecutive intervals demonstrate a constant acceleration or deceleration sequential variations of tachographic values. The results obtained demonstrated that in normal and transplanted subjects stationary and non stationary strips are evident. Both in normal and in transplanted subjects non-stationary strips are prevalent, although in different ways: in normal subjects the stationary and non-stationary ratio is 1:1.40; in transplanted subjects the ratio is 1:1.68. Non-stationary strips, that in the cartesian plane do not demonstrate any directional variation, in normal subjects are, on average, higher than in transplanted subjects. The same phenomenon is available for the strips with only one variation. The strips with three consecutive variations are much more evident (more 50%) in transplanted subjects. These strips are also more numerous compared to the sum of all the other strips with a single variation. The statistical analysis demonstrates that the difference between the normal and the transplanted subjects is significative. Our data can suggest an absent autonomic nervous system regulation and can confirm the results we obtained in these patients using a phase space analysis of the same Holter recording.

The autocorrelation of cardiac beat as a method of research of the heart's memory (first communication)

The AA. have studied the heart's memory by autocorrelation function of heart beats in healthy. The results have demonstrated that there is positive or negative correlation in the space of the first 25-35 pulsation which follow pulsation chosen at random.

Variability in the arterial pressure of newborns as compared to that of adults and old men

The systolic and diastolic blood pressure was monitored on healthy subjects of different ages, spanning from newborns (24-48 hs old, to elderly age (70-80 years old). Each subject was monitored for 15 minutes, and the pressure values collected every minute. This protocol allowed a statistical evaluation of both inter- and intraindividual variabilities among and within different class ages. As expected, increasing age is paralleled by a marked increase in the average values of systolic blood pressure; the trend of variabilities around the average, however, as traced by standard deviations, is just the opposite: a marked decrease going from newborns to adults is accompanied--in most cases--by a statistically significant difference in the same direction also between adults and old men. This can be rationalized, in the light of recent findings on the role of deterministic chaos in the functional behaviour of complex biological systems, in terms of decreased functional flexibility characteristic of the aging process.

[Individual arterial pressure variability in newborn infants, adults, and the elderly]

The complexity of the cardiovascular function is related to a wide interindividual variability (VA) that changes with age. The aim of our study was to investigate the spontaneous blood pressure (BP) VA in 3 groups of 20 healthy subjects (S) each, 10 M and 10 F: Group I newborns 24 hours old; Group II 30-40 yrs; Group III 70-80 yrs. Each S underwent BP monitoring in a comfortable condition for 15'. Our data show an increase, with age, of both the average systolic and diastolic BP, paralleled by a simultaneous decrease of their standard deviations. Furthermore, the three distributions show a reasonably gaussian behaviour (maximum absolute value of the skewness was 0.21). These results emphasize the age-dependent reduction in functional flexibility of the cardiovascular system. A major pool of subjects is required to confirm our preliminary data.