Novel direct factor IIa and Xa inhibitors: Mechanisms of action and preclinical studies

The need to overcome certain limitations of the existing anticoagulant agents (heparin, LMWH and VKAs) and to achieve more convenient long-term anticoagulation has fueled the quest for the "ideal anticoagulant", an agent that would exert at least similar antithrombotic effects with a substantially improved pharmacologic profile and significantly less bleeding complications. The major disadvantages of the traditional agents were the narrow therapeutic window with serious drug and food interactions and the need for regular blood monitoring. Coagulation factors IIa and Xa have proved the most attractive pharmacologic targets due to their key role in the coagulation process and the opportunity of blocking thrombin generation before the level of thrombin production that results in amplification of the anticoagulant effect while preserving some of thrombin hemostatic effect. This review summarizes the mechanism of action of some of the most promising novel oral direct factor IIa and Xa inhibitors with a focus on published preclinical trials that led to their clinical development. © 2012 Bentham Science Publishers

Cystatin C: An emerging biomarker in cardiovascular disease

Cystatin C (cys-C) is a small protein molecule (120 amino acid peptide chain, approximately 13kDa) produced by virtually all nucleated cells in the human body. It belongs to the family of papain-like cysteine proteases and its main biological role is the extracellular inhibition of cathepsins. It's near constant production rate, the fact that it is freely filtered from the glomerular membrane and then completely reabsorbed without being secreted from the proximal tubular cells, made it an almost perfect candidate for estimating renal function. The strong correlation between chronic kidney disease (CKD) and cardiovascular disease (CVD) along with the growing understanding of the role of cysteinyl cathepsins in the pathophysiology of CVD inspired researchers to explore the potential association of cys-C with CVD. Throughout the spectrum of CVD (peripheral arterial disease, stroke, abdominal aortic aneurysm, heart failure, coronary artery disease) adverse outcomes and risk stratification have been associated with high plasma levels of cys-C. The exact mechanisms behind the observed correlations have not been comprehensively clarified. Plausible links between high cys-C levels and poor cardiovascular outcome could be impaired renal function, atherogenesis and inflammatory mediators, remodeling of myocardial tissue and others (genetic factors, aging and social habits). The scope of the present article is to systematically review the current knowledge about cys-C biochemistry, metabolism, methods of detection and quantification and pathophysiological associations with different aspects of CVD. © 2013 Bentham Science Publishers

Myocardial deformation imaging unmasks subtle left ventricular systolic dysfunction in asymptomatic and treatment-naïve HIV patients

Background: Patients infected by the human immunodeficiency virus (HIV) and receiving highly active antiretroviral therapy have a higher incidence of cardiovascular disease than healthy subjects, but little is known about cardiac function in asymptomatic and treatment-naïve patients. We sought to study cardiac function in asymptomatic HIV-infected, treatment-naïve patients. Methods: We studied 41 HIV-infected and treatment-naïve patients and 20 age- and sex-matched healthy controls. Patients with cardiac symptoms, history of cardiac disease or NT-proBNP >100 pg/mL were excluded. We addressed cardiac function using standard echocardiography along with tissue Doppler (TDI) measurements, including strain/strain rate assessment. Results: Standard echocardiographic parameters did not differ between groups, except for transmitral E wave velocity (64.8 ± 14 cm/s in HIV vs 76.1 ± 10 cm/s in controls, p = 0.002). In contrast, TDI mitral and tricuspid annulus s velocity and all strain/strain rate measurements were significantly lower in HIV patients: s lateral, 10.2 ± 2.4/11.3 ± 0.7, p = 0.011; s septal, 8.1 ± 1.6/8.7 ± 0.8, p = 0.045; s tricuspid, 13.4 ± 2.3/14.9 ± 1.3, p = 0.002; strain/strain rate, septal (strain/strain rate, 15.1 ± 5.7/−0.9 ± 0.3, 25.3 ± 1.7/−1.9 ± 0.2, p < 0.001), anterior (16.7 ± 3/−1.0 ± 0.1, 26.7 ± 1.7/−1.9 ± 0.2, p < 0.001), lateral (16.0 ± 6/−1.0 ± 0.1, 27.5 ± 1.8/−2.2 ± 0.3, p < 0.001) and posterior (15.2 ± 5.8/−1.0 ± 0.2, 26.2 ± 1.8/−2.2 ± 0.3, p < 0.001) left ventricular wall. Conclusions: HIV infection itself is accompanied by subclinical systolic dysfunction, not apparent to standard echocardiography that can be unmasked though using sensitive echocardiographic techniques. © 2015, Springer-Verlag Berlin Heidelberg

Effects of angiotensin-converting enzyme inhibition with perindopril on left ventricular remodeling and clinical outcome - Results of the randomized Perindopril and Remodeling in Elderly with Acute Myocardial Infarction (PREAMI) study

Background: Angiotensin-converting enzyme inhibitors reduce mortality and remodeling after myocardial infarction in patients with left ventricular dysfunction. Methods: Perindopril and Remodeling in Elderly With Acute Myocardial Infarction (PREAMI), a doubleblind, randomized, parallel-group, multicenter, placebocontrolled study, determined whether similar benefits occur in elderly postinfarction patients with preserved left ventricular function. A total of 1252 patients 65 years or older with a left ventricular ejection fraction of 40% or higher and recent acute myocardial infarction were randomized to receive perindopril erbumine or placebo (8 mg/d) for 12 months. The combined primary end point was death, hospitalization for heart failure, or left ventricular remodeling. Secondary end points included cardiovascular death, hospitalization for reinfarction or angina, and revascularization. Results: The primary end point occurred in 181 patients (35%) taking perindopril and 290 patients (57%) taking placebo, with a significant absolute risk reduction of 0.22 (95% confidence interval, 0.16 to 0.28; P.001). A total of 126 patients (28%) and 226 patients (51%) in the perindopril and placebo groups, respectively, experienced remodeling. The mean increase in left ventricle end-diastolic volume was 0.7 mL with perindopril compared with 4.0 mL with placebo (P.001). In the perindopril group, 40 deaths (6%) and 22 hospitalizations (4%) for heart failure occurred, whereas 37 deaths (6%) and 30 hospitalizations (5%) occurred in the placebo group. Treatment did not affect death, whereas the hospitalization rate for heart failure was slightly reduced (absolute risk reduction, 0.01; 95% confidence interval, −0.01 to 0.02). No treatment effect on other secondary end points was detected. Conclusion:Wefound that 1-year treatment with 8mg/d of perindopril reduces progressive left ventricular remodeling that can occur even in the presence of small infarct size, but it was not associated with better clinical outcomes

PERTINENT - PERindopril-Thrombosis, InflammatioN, endothelial dysfunction and neurohormonal activation trial: A sub-study of the EUROPA study

BACKGROUND: Markers of thrombosis, inflammation, endothelial dysfunction and neurohumoral activation such as fibrinogen, D-dimer, C-reactive protein, von Willebrand factor, tumour necrosis factor-alpha and chromogranin-A are reported to be linked to the increase of cardiovascular risk for atherosclerosis progression and events in patients with cardiovascular diseases. METHODS: EUROPA is a double blind, placebo-controlled trial on 12,231 patients that evaluates the effect of an angiotensin converting enzyme inhibitor--perindopril--on prevention of cardiovascular events in patients with coronary artery disease. PERTINENT is a sub-study of EUROPA that evaluates (a) in Part A (300 patients): the influence of perindopril vs. placebo on fibrinogen, D-dimer, C-reactive protein, von Willebrand factor, tumour necrosis factor-alpha and chromogranin-A. In addition, NOS expression and induction of apoptosis on human umbilical vein endothelial cells and angiotensin converting enzyme levels are also studied; (b) in Part B (about 1200 patients): the predictive role of plasma levels of C-reactive protein and von Willebrand factor on the occurrence of cardiovascular events. To this end, matched case-control analyses are planned (patients with vs. patients without events). STATUS OF PERTINENT: Blood analyses are in progress in four specialised laboratories: (a) Gaubius Laboratory, Leiden, TNO-PG, The Netherlands; (b) University Department of Medicine, Birmingham, UK; (c) University of Pavia, Italy; (d) Fondazione Salvatore Maugeri, Cardiovascular Research Centre, Gussago, Italy. CONCLUSIONS: The PERTINENT sub-study might help elucidating the phenomena contributing to the pathophysiology of cardiovascular events in patients with coronary artery disease and the role of perindopril in such context

Early eplerenone treatment in patients with acute ST-elevation myocardial infarction without heart failure: The Randomized Double-Blind Reminder Study

Aims: We aimed to assess the impact of eplerenone on cardiovascular (CV) outcomes in STEMI without known heart failure, when initiated within 24 h of symptom onset. Methods and results: In this randomized, placebo-controlled, double-blind trial, we assigned 1012 patients with acute STEMI and without a history of heart failure to receive either eplerenone (25–50 mg once daily) or placebo in addition to standard therapy. The primary endpoint was the composite of CV mortality, re-hospitalization, or, extended initial hospital stay, due to diagnosis of HF, sustained ventricular tachycardia or fibrillation, ejection fraction ≤40%, or elevated BNP/NT-proBNP at 1 month or more after randomization. BNP elevation was defined as BNP levels or values above 200 pg/mL or NT-proBNP values above 450 pg/mL (in patients aged below 50); above 900 pg/mL (age 50–75 years) or above 1800 pg/mL (patients older than 75). After a mean follow-up of 10.5 months, the primary endpoint occurred in 92 patients (18.2%) in the eplerenone group and in 149 patients (29.4%) in the placebo group [adjusted hazard ratio (HR), 0.58; 95% confidence interval (CI), 0.45–0.76; P < 0.0001]. The primary endpoint was driven by a high BNP/NT-proBNP level (adjusted HR, 0.60; 95% CI, 0.45–0.79; P < 0.0003). Adverse event rates were similar in both groups. Serum potassium levels exceeded 5.5 mmol/L in 5.6 vs. 3.2% (P = 0.09) and were below 3.5 mmol/L in 1.4 vs. 5.6% of patients (P = 0.0002), in the eplerenone and placebo groups, respectively. Conclusion: The addition of eplerenone during the acute phase of STEMI was safe and well tolerated. It reduced the primary endpoint over a mean 13 months follow-up mostly because of significantly lower BNP/NT-proBNP levels. Additional studies are needed to clarify the role of early use of MRAs in STEMI patients without heart failure

Edoxaban versus warfarin in patients with atrial fibrillation

Contains fulltext : 125374.pdf (publisher's version ) (Open Access)BACKGROUND: Edoxaban is a direct oral factor Xa inhibitor with proven antithrombotic effects. The long-term efficacy and safety of edoxaban as compared with warfarin in patients with atrial fibrillation is not known. METHODS: We conducted a randomized, double-blind, double-dummy trial comparing two once-daily regimens of edoxaban with warfarin in 21,105 patients with moderate-to-high-risk atrial fibrillation (median follow-up, 2.8 years). The primary efficacy end point was stroke or systemic embolism. Each edoxaban regimen was tested for noninferiority to warfarin during the treatment period. The principal safety end point was major bleeding. RESULTS: The annualized rate of the primary end point during treatment was 1.50% with warfarin (median time in the therapeutic range, 68.4%), as compared with 1.18% with high-dose edoxaban (hazard ratio, 0.79; 97.5% confidence interval [CI], 0.63 to 0.99; P<0.001 for noninferiority) and 1.61% with low-dose edoxaban (hazard ratio, 1.07; 97.5% CI, 0.87 to 1.31; P=0.005 for noninferiority). In the intention-to-treat analysis, there was a trend favoring high-dose edoxaban versus warfarin (hazard ratio, 0.87; 97.5% CI, 0.73 to 1.04; P=0.08) and an unfavorable trend with low-dose edoxaban versus warfarin (hazard ratio, 1.13; 97.5% CI, 0.96 to 1.34; P=0.10). The annualized rate of major bleeding was 3.43% with warfarin versus 2.75% with high-dose edoxaban (hazard ratio, 0.80; 95% CI, 0.71 to 0.91; P<0.001) and 1.61% with low-dose edoxaban (hazard ratio, 0.47; 95% CI, 0.41 to 0.55; P<0.001). The corresponding annualized rates of death from cardiovascular causes were 3.17% versus 2.74% (hazard ratio, 0.86; 95% CI, 0.77 to 0.97; P=0.01), and 2.71% (hazard ratio, 0.85; 95% CI, 0.76 to 0.96; P=0.008), and the corresponding rates of the key secondary end point (a composite of stroke, systemic embolism, or death from cardiovascular causes) were 4.43% versus 3.85% (hazard ratio, 0.87; 95% CI, 0.78 to 0.96; P=0.005), and 4.23% (hazard ratio, 0.95; 95% CI, 0.86 to 1.05; P=0.32). CONCLUSIONS: Both once-daily regimens of edoxaban were noninferior to warfarin with respect to the prevention of stroke or systemic embolism and were associated with significantly lower rates of bleeding and death from cardiovascular causes. (Funded by Daiichi Sankyo Pharma Development; ENGAGE AF-TIMI 48 ClinicalTrials.gov number, NCT00781391.)