Current options in the management of coronary artery disease

Oral Antiplatelet Therapy in Coronary Disease

Ischemic heart disease is the major isolated cause of death worldwide, responsible for 7,249,000 deaths in 2008, 12.7% of deaths from any causes. The inhibition of platelet activation and aggregation is an important therapeutic target. Cyclooxygenase inhibitors and thienopyridines are currently the 2 most used pharmacological classes, but novel antiplatelet agents have currently an important role. The most recent thienopyridine, prasugrel, allows an irreversible inhibition of the P2Y12 platelet receptor associated to a faster and more consistent onset of action rather the previous antiplatelet agents of the same class. Cyclopentyl-triazolo-pyrimidines, a newer pharmacological class from which ticagrelor is an example, also act at the P2Y12 platelet receptor, and like prasugrel, ticagrelor inhibits platelet aggregation in a fast and consistent manner, however, in a reversible way. This article aims to conduct a review on the literature about the most recent information and guidelines on oral antiplatelet agents available for the management of coronary disease.

Visualization of network target crosstalk optimizes drug synergism in myocardial ischemia

Numerous drugs and compounds have been validated as protecting against myocardial ischemia (MI), a leading cause of heart failure; however, synergistic possibilities among them have not been systematically explored. Thus, there appears to be significant room for optimization in the field of drug combination therapy for MI. Here, we propose an easy approach for the identification and optimization of MI-related synergistic drug combinations via visualization of the crosstalk between networks of drug targets corresponding to different drugs (each drug has a unique network of targets). As an example, in the present study, 28 target crosstalk networks (TCNs) of random pairwise combinations of 8 MI-related drugs (curcumin, capsaicin, celecoxib, raloxifene, silibinin, sulforaphane, tacrolimus, and tamoxifen) were established to illustrate the proposed method. The TCNs revealed a high likelihood of synergy between curcumin and the other drugs, which was confirmed by in vitro experiments. Further drug combination optimization showed a synergistic protective effect of curcumin, celecoxib, and sililinin in combination against H₂O₂-induced ischemic injury of cardiomyocytes at a relatively low concentration of 500 nM. This result is in agreement with the earlier finding of a denser and modular functional crosstalk between their networks of targets in the regulation of cell apoptosis. Our study offers a simple approach to rapidly search for and optimize potent synergistic drug combinations, which can be used for identifying better MI therapeutic strategies. Some new light was also shed on the characteristic features of drug synergy, suggesting that it is possible to apply this method to other complex human diseases.

Osteopontin as a novel prognostic marker in stable ischaemic heart disease: a 3-year follow-up study

OBJECTIVES

Osteopontin (OPN) is a glycoprotein, which may play a major role in the regulation of biological phenomena. Increased levels of OPN have been linked to the presence and to the severity of atherosclerosis. This study was undertaken to assess the prognostic significance of plasma OPN levels in patients with stable ischaemic heart disease (IHD).

METHODS

In 101 patients with stable IHD and angiographically documented significant coronary artery stenosis, plasma OPN levels were measured at baseline (time of coronary arteriography). Patients were prospectively followed for a median time of 3 years (minimum 2.25, maximum 3.9 years). The primary study endpoint was the composite of cardiovascular death, non-fatal myocardial infarction, need for revascularization and hospitalization for cardiovascular reasons.

RESULTS

Baseline lnOPN levels were directly related to age (r = 0.27, P < 0.001) and inversely to left ventricular ejection fraction (r = -0.32, P < 0.01). Left ventricular ejection fraction was an independent predictor of plasma OPN levels after adjustment for age and gender (beta = -0.013, P = 0.02). Median OPN value was 55 ng mL(-1). In the univariate Cox-regression analysis, OPN levels > 55 ng mL(-1) (n = 50) were significantly related to adverse cardiac outcome (HR = 2.40, 95% CI: 1.11-5.23, P = 0.027). In multivariate model, OPN levels > 55 ng mL(-1) remained statistically significant independent predictor of adverse outcome after adjustment for age, gender, left ventricular ejection fraction and the number of diseased coronary arteries (HR = 2.88, 95% CI: 1.09-7.58, P = 0.032).

CONCLUSION

OPN may provide significant prognostic information independent of other traditional prognostic markers in patients with stable IHD.

Ethical issues, justification, referral criteria for budget limited and high-dose procedures

This paper reviews some of the issues connected with questions of ethics, health economics, radiation dose and referral criteria arising from a workshop held under the auspices of the Sentinel Research Program FP6-012909. An extensive bibliography of further reading is included.

Achieving lipid goals with rosuvastatin compared with simvastatin in high risk patients in real clinical practice: a randomized, open-label, parallel-group, multi-center study: the DISCOVERY-Beta study

The aim of this multi-center, open-label, randomized, parallel-group trial was to compare the efficacy of rosuvastatin with that of simvastatin in achieving the 1998 European Atherosclerosis Society (EAS) lipid treatment goals. 504 patients (> or =18 years) with primary hypercholesterolemia and a 10-year cardiovascular (CV) risk >20% or history of coronary heart disease (CHD) or other established atherosclerotic disease were randomized in a 2:1 ratio to receive rosuvastatin 10 mg or simvastatin 20 mg once daily for 12 weeks. A significantly higher proportion of patients achieved 1998 EAS low-density lipoprotein cholesterol (LDL-C) goal after 12 weeks of treatment with rosuvastatin 10 mg compared to simvastatin 20 mg (64 vs 51.5%, p < 0.01). Similarly, significantly more patients achieved the 1998 EAS total cholesterol (TC) goal and the 2003 EAS LDL-C and TC goals (p < 0.001) with rosuvastatin 10 mg compared with simvastatin 20 mg. The incidence of adverse events and the proportion of patients who discontinued study treatment were similar between treatment groups. In conclusion, in the DISCOVERY-Beta Study in patients with primary hypercholesterolemia greater proportion of patients in the rosuvastatin 10 mg group achieved the EAS LDL-C treatment goal compared with the simvastatin 20 mg group. Drug tolerability was similar across both treatment groups.

Coronary artery disease and a functional polymorphism of hTERT

Genetic variation, a -1327T/C polymorphism, of human telomerase reverse transcriptase (hTERT) is associated with leukocyte telomere length in healthy subjects, but clinical significances of this functional polymorphism are not clear. Recently, the relationship between the telomere system and coronary artery disease (CAD) was reported. We investigated the association between the -1327T/C polymorphism and (a) susceptibility to CAD and (b) telomere length in CAD patients. In a case-control study, 104 patients confirmed by coronary angiography and 115 age- and sex-matched controls were enrolled. There was a higher frequency of the -1327C/C genotype in CAD patients (51.9%) compared with controls (36.5%, p = 0.0218). Among the 104 CAD patients, leukocyte telomere length in the -1327C/C genotype (7.62+/-2.19 kb, mean+/-SD) was shorter than that in the -1327T/C and -1327T/T genotypes (8.74+/-2.92, p = 0.0287). These findings suggest that the -1327C/C genotype is a genetic risk factor for CAD and relates to shorter telomere length among CAD patients.

Intake of a single morning dose of standard and novel plant sterol preparations for 4 weeks does not dramatically affect plasma lipid concentrations in humans

Recommendations for decreasing the risk of developing cardiovascular disease include increasing the intake of plant sterols and fish oil. The cholesterol-lowering action of plant sterols, when provided in a fish-oil fatty acids vehicle, remains to be investigated in humans. A randomized, crossover-feeding, single-blind trial was conducted in 30 subjects with mild-to-moderate hypercholesterolemia to study the effects on plasma lipids of 2 novel forms of plant sterols: those combined with, or esterified to, fish-oil fatty acids. The treatments were margarine (control), free plant sterols, plant sterols esterified to fatty acids from sunflower oil, plant sterols esterified to very long-chained fatty acids from fish oil, and plant sterols combined with the same amount of very long-chained fatty acids from fish oil. Each sterol-containing food (1.0-1.8 g plant sterols/d) was consumed for 29 d as a single dose with breakfast under staff supervision. Compared with the control treatment, none of the plant sterol preparations reduced plasma total cholesterol or LDL cholesterol, triacylglycerol, apolipoprotein A-I, apolipoprotein B, lipoprotein (a), or C-reactive protein concentration. Relative to the control phase, all plant sterols treatment increased the plasma HDL cholesterol concentration (P < 0.05) by approximately 8%. In conclusion, because standard forms of plant sterols did not reduce plasma cholesterol concentrations, the efficacy of the new formulation of plant sterols cannot be confirmed from the present study design, where plant sterols were given as a single morning dose.

Off-pump coronary artery bypass graft surgery: where should we stand?

Coronary artery bypass grafting (CABG) performed with cardiopulmonary bypass has become a well-established treatment modality for patients with coronary artery disease. However, there is increasing evidence that cardiopulmonary bypass may be responsible for some of the morbidity associated with CABG surgery. Thus, it has been proposed that CABG surgery would be safer if cardiopulmonary bypass could be avoided. The development of cardiac stabilization devices has allowed for the creation of safe and reproducible coronary anastomoses on the beating heart. Several large, non-randomized, retrospective case series have demonstrated that CABG surgery can be performed safely without cardiopulmonary bypass (off-pump) and have in fact suggested benefits when compared with conventional CABG. However, the randomized controlled studies published to date have, as a whole, been unable to conclusively demonstrate the advantages of off-pump surgery. Taken together, the evidence to date suggests that a large-scale, prospective, randomized trial may be required to resolve the dilemma.

CORONARY VASODILATORY RESPONSE TO A NOVEL PEPTIDE, ADRENOMEDULLIN 2

1. Adrenomedullin-2 (AM2) is a novel peptide originally found in a fish and it is structurally related to mammalian AM or fish AM1. Cloning of AM2 cDNA in the mouse, rat and human has been successful. In the present study, the vasodilatory effect of synthetic human AM2 was analysed in isolated artery ring preparations of porcine. 2. Vasodilatory effect of AM2 was the most potent in the coronary artery, followed by the carotid and supramesenteric arteries, but absent in the femoral, pulmonary and renal arteries. 3. The effect of AM2 was equipotent with that of human AM/AM1 in these arteries. 4. AM2-induced relaxation was inhibited by human CGRP (8-37), but not by human AM/AM1 (22-52), suggesting that the vasodilatory response to AM2 is mediated through the CGRP1 receptor. 5. AM2 may share the same receptor (complex) with AM/AM1 for the vasorelaxation. This is the first report of the vasodilatory responses to AM2 in isolated vasculature.

Positional Isomerism Markedly Affects the Growth Inhibition of Colon Cancer Cells by Nitric Oxide-Donating Aspirin in Vitro and in Vivo

NO-donating aspirin (NO-ASA), a novel pharmacological agent currently undergoing clinical testing, consists of ASA to which a nitrate group is covalently linked via a spacer molecule. We synthesized the three positional isomers of NO-ASA with respect to the -CH(2)ONO(2) group (ortho, meta, and para) and examined whether this isomerism affects the biological activity of NO-ASA on HT-29 human colon cancer cells. The ortho- and para-isomers showed similar IC(50) values (1-5 microM) for cell growth inhibition over 72 h, whereas the IC(50) of the meta-isomer was 200 to 500 microM. The ortho- and para-isomers inhibited cell proliferation more potently than the meta-isomer. All three induced apoptosis but the ortho- and para-isomers also induced atypical cells (they maintain their shape but have diminished or absent nuclear material). Treatment for 3 weeks of Min (Apc(min)(/+)) mice, a model of intestinal cancer, with equimolar amounts of meta- and para-NO-ASA decreased the number of tumors in the small intestine by 36 and 59% (P < 0.01), respectively, compared with vehicle-treated controls, thus confirming their in vitro differences in potency. A structure-activity study of the three isomers revealed that substituting an aliphatic for the aromatic spacer or removing the -ONO(2) group profoundly diminished NO-ASA's ability to inhibit cell growth, whereas removal of the acetyl group on the ASA moiety did not affect cell growth inhibition. Thus, positional isomerism is critical for the pharmacological properties of NO-ASA against colon cancer and it should be taken into consideration in rational drug design.

Sudden cardiac death

Sudden cardiac death is often due to a ventricular arrhythmia. When a patient presents with a malignant arrhythmia unrelated to a transient reversible cause, there is a high probability of recurrent arrhythmia and sudden death. Clinical trials have shown a uniform survival benefit from implantable cardioverter-defibrillator (ICD) therapy in survivors of a malignant arrhythmia when compared with drug therapy. However, only 1% to 5% of patients survive an out-of-hospital cardiac arrest, emphasizing the need for primary prevention of sudden death. Clinical trial data available in this regard are largely limited to patients with coronary artery disease (CAD). Mortality can be reduced by the ICD in patients with CAD and depressed left ventricular ejection fraction (LVEF) less than 30%. If left ventricular function is only moderately depressed (LVEF between 30% and 40%), the presence of nonsustained ventricular tachycardia with inducible ventricular arrhythmia at electrophysiologic testing identifies patients who benefit from an ICD. The role of the ICD in primary prevention of sudden death in patients with nonischemic dilated cardiomyopathy is less clear at this time. Preliminary data indicate that the presence of heart failure symptoms in this population increases risk of sudden death that can be prevented by an ICD. Antiarrhythmic drugs have little role in prevention of sudden death; however, drugs that block the effects of beta-adrenergic stimulation, angiotensin, and aldosterone reduce mortality partly through their salutary effects on sudden death. Finally, a number of inherited defects of genes coding for ion channels, contractile sarcomeric proteins, and cell-to-cell junction proteins can result in primary electrical abnormalities and sudden death. The ICD is effective for secondary prevention, but its role in primary prevention is controversial and should be based on individual risk factors.