Review of antithrombotic agents used for acute coronary syndromes in renal patients

Chronic kidney disease in acute coronary syndromes

Chronic kidney disease (CKD) is associated with a high burden of coronary artery disease. In patients with acute coronary syndromes (ACS), CKD is highly prevalent and associated with poor short- and long-term outcomes. Management of patients with CKD presenting with ACS is more complex than in the general population because of the lack of well-designed randomized trials assessing therapeutic strategies in such patients. The almost uniform exclusion of patients with CKD from randomized studies evaluating new targeted therapies for ACS, coupled with concerns about further deterioration of renal function and therapy-related toxic effects, may explain the less frequent use of proven medical therapies in this subgroup of high-risk patients. However, these patients potentially have much to gain from conventional revascularization strategies used in the general population. The objective of this review is to summarize the current evidence regarding the epidemiology and the clinical and prognostic relevance of CKD in ACS patients, in particular with respect to unresolved issues and uncertainties regarding recommended medical therapies and coronary revascularization strategies.

The influence of poly-N-[(2,2-dimethyl-1,3-dioxolane)methyl]acrylamide on fibrin polymerization, cross-linking and clot structure

Poly-N-[(2,2-dimethyl-1,3-dioxolane)methyl]acrylamide (PDMDOMA) is a neutral synthetic water-soluble polymer. In this report, we evaluated the influence of PDMDOMA on blood hemostasis by studying the fibrin polymerization process, the three-dimensional clot structure, and the mechanical properties and fibrinolysis. PDMDOMA altered the normal fibrin polymerization by changing the rate of protofibril aggregation and resulting in a 5-fold increase in the overall turbidity. Fibrin clots formed in presence of PDMDOMA exhibited thinner fibers with less branching which resulted in a more porous and heterogeneous clot structure in scanning electron micrographs. The overall strength and rigidity of the whole blood clot also decreased up to 10-fold. When a combination of plasminogen and tissue-plasminogen activators were included in clotting reactions, fibrin clots formed in the presence of PDMDOMA exhibited highly shortened clot lysis times and was supported by the enhanced clot lysis measured by thromboelastography in whole blood. Further evidence of the altered clot structure and clot cross-linking was obtained from the significant decrease in d-dimer levels measured from degraded plasma clot. Thus, PDMDOMA may play an important role as an antithrombotic agent useful in prophylactic treatments for thrombosis by modulating fibrin clot structure to enhance fibrinolysis.

Association of level of kidney function and platelet aggregation in acute myocardial infarction

BACKGROUND

Decreased kidney function has been established as an important risk factor in patients presenting with acute coronary syndrome. In acute coronary syndrome, increased platelet aggregation is associated with vascular complications. The aim of this study is to examine whether decreased kidney function is associated with altered platelet function in patients presenting with acute myocardial infarction.

STUDY DESIGN

Prospective cohort.

SETTING & PARTICIPANTS

413 patients presenting with acute myocardial infarction admitted to the cardiac intensive care unit at Ostersund Hospital, Ostersund, Sweden.

PREDICTORS

Glomerular filtration rate less than 60 mL/min/1.73 m(2) estimated from serum cystatin C level, comorbidity, medications, and markers of inflammation and hemostasis.

OUTCOMES & MEASUREMENTS

Platelet aggregation was assessed by measuring the formation of small platelet aggregates (SPAs) by using a laser light scattering method. A greater SPA level indicates greater platelet aggregation. Platelet aggregation analysis was performed on days 1, 2, 3, and 5 in-hospital.

RESULTS

We observed a significant increase in platelet aggregation during the first 3 days in the hospital regardless of kidney function (P < 0.001). Platelet aggregation was more pronounced in patients with estimated glomerular filtration rate less than 60 mL/min/1.73 m(2) on day 2 (SPA count, 65,000 versus 47,000; P = 0.01) and day 3 (SPA count, 77,000 versus 52,000; P = 0.02). In a multiple linear regression analysis, decreased kidney function was no longer significantly associated with increased platelet aggregation. Older age, greater plasma fibrinogen level, and diabetes mellitus were associated with increased platelet aggregation in the multivariable model.

LIMITATIONS

During the study period, 78 patients presenting with acute myocardial infarction were not eligible for inclusion. Differences in treatment with antiplatelet medication between the 2 groups might have affected our findings.

CONCLUSIONS

Platelet aggregation increases during the first days after acute myocardial infarction regardless of kidney function. There is no difference in platelet aggregation in patients according to level of kidney function.

Use of Low Molecular Weight Heparins and Glycoprotein IIb/IIIa Inhibitors in Patients with Chronic Kidney Disease

Despite aggressive intervention, cardiac causes of death, including acute coronary syndrome (ACS), continue to be a major source of mortality in patients with chronic kidney disease (CKD), including end-stage renal disease (ESRD). Multiple large prospective trials have demonstrated the clinical benefits of both low molecular weight heparin (LMWH) and glycoprotein (Gp) IIb/IIIa inhibitors in treating patients with ACS. Unfortunately patients with significant impairment of kidney function have generally been excluded from these major clinical trials. Consequently relatively little is known about the pharmacokinetics, appropriate dosing, efficacy, and safety of these medications in patients with CKD of various stages. This article examines the available literature regarding the pharmacokinetics, dosing, efficacy, and safety of LMWH and Gp IIb/IIIa inhibitors in patients with CKD.

Different Types of Renal Dysfunction in Patients with Acute Myocardial Infarction Treated with Percutaneous Coronary Intervention

BACKGROUND

The prognostic significance of different types of renal dysfunction in patients with acute myocardial infarction (AMI) treated with percutaneous coronary intervention (PCI) has not been well characterized.

METHODS

The single-center AMI registry encompassed 1,486 consecutive AMI patients treated with PCI, who were followed by mean 29.7 months. Subjects with an estimated glomerular filtration rate <60 mL/min per 1.73 m2 at baseline were selected (n = 283, 19.0%) and incorporated into the chronic kidney disease (CKD) group. The control group consisted of 1,203 subjects with normal renal function (81.0%). The CKD patients were divided into subgroups: with contrast-induced nephropathy - CKD + CIN (n = 68, 4.6%) and without - CKD-CIN (n = 215, 14.5%).

RESULTS

Remote mortality rate was significantly higher in CKD group (34.6%) and in particular subgroups: CKD + CIN (47.0%), CKD-CIN (31.0%) than in controls (9.1%, P < 0.001 for all study groups vs controls). Multivariate analysis identified CKD as an independent predictor of any-cause death in the whole population (hazard ratio [HR] 1.77, 95% confidence interval [CI] 1.60-1.94, P < 0.001). Similarly, CKD + CIN contrary to CKD-CIN had significant and independent influence on remote survival in study population (HR 2.16, 95% CI 1.95-2.37, P < 0.001).

CONCLUSIONS

CKD and its types have significant, negative influence on long-term survival in AMI patients treated with PCI. It is especially strongly expressed in those CKD patients who develop contrast-induced nephropathy, which occurrence is an independent risk factor of mortality associated with over twofold increase of death hazard.

Kidney Disease and Cardiovascular Risk

Kidney failure and chronic kidney disease (CKD) are associated with accelerated cardiovascular disease, apparently because of a high burden of traditional vascular risk factors and possibly nontraditional risk factors such as inflammation, chronic volume overload, and abnormal calcium-phosphate metabolism. Although the burden of cardiovascular disease in CKD patients is well documented, potentially beneficial therapies appear to be underused in mild to moderate CKD and are relatively understudied in those with kidney failure. This review describes the epidemiology and pathophysiology of cardiovascular disease in CKD. We also discuss the clinical and public health implications of current knowledge and outline opportunities for further research.

Chronic kidney disease in patients with non-ST-segment elevation acute coronary syndromes

PURPOSE

Chronic kidney disease has been linked to high mortality rates in patients with ST-segment elevation myocardial infarction but has not been well described for patients with non-ST-segment elevation acute coronary syndromes. We examined the treatment and outcomes of patients with both non-ST-segment elevation acute coronary syndromes and moderate to severe chronic kidney disease.

SUBJECTS AND METHODS

We evaluated 45343 patients with non-ST-segment elevation acute coronary syndromes enrolled in the CRUSADE Quality Improvement Initiative and compared treatments and outcomes in patients with and without moderate to severe chronic kidney disease.

RESULTS

Patients presenting with moderate to severe chronic kidney disease (n = 6560) were older, more often diabetic, and more likely to present with signs of congestive heart failure. Adherence to Class IA/IB guidelines recommendations was lower in patients with moderate to severe chronic kidney disease, who were significantly less likely to be treated with medications, undergo invasive cardiac procedures, and be given discharge counseling. Moderate to severe chronic kidney disease was associated with a 50% increased risk of mortality and a 70% increased likelihood of transfusion. Despite having a higher risk of adverse outcomes, patients with moderate to severe chronic kidney disease were treated less aggressively than patients with normal renal function.

CONCLUSIONS

These findings suggest that, in patients with moderate to severe chronic kidney disease, safety concerns about adverse outcomes and the absence of trial data for this population may limit the use of guidelines-recommended therapies and interventions for non-ST-segment elevation acute coronary syndromes. The decreased use of discharge counseling in patients with moderate to severe chronic kidney disease and non-ST-segment elevation acute coronary syndromes may represent therapeutic nihilism.

Coronary artery disease and peripheral vascular disease in chronic kidney disease: an epidemiological perspective

The enormous burden of CAD and PVD inpatients who have CKD contributes substantially to increased morbidity and mortality. The increased risk of vascular disease observed in CKD patients is likely to be multifactorial, with contributions from traditional and nontraditional cardiovascular factors. Given the overwhelming evidence on the known benefits of cardioprotective medications, their underuse remains puzzling in a population at enormous risk. During the past 5 years, the research community and national interest groups have made significant progress in organizing a concerted approach to improve the management of patients who have CKD and vascular disease. Much work remains to be done. The development of national guidelines in the management of these patients at high risk for future cardiovascular events will be a welcome step. The evaluation of multitargeted interventions for reduction of cardiovascular risk through randomized clinical trials is desperately needed. Finally, the low use of known cardioprotective strategies in this high-risk group is a serious issue and warrants immediate attention at local and national levels.