Early Statin Therapy and In-Hospital Outcomes in Acute Coronary Syndrome Patients Presenting with Advanced Killip Class at Admission: Findings from the CCC-ACS Project

PURPOSE

It is unknown if acute coronary syndrome (ACS) patients presenting with advanced Killip class (III/IV) would benefit from early statin therapy. Therefore, we aimed to explore the relationship between statin therapy within the first 24 h of medical contact and in-hospital outcomes in this patient population in a nationwide registry.

METHOD

In the Improving Care for Cardiovascular Disease in China-ACS project, among ACS patients presenting with Killip class III/IV, we performed the following three analyses: (i) the associations between early statin therapy and risks for in-hospital mortality and ischaemic events; (ii) the dose effect of statins on mortality and (iii) the interaction between low-density lipoprotein cholesterol (LDL-C) levels and statins on mortality.

RESULT

Among 104,516 ACS patients, 12,149 presented with advanced Killip class and 89.3% received early statins. Multivariable-adjusted logistic regression models revealed a 69% reduction in mortality in the statin group (adjusted odds ratio [OR] 0.31; 95% confidence interval [CI] 0.25-0.39), parallel with a reduction in ischaemic events (adjusted OR 0.50, 95% CI 0.33-0.74), compared with those not receiving early statins, which was consistent in multiple sensitivity analyses. Additionally, the protective association of early statins on in-hospital mortality was observed even among patients that received a low-to-moderate dose. Finally, the short-term survival benefit of early statins was independent of LDL-C.

CONCLUSION

In a nationwide ACS registry, statin therapy initiated within the first 24 h of medical contact was associated with a reduced risk of in-hospital mortality in ACS patients presenting with advanced Killip class.

Statins and myocardial infarction: Type, dose, and administration time: Does it matter?

Patients with ST-elevation myocardial infarction (STEMI) constitute a vulnerable group that demands the careful assessment and application of all the up-to-date clinical and experimental knowledge, with final aim, the improvement of their prognosis. Statins are an indispensable part of the primary and secondary prevention of coronary artery disease (CAD), not only due to their strong hypolipidemic effect, but also due to their numerous pleiotropic properties that play an important role in the treatment of CAD, especially when the more vulnerable group of STEMI patients is addressed. Nevertheless, there are still issues that require further discussion and clarification, such as the type of statin, the dose of the regimen, the administration time, and the treatment duration.

Effects of atorvastatin loading prior to primary percutaneous coronary intervention on endothelial function and inflammatory factors in patients with ST-segment elevation myocardial infarction

Previous studies have demonstrated the beneficial effect of statin loading prior to elective and early percutaneous coronary intervention (PCI), in which the 'pleiotropic effects' of statins may contribute to these clinical benefits. The aim of the present study was to examine the potential effects of atorvastatin loading prior to primary PCI on coronary endothelial function and inflammatory factors in patients with acute ST-segment elevation myocardial infarction (STEMI). A total of 60 patients with STEMI were randomized into three groups: Loading dose (80 mg atorvastatin prior to PCI; n=20), regular dose (20 mg atorvastatin prior to PCI; n=20) and control (without atorvastatin prior to PCI; n=20). The plasma samples were collected prior to, and immediately, 6 and 24 h after PCI in all the patients. The plasma concentrations of endothelial nitric oxide synthase (eNOS), nitric oxide (NO), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) and intercellular adhesion molecule-1 (ICAM-1) were examined using ELISA. The plasma eNOS levels immediately and 24 h after PCI were significantly higher in the regular dose group compared with the other groups. However, there were no significant differences in the plasma eNOS concentration prior to and 6 h after PCI, or in the plasma NO concentration at any of the time-points among the three groups. The plasma IL-6 levels prior to PCI were significantly lower in the loading dose group compared with the other groups; however, there were no significant differences in the plasma concentration of IL-6 following PCI or in the concentrations of TNF-α and ICAM-1 at any of the time-points among the three groups. In conclusion, atorvastatin loading in patients with STEMI undergoing primary PCI may not have protective effects on endothelial function and the inflammatory reaction.

Cardiogenic Shock and the ICU Patient

Cardiogenic shock is one of the most important complications of acute myocardial infarction (MI) and acute left ventricular failure (LVF). It threatens the life of 5–10% of patients with ST-segment elevation myocardial infarction (STEMI) particularly in the presence of inappropriately low peripheral vascular resistance. Cardiogenic shock results in poor tissue perfusion, end-organ damage and carries a high mortality risk. The goal of therapy is to prevent end-organ dysfunction and severe metabolic derangement by raising mean arterial blood pressure, which is achieved with the use of inotropes and vasopressors, often at the expense of tachycardia, elevated myocardial oxygen consumption and extended myocardial ischaemia. Current therapeutic approaches include early coronary artery revascularisation (which has significantly improved the survival rate), fluid resuscitation, inotropic support and mechanical circulatory support using intra-aortic balloon pumps or ventricular assist devices. In this article, we review the pathophysiology, diagnosis and management of cardiogenic shock.

Effect of early statin treatment in patients with cardiogenic shock complicating acute myocardial infarction

Background and Objectives

The benefit of early statin treatment following acute myocardial infarction (MI) complicated with cardiogenic shock (CS) has not been well studied. We sought to assess the effect of early statin therapy in patients with CS complicating acute MI.

Subjects and Methods

We studied 553 statin-naive patients with acute MI and CS (Killip class IV) who underwent revascularization therapy between November 2005 and January 2008 at 51 hospitals in the Korea Acute Myocardial Infarction Registry. Patients were divided into 2 groups: those who received statins during hospitalization (n=280) and those who did not (n=273). The influence of statin treatment on a 12-month clinical outcome was examined using a matched-pairs analysis (n=200 in each group) based on the propensity for receiving statin therapy during hospitalization.

Results

Before adjustment, patients receiving statin, compared to those not receiving statin, had a more favorable clinical profile, were less likely to suffer procedural complications, and more likely to receive adequate medical therapy. Patients receiving statin had lower unadjusted in-hospital mortality and composite rate of mortality, MI, and repeat revascularization at 12 months, which remained significantly lower after adjustment for patient risk, procedural characteristics, and treatment propensity.

Conclusion

In CS patients with acute MI undergoing revascularization therapy, early statin treatment initiated during hospitalization was associated with lower rates of in-hospital death and 12-month adverse cardiac events.

Targeting reperfusion injury in acute myocardial infarction: a review of reperfusion injury pharmacotherapy

INTRODUCTION

Acute myocardial infarction (AMI) (secondary to lethal ischemia-reperfusion [IR]) contributes to much of the mortality and morbidity from ischemic heart disease. Currently, the treatment for AMI is early reperfusion; however, this itself contributes to the final myocardial infarct size, in the form of what has been termed 'lethal reperfusion injury'. Over the last few decades, the discovery of the phenomena of ischemic preconditioning and postconditioning, as well as remote preconditioning and remote postconditioning, along with significant advances in our understanding of the cardioprotective pathways underlying these phenomena, have provided the possibility of successful mechanical and pharmacological interventions against reperfusion injury.

AREAS COVERED

This review summarizes the evidence from clinical trials evaluating pharmacological agents as adjuncts to standard reperfusion therapy for ST-elevation AMI.

EXPERT OPINION

Reperfusion injury pharmacotherapy has moved from bench to bedside, with clinical evaluation and ongoing clinical trials providing us with valuable insights into the shortcomings of current research in establishing successful treatments for reducing reperfusion injury. There is a need to address some key issues that may be leading to lack of translation of cardioprotection seen in basic models to the clinical setting. These issues are discussed in the Expert opinion section.

Cardiogenic shock in ACS. Part 1: prediction, presentation and medical therapy

Ischemic cardiogenic shock is a complex, self-perpetuating pathological process that frequently causes death irrespective of medical therapy. Early definition of coronary anatomy is a pivotal step towards survival. Those destined to develop shock are likely to have three-vessel or left main stem disease with previously impaired left ventricular function. Early reperfusion of the occluded artery can limit infarct size, but ischemia-reperfusion injury or the 'no-reflow' phenomenon can preclude improvement in myocardial contractility. Emergence of shock depends upon the volume of ischemic myocardium, stroke volume, and peripheral vascular resistance. If cytokine release triggers the systemic inflammatory response, systemic vascular resistance falls and inadequate coronary perfusion pressure heralds the downward spiral. Survival depends on early recognition of shock, followed by aggressive targeted treatment of left, right, or biventricular failure. The goal is to prevent end-organ dysfunction and severe metabolic derangement by raising mean arterial pressure, which is achieved with inotropes and vasopressors, often at the expense of tachycardia, elevated myocardial oxygen consumption, and extended ischemia. The value of intra-aortic balloon counter-pulsation is now questioned in patients with advanced shock. When mean arterial pressure is <55 mmHg with serum lactate >11 mmol/l, death is likely and mechanical circulatory support becomes the only chance for survival.

On causation in therapeutic research: observational studies, randomised experiments and instrumental variable analysis

The counterfactual theory defines a conceptual framework for judging causation of therapeutic interventions. The main assumption underlying the claim that a counterfactual statement holds is that compared groups are exchangeable. In observational studies for therapeutic effects causal claims are hard to justify because the lack of exchangeability between compared groups. Randomised studies have a rather straightforward causal interpretation, based on the randomisation procedure that leads to expected exchangeability between compared groups. The use of instrumental variables can theoretically overcome the problems adherent to observational data, at least to a certain extent. The general idea of instrumental variables is to mimic a randomised trial, by searching for a variable that determines the probability of exposure (treatment) but that is not in other ways associated with the outcome under study. The assumptions for causal claims in IV analyses are strong, but the alternative of avoiding causal statements based on observational data, is less appealing.