Acute coronary syndromes: unstable angina/non-ST elevation myocardial infarction

Updates in Anti-anginal and Anti-ischemic Therapies for Acute Coronary Syndromes

PURPOSE OF REVIEW

Acute coronary syndrome is a major health problem affecting ~ 1.5 million individuals a year in the USA. We review the contemporary role of anti-anginal and anti-ischemic therapies in the management of an individual presenting with an acute coronary syndrome.

RECENT FINDINGS

Early diagnosis and appropriate evidence-based therapies significantly improve clinical outcomes in acute coronary syndrome patients. Typically, acute coronary syndrome is associated with rupture of an atherosclerotic plaque and either partial or complete thrombotic occlusion of a coronary artery. Management of an acute coronary syndrome is targeted towards this underlying pathophysiology. The last few years have seen significant advances in anti-anginal and anti-ischemic therapies in the management of patients with acute coronary syndrome. It is important to have a team effort to target risk reduction measures and to emphasize medication and dietary compliance. Long-term pharmacotherapy should include aspirin, beta-blocker, DAPT (for at least 1 year), statins, and ACE inhibitors and PCSK9 inhibitors if indicated.

Role of the ECG in initial acute coronary syndrome triage: primary PCI regardless presence of ST elevation or of non-ST elevation

The major initial triaging decision in acute coronary syndrome (ACS) is whether or not percutaneous coronary intervention (PCI) is the primary treatment. Current guidelines recommend primary PCI in ST-elevation ACS (STEACS) and initial antithrombotic therapy in non-ST-elevation ACS (NSTEACS). This review probes the question whether this decision can indeed be based on the ECG. Genesis of STE/NSTE ECGs depends on the coronary anatomy, collateral circulation and site of the culprit lesion. Other causes than ischaemia may also result in ST-segment changes. It has been demonstrated that the area at risk cannot reliably be estimated by the magnitude of the ST change, that complete as well as incomplete occlusions can cause STE as well as NSTE ECGs, and that STE and NSTE patterns cannot differentiate between transmural and non-transmural ischaemia. Furthermore, unstable angina can occur with STE and NSTE ECGs. We conclude that the ECG can be used to assist in detecting ischaemia, but that electrocardiographic STE and NSTE patterns are not uniquely related to distinctly different pathophysiological mechanisms. Hence, in ACS, primary PCI might be considered regardless of the nature of the ST deviation, and it should be done with the shortest possible delay, because ‘time is muscle’.

P2Y12 Receptor Inhibitors in Acute Coronary Syndromes: What Is New on the Horizon?

Dual antiplatelet therapy with aspirin and a P2Y₁₂ receptor inhibitor represents the cornerstone therapy for patients with acute coronary syndromes or undergoing percutaneous interventions, leading to a reduction of subsequent ischemic events. Variable response to clopidogrel has received close attention, and pharmacokinetic, pharmacodynamic, and pharmacogenomic factors have been identified as culprits. This led to the introduction of newer, potentially safer, and more effective antiplatelet agents (prasugrel and ticagrelor). Additionally, several point-of-care assays of platelet function have been developed in recent years to rapidly screen individuals on antiplatelet therapy. While the routine use of platelet function testing is uncertain and not currently recommended, it may be useful in instances when the degree of platelet inhibition may be uncertain such as high-risk patients undergoing percutaneous coronary intervention or when there may be a suspected pharmacodynamic interaction with other drugs. The current paper focuses on the P2Y₁₂ receptor inhibitors and their pharmacogenetics and indications in patients with acute coronary syndromes or receiving percutaneous coronary interventions as well as the applicability of platelet function testing in this clinical context.

Regular primary care plays a significant role in secondary prevention of ischemic heart disease in a Western Australian cohort

BACKGROUND

Secondary prevention for established ischaemic heart disease (IHD) involves medication therapy and a healthier lifestyle, but adherence is suboptimal. Simply having scheduled regular appointments with a primary care physician could confer a benefit for IHD patients possibly through increased motivation and awareness, but this has not previously been investigated in the literature.

OBJECTIVE

To estimate the association between regular general practitioner (GP) visitation and rates of all-cause death, IHD death or repeat hospitalisation for IHD in older patients in Western Australia (WA).

DESIGN

A retrospective cohort design.

PARTICIPANTS

Patients aged  ≥  65 years (n  = 31,841) with a history of hospitalisation for IHD from 1992-2006 were ascertained through routine health data collected on the entire WA population and included in the analysis.

MAIN MEASURES

Frequency and regularity of GP visits was determined during a three-year exposure period at commencement of follow-up. A regularity score (range 0-1) measured the regularity of intervals between the GP visits and was divided into quartiles. Patients were then followed for a maximum of 11.5 years for outcome determination. Hazard ratios and 95% confidence intervals were calculated using Cox proportional hazards models.

KEY RESULTS

Compared with the least regular quartile, patients with greater GP visit regularity had significantly decreased risks of all-cause death (2(nd) least, 2(nd) most and most regular: HR = 0.76, 0.71 and 0.71); and IHD death (2(nd) least, 2(nd) most and most regular: HR = 0.70, 0.68 and 0.65). Patients in the 2(nd) least regular quartile also appeared to experience decreased risk of any repeat IHD hospitalisation (HR =  0.83, 95%CI 0.71-0.96) as well as emergency hospitalisation (HR = 0.81, 95%CI 0.67-0.98), compared with the least regular quartile.

CONCLUSIONS

Some degree of regular GP visitation offers a small but significant protection against morbidity and mortality in older people with established IHD. The findings indicate the importance of scheduled, regular GP visits for the secondary prevention of IHD.

Macrophage roles following myocardial infarction

Following myocardial infarction (MI), circulating blood monocytes respond to chemotactic factors, migrate into the infarcted myocardium, and differentiate into macrophages. At the injury site, macrophages remove necrotic cardiac myocytes and apoptotic neutrophils; secrete cytokines, chemokines, and growth factors; and modulate phases of the angiogenic response. As such, the macrophage is a primary responder cell type that is involved in the regulation of post-MI wound healing at multiple levels. This review summarizes what is currently known about macrophage functions post-MI and borrows literature from other injury and inflammatory models to speculate on additional roles. Basic science and clinical avenues that remain to be explored are also discussed.