Eplerenone: Will it have a role in the treatment of acute coronary syndromes?

Aldosterone is known to have multiple adverse cardiovascular effects that are reminiscent of but independent from angiotensin II. These effects include endothelial dysfunction, heightened thrombogenicity, inflammation, and reparative fibrosis, and have been described in experimental and human models of aldosterone excess. Recently a number of clinical investigations have demonstrated that mineralocorticoid receptor (MR) antagonism, even in conditions not traditionally associated with systemic activation of the renin-angiotensin II-aldosterone pathway, may provide additional benefits above and beyond angiotensin-converting enzyme (ACE) inhibition and angiotensin receptor blockade. The Eplerenone Neurohormonal Efficacy and Survival Study (EPHESUS) with eplerenone in patients who were post-myocardial infarction underscores the additive benefit of such a strategy in postinfarction patients that typify an at-risk population for recurrent cardiovascular events. The mechanisms operative in acute coronary syndromes (ACS), including inflammation, altered hemostasis, and endothelial dysfunction, overlap significantly with those seen in the EPHESUS patient population. One may therefore hypothesize that MR antagonism with eplerenone may be beneficial in patients with ACS. Another advantage of using eplerenone is that it offers the advantages of MR antagonism without the side effects due to blockade of other nuclear receptors such as the androgen and progesterone receptors. If MR blockade is found to be beneficial in patients with ACS, the potential reduction in morbidity, mortality, and health care costs are profound.     

Does the timing of treatment with intra-aortic balloon counterpulsation in cardiogenic shock due to ST-elevation myocardial infarction affect survival?

Abstract

Background: Intra-aortic balloon pump (IABP) counterpulsation and primary percutaneous coronary intervention (PCI) are standard treatment modalities in cardiogenic shock (CS) complicating acute myocardial infarction. The aim of this study was to investigate the impact of the timing of IABP treatment start in relation to PCI procedure.

Methods: Data were obtained from the SCAAR registry (Swedish Coronary Angiography and Angioplasty Registry) about 139 consecutive patients with CS due to ST-elevation myocardial infarction (STEMI) who received IABP treatment. The patients were hospitalized at Sahlgrenska University Hospital, Gothenburg, during 2004–2008. The cohort was divided into the two groups: group (A) in whom IABP treatment started before start of PCI (n = 72) and group (B) in whom IABP treatment started after PCI treatment (n = 67). The primary endpoint was 30-day mortality. Propensity score (PS) adjusted Cox proportional hazards regression was used to analyze predictors of 30-day mortality.

Results: Mean age was 66.5 ± 12 and 28% were women. All patients have received IABP treatment 30 min before or 30 min after primary PCI. 63% had diabetes and 28% had hypertension. 16% were active tobacco smokers. The mortality rate at 30 days was 38%. IABP treatment commenced before or after PCI was not an independent predictor of mortality (P = 0.72).

Conclusion: In this non-randomized trial the treatment with insertion of IABP before primary PCI in patients with CS due to STEMI is not associated with a more favorable outcome as compared with IABP started after primary PCI.     

What seals the inflammation in acute coronary syndromes?

Inflammation plays a key role in the development of acute coronary syndromes and its consequences. Coronary stenting provides improved mortality and morbidity in appropriate cases by several routes. However the beneficial effects of the coronary stenting on inflammation remain controversial as the coronary stenting might lead to--systemically detected--local inflammatory reaction.     

Does chronic Chlamydia pneumoniae infection increase the risk of myocardial injury? Insights from patients with non-ST-elevation acute coronary syndromes

Background Cumulative evidence suggests a positive association between Chlamydia pneumoniae (Cpn) infection and risk of future coronary events among patients with stable coronary artery disease. However, its prognostic role in unstable coronary syndromes is less well defined. Because Cpn immunoglobulin A (IgA) may be a more reliable indicator of chronic infection than immunoglobulin G (IgG), we speculated that in patients with non-ST-elevation acute coronary syndromes (ACS), this marker might serve as a more useful prognostic tool. Accordingly, we evaluated plasma samples acquired at presentation in 178 patients with ACS for a possible association between Cpn IgA titer and biochemical evidence of myocardial injury. Methods Cpn IgG (positive if ≥1:32), and IgA titers (positive if ≥1:16) were measured by use of the microimmunofluorescence technique in 70 patients with ACS in whom myocardial injury developed associated with their presenting events (elevated CK-MB and/or troponin I); and in 108 patients with ACS without such injury. The odds ratios (ORs) for myocardial injury associated with consecutive antibody titers were determined for each of Cpn IgG and IgA. Multiple logistic regression was applied to adjust for key baseline characteristics. Results Median age of subjects was 64 years; 63% were male and 33% were smokers. The median antibody titers among those with and without myocardial injury respectively were as follows: IgG (1:128 vs 1:128), IgA (1:32 vs <1:16, P = .2). The adjusted ORs for myocardial injury associated with consecutive IgA titers were as follows: IgA ≥1:16, adjusted OR 1.49 (P = .22); ≥1:32, OR 1.95 (P = .04); ≥1:64, OR 1.37 (P = .38); ≥1:128, OR 0.77 (P = .55). No significant trend was found for any IgG titer. Conclusions Among patients with non-ST-elevation ACS, a Cpn IgA ≥1:32 at presentation was associated with a significantly higher risk of myocardial injury complicating the presenting event. (Am Heart J 2002;144:987-94.)