When is the Best Time for the Second Antiplatelet Agent in Non-St Elevation Acute Coronary Syndrome?

Dual antiplatelet therapy is a well-established treatment in patients with non-ST elevation acute coronary syndrome (NSTE-ACS), with class I of recommendation (level of evidence A) in current national and international guidelines. Nonetheless, these guidelines are not precise or consensual regarding the best time to start the second antiplatelet agent. The evidences are conflicting, and after more than a decade using clopidogrel in this scenario, benefits from the routine pretreatment, i.e. without knowing the coronary anatomy, with dual antiplatelet therapy remain uncertain. The recommendation for the upfront treatment with clopidogrel in NSTE-ACS is based on the reduction of non-fatal events in studies that used the conservative strategy with eventual invasive stratification, after many days of the acute event. This approach is different from the current management of these patients, considering the established benefits from the early invasive strategy, especially in moderate to high-risk patients. The only randomized study to date that specifically tested the pretreatment in NSTE-ACS in the context of early invasive strategy, used prasugrel, and it did not show any benefit in reducing ischemic events with pretreatment. On the contrary, its administration increased the risk of bleeding events. This study has brought the pretreatment again into discussion, and led to changes in recent guidelines of the American and European cardiology societies. In this paper, the authors review the main evidence of the pretreatment with dual antiplatelet therapy in NSTE-ACS.

[Angiographic geometric predictors of myocardial infarction are not associated with ultrasonographic markers of plaque vulnerability]. / Preditores geométricos angiográficos de infarto do miocárdio não são associados com marcadores ultra-sonográficos de vulnerabilidade da placa.

OBJECTIVE: Some angiographic geometric features of coronary lesions have recently been described as independent predictors of myocardial infarction. The purpose of this study was to correlate these geometric markers with intravascular ultrasound findings known to be associated with greater vulnerability to plaque rupture. METHODS: A total of 30 patients with stable coronary syndromes and de novo lesions (31 lesions) underwent coronary angiography and intravascular ultrasound (IVUS). For each lesion, angiographic geometric features (degree of symmetry, degree of stenosis, lesion length, and outflow angle) were correlated with the following ultrasound variables: type of plaque (soft, fibrous, mixed, or calcified), plaque burden and remodeling index. RESULTS: Mean lesion length was 9.2 +/- 4.4 mm, percent stenosis was 50.0% to 89.0% (mean 67.7 +/- 12.1%), inflow angles ranged from 8.48 degrees to 48.78 degrees (mean 24.0 +/- 11.4 degrees), outflow angles ranged from 8.30 degrees to 53.03 degrees (mean 23.8 +/- 11.7 degrees), and the symmetry index ranged from 0 to 1 (mean 0.56 +/- 0.32). On ultrasound evaluation, frequency of soft or calcified plaques, positive remodeling, and magnitude of plaque burden were not associated with any angiographic geometric feature (p > 0.05 for all analysis). CONCLUSION: Angiographic geometric features that predispose to acute occlusion do not correlate with IVUS morphologic and quantitative findings associated with plaque vulnerability.