Обзор американских кардиологических журналов за неделю (ссылки)

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Title: Metabolic Syndrome and Risk of Acute Myocardial Infarction: A Case-Control Study of 26,903 Subjects From 52 Countries
Topic: Prevention/Vascular
Date Posted: 5/18/2010
Author(s): Mente A, Yusuf S, Islam S, et al., on behalf of the INTERHEART Investigators.
Citation: J Am Coll Cardiol 2010;55:2390-2398.
Clinical Trial: No
Related Resources
JACC Article: Metabolic Syndrome and Risk of Acute Myocardial Infarction: A Case-Control Study of 26,903 Subjects From 52 Countries
Trial: A Study of Risk Factors for First Myocardial Infarction in 52 Countries and Over 27,000 Subjects (INTERHEART)

Study Question: What is the risk of acute myocardial infarction (MI) conferred by the metabolic syndrome (MS) and its individual factors in multiple ethnic populations?
Methods: Participants in the INTERHEART study (n = 26,903) involving 52 countries were classified using the World Health Organization (WHO) and International Diabetes Federation (IDF) criteria for MS, and their odds ratios (ORs) for MI were compared with the individual MS component factors.
Results: The MS is associated with an increased risk of MI, both using the WHO (OR, 2.69; 95% confidence interval [CI], 2.45-2.95) and IDF (OR, 2.20; 95% CI, 2.03-2.38) definitions, with corresponding population attributable risks of 14.5% (95% CI, 12.7-16.3%) and 16.8% (95% CI, 14.8-18.8%), respectively. The associations are directionally similar across all regions and ethnic groups. Using the WHO definition, the association with MI by the MS is similar to that of diabetes mellitus (OR, 2.72; 95% CI, 2.53-2.92) and hypertension (OR, 2.60; 95% CI, 2.46-2.76), and significantly stronger than that of the other component risk factors. The clustering of ≥3 risk factors with subthreshold values is associated with an increased risk of MI (OR, 1.50; 95% CI, 1.24-1.81) compared with having component factors with “normal” values. The IDF definition showed similar results.
Conclusions: In this large-scale, multi-ethnic, international investigation, the risk of MS on MI is generally comparable to that conferred by some, but not all, of its component risk factors. The characterization of risk factors, especially continuous variables, as dichotomous will underestimate risk and decrease the magnitude of association between MS and MI.
Perspective: The risk of MI was not significantly associated with MS among North Americans, although subanalyses by ethnicity show that MS is consistently associated with MI. The authors suggested this may reflect the heterogeneity of the subjects recruited from Canada and the United States. Because fasting samples were not available, it is not possible to draw conclusions about the value of triglycerides as used in the Adult Treatment Panel III definition for the MS. An interesting and intuitive finding is that clinical clustering of subthreshold values for MS parameters is associated with an increased risk of MI, a finding that has considerable importance when discussing potential value of lifestyle changes in men and women. Melvyn Rubenfire, M.D., F.A.C.C.

Title: Intravascular Ultrasound-Derived Measures of Coronary Atherosclerotic Plaque Burden and Clinical Outcome
Topic: Noninvasive Cardiology
Date Posted: 5/18/2010
Author(s): Nicholls SJ, Hsu A, Wolski K, et al.
Citation: J Am Coll Cardiol 2010;55:2399-2407.
Clinical Trial: No
Related Resources
JACC Article: Intravascular Ultrasound-Derived Measures of Coronary Atherosclerotic Plaque Burden and Clinical Outcome

Study Question: What is the relationship between intravascular ultrasound (IVUS)-derived measures of atherosclerosis and cardiovascular outcomes?
Methods: The authors evaluated coronary plaque progression as assessed by IVUS in 4,137 patients enrolled in six clinical trials, and assessed the association between baseline and change in percent atheroma volume (PAV) and total atheroma volume with incident major adverse cardiovascular events (MACE).
Results: There was an increase in PAV by 0.3% (p < 0.001) over the study period. MACE occurred in 19.9% of subjects, with most of the events being coronary revascularization (0.9% death, 1.8% myocardial infarction, 18.9% coronary revascularization). Patients with evidence of greater baseline PAVs were more likely to experience a myocardial infarction (PAV 42.2% vs. 38.6%), and coronary revascularization (41.2% vs. 38.1%). The average follow-up was 21 months. Greater increases in PAV were observed in subjects who experienced coronary revascularization compared with those who did not (0.96% vs. 0.46%, p < 0.001). After adjusting for other factors, independent predictors of MACE were baseline PAV, change in PAV, smoking, and hypertension.
Conclusions: There is a direct association between baseline burden of atherosclerosis, its progression, and occurrence of MACE.
Perspective: Multiple trials have used IVUS to assess change in plaque burden as a surrogate for anti-atherosclerotic efficacy of various therapeutic agents, although there are limited data to suggest that these changes in plaque correlate with reduction in hard clinical events. This study provides some evidence that slower progression of plaque may be associated with a reduction in clinical events, although this was driven predominantly by fewer myocardial revascularizations. Further studies are needed to clarify if plaque imaging can help predict hard events and whether it can be used as a surrogate marker for evaluation of hard clinical events. Hitinder S. Gurm, M.B.B.S., F.A.C.C.