Обзор американских кардиологических журналов за неделю (ссылки)

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Title: Impact of Pressure Recovery on Echocardiographic Assessment of Asymptomatic Aortic Stenosis: A SEAS Substudy
Topic: Noninvasive Cardiology
Date Posted: 6/9/2010 5:00:00 PM
Author(s): Bahlmann E, Cramariuc D, Gerdts E, et al.
Citation: JACC Cardiovasc Img 2010;3:555-562.
Clinical Trial: No
Related Resources
Trial: Simvastatin and Ezetimibe in Aortic Stenosis (SEAS)

Study Question: What is the diagnostic importance of pressure recovery in the evaluation of aortic stenosis (AS) severity?
Methods: Data from 1,563 patients in the SEAS (Simvastatin and Ezetimibe in Aortic Stenosis) study were used. Inner aortic diameter was measured at the annulus, sinuses of ********, sinotubular junction, and supracoronary level. Aortic valve area index (AVAI) was calculated by the continuity equation, and pressure recovery and pressure recovery adjusted AVAI (energy loss index [ELI]) were calculated by validated equations. Primarily, sinotubular junction diameter was used to calculate pressure recovery and ELI, but pressure recovery and ELI calculated at different aortic root levels were compared. Severe AS was identified as AVAI and ELI ≤0.6 cm2/m2. Patients were grouped in tertiles of peak transaortic velocity.
Results: Pressure recovery increased with increasing peak transaortic velocity. Overestimation of AS severity by unadjusted AVAI was largest in the lowest tertile, and if pressure recovery was assessed at the sinotubular junction. In multivariate analysis, a larger difference between AVAI and ELI was associated with lower peak transaortic velocity (beta = 0.35) independent of higher left ventricular ejection fraction (beta = -0.049), male sex (beta = -0.075), younger age (beta = 0.093), and smaller aortic sinus diameter (beta = 0.233) (multiple R2 = 0.18, p < 0.001). Overall, 47.5% of patients classified as having severe AS by AVAI were reclassified to nonsevere AS when pressure recovery was taken into account.
Conclusions: For accurate assessment of AS severity, pressure recovery adjustment of AVA should be routinely performed. Estimation of pressure recovery at the sinotubular junction is suggested.
Perspective: Success can breed complacency. Doppler echocardiography has been appropriately accepted as the ‘gold standard’ for hemodynamic assessment of heart valve disease. Exceptions to the rules, instances in which echo/Doppler substantially under- or over-estimates transvalvular stenosis severity, have been well described, but are clinically neglected. Since its early recognition as a factor in Doppler estimation of valve stenosis, pressure recovery has taken on the role of a curiosity, occurring only in certain unusual clinical settings. However, this study serves as a wake-up call. Echo/Doppler rightly deserves to be the ‘gold standard’ for the assessment of valve hemodynamics, but it must be done right. If pressure recovery accounts for a change in the clinical grade of AS severity in a substantial number of patients with AS, then considering the impact of pressure recovery should become routine practice in the clinical echocardiography laboratory. The bad news is that a little bit of physics might have to find its way back into the world of cardiology. David S. Bach, M.D., F.A.C.C.

Title: Population Trends in the Incidence and Outcomes of Acute Myocardial Infarction
Topic: General Cardiology
Date Posted: 6/9/2010 5:00:00 PM
Author(s): Yeh RW, Sidney S, Chandra M, Sorel M, Selby JV, Go AS.
Citation: N Engl J Med 2010;362:2155-2165.
Clinical Trial: No
Study Question: Have trends in the incidences and outcomes related to acute myocardial infarction (AMI) changed in recent times?
Methods: Data from Kaiser Permanente Northern California, a large, community-based population of patients hospitalized for AMI, were used for the present analysis. Patients were included if they were 30 years or older and experienced an AMI between 1999 and 2008. Patient characteristics, outpatient medications, and cardiac biomarker levels were identified from health plan databases. Mortality (30-day) was assessed through administrative databases, state death data, and Social Security Administration files. The outcomes of interest were age- and sex-adjusted incident rates of AMI, ST-elevation myocardial infarction (STEMI), and non-STEMI (NSTEMI).
Results: A total of 46,086 hospitalizations for AMI over 18,691,131 person-years of follow-up (from 1999 to 2008) were included. The majority of AMIs were NSTEMIs (66.9%) and 33.1% were STEMIs. The proportion of STEMIs decreased over time, from 47% in 1999 to 22.9% in 2008. Age- and sex-adjusted incidence of MI increased from 274 cases per 100,000 person-years in 1999 to 287 cases per 100,000 person-years in 2000, after which a decline was observed to 208 cases per 100,000 person-years in 2008. This represented a 24% relative decrease over the time period examined. For STEMI, both the age- and sex-adjusted incident rate decreased over time from 133 cases per 100,000 person-years in 1999 to 50 cases per 100,000 person-years in 2008. The incidence of NSTEMI increased from 155 cases per 100,000 person-years in 1999 to 202 cases per 100,000 person-years in 2004, after which rates decreased. In more recent years, patients hospitalized with AMI were more likely to be older, female, and have coexisting illness including hypertension, diabetes mellitus, and dyslipidemia. The number of patients who underwent revascularization procedures within 30 days after AMI increased from 40.7% in 1999 to 47.2% in 2008. For patients admitted with STEMI, the rates of revascularization increased from 49.4% in 1999 to 69.6% in 2008. For patients with NSTEMI, the rates of revascularization increased from 33.4% in 1999 to 41.3% in 2008. Age- and sex-adjusted 30-day mortality decreased from 10.5 in 1999 to 7.8% in 2008. This decrease was largely due to a reduction in case fatality rates for NSTEMI (from 10.0% in 1999 to 7.6% in 2008). No significant changes were observed for STEMI. The adjusted odds of 30-day mortality in 2008 as compared to 1999 was 0.76 (95% confidence interval [CI], 0.65-0.89). The adjusted odds of 30-mortality over time for patients with NSTEMI was 0.82 (95% CI, 0.67-0.99) and the odds of 30-mortality over time for patients with STEMI was 0.93 (95% CI, 0.71-1.20).
Conclusions: The investigators concluded that in this population, the incidence of AMI has decreased over time with a significant reduction in the incidence of STEMI as well as a lower death rate after NSTEMI. Potential factors related to the decline in AMI rates include smoking bans, and improved management of blood pressure and lipids.
Perspective: These data demonstrated an encouraging trend in the reduction of AMI. However, continued efforts to prevent AMI, in particular NSTEMI, are warranted. Given the prevalence of obesity and related cardiac risk factors such as hypertension and diabetes mellitus, continued aggressive prevention measures combined with monitoring of population trends are needed. Elizabeth A. Jackson, M.D., F.A.C.C.