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Articles by K Nasir
Total Records ( 2 ) for K Nasir
  B. D Rosen , V. R.S Fernandes , K Nasir , T Helle Valle , M Jerosch Herold , D. A Bluemke and J. A.C. Lima
 

Background— Age and left ventricular (LV) hypertrophy are risk factors for the development of LV dysfunction and congestive heart failure. Our goal was to study the relationships of LV mass and age with myocardial dyssynchrony among asymptomatic participants of the Multi-Ethnic Study of Atherosclerosis.

Methods and Results— A total of 1100 individuals underwent tagged magnetic resonance imaging. Regional LV function was analyzed with the use of harmonic phase imaging. Time to peak systolic circumferential strain and strain rate were measured in 12 segments, and myocardial dyssynchrony was expressed as the SD of time to peak strain and strain rate. Relationships of age, LV mass, and myocardial perfusion with timing of strain, strain rate, and dyssynchrony were studied. There was a positive relationship between age and time to peak strain before (regression coefficient=0.37 ms/year of age; 95% confidence interval, 0.05 to 0.70; P=0.025) and after adjustment for demographic characteristics and risk factors (P=0.007). Positive associations between age and SD of time to peak strain (regression coefficient=0.33 ms/year of age; P=0.002) and SD of time to peak systolic strain rate were documented (P=0.045). Importantly, we found that LV mass index is directly related to time to peak strain (P<0.001), time to peak strain rate, and the SD of time to strain rate (P=0.001 for all). Finally, decreased myocardial perfusion at rest was associated with delayed contraction and increased extent of dyssynchrony.

Conclusions— In asymptomatic individuals, age, increased LV mass, and decreased myocardial perfusion are related to delayed myocardial contraction and greater extent of dyssynchrony. Increased dyssynchrony may mediate the association of myocardial dysfunction with age and LV hypertrophy.

  K Nasir , R. L McClelland , R. S Blumenthal , D. C Goff , U Hoffmann , B. M Psaty , P Greenland , R. A Kronmal and M. J. Budoff
 

Background— Whether measuring and reporting of coronary artery calcium scores (CACS) might lead to changes in cardiovascular risk management is not established. In this observational study, we examined whether high baseline CACS were associated with the initiation as well continuation of new lipid-lowering medication (LLM), blood pressure–lowering medication (BPLM), and regular aspirin (ASA) use in a multi-ethnic population-based cohort.

Methods and Results— The Multi-Ethnic Study of Atherosclerosis (MESA) is a prospective cohort study of 6814 participants free of clinical cardiovascular disease at entry who underwent CAC testing at baseline examination (examination 1). Information on LLM, BPLM, and regular ASA usage was also obtained at baseline and at exams 2 and 3 (average of 1.6 and 3.2 years after baseline, respectively). In this study, we examined (1) initiation of these medications at examination 2 among participants not taking these medications at baseline; and (2) continuation of medication use to examination 3 among participants already on medication at baseline. Among MESA participants, initiation of LLM, BPLM, and ASA was greater in those with higher CACS. After taking into account age, sex, race, MESA site, LDL cholesterol, diabetes mellitus, body mass index, smoking status, hypertension, systolic blood pressure, and socioeconomic status (income, education, and health insurance), the risk ratios for medication initiation comparing those with CACS >400 versus CACS=0 were 1.53 (95% confidence interval [CI], 1.08, 2.15) for LLM, 1.55 (95% CI, 1.10 to 2.17) for BPLM, and 1.32 (95% CI, 1.03 to 1.69) for ASA initiation, respectively. The risk ratios for medication continuation among those with CAC >400 versus CACS=0 were 1.10 (95% CI, 1.01 to 1.20) for LLM, 1.05 (95% CI, 1.02 to 1.08) for BPLM, and 1.14 (95% CI, 1.04 to 1.25) for ASA initiation, respectively.

Conclusions— CACS >400 was associated with a higher likelihood of initiation and continuation of LLM, BPLM, and ASA. The association was weaker for continuation than for initiation of these preventive therapies.

 
 
 
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