Two Tests Aid in Identifying Heart Disease
A high level of lead in the bloodstream has long been recognized as a significant health risk, particularly in children, a study conducted at the Tulane University School of Medicine suggests that even low levels of lead may be associated with an increased risk for significant cardiovascular disease (stroke and/or heart attack).
The report, which will appear in the September 26th issue of Circulation, was based on an analysis of datafrom 13,946 adult subjects who had participated in the Third National Health and Nutrition Examination Survey from 1988 to 1994 and were subsequently followed for up to 12 years.
The average serum lead level in the study population was 2.58 micrograms/dL. Subjects with levels of 3.62 micrograms/dL (mcg/dL) or higher were 25% and 55% more likely to die from all causes and cardiovascular etiologies, respectively, than those subjects with levels below 1.94 mcg/dL.
The authors of this report admitted that they did not analyze the potential risk, if any, that may be associated with a serum lead level = 2.0 mcg/dL nor did they attempt to evaluate the possibility that socio-economic factors such as poverty or environmental pollution were associated with the higher lead levels.
Discussion
Conclusive evidence that lead poses a significant health risk in preschool and school-age children has been available for years but there has been relatively little published data regarding lead and long-term health risks in the adult population. The research summarized above will hopefully motivate further research in this area.
Citation:
Menke, A. et al. Blood Lead Below 0.48 �µmol/L (10 �µg/dL) and Mortality among US Adults.Circulation 2006; 114: In Press.
Computed Tomography versus Magnetic Resonance Imaging in the Detection of Coronary Artery DiseaseThe results of a study that compared the accuracy of computed tomography (CT) and Magnetic Resonance Imaging (MRI) in the detection of coronary artery disease appears in the September 19, 2006 issue of theAnnals of Internal Medicine.
129 consecutive patients that had been referred to a medical center in Berlin, with a provisional diagnosis of suspected coronary artery disease were examined by both multislice CT and MRI. Of the 129, 108 subjects (representing a total of 480 coronary arteries) were subsequently examined by coronary angiography within 24 hours. The results of the CT and MRI exams were evaluated against the angiography data.
When compared with the angiography results CT was 92% sensitive in diagnosing CAD compared to 74% for MRI. The difference in sensitivities was even more pronounced regarding clinically significant stenoses (= 50% by diameter) where CT was 82% sensitive as opposed to 54% for MRI.
In per-vessel analysis, multislice CT had a specificity of 90% and a negative predictive value of 95% in diagnosing CAD. The corresponding values for MRI were lower, being reported as 87% specific and a negative predictive value of 90%.The authors identified several weaknesses in their protocol that may have influenced the results. These included a relatively small sample population and that their results were based on results from a single institution.
Discussion
This study adds to the ever-increasing amount of data suggesting that multislice CT (a technique that allows reliable detection of smaller objects such as the inner diameter of arteries) may well become part of the evaluation of patients presenting with atypical (not suggesting a cardiac origin) chest pain and either a low or moderate risk for CAD.
As health care facilities are facing an increasing demand for services caused by an aging population base, studies such as this will prove valuable in the determination of which patients would benefit from a more aggressive approach to management of their chest pain.
Citation:Dewey, M. et al. Noninvasive Detection of Coronary Artery Stenoses with Multislice Computed Tomography or Magnetic Resonance Imaging.Ann Intern Med 2006; 145:407-415,466-467.
Disclaimer
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