High Systolic Blood Pressure Increases Cardiovascular Risk
High systolic blood pressure increases the risk of a cardiovascular event in women who have heart disease or at least 3 risk factors for it, said researchers who participated in a Women’s Antioxidant Cardiovascular Study (WACS) in a report in this week’s Circulation (Circulation. 2004;109:1623–1629OpenUrl). Surprisingly, the researchers, led by Peter J. Mason, MD, MPH, of Harvard Medical School, noted that use of antihypertensive medication “did not modify the relationship between systolic blood pressure and cardiovascular events.”
WACS is a double-blind, placebo-controlled, secondary prevention trial in which the value of taking antioxidant vitamins, folic acid, vitamin B5, and vitamin B12 is being tested. In this substudy, 5218 women were monitored for 6.5 years. There were 661 confirmed events (nonfatal myocardial infarction, nonfatal stroke, coronary artery bypass graft procedure, percutaneous coronary angioplasty, or cardiovascular disease death) during that time. In this group, systolic blood pressure was a strong predictor of cardiovascular events. For each 10-mm Hg increase in systolic blood pressure, there was a 9% increase in the risk of cardiovascular events. Weaker predictors of risk were diastolic blood, mean arterial, and pulse pressures.
The researchers wrote: “Our data suggest that women with CVD [cardiovascular disease] and borderline elevations in SBP [systolic blood pressure] are at increased risk of future events and might benefit from a lower targeted BP [blood pressure].”
HIV Patients Have Higher Carotid Intima-Media Thickness
Patients with HIV had higher carotid intima-media thickness than age-matched control subjects who did not have the virus, said researchers in a report that appeared in this week’s issue of the journal Circulation (Circulation. 2004;109:1603–1608OpenUrl).
In this study, conducted by San Francisco General Hospital and the Department of Medicine, University of California, San Francisco, blood lipids, inflammatory markers, and carotid intima-media thickness were measured in 146 HIV-infected adults and in 63 age- and sex-matched control subjects. Patients had had HIV for an average of 11 years, and they had been on highly active antiretroviral therapy, including protease inhibitors, for an average of 3.3 years.
Mean intima-media thickness at baseline was 0.91 mm in patients with HIV and 0.74 mm in the control patients. Predictors of the baseline intima-media thickness in those with HIV were low-density lipoprotein cholesterol, number of cigarette packs smoked per year, Latino race, and hypertension. When control patients were added to the analysis, HIV infection was an independent predictor of increased intima-media thickness. The rate of progression among the 121 patients with HIV was 0.074 mm at 1 year, compared with 0.006 mm among the matched controls.
The researchers, led by Priscilla Y. Hsue, MD, wrote: “Carotid IMT [intima-media thickness] is higher in HIV patients than in age-matched control subjects and progresses much more rapidly than previously reported rates in non-HIV cohorts.”
C-Reactive Protein a Moderate Coronary Heart Disease Predictor
C-reactive protein can be moderately used to predict coronary heart disease, said researchers from the United Kingdom in a report in the April 1, 2004, issue of The New England Journal of Medicine (N Engl J Med. 2004;350:1387–1397OpenUrlCrossRefPubMed).
The researchers led by John Danesh, MB, ChB, DPhil, of the Department of Public Health and Primary Care, University of Cambridge, Cambridge, United Kingdom, obtained baseline measurements of inflammatory markers in 2459 patients who had nonfatal myocardial infarctions or died of coronary heart disease during the period of the study. They had baseline measurements taken from 3969 controls who had no coronary heart disease events in a prospective study of 18 569 participants in a study in Reykjavik, Iceland. Measurements were also made in paired samples obtained 12 years apart from 379 of the participants to quantify fluctuation of inflammatory markers within individual subjects.
They found that C-reactive protein was a stronger predictor of coronary artery disease than the erythrocyte sedimentation rate and the von Willebrand factor concentration but was weaker than established risk factors such as an increased cholesterol concentration and cigarette smoking.
A meta-analysis performed by the authors confirmed the moderate value of C-reactive protein information.
They wrote: “In comparison with major established risk factors (such as an increased total serum cholesterol concentration and cigarette smoking), the C-reactive protein concentration was a relatively moderate predictor of the risk of coronary heart disease and added only marginally to the predictive value of established risk factors for coronary heart disease. These findings suggest that recent recommendations regarding the use of measurements of C-reactive protein in the prediction of coronary heart disease may need to be reviewed.”
In an accompanying editorial (N Engl J Med. 2004;350:1450–1451), Alan R. Tall, MB, BS, of Columbia University Medical Center in New York, noted that the risk levels associated with C-reactive protein in this study are somewhat less than those seen in previous large studies.
“The new findings call into question the clinical value of measuring CRP [C-reactive protein] as a predictor of the risk of CHD [coronary heart disease] and indicate that further research is needed to clarify the place of this approach in clinical medicine,” he wrote. “Although these findings confirm pioneering work showing that the CRP level is an indicator of the risk of CHD, they call into question the magnitude of the effect.”
However, he pressed for more definitive work to determine markers of cardiovascular disease. “There is a pressing need for research that will lead to the development of better genetic, biochemical, or imaging indicators of risk and thus allow the earlier identification of patients who are at risk for CHD and stroke,” he wrote.