Low-Dose Coated Aspirin Inadequate
Many patients taking daily low-dose enteric-coated aspirin to prevent cardiovascular events show incomplete platelet inhibition, reported Andrew O. Maree, M.D., of the Royal College of Surgeons, Dublin, and his associates.
In a study involving healthy volunteers, Dr. Maree and his associates found that enteric-coated aspirin was less effective than plain aspirin at achieving platelet inhibition. They then assessed platelet response in 131 patients with stable cardiovascular disease (median age 63 years) who were taking 75 mg of coated aspirin daily.
Fifty-eight of these subjects (44%) showed an inadequate response to aspirin therapy, a finding “of increasing importance because many patients who take aspirin … for secondary prevention of CV events now receive low-dose enteric-coated preparations,” the investigators said (J. Am. Coll. Cardiol. 2005;47:1258–63).
Patient weight, body mass index, and age were significant predictors of this so-called aspirin resistance, with heavier and younger patients less likely to respond to aspirin therapy. It's likely that coated aspirin is less bioavailable than plain aspirin, which makes low doses of it insufficient to inhibit platelets in larger patients. It's also possible that younger patients are less responsive to aspirin because they have not yet developed age-related increases in drug sensitivity.
ED Signals Early Atherosclerosis
Erectile dysfunction predicted both the presence and the severity of subclinical coronary atherosclerosis in a study of 143 men, independently of traditional CAD risk factors, according to Emilio Chiurlia, Ph.D., and his associates at the University of Modena (Italy) Institute of Cardiology.
The researchers used CT-based estimates of coronary artery calcification to noninvasively assess 70 men with ED but no known CAD, as well as 73 control subjects matched for age, race, and coronary risk score. Asymptomatic atherosclerosis was more prevalent and more severe in the ED group. Endothelial function was significantly impaired in the ED patients, and their levels of subclinical systemic inflammation were significantly higher than those of controls (J. Am. Coll. Cardiol. 2005;46:1503–6).
“These data suggest that ED may be the earliest manifestation of a generalized vascular disease and that these patients may be at an increased risk of later developing CAD,” the investigators said.
Black Ethnicity a Risk Factor for PAD
African Americans have a significantly higher probability of developing peripheral artery disease than other ethnic groups—so much so that black ethnicity “can now be considered a consistent and independent risk factor for PAD at a magnitude similar to that of other established risk factors,” reported Michael H. Criqui, M.D., and his associates at the University of California, San Diego.
The researchers assessed the prevalence of PAD in a study of 2,343 current and retired UCSD employees and their spouses. They found 104 cases of PAD, for an overall prevalence of 4.4%. Blacks had the highest prevalence of PAD (7.8%), followed by whites (4.9%), Hispanics (1.8%), and Asians (1.4%) (Circulation 2005;112:2703–7).
The reason for this excess in PAD remains unknown. Although black subjects in general had lower occupational status and higher rates of diabetes and hypertension, those factors only partly accounted for their excess risk. It is possible that blacks have a greater genetic susceptibility to PAD, or that some unmeasured psychosocial variables may play a role, the investigators said.
Dyspnea Tied to High Mortality Risk
Patients who present for noninvasive cardiac testing with the sole symptom of dyspnea are at increased risk for cardiac death and death from any cause, even if they have no evidence of coronary artery disease or left ventricular systolic dysfunction.
This finding, from a study of nearly 18,000 subjects followed for a mean of 2 years, suggests that it may be appropriate to evaluate dyspnea in all patients referred for cardiac testing, said Aiden Abidov, M.D., Ph.D., of Cedars-Sinai Medical Center, Los Angeles, and his associates.
The researchers collected data on dyspnea from all patients undergoing myocardial-perfusion SPECT at rest and during exercise testing. They assessed data on 17,991 such patients and found that those with dyspnea but no other symptoms had a fourfold higher risk of cardiac death and more than twice the risk of noncardiac death during follow-up than patients with typical angina (N. Engl. J. Med. 2005;353:1889–98).
In an editorial, Thomas H. Marwick, M.B., Ph.D., of the University of Queensland, Brisbane, Australia, noted that these results “should remind us that cardiac symptoms other than chest pain are of value in evaluating patients with suspected CAD” (N. Engl. J. Med. 2005;353:1963–4).