Rosiglitazone (Avandia) Affects More Than Insulin Resistance
Six months of treatment with rosiglitazone (Avandia) appears to have lowered some inflammatory markers of cardiovascular disease and/or myocardial infarction risk, according to researchers from the University of Texas at San Antonio, Tufts-New England Medical Center in Boston, Mass, and GlaxoSmithKline, the maker of Avandia, who published their research in this week’s issue of Circulation (Circulation. 2002;106:679–684OpenUrl).
The researchers noted that after 26 weeks of treatment with rosiglitazone, patients’ serum showed a statistically significant reduction of the mean levels of C-reactive protein, matrix metalloproteinase-9 (which has been implicated in plaque rupture), and white blood cells. Reduction of interleukin-6, another marker considered, was small and not much different from placebo groups. The researchers, led by Steven M. Haffner, MD, of the University of Texas Health Science Center at San Antonio, concluded that rosiglitazone has an overall beneficial effect on the risk of cardiovascular disease because it reduces blood levels of matrix metalloproteinase-9 and C-reactive protein—both markers for heart disease risk.
Coronary Vascular Endothelial Dysfunction Has Prognostic Value
Impaired vascular endothelial function appears to be associated with an increased risk of cardiovascular events, such as death from heart disease, myocardial infarction, stroke, and unstable angina, according to researchers from the Cardiology Branch and the Office of Biostatistics Research at the National Heart, Lung, and Blood Institute in a report in this week’s issue of Circulation (Circulation. 2002;106:653–658OpenUrl).
The scientists, led by Julian P.J. Halcox, MA, MRCP, measured changes in coronary vascular resistance, epicardial diameter, endothelium-dependent function, and endothelium-independent vascular function in 308 patients who were undergoing cardiac catheterization. Of those patients, 132 had coronary artery disease and 176 did not. They were monitored for an average of 46 months.
Thirty-five of the patients suffered one of the index vascular events. The researchers found that changes in coronary vascular resistance and epicardial constriction were independent predictors of the events. Other independent factors included advancing age, coronary artery disease, and body mass index.
“Whether patients with endothelial dysfunction have more rapidly progressive atherosclerosis, as suggested by our data, will require confirmation in a prospective angiographic study,” the authors noted. “Likewise, these data raise another intriguing question: will interventions such as exercise, diet and pharmacological therapy that are designed to enhance endothelial function also improve prognosis. . .?”
The Oxygen You Breathe Predicts Your Future
Exercise capacity demonstrated by peak oxygen intake was the major long-term factor affecting the prognosis of 12 169 men who had had myocardial infarction, coronary artery bypass graft, or documented cases of ischemic heart disease in a provocative study conducted by researchers from the University of Toronto and George Washington University in Washington, DC. The study, which appears in this week’s issue of Circulation (Circulation. 2002;106:666–671), supports the use of rehabilitation to reduce the risks of patients who have suffered major heart disease.
The researchers, led by Terence Kavanagh, MD, of the University of Toronto, took measured peak cardiorespiratory exercise data from 12 169 men (aged 55 years, on average) who were candidates for cardiac rehabilitation. They then monitored the patients for an average of ≈8 years. During that period, there were 1336 cardiac and 2352 all-cause deaths.
The researchers found that measured peak oxygen intake was a powerful predictor of cardiac and all-cause deaths. “The data demonstrate that the primary factor influencing prognosis in coronary heart disease patients is the individual’s effort tolerance, as assessed objectively by the measurement of VO2peak,” they concluded.
“Whether a cardiac patient is referred for rehabilitation after MI [myocardial infarction], CABG [coronary artery bypass graft] or the onset of ischemic heart disease, the most important single predictor of both cardiac and all-cause deaths is the VO2peak as measured by cardiorespiratory testing. Even a small exercise-induced gain in aerobic power should thus make a major difference not only to functional capacity but also to survival prospects.”
More Fat Equals More Risk
Researchers from the Framingham Heart Study and related agencies found that the risk of heart failure increased with each increment of 1 in the body mass index (BMI)—meaning that people considered obese faced a doubled risk of heart failure. In a report published in the August 1, 2002, issue of The New England Journal of Medicine (N Engl J Med. 2002;347:305–313), the researchers, led by Satish Kenchaiah, MD, investigated the relationship between BMI (obtained by taking the weight in kilograms divided by the square of the height in meters) and heart failure in the 5881 subjects who were part of the historical Framingham study.
Of the subjects, 496 developed heart failure. The researchers determined that the increase in heart failure was 5% for men and 7% for women for each increment of 1 in the BMI. A BMI of 18.5 to 24.9 is considered normal; 25 to 29.9, overweight; and ≥30.0, obese.
“Our findings suggest that obesity is an important risk factor for heart failure in both women and men. Approximately 11 percent of cases of heart failure among men and 14 percent among women in the community are attributable to obesity alone. The contribution of obesity to the risk of heart failure has not been adequately recognized, and our observational data suggest that efforts to promote optimal body weight may reduce the risk of heart failure,” they wrote.