Metabolic Syndrome, Stroke, and Heart Attack
A strong positive association between stroke and myocardial infarction and the constellation of cardiovascular risk factors known as metabolic syndrome has been demonstrated in a retrospective study of subjects who participated in the National Cholesterol Education Program Adult Treatment Panel III (NCEP-ATP III) published in this week’s issue of the journal Circulation (Circulation. 2004;109:42–46OpenUrl).
In a study by researchers at the University of California, San Diego; representatives of Ingenix Epidemiology in Auburndale, Mass; and researchers at Bristol-Myers Squibb Pharmaceutical Research Institute in Princeton, NJ, 10 357 participants in the national study were evaluated for insulin resistance, abdominal obesity based on waist circumference, hypertriglyceridemia, low high-density lipoprotein cholesterol, and hypertension, as well as for the full metabolic syndrome of which these are important factors. Researchers determined that subjects had the full syndrome if they demonstrated 3 of the component factors. They correlated the factors as well as the syndrome with a history of myocardial infarction or stroke. The results were adjusted for age, sex, race, and a history of tobacco use.
Metabolic syndrome was significantly associated with myocardial infarction and stroke in both men and women.
The researchers wrote: “These findings reaffirm the clinical importance of the metabolic syndrome as a significant risk factor for cardiovascular disease and the need to develop strategies for controlling this syndrome and its component conditions.”
Genes and the Hearts of Danes
A gene mutation (R213G) may increase the risk of developing atherogenesis. In a study in this week’s issue of the journal Circulation (Circulation. 2004;109:59–65), Danish researchers participating in The Copenhagen City Heart Study hypothesized that in the 2% to 3% of Danes who carry an R213G substitution, the plasma concentration of extracellular superoxide dismutase—an antioxidative enzyme abundant in the arterial wall—the plasma concentrations of the enzymes are increased 10-fold. They thought that the subsequent reduction in the concentration of the enzyme in the arterial wall could result in increased intimal low-density lipoprotein oxidation and cause accelerated atherogenesis and a predisposition to heart disease.
In a study of 9188 participants in the Copenhagen City Heart Study with 956 incidents of ischemic heart disease events during a 23-year follow-up, those with a history of ischemic heart disease events were matched to subjects who had no heart disease or stroke history. They found that those who were heterozygous for the genetic mutation were predisposed to develop ischemic heart disease and that the genotyping provided an important predictive tool.
Results from a randomized, prospective study comparing off-pump coronary artery bypass surgery with and without the cardiopulmonary bypass pump provided mixed reviews of the outcomes of the two techniques. Although off-pump surgery was found as safe as on-pump surgery, graft patency appeared more durable in the on-pump group that received a more classical form of surgery, said researchers in a report in the January 1, 2004, issue of The New England Journal of Medicine (N Engl J Med. 2004;350:21–28OpenUrlCrossRefPubMed).
In this study by British and Swiss researchers, 50 patients were randomly assigned to undergo on-pump coronary artery bypass grafting and 54 to receive off-pump surgery. Three months after the surgery, all patients underwent coronary angiography to determine graft patency. At that time, 127 of the 130 grafts received by the on-pump group were patent. In contrast, 114 of the 130 grafts received by the off-pump group were patent. The researchers wrote: “In this randomized study, off-pump coronary surgery was as safe as on-pump surgery and caused less myocardial damage. However, the graft-patency rate was lower at three months in the off-pump group than in the on-pump group, and this difference has implications with respect to the long-term outcome.”
In an accompanying perspective (N Engl J Med. 2004;350:3–4), Thomas E. MacGillivray, MD, and Gus J. Vlahakes, MD, from the Division of Cardiac Surgery, Massachusetts General Hospital, Boston, wrote: “The surgical treatment options must be tailored to each patient in order to optimize the benefits and minimize the risk of detrimental effects. In deciding whether or not to use the pump, surgeons should consider which intervention would maximize the long-term benefits of coronary-artery revascularization while minimizing the risks. . . . Methods of treatment should not compete for patients but should be selected according to individual patients’ needs in order to optimize their care.”