Choose Your Poison
Moderate consumption of wine, and to a lesser extent, perhaps beer, appears to be associated with reduced vascular risk, according to a meta-analysis of 26 studies on the relationship between wine or beer consumption and vascular risk conducted by researchers reporting in this week’s issue of Circulation (Circulation. 2002;105:2836–2844). The analysis was led by Augusto Di Castelnuovo, MS, and colleagues at the Department of Vascular Medicine and Pharmacology at the Istituto de recherché Framacologiche Mario Negri, Consorzio Mario Negri Sud, Santa Maria Imbaro, Italy, and at the Center for High Technology Research and Education in Biomedical Sciences at Catholic University in Campobasso, Italy.
In 13 studies involving 209 418 people, the relative risk of vascular disease associated with the intake of wine was 0.68, relative to nondrinkers. In 10 studies, the evidence of a J-shaped relationship was clear, indicating that the vascular risk varied with different amounts of wine intake. The researchers reported that the statistically significant inverse relationship between wine intake and vascular risk existed with a daily intake of ≤150 mL of wine. In 15 studies involving 208 036 people, the relative risk of vascular disease associated with moderate beer consumption was 0.78, relative to nondrinkers. However, it was not possible to determine a meaningful relationship between amounts of beer consumed and vascular risk, the researchers reported.
In an associated editorial (Circulation. 2002;105:2806–2807) by Eric B. Rimm, ScD, of the Departments of Epidemiology and Nutrition at Harvard School of Public Health, and Meir J. Stampfer, MD, DrPH, of the Channing Laboratory, Department of Medicine at The Brigham and Women’s Hospital and Harvard School, the authors noted that the association between moderate alcohol consumption and reduced vascular risk has been documented in as many as 100 studies. “The finding of a strong interaction of alcohol intake and a common polymorphism in the gene for alcohol dehydrogenase strongly supports causality because such a result cannot plausibly be attributed to confounding factors (that is, the polymorphism can be considered as distributed at random with regard to other lifestyle practices like diet and exercise),” they wrote.
They note that although other studies have found a stronger inverse association for wine rather than beer, others have found the association to be virtually the same. “Thus, we concluded it was unlikely than any one beverage was substantially more beneficial. It is therefore helpful to examine their results in more detail and to explore the importance of potential biases, if any, that may have influenced the findings.”
They concluded, “To test the difference between the health effects of beverage preference, a trial may need to last for 1 to 2 years and measure risk factors, such as change in lipids, insulin sensitivity, hemostatic parameters, and oxidation status, and more complex markers of cardiovascular disease, such as change in intima-media thickness or carotid plaques. Even more creative approaches may be required because the power to detect small differences between beverages, if they exist at all, will be limited. Until such results are available, the interpretation of purported differences in the health effects of beverage type should be viewed cautiously.”
A Heart No Bigger Than a Thumb
Evidence from the first 10 patients to receive the tiny Jarvik 2000 implantable left ventricular assist system (LVAS), published in this issue of Circulation (Circulation. 2002;105:2855–2860), indicates that it can be safely used as bridge to transplantation, partially unloading the burden on the left ventricle, according to researchers from the Houston-based Texas Heart Institute’s Cullen Cardiovascular Laboratories, St Luke’s Episcopal Hospital, Jarvik Heart, Inc, in New York City, and Oxford Heart Centre in the United Kingdom. The researchers, led by O.H. Frazier, MD, noted that small, efficient, axial-flow pumps have the potential for improving the length and quality of life for patients with heart failure by unloading the left ventricle and “optimizing the patient’s hemodynamics.”
The patients who received the Jarvik LVAS were, on average, aged 51.3 years and in New York Heart Association class IV. The implanted system remained in place, on average, for 84 days. Within 2 days of the original implant surgery, the researchers noted a 43% increase in cardiac index, a decrease of 52% in capillary wedge pressure, and a significant decrease in systemic vascular resistance. While the patients were on the LVAS, inotropic support was unnecessary. Eight of the 10 patients became NYHA class I after physical rehabilitation. Seven of the patients received donor hearts, and 3 died while on the support system. No blood clots were observed during the support period.
In part, the reason for the Jarvik’s initial success was its placement, according to the researchers. “We believe there are definite advantages to an intraventricular pump. In our early experiments, an inlet cannula was shown to introduce abnormal rheology by generating negative pressure to fill the pump,” the researchers noted. The resulting deformation of the platelets was part of the reason they became activated and “may contribute to thrombosis and pannus formation in the inlet graft,” they concluded.
They had hoped that the Jarvik 2000 would be reliable, easy to implant, and simple to operate—goals that they felt were met in the current series. More recently, they noted, they had modified their procedure to allow the Jarvik to be implanted without placing the patient on cardiopulmonary bypass or with bypass time <10 minutes, a method that reduces surgical complications.
In an accompanying editorial (Circulation. 2002; 105:2808–2809), well-known heart surgeon Denton Cooley, MD, President and Surgeon-in-Chief of the Texas Heart Institute, noted the decades of work that had gone into the device. “At this early stage, the Jarvik 2000 seems to hold much promise for many patients with heart failure. . .LVAD (left ventricular assist device) therapy with the Jarvik 2000 has the potential to convert these seriously ill patients with heart failure from nonproductive consumers of healthcare resources into productive consumers as they resume active, high-quality lives.”
Fibroblast Growth Factor Gives TRAFFIC a Boost
Doses of recombinant fibroblast growth factor-2 (an angiogenic growth factor) appeared to increase the duration of walking times in patients with intermittent claudication who received the factor intra-arterially, according to researchers representing investigators in the Therapeutic angiogenesis with recombinant fibroblast growth factor-2 for intermittent claudication (TRAFFIC) study, which appears in the June 15, 2002, issue of Lancet (Lancet. 2002;359:2053–2058).
The study investigated whether 1 or 2 doses of the material improved exercise capacity in 190 patients with intermittent claudication caused by infrainguinal atherosclerosis. They were randomly assigned to receive 1 or 2 doses of either the growth factor or placebo. At 90 days, researchers measured the peak walking time. They found that peak walking time increased 0.60 minutes with placebo, 1.77 minutes with a single dose, and 1.54 minutes with a double dose of the growth factor.