Heart disease is the biggest killer in the industrialized world, making it a critical target for research. On Nov. 13-16, scientists presented 3,800 studies at the American Heart Assn.'s annual Scientific Sessions in Dallas. Some highlights...
How useful is that inflatable cuff that measures blood pressure in the arm? Doctors have long assumed this widely used measure reflected blood pressure throughout the body, but now it appears that pressure around the heart can be very high -- a sign that a heart attack could be imminent -- and still be normal in the arm.
A research team led by Dr. Bryan Williams of Britain's University of Leicester tested the standard arm cuff against the SphygmoCor system made by Australia's AtCor Medical in Sydney. This computerized monitoring device estimates pressure in the central aorta by measuring the pulse wave in the wrist.
The researchers were particularly eager to find out why patients in an earlier study who took Norvasc, a blood-pressure-lowering drug from Pfizer (PFE), had a 14% lower risk of death than those on beta blockers and diuretics, despite virtually identical blood pressure readings. Testing 2,199 patients with the SphygmoCor, they found substantial differences in blood pressure around the heart between the two groups.
Using stem cells to repair damaged organs is still more dream than reality. But researchers are getting close with heart disease -- especially when they use progenitor cells that are derived from stem cells found in the patients' bone marrow.
Embryonic stem cells can develop into many tissues, including bone, muscle, or heart. But in experiments, they have proved difficult to control -- whereas adult progenitor cells seem to obey orders. In a study involving 204 patients at 17 medical centers in Europe, a team led by Dr. Volker Schachinger of Goethe University in Frankfurt infused progenitor cells into the hearts of half of the group, while the other half received placebo infusions. After four months, the hearts of patients who received the cells showed twice as much pumping activity as the control group. And the benefits were most pronounced in those patients who had suffered the most damage from heart attacks.
Statin drugs fight heart disease by lowering "bad" cholesterol, called low- density lipoprotein (LDL). But the drugs may be bumping up against their limitations. In a six-year study of 8,800 patients, half were given 80 milligrams of Pfizer's Lipitor while the other half got 20 to 40 mg of Merck's statin Zocor. Although the Lipitor group achieved lower LDL levels, there was no great disparity in overall death rates, acute heart attacks, or cardiac arrest, compared with the Zocor group. The study was headed by Norway's Dr. Terje Pedersen of Ulleval University Hospital in Oslo.
-- Anti-smoking ordinances seem to improve heart health. Heart attack rates fell by 27% in the 18 months after a 2003 ban on smoking in all public spaces took effect in Pueblo, Colo., a city of 104,000 people. The study's lead author, Dr. Mori J. Krantz of the Colorado Prevention Center, says that 399 heart attack patients were admitted to the city's hospitals in the 18 months before the ban went into effect. In a comparable period afterwards, there were only 291 heart attack admissions. Neighboring communities with no smoking ban showed no change in admission rates over the same period. Krantz attributed much of the decline in hospital admissions to a drop in secondhand smoke, which has the ability to worsen cardiovascular health within minutes of exposure.
-- In two studies involving 2,000 smokers, 44% of those taking Pfizer's anti-smoking drug, Varenicline, quit smoking after 12 weeks, compared with 30% on Zyban, an existing GlaxoSmithKline product designed to ease nicotine cravings. Only 17.7% of those on a placebo quit. In a one-year, follow-up study, 22.1% of the Varenicline group were smoke-free, Pfizer reports.