A jolt to decaf drinkers
Answering the “decaf or regular” question has become more problematic.
Caffeine can give some people the jitters, keeping them awake or speeding up their heart rate, but decaffeinated coffee, researchers have found, may be bad for your heart.
Java without the jolt increases the levels of so-called bad cholesterol in the bloodstream and reduces levels of good cholesterol, researchers reported last week at a meeting of the American Heart Assn. in Dallas. Among other research presented were studies on growing blood vessels in labs and performing angioplasty through an opening in the wrist.
Dr. H. Robert Superko, who presented the study on decaffeinated coffee, said the problem might have less to do with whether caffeine is present than with the nature of the beans used to make the coffee.
The decaffeination process removes flavonoids and other ingredients that give coffee its flavor. Manufacturers of decaf overcome this problem by replacing the normal Arabica coffee species with beans from the robusta species, which has higher concentrations of flavoring agents, said Superko, who is director of the Fuqua Heart Center in Atlanta, but who did the research while a faculty member at Stanford University.
Unfortunately, robusta also has higher levels of fats, which can alter cholesterol concentrations in the bloodstream.
For the government-sponsored research, Superko enrolled 187 people in a three-month study and randomly assigned them to one of three groups: those who drank three to six cups of regular coffee daily, those who drank three to six cups of decaf and those who drank no coffee.
Each coffee drinker in the study was given a coffeemaker, premeasured bags of coffee and precise instructions on how to prepare the coffee. All drank the coffee black.
After three months, those drinking the decaf had lipid levels in their blood that were 8% to 18% above normal; people in the regular-coffee and no-coffee groups had normal lipid levels. The lipids are precursors of low-density lipoprotein, bad cholesterol.
Though provocative, the differences were small. “I don’t think there’s a health threat” associated with either type of coffee, Superko said.
Dr. Donald Lavan, a cardiologist at the University of Pennsylvania and a spokesman for the heart association, agreed. “That’s interesting, but it would not affect my recommendations to patients,” he said.
Also at the meeting, researchers from a small Novato, Calif., company reported the first implant into humans of blood vessels grown in a laboratory. The synthetic vessels could find wide use in diabetics who must undergo routine kidney dialysis, children born with defective blood vessels and patients undergoing heart bypass surgery.
“We think there are a large number of patients who could benefit from tissue-engineered vessels,” said Dr. Elizabeth Nabel, director of the National Heart Lung and Blood Institute. The agency has poured more than $2.5 million into the development of the vessels.
To make the vessels, researchers begin with small bits of skin and vein taken from the back of the hand. These are grown in the laboratory to produce two types of tissue: a tough, structural material that gives the vessel its shape and a softer material that serves as the lining and prevents blood clots.
Once sheets of cells have been grown, they are stacked and rolled into vessels about 6 to 8 inches long.
The process takes six to nine months and costs about $10,000, but Cytograft Tissue Engineering, the company that makes the vessels, hopes to make it faster and cheaper.
In the first test, Argentine surgeon Dr. Sergio Garrido implanted vessels in a 56-year-old Buenos Aires woman and in a 61-year-old man. Both are diabetics who were running out of healthy vessels that could be used as a shunt to connect the dialysis machine.
The woman’s vessel has been punctured three times a week for dialysis for six months without damage, McAllister said. The man’s has successfully withstood treatment for three months.
The company has permission to treat 25 diabetics in Argentina and, in a separate study, 25 heart bypass patients in England. It hopes to get permission from the Food and Drug Administration next year for a study in the U.S.
In a third study, Canadian researchers reported that angioplasty to open blocked blood vessels feeding the heart can be safely performed through an artery in the wrist, increasing the safety of a procedure that is now commonly performed using a groin artery.
Although patients receiving angioplasty are routinely kept overnight in the hospital because of the risk of bleeding, about half of those treated with the new procedure could go home the same day, reducing hospitalization costs, said Dr. Olivier Bertrand of Laval University in Quebec City.
The radial artery in the wrist is far smaller than the groin artery, Bertrand said, so physicians can use smaller amounts of blood thinners to prevent clotting. The risk of bleeding caused by the blood thinners is the primary reason patients are kept in the hospital after angioplasty.
Bertrand and his colleagues studied 1,005 patients who underwent angioplasties through the wrist artery. Half were given a single dose of blood thinner and sent home within four to six hours, while the other half were given the conventional treatment of a single dose of blood thinner plus a 12-hour infusion while they were observed overnight in the hospital.
Among the 504 patients sent home, 30 had major bleeding or a heart attack or needed a repeat angioplasty. Among the 501 patients given conventional treatment, 28 had the same problems.
In other studies presented at the Dallas meeting:
* Mechanical pumps called left ventricular assist devices can improve survival in heart failure patients who are not candidates for transplants, said Dr. Joseph G. Rogers of the Duke University School of Medicine.
Rogers and his colleagues studied 55 patients with severe heart failure. Eighteen were given conventional intravenous medications and 37 received a pump. Those receiving medications had an average survival of three months, he reported, while those on the pumps averaged more than 10 months.
* Riding an amusement park roller coaster can be a death-defying experience for many people with heart disease, said Dr. Jurgen Kuschyk of University Hospital in Mannheim, Germany. The excitement increases heart rates and blood pressure and, in people with preexisting heart conditions, could produce potentially dangerous irregular heart rhythms and sudden cardiac death, he said.
Kuschyk attached portable heart monitors to 55 young, healthy volunteers who then rode a coaster. Their heart rates averaged 91 beats per minute before the ride, but increased to 148 for men and 165 for women one minute into the ride. Nearly 44% of the volunteers had arrhythmias that lasted up to five minutes after the ride, and one had rapid atrial fibrillation, a rapid and chaotic heartbeat.
* Heart attacks and the need for bypass surgery or angioplasty were reduced in patients who took a cholesterol-lowering drug called fenofibrate, but the drug produced no significant reduction in deaths, according to an Australian study of about 10,000 patients with Type 2 diabetes.
But patients given placebos in the study were administered a different family of cholesterol-lowering drugs called statins if they were needed, said the study’s lead author, Dr. Anthony Keech of the University of Sydney, and that may have masked some of the benefits of fenofibrate.
Overall, patients receiving the drug had a 24% reduction in the risk of nonfatal heart attacks and a 21% reduction in the need for coronary interventions. The patients were 11% less likely to die, but the difference was not statistically significant.
