TUESDAY, May 30, 2006 (HealthDay News) -- Researchers have identified different risk factors for the two kinds of lower leg problems that plague an estimated 8 million to 12 million Americans with the condition called peripheral artery disease (PAD).
PAD is the same sort of artery blockage that causes heart attacks and other ailments when it occurs in the heart's blood vessels. A new study, published in the May 30 issue of Circulation, finds crucial differences between PAD that affects large blood vessels and the version that affects small blood vessels.
"The interesting thing here is that we separately looked at smaller vessels and larger vessels," said Dr. Michael H. Criqui, a professor of medicine, family medicine and preventive medicine at the University of California, San Diego, School of Medicine. "Small vessel risk was entirely related to diabetes, while a bunch of things affect large vessel risk," he said.
The two versions of PAD have different symptoms. Someone whose large leg vessels are affected usually has painful cramps that are felt in the hips, thighs or calves and ease after a few minutes of rest. The small-vessel version makes the feet feel cool to the touch and heal slowly after injury. Very serious cases may end with amputation.
Criqui and his co-author, Dr. Victor Aboyans, a cardiologist with Dupuytren University Hospital in Limoges, France, who took part in the study as a visiting scholar at San Diego, evaluated 403 men and women with large-vessel PAD and 290 with small-vessel PAD. The researchers made measurements at the start of the study and then 4.6 years later.
They compared blood pressure readings in the arms with those in the ankles and toes. Ankle blood pressure less than 90 percent of the arm pressure and a toe reading 70 percent less than the arm reading are indicators of PAD. Then the researchers matched deterioration in those ratios with known risk factors such as diabetes, high blood pressure, smoking and blood cholesterol levels.
For small-vessel PAD, the only significant predictor of deterioration was diabetes, the researchers found.
"The clinical implication is that tight control of diabetes might prevent progression of small-vessel PAD," Criqui said. "We know this is true of small vessels in the eye, and the same thing might be true here."
For large-vessel PAD, the most significant predictor of deterioration was a well-known villain -- smoking. Smokers were 3.2 times more likely to have major deterioration than nonsmokers. Another major indicator, high blood cholesterol, was also identified. Heavy drinking (more than 21 drinks a week) and high blood pressure were borderline indicators of deterioration, the researchers said.
"The most surprising result was the absence of an impact of diabetes in large-vessel PAD progression," Aboyans said in a statement.
The study has a lesson for doctors about assessing PAD, Criqui said. It's important for them to measure both ankle and toe blood pressure, particularly for people with diabetes, he said.
The results also reinforce current guidelines for treatment of PAD, which call for anti-clotting drugs and cholesterol-lowering statin medications.
"Antiplatelet agents like aspirin, as well as statins, are helpful for patients with PAD," Criqui said.
More information
The American Heart Association offers an introduction to PAD symptoms and treatment.
