The arteries that supply blood to the buttocks (gluteal arteries) and pelvis are the main branches of the iliac artery, which stems from the abdominal aorta to supply blood to the legs. The aorta is the body's largest artery and the main "trunk" for the rest of the body's arteries.
Researchers sought to find a noninvasive way to detect blood flow impairment in the pelvic area (pelvic ischemia). Pelvic ischemia is an important cause of claudication (lower limb pain while walking) and male impotence, says lead author Pierre Abraham, M.D., Ph.D., of the department of vascular studies at University Hospital of Angers, France.
The research team analyzed whether using transcutaneous oxygen pressure (tcPO2) on the skin of the buttocks during exercise is accurate in detecting where an artery is blocked in people with suspected pelvic blood flow problems.
"The potential advantage is that tcPO2 can identify patients who may need further testing," Abraham says. "This would significantly shorten a diagnostic work-up in patients who need revascularization by reducing the delay to arteriography."
Arteriography is an imaging technique that makes blood flow in the arteries visible after injecting them with a special dye.
The origin of pelvic ischemia can be difficult to pinpoint, especially in patients with atypical signs such as hip, back, or buttock pain, or lower limb pain while walking, signs that also mimic other disorders such as sciatic nerve pain. The sciatic nerves run from the lower back down each leg. When these nerves are compressed a person can have lower back pain, hip pain and leg pain when walking. Traditionally, vascular diseases are considered to cause pain at the calves or lower leg, he says. "Transcutaneous oxygen pressure can identify that the problem is vascular in those patients who may have been misdiagnosed and treated inadequately for months." The researchers studied tcPO2 in 43 patients with suspected pelvic ischemia and 34 patients not suspected of having the disorder. Electrodes were placed on both buttocks and one on the chest to serve as a reference. Researchers used arteriography to view artery blockages in either the right or left side of the buttocks. Measurements were taken at rest and during and after treadmill testing. They then compared arteriography findings with tcPO2 findings to determine the new technique's accuracy.
TcPO2 during exercise was 90.6 percent accurate for identifying artery blockages in patients with suspected pelvic ischemia. It was 81 percent accurate in ruling out the disease in people who did not have symptoms of it, the researchers report.
"TcPO2 is a sensitive and reliable index in the diagnosis of pelvic vascular disease, particularly after exercise," the authors write. "Its use in the buttocks to identify pelvic ischemia appears to be especially effective in patients with atypical signs," Abraham says.
He adds that one distinct advantage of tcPO2 is in the obese patient, where the thickness of subcutaneous fat (fat under the skin) can interfere with ultrasound. "Fat affects absolute pressure values, but it does not affect changes in tissue oxygen pressure over time with the tcPO2 technique," Abraham says. "This measurement performs equally well in the overweight or lean patient."
The investigators note that other reports suggest that pelvic ischemia occurs in about 40 percent of diabetic patients and can occur with or without claudication. TcPO2 might be a good screening tool for this population, Abraham says.
Co-authors are Jean Picquet, M.D.; Bruno Vielle, M.D.; Dominique Siguaudo-Roussel, Ph.D.; Francine Paisant-Thouveny, M.D.; Bernard Enon, M.D., Ph.D.; and Jean-Louis Saumet, M.D., Ph.D.
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