April 29, 2009
Arterial Disease of The Leg Commonly Overlooked in Patients with Heart Disease
Peripheral arterial disease (PAD) of the legs, in which the arteries become blocked with plaque and blood supply to the legs is reduced, affects eight million people in the U.S. Early detection of PAD is important because it can limit the ability to walk and exercise, it may place patients at greater risk for limb loss and it increases the chance of having a heart attack or stroke. Coronary artery disease (CAD) is prevalent in patients with PAD and it is known that PAD is under diagnosed in the primary care setting, but a new study found that it is often overlooked even in patients with known heart disease who are under a cardiologist's care. The study was published in the May issue of Catheterization and Cardiovascular Interventions, the official journal of The Society for Cardiovascular Angiography and Interventions (SCAI).
Led by Dr. Issam D. Moussa of New York Presbyterian Hospital/Weill Cornell Medical Center, the study involved nearly 800 patients with ischemic heart disease who were to undergo coronary angiography and/or intervention and were either at least 70 years old, or between the ages of 50 and 69 and had a history of diabetes mellitus and/or tobacco use. Researchers determined if patients had PAD by calculating the Ankle-Brachial Index, the ratio of the blood pressure in the lower legs to blood pressure in the arms, which is normally the first test administered to patients in cases where PAD is suspected. Patients also answered questionnaires on PAD awareness and functional status.
The results showed that approximately one out of six patients had previously unrecognized PAD, despite being under the care of a cardiovascular specialist. The researchers point out that this includes only those with previously undiagnosed PAD and does not represent the total prevalence of PAD in patients with heart disease, which is actually much higher. Most patients with PAD did not limp or have leg pain, two symptoms of the disease. "The combination of physician lack of awareness and lack of symptoms among patients results in failure to diagnose PAD, even in patients who are at high risk," the researchers state. "Furthermore, clinical evaluation alone often lacks the sensitivity and specificity to optimally identify PAD particularly in less advanced stages and in hospitalized patients with CAD."
The study also found that previously missed PAD was more frequent in older patients and women, which goes against the conventional wisdom that PAD is more prevalent in men and suggests that PAD is more frequently overlooked in women than men in outpatient settings. In addition, the study showed that patients with PAD had a more severe form of CAD, which may account for the worse outcome of heart patients who also have PAD compared to those who do not. The authors note that "making a diagnosis of PAD in a patient with CAD should prompt the clinician to be more aggressive with risk factor intervention, foot protection and a high clinical index of suspicion for progressive PAD symptoms," adding that these patients should be viewed as exceptionally high risk.
They also note that establishing an early diagnosis of PAD promotes the preservation of functional status in the lower limbs, which is particularly important in patients CAD, since PAD may limit active participation in cardiovascular rehabilitation following coronary interventions. Many physicians cite the lack of space, time and resources as barriers to implementing a systematic PAD screening program, however new guidelines by the American Heart Association and the American College of Cardiology advocate screening for PAD in patients with CAD. The authors conclude that their findings present a compelling argument that screening for PAD should become standard of care in these patients.
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