The test – the Ankle Brachial Index (ABI) – compares blood pressure in the arms with those in the legs. “Today, ABI is the most effective, accurate and practical method for PAD detection. It is quick, easy, non-invasive and cost effective,” Diehm said. “We have to implement ABI in general practice to identify higher risk patients.”
The German epidemiological trial on ABI (getABI) was initiated in 2001 to test the accuracy of ABI and to quantify the risks associated with asymptomatic PAD. It included 6880 unselected patients, aged 65 and over, in 344 German primary care offices.
The study found that an ABI score of 0.9 or lower (tibial anterior or posterior BP/brachial artery BP) identified PAD with a sensitivity of 95% and specificity of 50%. This is better than mammography for breast cancer, or the PSA test for prostate cancer, Diehm said.
Of the total study cohort, 20.8% had a pathological ABI test, but the majority had no clinical signs or complaints. This asymptomatic PAD was as dangerous as symptomatic PAD: the groups did not differ significantly in terms of cardiovascular risk. PAD itself was a strong and independent predictor of mortality: at five years, all cause mortality was 24% in patients with symptomatic PAD and 19% among those with no signs or symptoms.
Existing AHA/ACC guidelines and the TASC II Document on PAD state that antithrombotic treatments should only be used in symptomatic patients. Diehm: “We have to change these very quickly now because we know that if you have the disease, whether symptomatic or asymptomatic, you die almost 10 years earlier. Therefore you need optimal secondary prevention.”
The patients were under-treated, Diehm said. Antiplatelet therapy was given to only 56% of patients and statins to 23%. Beta-blockers are the optimal therapy for those with underlying coronary artery disease, but were given to only 25%. He said betablockers are not contraindicated, as many still believe.
Discussant Don Poldermans from the Netherlands, stressed that only a few patients with PAD have no other disease and they require further investigation: “Most of the affected organs are asymptomatic. Screen for aortic aneurysms, screen for carotid disease, screen for coronary artery disease,” he urged.
Poldermans also stressed the need for PAD patients to be treated: “We all know these patients will benefit from medical therapy, butwe just don’t do it and that’s the point.”