What is Ankle-Brachial Index (ABI)?
The Ankle-Brachial Index (ABI) is a simple, painless test that compares the blood pressure in your ankles to the blood pressure in your arms. This comparison helps your doctor evaluate how well blood is flowing through your arteries, particularly in your legs. The test is one of the most effective ways to detect peripheral artery disease (PAD), a condition where narrowed arteries reduce blood flow to your limbs.
Why is it Performed?
Your doctor may recommend an ABI test if you're experiencing symptoms such as leg pain when walking, numbness or weakness in your legs, coldness in your lower leg or foot, or sores on your legs that won't heal. The test is also commonly ordered for patients with risk factors for PAD, including diabetes, smoking history, high blood pressure, high cholesterol, or being over age 50. Since PAD can increase your risk of heart attack and stroke, early detection through ABI testing is crucial for preventing serious complications.
What to Expect
During the ABI test, you'll lie comfortably on an exam table while a technician measures your blood pressure in both arms using a regular blood pressure cuff. Then, they'll measure the blood pressure at your ankles using specialized cuffs and a handheld ultrasound device called a Doppler probe. The probe allows the technician to hear your blood flow and get accurate readings. The entire process takes about 10-15 minutes and is completely painless. You may feel the familiar squeeze of the blood pressure cuff, but there are no needles or invasive procedures involved.
Preparing for Your Test
The ABI test requires minimal preparation. Wear loose, comfortable clothing that allows easy access to your arms and legs. Avoid tight pants or socks that may be difficult to remove. You can eat and drink normally before the test, and you should continue taking your regular medications unless your doctor specifically instructs otherwise. If you're a smoker, avoid smoking for at least two hours before the test, as nicotine can temporarily affect your blood pressure readings.
Understanding Your Results
Your ABI result is calculated by dividing the blood pressure at your ankle by the blood pressure in your arm. A normal ABI is between 1.0 and 1.4, indicating healthy blood flow. An ABI between 0.9 and 1.0 suggests borderline PAD, while readings below 0.9 indicate PAD of varying severity. The lower the number, the more severe the blockage. Your cardiologist will explain your results and discuss any necessary lifestyle changes, medications, or further testing based on your individual numbers.
Have questions about Ankle-Brachial Index testing? Our experienced cardiology team is here to help. Contact Advanced Cardiovascular Specialists & Primary Care at (203) 334-2100 to schedule your appointment or discuss any concerns.
