What is Fractional Flow Reserve? | MedStar Health

Measuring blood flow in the heart’s coronary arteries

Fractional flow reserve, also known as FFR, is a measurement of how well blood can flow through the coronary arteries. These arteries bring oxygen-rich blood to the heart to be pumped throughout the rest of the body.

Narrowing or blockages in these arteries is called coronary artery disease. This can lead to a heart attack without treatment. FFR studies help us decide the best treatment for coronary artery disease, such as:

Our cardiac imaging program is one of the most advanced in the region, which allows us to provide leading technologies like FFR studies. We review findings from doctors throughout the region, which lets us quickly recognize rarely seen problems for the most accurate diagnosis and treatment.

What to expect from a fractional flow reserve study

We perform FFR studies during cardiac catheterization in which we use a long, flexible tube called a catheter to thread a wire up to your heart through a small incision in your groin. The wire measures blood pressure and blood flow through the artery. An FFR value that’s especially low means you’re at greater risk for a heart attack and need more immediate treatment. Higher values may mean you can be treated with medication or that you may not need treatment at all.

You’ll be given instructions on how to prepare for your test. You won’t be allowed to eat or drink for six to eight hours before it. You’ll be awake and able to follow instructions during the procedure, although you’ll receive medicine to help you relax. Afterward, you’ll need to lie still for a while to allow your medication to wear off.

Depending on how quickly you recover and whether you have any other procedures done at the same time as your FFR study, you may be able to go home the same day, or you may need to stay in the hospital overnight. You’ll need someone to drive you when it’s time to go home.


Angioplasty improves blood flow through the arteries by clearing plaque build-up.

Coronary artery bypass surgery

Coronary artery bypass surgery, also known as coronary artery bypass graft (CABG) surgery, restores normal blood flow through narrowed or blocked coronary arteries by using a healthy blood vessel taken from your leg, arm, or chest to create a detour around the problem area.

Coronary artery stenting

Coronary artery stents are small mesh tubes placed within the artery to prevent blockages and allow better blood flow.


Stenting uses a mesh tube to open narrow blood vessels and improve blood flow.

Our providers

Dr. Nauman Siddiqi and Dr. John Wang

Expert cardiology care

Getting the care you need starts with seeing one of our interventional cardiologists.

Ask MedStar Heart & Vascular Institute

Have general questions for our heart and vascular program? Email us at AskMHVI@medstar.net. If you have clinically-specific questions, please contact your physician’s office.