Fractional flow reserve

A guide to understanding Fractional Flow Reserve in cardiology

Fractional Flow Reserve

File:Coronary artery angiogram.jpg

Coronary angiogram showing a stenosis in the left anterior descending artery.

Fractional Flow Reserve (FFR) is a diagnostic technique used in cardiology to assess the physiological impact of a coronary artery stenosis. It is a measure of the pressure differences across a coronary artery stenosis to determine the likelihood of the stenosis impeding oxygen delivery to the heart muscle.

Principle

FFR is based on the principle that the severity of a coronary artery stenosis can be quantified by measuring the pressure drop across the stenosis during maximal blood flow, which is induced pharmacologically. The FFR value is calculated as the ratio of the maximum achievable blood flow in a diseased coronary artery to the theoretical maximum flow in a normal coronary artery.

Procedure

The procedure involves the insertion of a specialized pressure wire into the coronary artery during coronary angiography. A vasodilator, such as adenosine, is administered to induce maximal hyperemia. The pressure distal to the stenosis is measured and compared to the aortic pressure. The FFR is calculated using the formula:

FFR = (Distal coronary pressure) / (Aortic pressure)

An FFR value of 0.80 or less is generally considered indicative of a hemodynamically significant stenosis, warranting intervention such as percutaneous coronary intervention (PCI).

Clinical Significance

FFR is a valuable tool in the management of patients with coronary artery disease (CAD). It helps in decision-making regarding the need for revascularization procedures. Studies have shown that FFR-guided PCI improves patient outcomes compared to angiography-guided PCI alone.

Advantages

• Provides a functional assessment of coronary stenosis.
• Reduces unnecessary stenting by identifying lesions that do not require intervention.
• Improves patient outcomes by guiding appropriate treatment.

Limitations

• Requires the use of pharmacological agents to induce hyperemia.
• Invasive procedure with associated risks.
• May not be applicable in certain anatomical situations, such as severe tortuosity or calcification.

Related pages

• Coronary artery disease
• Percutaneous coronary intervention
• Coronary angiography
• Adenosine