Fractional Flow Reserve, or FFR, is a guide wire-based procedure. Its utilility is that it can accurately measure blood pressure and flow rate through a specific part of the coronary artery. Is is performed through a standard diagnostic catheter during the actual coronary cathaterization. Using Fractional Flow Reserve, the interventinalist can assess whether or not to perform angioplasty or stenting on “intermediate” blockages – blocakges that may or may not cause angina symptoms or lead to serious ischemic events.

The entire point of using a stent in the coronary arteries is to increase blood flow to the heart. However, a number of studies have shown that if a “functional measurement”, such as Fractional Flow Reserve, indicates the flow is not significantly obstructed, the blockage or lesion does not need to be revascularized (angioplasty) and the patient can be treated safely with medical therapy.

The Interventinalist’s tendency to stent is well documented. Some more aggressive than others. In the case of my cardiologist, if he notices a blockage of 75% or greater, he will stent it. Some cardiologists will stent a 50% blockage. But what if FFR indicated that an intervention won’t have a significant impact on a particular blockage? Being able to better select cases not only saves health care costs, but contributes to more appropriate patient care.

The recent COURAGE trial has only re-emphasized what all current medical guidelines recommend: that for low risk patients, even those experiencing angina, optimal medical therapy should be the initial treatment. For those patients whose disease progresses, or for whom chest pain is not alleviated, revascularization, either through angioplasty and stenting or surgery, should be performed. Fractional Flow Reserve can be a significant tool to help physicians in deciding whether to intervene or not. Here are some results of some additional studies:

• DEFER study: Patients who have been screened out of angioplasty by using FFR have not experienced an increase in adverse outcomes. And in these studies, two-thirds of the patients were judged not to need an intervention with balloons or stents.
• FAME study: FFR allowed elimination of a third of the lesions that might have been stented using angiography alone, with better outcomes for patients.

In the next post we will be talking about Intravascular Ultrasound (IVUS) and why you should insist your cardiologist use this technology if you are going to get a stent.