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Fractional flow reserve measures the difference between the maximum blood flow that can be achieved in a diseased coronary artery and the maximum flow that might potentially be achieved in a healthy coronary artery (FFR).

Divide the pressure farther (distal) from the blockage by the pressure nearer (proximal) to the barrier to calculate the fractional flow reserve. During cardiac catheterization, your healthcare provider measures the fractional flow reserve.

The ratio between the greatest blood flow that can be achieved in a diseased coronary artery and the maximum flow that might theoretically be achieved in a normal coronary artery is what is measured by fractional flow reserve (FFR). Most people consider an FFR of 1.0 to be typical. Myocardial ischemia is typically thought to be related to an FFR of less than 0.75-0.80. (MI). Using a pressure wire to determine the ratio between the coronary pressure distal to coronary artery stenosis and the aortic pressure under conditions of maximum myocardial hyperemia, FFR can be easily assessed during routine coronary angiography. The possible reduction in coronary flow distal to the coronary stenosis is represented by this ratio.

A minimally invasive procedure called fractional flow reserve (FFR) can be used to assess the severity of coronary artery stenosis. Your healthcare practitioner achieves this by monitoring your coronary artery blood flow and blood pressure. Your doctor analyses your blood flow at its peak with and without a blockage.

The fractional flow reserve test is performed by medical professionals as part of coronary angiography or a cardiac catheterization of the left side of the heart. They use the findings to determine the best course of treatment for you.

Patient Population

The R3F (October 2008–June 2010) and POST–IT cohorts were combined to create the PRIME–FFR population (n = 1983), which was employed for this cross-sectional analysis (March 2012-November 2013). These cross-country prospective studies all had the same goal of examining the routine use of FFR during diagnostic angiography and its relationship to patient management choices and 1-year clinical outcomes. In 40 European facilities, a total of 1983 individuals were referred for coronary angiography and were subsequently included in the registries. Additionally, the Commission National Informatique et Liberté gave its approval to the R3F study. The preservation and use of their clinical data, as well as clinical follow-up, were all subject to written informed consent from all patients. Before being stored, all data had been de-identified.

Both studies used specialized computerized case report forms to prospectively capture baseline clinical and angiographic measurements. The eMethods in the Supplement contain the inclusion and exclusion criteria for each of the original registries as well as a definition of clinical variables (including diabetes).

Angiography and FFR Procedure

Angiography was carried out using acknowledged standards and acceptance criteria, as well as qualitative and quantitative lesion characterization. After administering intracoronary nitrate, fractional flow reserve was carried out using diagnostic or interventional catheters. Adenosine was used to induce hyperemia and was given either intravenously (>140 g/kg/min) or intracoronary (100 g) in accordance with local customs. The decision of which lesions or vessels to examine was left up to the operators; extensive FFR examination was not required. Analysis was done in accordance with the verified FFR threshold (0.80).

When your doctor is determining if you require angioplasty and a stent in one of your coronary arteries, you could need this test. They deliver oxygen-rich blood to your heart muscle. When imaging reveals you have a 50% to 70% diameter narrowing, providers employ this affordable, straightforward test (stenosis). In some circumstances, healthcare professionals may examine the fractional flow reserve in patients with a narrowing of up to 90%. If your narrowing is greater than 70% or less than 30%, you shouldn't require this test. This is due to the fact that it is obviously obvious that if you have modest stenosis, you do not require angioplasty, but if your number is large, you do.

  • FFR is typically assessed in the catheterization lab after coronary angiography. The FFR measurement needs a guiding catheter, a pressure monitoring guidewire, and a hyperemic stimulus.
  • Although a diagnostic catheter (4 Fr or 5 Fr) is technically possible, it is advised that FFR be performed with a regular guiding catheter instead, not only for simpler handling but also for quick access with balloons or stents in the extremely unlikely event of vascular dissection or perforation.
  •  A particular solid-state sensor installed on a guidewire with a floppy tip must be used to measure intracoronary pressure. There are two 0.014 inch pressure monitoring guide wires available: Wave Wire and Pressure Wire (both from St. Jude Medical Inc. in Minneapolis, Minnesota, and Uppsala, Sweden) (Volcano Inc, Rancho Cordova, CA). The sensor is 3 cm from the distal tip of the pressure guide wire, at the intersection of the radiolucent and radiopaque parts.
  • In order to produce the greatest degree of coronary artery hyperemia, a vasodilator must be administered.
  • The optimum hyperemic stimulus should be simple to give, brief in duration until maximum hyperemia is reached, long enough for pressure pullback recordings (a few minutes), have few side effects, and disappear quickly.
  • What to expect when facing the fractional flow reserve test?
  • Your healthcare provider will:
  • Give yourself a local anesthetic injection.
  • Stick a needle in your neck, groin, or arm.
  • Insert a catheter into your artery using the needle.
  • Push the catheter through arteries to reach the aorta, then the coronary arteries that emerge from it. Your doctor can better observe where the catheter is going via fluoroscopy (X-ray).
  • To make your coronary arteries more visible, inject liquid contrast media through the catheter into them.
  • Inspect your coronary arteries for obstructions.
  • To examine your blood flow, place an ultrasound device on the catheter.
  • Heparin and nitroglycerin (Nitronal® or Tridil®) should be administered to you before inserting a pressure wire into the confined space.
  •  Check the pressure on either side of the coronary artery's narrow section using the catheter's pressure sensors. When blood flow is at its peak, this is checked for accuracy. To improve your blood flow, they administer medication (such as adenosine or papaverine).
  •  If necessary, perform an angioplasty and install a stent in your coronary artery.
  •  After the angioplasty is complete and the stent is implanted, recheck your FFR.
  •  In order to apply pressure to your access site, remove the catheter.
  • What can I expect after the fractional flow reserve procedure?
  • An FFR test rarely causes complications and doesn't cause much discomfort in patients. A few hours following their FFR surgery, the majority of patients can return home. However, you might need to spend the night in the hospital if you have an angioplasty and a stent.

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