Search our website Find job opportunies at THI and St. Luke's Find a doctor location and contact information
Heart Information Center
Ask a Heart Doctor
  Back to previous page


Help us improve this service.

Your feedback will help guide us in developing this site.

Ask a Texas Heart Institute Doctor 
Informed patients make better patients.


When are fractional flow rate (FFR) and intravascular ultrasound (IVUS) tests appropriate? 

Hi, I was wondering why fractional flow rate and intravascular ultrasound are not done with blockages that are under 50? I had bypass in 2005 for a block of the left main. In 2006, I had a stent put in the left main as they said the LIMA graft failed to mature. I have 30 percent blockage in the RCA, 40 in the circumflex and 30 throughout the LAD. I have chronic chest pain down my left arm across my chest when walking. I have been just diagnosed with small vessel disease and understand this can cause my symptoms. I was hoping they would do these tests with my cath. Is the intravascular test something that I should try to get at some point?  Thank you. 

submitted by Chris from Illinois on 9/4/2013


Neil E. Strickman, MDby Texas Heart Institute cardiologist, Neil E. Strickman, MD  

Great question.  Intravascular Ultrasound [IVUS] and Fractional Flow Rate [FFR] have been studied extensively.  It is well documented that an FFR <80% is predictable that the blockage, if fixed, will benefit the patient. If FFR is > 80%, there is no benefit to fixing the blockage.  This and IVUS correlate very well with the fact that it takes at least a 70% narrowing to cause clinical concern. These tests are expensive, thus cost becomes an issue if not clinically indicated.  Good luck. 

See also on this site:  

Has your question or a similar one already been answered?
Search all the Heart Doctor questions and answers.

To search for a doctor or access St. Luke's physician referral service, use the "Find a Doctor" link at the top of this page.

Updated September 2013
Like us on Facebook Follow us on Twitter Subscribe to us on YouTube Find Us on Flicikr Follow Us on Pinterest Add us on Google+ Find us on LinkedIn 

Please contact our Webmaster with questions or comments.
Terms of Use and Privacy Policy
© Copyright Texas Heart Institute
All rights reserved.