Flow complication avoided by use of TTFM & HFUS


This case from the REQUEST Study describes how the combined use of Transit Time Flow Measurement (TTFM) and High frequency ultrasound (HFUS) revealed a compromised graft. These insights helped the surgeon identify the issue and address it appropriately.

The patient had a 40% main stem stenosis, an EF% of 60, and was scheduled for an on-pump CABG with two grafts.

  • SVG-OM

Intraoperative surgical guidance

TTFM of the first graft (SVG-OM), after the patient had come off bypass, provided unsatisfactory results. The Mean flow was almost zero, the PI was very high, and the DF% was low as seen in image 1. This indicates that there was some form of blockage in the graft. HFUS confirmed an obstruction in the anastomosis (see image 2) and based on these results the surgeon decided to revise the graft.

When initiating the revision, the surgeon found a clip that was partially occluding the SVG lumen. Removing the clip restored the flow without the need for a full graft revision. The surgeon stated that they would not have seen the obstruction had it not been for the Medistim system.

The TTFM measurement as seen in image 3, shows the improved results after the occluding clip was removed. The flow has greatly increased, the PI is low and the DF% is also at a good level.

When constructing the LIMA-LAD graft it was discovered that the LIMA was too short and had to be extended with an SVG. No other complications were registered for the LIMA graft. The patient had no complications by the time of discharge.

Patient information

  • 68-year-old male
  • BMI 22.1
  • Renal transplant, Previous CEA, Hypertension, Hyperlipidemia
  • 40% main stem stenosis, EF% 60, CCS I-II, NYHA II

Technology used

Medistim MiraQ Cardiac System with TTFM and L15 HFUS probes.

Case Attachments