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.

Case story

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

The patient was scheduled for an On-pump CABG with two grafts.

  • LIMA-LAD
  • 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 (Image 1). This indicated that there was some form of blockage in the graft. HFUS confirmed an obstruction in the anastomosis and based on these results the surgeon decided to revise the graft (Image 2).

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.

Remeasured TTFM showed the improved results after the occluding clip was removed. The flow had greatly increased, the PI was low and the DF% was 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.

Case attachments

Click images below to view.
Data output on the screen of the MiraQ instrument

TTFM in SVG-OM graft indicating an obstruction

TTFM in SVG-OM graft indicating an obstruction

Obstruction captured by ultrasound imaging

Obstruction confirmed by HFUS

Obstruction confirmed by HFUS

Post-revision TTFM reading

Improved TTFM after clip was removed

Improved TTFM after clip was removed

Data output on the screen of the MiraQ instrument
Image 1

Image 1

Obstruction captured by ultrasound imaging
Image 2

Image 2

Post-revision TTFM reading
Image 3

Image 3

Reference

REQUEST study

Registry for Quality Assessment with Ultrasound Imaging and Transit-time Flow Measurement in Cardiac Bypass Surgery

Taggart DP et al. Intraoperative transit-time flow measurement and high-frequency ultrasound assessment in coronary artery bypass grafting. J Thorac Cardiovasc Surg. 2019; 159: 1283-1292.
DOI: https://doi.org/10.1016/j.jtcvs.2019.05.087

Technology used

Medistim MiraQ™ Cardiac System with QuickFit™ TTFM Probes (PS series) and L15 High-Frequency Imaging Probe.

Data output on the screen of the MiraQ instrument

TTFM in SVG-OM graft indicating an obstruction

TTFM in SVG-OM graft indicating an obstruction

Obstruction captured by ultrasound imaging

Obstruction confirmed by HFUS

Obstruction confirmed by HFUS

Post-revision TTFM reading

Improved TTFM after clip was removed

Improved TTFM after clip was removed