Dissected LIMA discovered 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 dissected LIMA. These insights helped the surgeon identify the issue and address it appropriately.

Case story

Patient Information

  • 83-year-old male
  • BMI 26
  • Hypertension, high cholesterol, NSTEMI 22 years ago, stable angina

Pre-OP angio indicated that the patient had a moderate to severe lesion (50-75%) proximally in the LAD, CX was calcified proximally, and the RCA was occluded proximally.

Intraoperative guidance

The surgical plan was to perform a LIMA-LAD and create a Y-graft with a SVG sequential branch to OM and the PDA (Image 1).

Upon completion of the graft the different segments were checked with TTFM. The SVG graft was good, as was the proximal part of the LIMA. All anastomoses were checked with HFUS and all good. Poor TTFM values in the distal LIMA segment (Image 2) and HFUS of the distal anastomosis led to scan of the LIMA body, where a dissection was discovered. Location of the poor TTFM reading is indicated on the graft schematic (Image 1).

The annotated HFUS images show how the dissection was located and diagnosed.

  • Image 3 shows the LAD anastomosis and a collapsed portion of the LIMA.
  • Image 4, which is recorded slightly proximally from Image 3, shows the dissection in the LIMA where the false lumen is annotated.

Using this insight, the surgical team was able to accurately locate the dissection and replace the damaged portion with a part of the SVG graft.

TTFM shows the improved results after the collapsed part of the LIMA had been replaced with the SVG (Image 5). The revised graft schematic shows the final construction and the location where the TTFM measurement was captured (Image 6).

"Great benefit in graft patency verification. Very accurately able to detect dissection as the problem."

Ref. operating surgeon

Case attachments

Click images below to view.

Initial schematic of graft construction including probe placement

Initial schematic of graft construction including probe placement

TTFM in the distal LIMA showing poor flow parameters

TTFM in the distal LIMA showing poor flow parameters

HFUS of LAD anastomosis and collapsed portion of the LIMA

HFUS of LAD anastomosis and collapsed portion of the LIMA

HFUS of dissection in the LIMA with false lumen

HFUS of dissection in the LIMA with false lumen

TTFM improved after revision

TTFM improved after revision

Revised graft schematic showing final construction and probe placement

Revised graft schematic showing final construction and probe placement

Image 1

Image 1

Image 2

Image 2

Image 3

Image 3

Image 4

Image 4

Image 5

Image 5

Image 6

Image 6

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 MiraQTM Cardiac System with QuickFitTM TTFM Probes (PS series) and L15 High-Frequency Imaging Probe.

Initial schematic of graft construction including probe placement

Initial schematic of graft construction including probe placement

TTFM in the distal LIMA showing poor flow parameters

TTFM in the distal LIMA showing poor flow parameters

HFUS of LAD anastomosis and collapsed portion of the LIMA

HFUS of LAD anastomosis and collapsed portion of the LIMA

HFUS of dissection in the LIMA with false lumen

HFUS of dissection in the LIMA with false lumen

TTFM improved after revision

TTFM improved after revision

Revised graft schematic showing final construction and probe placement

Revised graft schematic showing final construction and probe placement