What to do when the flow doesn’t improve as expected?


Occasionally, when the measured flow values are not great, just waiting a little bit will solve the issue as the heart settles and accepts the blood flow from the graft. But sometimes, that doesn’t work, indicating something is wrong with the graft. This case shows how a surgeon was swiftly able to identify the problem using TTFM and Ultrasound Imaging.


The patient, slated for an all-arterial revascularization, received an uneventful LIMA-LAD graft and a more eventful RA-PDA.

The initial Transit Time Flow Measurement (TTFM) was poor (Image 1) with a very low flow, high PI and low DF%. The surgeon opted to leave it alone for a while to see if it would improve without any changes.

After waiting approximately 15 minutes a second measurement confirmed that the flow had not improved (Image 2). At this point the decision was made to revise the graft and Ultrasound imaging was employed to identify the flow obstruction.

Imaging of the distal anastomosis was attempted but was difficult to perform as the heart did not tolerate manipulation well. The proximal anastomosis was imaged and confirmed to be patent. Imaging of the graft revealed a dissection in the RA (Image 3). The resulting thrombus was flow-obstructing and would explain why the flow measurements actually got worse by waiting.

Color flow Imaging of the RA distal to the damaged area confirmed no flow (Video 1).

Immediately post revision, the PDA went into spasm and TTFM readings were poor. Waiting 10 minutes for the spasms to end, yielded an improved TTFM reading (picture 4). PI is still slightly high and DF% is lower than optimal, but considering the condition of the heart the results were acceptable.

By using the combination of TTFM and ultrasound Imaging, the surgical team was able to identify a flow obstruction and to make an informed decision about how to proceed.

Case Attachments