An intraoperative tool that can predict vascular graft patency—and is supported by twenty years of Mayo Clinic research? Surely such a valuable tool cannot have existed outside common vascular knowledge for so long?

Read on.

The Mayo Clinic has released a paper that is not only a landmark, but a timely one. Vascular surgery, indeed all surgery, is at a crossroads between traditional open and endovascular. We all applaud progress, nevertheless, open surgery cannot vanish soon. For years to come, endo and open will continue to complement one another. In this is the case, shouldn’t we focus on better tools to elevate open procedure outcomes? Especially if a tool stands on twenty years of solid ground…

Mayo Clinic researchers performed a retrospective study on the patency-predicting value of intraoperative flow measurements during below the knee popliteal-tibial bypasses in patients with chronic limb-threatening ischemia. The study reviewed 20 years of surgical data from 163 patients (177 bypasses total) with a median age of 71 years (and a 56% smoking history.) Conduits were mostly saphenous, but included a smaller percentage of composite grafts, and a few arm vein grafts.

Median intraoperative graft flow was 132ml/min, and researchers set the threshold of postoperative patency at 110ml/min. The results were glaring. Graft flows of less than the threshold were directly associated with loss of patency in all three categories: primary patency, secondary patency, and primary assisted patency.

Despite the obvious prognostic value of this, and its intraoperative utility (modification of surgical protocol, anticoagulation consideration) a more important realization lies here.

Transit Time Ultrasound was quickly accepted into research and has been the standard of flow measurement in that arena since the 1980’s. CABG was accepted almost as quickly, and has been used across the world since the 1990’s. Vascular grafting has the same need for TTFM as CABG grafting because both are flow augmentation/restoration surgeries. Why perform a flow surgery without measuring it?

It sounds illogical, so I will reiterate: it is standard vascular procedure to perform flow-augmentation surgery… without making any quantitative assessment of that flow.

The standard is illogical. It’s also twenty years outdated.

So isn’t it time to change it?

Thanks for reading,

               Transonic Systems, Inc

                        The Measure of Better Results

Reference:

Vaddavalli VV, Shuja F, DeMartino RR, Colglazier JJ, Rasmussen TE, Schaller MS, Gloviczki P, Bower TC, Kalra M. Prognostic significance of intraoperative graft flow on long-term patency of below knee popliteal and tibial bypasses with autologous vein in patients with chronic limb-threatening ischemia. J Vasc Surg. 2025 Nov;82(5):1770-1778.e2. (Transonic Reference # Vaddavalli VS 11-2025)