Study shows risk of major amputation in diabetics with CLTI

x-ray image below knee amputation or BKA amputation

A retrospective study supports the use of the Wound, ischaemia, and foot infection (WIfI) classification system to predict the revascularisation benefit for diabetic patients with chronic limb-threatening ischaemia (CLTI).

The WIfI classification system was developed to stratify the risk of major amputation at one year for patients presenting with chronic limb-threatening ischemia (CLTI). Recently, this system was used to identify patients most likely to benefit from revascularization. WIfI scores were used to define the estimated revascularization benefit quartiles ranging from high benefit (Q1) to questionable benefit (Q4).

“The aim of our study was to evaluate the revascularization benefit quartiles in a cohort of diabetic patients who had presented with critical limb ischemia,” said first author Caitlin Hicks, MD, of Johns Hopkins University.”

As reported in the October issue of the Journal of Vascular Surgery, researchers from the university’s Diabetic Foot and Wound Service, led by Hicks and senior author Christopher Abularrage, MD, evaluated 136 diabetic patients (187 limbs) who underwent lower extremity revascularization between 2012 and 2020 at their institution. The primary outcome of their study was one-year major amputation.

Demographic characteristics of these diabetic patients included:

  • Age 65 +/- 11 years
  • 63% male
  • Presentation with ulcer (51%), gangrene (43%) or rest pain (6%)

Revascularization procedures were either endovascular (67%) or open (33%).

The estimated one-year amputation rates for each quartile were:

  • Q1          7 +/- 4%
  • Q2          4 +/- 3%
  • Q3          7 +/- 5%
  • Q4          26 +/- 8%

Analysis revealed the Q4 group had a significantly greater risk of amputation compared with the Q1 group (hazard ratio 4.3).

For the 137 limbs with greater than one-year follow-up after revascularization, a total of 16 (12%) required amputation. Nine of these were in the Q4 group.

“Overall, our data support the use of the WIfI benefit of revascularization quartiles for estimating the one-year major amputation risk for diabetic patients presenting with critical limb ischemia,” said Hicks. “We did, however, observe our actual amputation rate in the Q4 group was one half of what was expected. This may be explained by the fact that all of our diabetic patients are treated by our multidisciplinary team, which has been previously shown to have robust limb salvage outcomes.”

“Up to one half of the Q4 patients who underwent amputation did so despite patency of their revascularization procedure. This suggests wound size and infection burden are the driving factors behind the elevated risk in this group.”

The decision to perform revascularization in a patient with critical limb ischemia must be made carefully, particularly given their often extensive list of co-morbidities, researchers said. This study supports the use of the WIfI system to predict which diabetic patients with critical limb ischemia might best be served by revascularization and highlights the importance of multidisciplinary teams for complex medical and surgical patients.


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