Point/Counterpoint: Is limb salvage always best in diabetes?

January 3, 2017|Clinical Endocrinology News

Trissa A. Babrowski, MD;Timothy J. Nypaver, MD

Primary amputation can be OK

I am not an amputationalist. I do practice limb salvage. In fact I’m probably the most aggressive limb salvage surgeon in my hospital. But primary amputation is a completely acceptable option for a selected group of patients with diabetes. We should not try to do limb salvage “at all costs.”

I do not find this to be a contradictory position. In fact, I think it adds credence to my support of limb salvage that I think primary amputation can be OK. In all honesty, there are very few things in life that should be done at all costs.

Bypass revascularization efforts to prevent amputation can fail, and many of them do so frequently in the first year. These failures can often be predicted preoperatively. Appropriate application of primary amputation based on data not only improves cost-effectiveness and patients’ quality of life, but improves our outcomes overall for critical limb ischemia (CLI).

A study out of Loma Linda University involving patients with CLI compared primary amputation vs. revascularization; 43% of patients had a primary amputation (Ann Vasc Surg. 2007;21:458-63). A multivariate analysis showed that patients with major tissue loss, end-stage renal disease (ESRD), diabetes and nonambulatory status were more likely to undergo primary amputation rather than revascularization.

While major tissue loss (Rutherford category 6) is certainly an indication for primary amputation, ambulatory status can represent a gray area in determining the best course. ESRD and diabetes are much more nonspecific factors; probably more than 10% of the patients that we see with CLI have ESRD. Also, 50%-70% of these patients with CLI, and in some series even higher percentages, have diabetes. Thus, these factors by themselves do not assist us in determining which patients potentially should be offered primary amputation vs. revascularization.

In general, we know that we can get good results in limb bypass or revascularization in patients with CLI: The PREVENT III multicenter trial, with the use of the vein as the conduit, showed 1-year limb salvage rates of 88% in these high-risk patients (J Vasc Surg. 2006;43:742-51). However, one of the major risk factors that adversely affected outcome was ESRD.

We know that ESRD is a significant predictor of lowering our chances of saving a limb successfully. Knowing the cost of multiple continued episodes of revascularization in these patients prior to proceeding with an amputation, it’s intuitive that these patients would benefit from a more precise process in their treatment from the beginning. A number of papers have concluded that a primary amputation may be the preferred approach in patients with ESRD.

Can we preoperatively predict which patients with CLI will fail operative revascularization? Data from the New England Vascular Quality Initiative identified eight variables associated with failure of revascularization, among them age younger than 59, ESRD, diabetes, CLI, conduit requiring venovenostomy, tarsal target, and nursing home residence (Ann Vasc Surg. 2010;24:57-68). The presence of three or more risk factors has a 27.7% risk of limb loss and/or graft thrombosis within 1 year.

Postponing amputation is a major cost issue. Direct costs of bypass for critical limb ischemia were $3.6 billion in 2004 (J Vasc Surg. 2011;54:1021-31), and we know that a functional outcome can be problematic in this patient group. Factors associated with a poor functional outcome include dementia, dependent-living situation preoperatively and nonambulatory status.

Unfortunately, there are not a lot of data that deal with quality of life outcomes for patients with CLI who have undergone bypass. Using a point system comprised of dialysis (4 points), tissue loss (3 points), age above 75 (2 points), hematocrit less than or equal to 30 (2 points), and coronary artery disease (1 point), a follow-up study of patients in the PREVENT III trial found that a high-risk group (greater than or equal to 8 points) had an amputation-free survival of only 45% (J Vasc Surg. 2009;50:769-75). Again, these results do not justify the effort and costs of limb salvage in this high-risk patient group.

We should consider the following options carefully in selecting a cost-effective patient-focused approach in patients with CLI: wound care, primary amputation, bypass revascularization, or endovascular revascularization. I would argue that the vascular surgeon who is qualified as an expert in all of the above is best positioned to select an appropriate plan of treatment based upon the patient’s risk factors, wound factors, ambulatory ability, pattern of disease, severity of ischemia, and living status.

Thus, upon presentation, a patient with CLI should undergo confirmatory tests and optimize his or her risk factors. The vascular surgeon then has the option, in discussion with the patient and family, to pursue an appropriate treatment plan inclusive of primary amputation – not one of limb salvage “at all costs.”

Primary amputation should be used in situations where there is dementia and nonambulatory status, and in patients who are poor candidates for revascularization because of high risk of failure and limited life expectancy. The recently developed WIfI (wound, ischemia, and foot infection) classification can also be utilized, as stage 4 WIfI classification is associated with high risk of limb loss – 38%-40% at 1 year.

Primary amputation is an option that can result in better care overall, and it is a cost-effective approach for a selected group of patients. We should not try to do limb salvage at all cost. Primary amputation, in selected patients, is OK.