The Cost of CLTI: How Many Amputations Occur Each Year and What Is the Cost to the Patient and Society?

The VIVA@LINC session of "Big Picture Trends in Chronic Limb-Threatening Ischemia (CLTI)" saw Joshua Beckman, MD, from Boston, Massachusetts, present the cost implications–in every sense–of amputation. “The definition of CLTI is the combination of peripheral artery disease (ankle brachial index [ABI] < 0.9) and symptoms at rest, ranging from rest pain to ulceration present for 2 or more weeks, and/or gangrene,” he said. “There is no specific ABI threshold or ankle/toe pressure required, but the likelihood of severe disease does increase as the ABI decreases.”

Turning to the approximate prevalence of CLTI in peripheral arterial disease (PAD) patients, Dr. Beckman noted that, in the US, the annual incidence of CLTI is approximately 0.3 to 0.4%, with as many as 10% (although likely lower) patients with PAD developing CLTI. “The development of CLTI is commonly associated with disease in more than 1 limb vessel; however, distal disease is commonly present,” he said. “Also key is understanding that the risks of progression from PAD with symptoms with exercise or no symptoms to CLTI include smoking, diabetes, and chronic kidney disease. The latter two also predispose to a higher rate of vessel calcification rendering a revascularization more difficult.”

He went on to say that, compared to coronary and carotid disease, the evidence for revascularization in peripheral disease is rather limited. “That said, the soon to be published BEST-CLI trial should provide a significant increase in information upon which to rely for clinicians in decision making. There has been a rise in clinical trials, but not enough. That is one of the significant deficiencies in this space. Personally, I think tools used in the endovascular care of patients should be subject to a more stringent threshold for active use and coverage by insurers.”

Dr. Beckman noted that the mortality in the setting of CLTI is quite high, with recent estimates suggesting a 20 to 30% 2-year mortality. And crucially, amputation further increases the rate of mortality and disability. “Recent reports have estimated a 40 to 80% mortality after below-the-knee amputation,” he said. “Randomized clinical trial data has shown a 10% annualized mortality rate.”

Posed with the question as to whether there are predictors of likely revascularization success (or indeed, chance of amputation) that might be more important than others, Dr. Beckman commented: “I would suggest 3 features that point against success: 1) distal disease – the involvement of vessels that extend into the foot makes for more difficult revascularization; 2) calcification – calcified vessels commonly mask severe disease and are poor targets for both surgical and, commonly, endovascular approaches; and 3) microvascular disease – we showed that the presence of microvascular disease amplifies the risk with all kinds of PAD and cannot be addressed by endovascular or surgical approaches.”

In terms of the decision-making for revascularization vs amputation, Dr. Beckman said that is important to understand that wound healing may take months. “The revascularization can be just the first step in a long process. Understanding the baseline frailty of the patient helps clarify whether this kind of intensive stress and treatment will be well tolerated. In addition, patients who weren’t ambulatory prior to the CLTI are very unlikely to be ambulatory afterward, and should probably just have an amputation. Finally, patients who cannot understand what is happening should also likely have an amputation.”

Another consideration is cost. As he described, in the United States, the annual cost of amputation is ~6.5 billion dollars. Amputation is more expensive than revascularization, which is more expensive than exercise therapy. “The more we can find/treat patients prior to CLTI and amputation, the more we can save limbs and costs.”

Dr. Beckman added his take-home message for the LINC audience: “Amputation is too common and not improving. This behoves us to begin better PAD discovery in our patients, better medical therapies, and better surveillance to discover disease prior to the point when amputation is needed. For this audience, in addition to understanding how to fix the vessels, we must make sure that all guideline-recommended therapies are applied when patients leave our care and go back to more chronic settings.”