Lower Than Expected 5-Year Mortality After Amputation Related to Chronic Limb-Threatening Ischemia: A Statewide Registry Analysis

High mortality has been historically associated with below- and above-the-knee amputations (BKA and AKA) performed for chronic limb-threatening ischemia (CLTI). Although 30-day mortality rates have declined, the reported 5-year mortality rates have remained as high as 83%. We investigated the 5-year mortality after BKA and AKA in a modern cohort using a statewide registry. The California Office of Statewide Planning and Development hospital database was queried for patients who had undergone BKA or AKA secondary to CLTI between 2007 and 2018. The cases were selected using the International Classification of Diseases, 9th revision, Clinical Modification diagnosis and procedure codes. Patients who had required amputation after traumatic injury and those with diabetes but without known arterial disease were excluded. Hospital readmission and mortality for a 5-year period after amputation were the outcomes of interest. A total of 26,669 were patients identified: 67% had undergone BKA and 33%, AKA. The average age at surgery was 67 years for the BKA group and 74 years for the AKA group. The most common complications during the initial admission were heart failure (23.88%), dysrhythmia (20.35%), and sepsis (7.81%). The 5-year hospital readmission rate was 71%. The 30-day, 90- day, 1-year, and 5-year mortality rates were 4.82%, 8.62%, 12.47%, and 18%, respectively (Fig). Women had statistically significant higher mortality compared with men (P = .037) across all time periods. When stratified by amputation site, the 5-year mortality was 16% for BKA and 23% for AKA. The mortality difference between AKA and BKA was robust to adjustment for age and comorbidities. Mortality risk associated with vascular disease after amputation was 11 times greater than the risk associated with amputation-specific complications. These results challenge the traditionally ascribed high mid-term mortality rate for patients undergoing amputation for complications of CLTI, with an observed 5-year mortality rate of 18%. Mortality remains higher after AKA than after BKA, likely resulting from the more advanced vascular disease and older age at amputation. Further study is warranted to elucidate whether this observed mortality reduction is from previous rates being exaggerated or advances in patient care.