Association Between Laboratory Metrics and Mortality After Major Lower Extremity Amputation in Peripheral Artery Disease Patients

Introduction: Apart from their high burden of disease, major amputations, especially due to macro- and microangiopathic malperfusion, persist to inflict a relevant socioeconomic impact in most geographic regions. It has been repeatedly shown that lower extremity amputations are associated with impaired post-operative survival. In the present study, we investigated whether metrics derived from routine laboratory studies after amputation are associated with post-operative survival. Methods: In this retrospective single-center analysis, 244 patients undergoing lower extremity amputation between 2012 and 2016 were included. Serum hemoglobin and leukocyte counts of the first 21 post-operative days as well as derived metrics were analyzed in addition to clinical and demographic variables. Kaplan-Meier estimates and adjusted Cox regressions were fitted including relevant parameters. Results: In summary, 71.3% of patients underwent transtibial and 28.7% transfemoral amputations. The most frequent post-operative complications were wound-related (43.0%). Long-term survival analyses showed that advanced age and higher ASA class were significantly associated with reduced post-operative survival, while no significant survival differences were observed based on sex, smoking history, or type of amputation. Laboratory parameter analysis showed impaired peri-operative outcomes in patients with elevated leukocyte counts, with leukocyte-derived metrics showing significant associations with long-term survival after adjustment for age and ASA class. Conclusions: This study highlights the potential of routine laboratory parameter-derived metrics in predicting mortality after major lower extremity amputations in PAD patients.