BACKGROUND: Lymphovenous anastomosis (LVA) enables lymphatic fluid to drain into the venous system. However, no study has investigated the association between LVA and heart failure (HF) caused by fluid overload in the blood circulating system. The purpose of our study was to determine whether LVA increases the risk of HF and mortality. MATERIAL AND METHODS: This nationwide retrospective study evaluated a total of 1400 lymphedema patients who underwent LVA and two control cohorts with 28 000 lymphedema who did not undergo LVA and 70 000 age-matched and sex-matched participants from the Korean National Health Insurance database were included. Blood pressure, body mass index (BMI), glucose and cholesterol levels, smoking history, and comorbidities were obtained during National Health Insurance Service - Health Screening (NHIS-HealS). The incidence, adjusted risk for HF, and mortality were evaluated. RESULTS: Adjusted HRs for HF were 1.20 (confidence interval [CI], 1.03-1.40) and 1.30 (CI, 1.12-1.50), referenced by the general population control cohort and patients with lymphedema without LVA, respectively. In age, sex, BMI, and smoking status-stratified analyses, heightened risk of HF was evident across all sexes, spanning both young and old age groups, encompassing individuals with various smoking statuses, and those with a BMI of 18.5 or higher. Among these groups, the risk was notably greater in males compared to females, higher in younger individuals as opposed to older ones, and further elevated within the BMI range of 18.5-25. CONCLUSIONS: LVA is associated with an increased HF risk, independent of cardiovascular risk factors and associated comorbidities. This association is prominent in participants aged <50 years, in males, and in the normal-to-obese (BMI ≥18.5 kg/m 2 ) group. Among patients with lymphedema, LVA did not significantly affect mortality.