Features of asymptomatic contralateral limb in patients with chronic limb-threatening ischemia

The current study aimed to reveal clinical features and prognosis of asymptomatic contralateral limbs in patients undergoing revascularization for chronic limb-threatening ischemia (CLTI).We analyzed a database of 520 CLTI patients registered in a prospective, multicenter registry in Japan. Severe ischemia in asymptomatic contralateral limbs was determined as the Wound, Ischemia, and foot Infection (WIfI) classification system Ischemia (I) grade 2/3.The prevalence of diabetes mellitus and dialysis-dependent renal failure was 74.2% and 53.5%, respectively. Asymptomatic limbs accounted for 65.0% [95% confidence interval (CI), 60.9-69.1%] of the overall population, and 55.0% (95% CI, 49.6-60.4%) of the asymptomatic contralateral limbs had WIfI I-2/3. The multivariate analysis identified age ≥65 years, dialysis-dependent renal failure, WIfI I-3 in the index limb, and loss of pressure sensation in the contralateral limb as independent risk factors for WIfI I-2/3 in asymptomatic contralateral limbs (all p 0.05). The 3-year cumulative incidence rate of major adverse limb events (MALE) in asymptomatic contralateral limbs was 19.3% (95% CI, 15.1-23.7%), whereas that of all-cause mortality was 46.9% (95% CI, 41.0-52.5%). The corresponding rate including a composite of mortality and MALE was 58.8% (95% CI, 52.9-64.6%). In asymptomatic contralateral limbs, the adjusted hazard ratio of WIfI I-2/3 versus I-0/1 was 1.53 (95% CI, 1.11-2.10) for a composite of mortality and MALE, 1.96 (95% CI, 1.14-3.36) for MALE, and 1.37 (95% CI, 0.95-1.96) for mortality (p = 0.009, 0.015, and 0.091, respectively).Two-thirds of CLTI patients had an asymptomatic contralateral limb, and approximately half of the asymptomatic contralateral limbs were exposed to severe ischemia. Older age, dialysis-dependent renal failure, WIfI I-3 in the index limb, and loss of pressure sensation in the contralateral limb were independently associated with severe ischemia in asymptomatic contralateral limbs. In addition to mortality, MALE commonly occurred in asymptomatic contralateral limbs, especially with WIfI I-2/3.