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OBJECTIVE: We hypothesized that the severity of foot poikilothermy can be used for better differentiation of grades of acute limb ischemia. Thus, the study aim was evaluation of the value of non-contact foot thermometry, performed using a low-cost infrared medical thermometer, as an adjunct for clinical diagnosis of immediately threatened acute limb ischemia. METHODS: It was a single-center observational prospective study performed over 3 years. Patients with acute limb ischemia of lower limbs grade I-IIB Rutherford treated with urgent revascularization were included. Grade of ischemia was determined independently by two experienced vascular surgeons. Thermometry of the ischemic foot was performed using a medical digital infrared non-contact thermometer (CK-T1501, Cooligg, China) with measuring accuracy of ±0.2°C. Temperature was measured in three points: the dorsal surface of the foot, plantar surface of the foot (both in the metatarsal region), and forehead. The maximal temperature gradient between patient's forehead and foot (∆Tmax F-F) was calculated. Measurements were repeated 6-12 h after revascularization. RESULTS: A total of 147 patients were included. Only 3 (2%) patients presented rest pain without sensory loss and motor deficit, while the majority were diagnosed with mild (63/147, 42.8%) or moderate (27/147, 18.3%) motor deficit. The temperature of the ischemic foot varied from 20 to 36.1°C, while median value of the temperature was 26.7 [24.5-29.9] °C on the dorsal surface and 26.8 [24.5-29.6] °C on the plantar surface of the foot (p = 0.85). Patients with Grade IIB ischemia had significantly lower dorsal foot temperature, plantar foot temperature, and larger ∆Tmax F-F than the patients with grades I-IIA: 25.1 [23.9-26.8] °C versus 29.9 [27.6-30.8] °C; 25.2 [23.8-27.5] °C versus 29.6 [28-31.1] °C; and 11.6 [9.7-12.8] °C versus 7.2 [6-9] °C (p < 0.0001). Areas under ROC curve for diagnosis of Grade IIB ischemia were similar for dorsal foot temperature (0.82), plantar temperature (0.81), and ∆Tmax F-F (0.82). The best cutoff value by Youden was ≥9.5°C for ∆Tmax F-F, ≤26.8°C for dorsal, and ≤27.7°C for plantar temperature. Criterion ∆Tmax F-F offered the highest specificity of 86% (95%CI 74.2-93.7) and positive predictive value of 89.2% (95%CI 79.5-93.2), while plantar temperature offered sensitivity of 82.5% (95%CI 70.1-91.3) and negative predictive value of 69.1% (95%CI 57.6-83.2). In multivariate analysis including age, gender, and etiology of arterial occlusion, the criterion ∆Tmax F-F of ≥9.5°C was a unique variable significantly associated with risk of amputation (adjusted OR 2.6, 95%CI 1.2-5.9, p = 0.01). CONCLUSION: Current study demonstrated that patients with immediately threatening ALI have significantly lower foot temperature than those with viable and marginally threatened limbs. Severe foot poikilothermy at admission is associated with poor outcomes of revascularization, mostly with limb loss.
RESUMEN
BACKGROUND: The purpose of the study was to compare the clinical presentation, management, and outcomes of surgical revascularization for acute limb ischemia (ALI) in 2 groups of patients-with and without SARS-CoV-2 infection. METHODS: During the 2 years (01.01.2020-31.12.2021) all consecutive patients diagnosed with ALI and treated with urgent revascularization were prospectively enrolled. Based on the results of polymerase chain reaction swab for SARS-CoV-2 infection patients were allocated to group A-infected or group B-noninfected. Demographic characteristics, clinical, imaging, laboratory data, and details of treatment were collected prospectively. The composite endpoint of major amputation and/or death at 30 days after surgery was defined as main study outcome. The postoperative ankle-brachial index value, reinterventions, complications, and length of hospital stay were considered as secondary outcomes. RESULTS: Overall, 130 patients (139 limbs with ALI) were analyzed-21 patients (23 limbs) in group A and 109 patients (116 limbs) in group B. The anatomical site of arterial occlusion, duration, and severity of ischemia did not differ significantly between the groups. Patients with COVID-19 had significantly shorter time from ALI onset till administration of the first dose of anticoagulant: 8 (2.5-24) hr vs. 15.7 (6-72) hr in group B, P = 0.02. Vascular imaging was performed before intervention only in 5 (23.8%) infected patients compared to 78 (71.5%) patients in group B, P < 0.001. The main outcome was registered in 38 (29.2%) patients, significantly more frequent in infected cohort: 12 (57.1%) patients in group A versus 26 (23.8%) in group B, P = 0.003. Difference was preponderantly caused by high mortality in group A-9 (42.8%) patients, compared to 17 (15.5%) patients in group B, P = 0.01. The difference in the rate of limb loss was not statistically significant: 4 (17.3%) limbs were amputated in COVID-19 patients and 12 (10.3%) limbs-in noninfected patients (P = 0.3). Combination of ALI and COVID-19 resulted in increased 30-day mortality-risk ratio (RR) 2.7 (95% confidence interval [CI]: 1.42-5.31), P = 0.002, but did not lead to significantly higher amputation rate-RR 1.6 (95% CI: 0.59-4.75), P = 0.32. In group A initial admission of the patient in the intensive care unit was an independent risk factor for amputation/death. Excepting systemic complications which were more frequently registered among COVID-19 patients: 7 (33%) cases vs. 14 (12.8%) in group B, P = 0.04; no differences in other secondary outcomes were observed between the groups. CONCLUSIONS: Study demonstrates the significant negative impact of COVID-19 upon the 30-day amputation-free survival in patients undergoing urgent surgical revascularization for ALI. The difference in outcome is influenced by higher rate of mortality among infected patients, rather than by the rate of limb loss. Severity of COVID-19, namely requirement of intensive care, mostly determines the outcome of ALI treatment.