Study design
A retrospective, single-center analysis of prospectively collected clinical data of patients with BALI admitted between January 1, 2010, and January 1, 2019, was performed. The clinical and anamnestic data were retrieved from the medical documentation. Informed consent was obtained for the collection and processing of the clinical data, according to the principles of the Declaration of Helsinki. An approval for the retrospective analysis of the prospectively cumulated clinical data was received from the local ethics committee of Krasnodar Regional Clinical Hospital #1 (protocol no.115 − 23/05/2019). The study was retrospectively registered in TCTR international registry (identification no. TCTR20210609002, date of registration 09/06/2021).
Study Population
Patients with BALI due to primary acute occlusion of the infrarenal aorta were included in this study. Patients with unilateral ALI, BALI secondary to suprarenal aortic occlusion or bilateral occlusion of aortobifemoral grafts, or multiple acute simultaneous arterial occlusions of the upper and lower extremities were excluded (Fig. 1). All patients with unknown timepoints of symptom onset and/or thrombophilia were excluded.
Treatment Protocol
All patients who presented with viable lower limb musculature and reversible BALI were scheduled for revascularization. A decision of palliation was made for critically ill patients with uncontrolled hypotension and with extended bilateral buttock, thigh, and calf rigor. Primary thigh amputation with blood flow restoration in the deep femoral artery was performed in cases of irreversible calf ischemia.
After admission, all patients received full heparinization with a 100 IU/kg intravenous bolus, followed by a supporting dose of 1000 IU/hour under the control of the partial thromboplastin time (PTT). The therapeutic level of PTT was estimated to be 60–70 seconds.
Preoperatively, duplex ultrasound and/or contrast-enhanced spiral computed tomography angiography of the entire aorta, with a slice thickness of 1 mm, were performed to estimate the level and extension of occlusion (Fig. 2).
All operations were performed by certified vascular surgeons. The revascularization procedure was performed as an aortic thrombectomy through the standard transfemoral approach using the Fogarty balloon catheter. Intraoperative balloon catheter-mediated revision of the distal run-off was obligatory. All patients received bilateral four-compartment calf fasciotomy after revascularization, with subsequent secondary wound closure.
Postoperatively, in-hospital full anticoagulation with intravenous heparin under PTT control was administrated. After discharge, lifelong anticoagulation with oral anticoagulants was recommended.
Follow-up
The standard FU protocol included clinical and sonographic examinations before discharge and annually thereafter. All sonographic series were assessed by an independent collaborator for radiology. The control examination was performed by vascular surgeons.
All patients (100%, 5/5) who exhibited amputation-free survival within 30 days after revascularization were followed up until November 2020.
Definitions
“Acute” ischemia was defined as the sudden onset of lower extremity ischemic symptoms lasting less than 2 weeks.(5) The grade of acute lower extremity ischemia was classified using international clinical and sonographic criteria.(11)
Technical success was defined as the prompt restoration of antegrade arterial flow in a target vessel based on the absence of residual arterial stenosis > 40% on postoperative duplex examination.
Procedural success was defined as technical success without complications.(11)
Duration of ischemia was defined as the period between symptom onset and flow restoration (in case of revascularization) or until decision-making (in case of palliation).
The definition of early-term FU (up to 30 days) and mid-term FU (1–5 years) was made respective to current reporting standards.(12)
Myocardial infarction (MI) was defined as myocardial necrosis accompanied by a rise and/or fall in cardiac biomarker values (preferably, cardiac troponin), clinical symptoms of ischemia, new significant ST segment-T wave (ST-T) changes, and a new left bundle branch block or development of pathological Q waves on electrocardiogram.(13)
Statistical analysis
Statistical analyses were performed using SPSS version 25.0 (SPSS, Inc., Chicago IL, USA). Continuous data were presented as mean and standard deviation (mean ± SD). Categorical variables were presented as absolute numbers and percentages. А crosstab analysis was performed to characterize the sample. Univariate analysis was performed to find differences between the compared groups using the χ2-test in the case of the categorical data and the Mann-Whitney U test in the case of the continuous data. Cramer’s V coefficient was used to measure the effect size of the differences. Values below .1, .1-.2.9, .3-.4.9, and above .5 were considered little if any, low, moderate and large effect sizes respectively (14). The Kaplan-Meier curve was used to present survival. The log-rank test was used to compare amputation-free survival between groups. The level of significance for all the statistical tests was determined as p < .05.