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Although the prevalence of acute kidney injury (AKI) associated with acute coronary syndrome management is well-described, similar knowledge regarding AKI in patients being treated for critical limb ischemia (CLI) is poor. We determined the prevalence of and clinical characteristics associated with AKI in patients admitted with CLI undergoing revascularization.
We prospectively studied 189 patients presenting to a single academic medical center with CLI, defined as Rutherford class IV-VI. Patients underwent either lower extremity bypass surgery or endovascular intervention. Demographics, procedural and clinical variables were collected. Patients were followed for the occurrence of AKI as well as major adverse cardiac and limb events. AKI was diagnosed based on changes in serum creatinine during the hospitalization in accordance with AKIN criteria, defined as either a 1.5 fold increase or 0.3 mg/dL absolute increase in serum creatinine (Cr) from baseline. Comparisons between the two groups were performed using Fischer exact and t-testing.
Of the 115 patients included in the analysis, 31 patients (27%) developed AKI. 74 patients were excluded because they did not undergo a bypass or endovascular procedure or they were on dialysis. There was no difference in demographic or clinical characteristics between patients who did and did not develop AKI. Compared to those who did not develop AKI, patients who developed AKI had on average a longer length of hospital stay (16d vs. 29d, p<0.01) and a longer length of ICU days (2d vs. 7d, p=0.04). In addition to significantly higher peak Cr values (2.8 vs. 1.1, p<0.01), patients who developed AKI also had significantly higher discharge Cr values compared to those who did not develop AKI. The development of AKI in the bypass versus endovascular groups approached statistical significance (36% vs. 21%, p=0.06). There was no significant difference in adverse inpatient cardiac and limb events between individuals who did and did not develop AKI.
The development of AKI is common in individuals admitted for CLI and is associated with a longer hospital stay and number of days spent in the ICU. The difference between the development of AKI in the endovascular versus the bypass group did not reach statistical significance, however, it may have if our study had more power. Studies trying to identify individuals who may be at increased risk for AKI and to determine whether the development of AKI is associated with increased adverse long-term cardiac and limb events will be important.